[HN Gopher] FAA approves unleaded fuel for piston fleet
___________________________________________________________________
FAA approves unleaded fuel for piston fleet
Author : sokoloff
Score : 553 points
Date : 2022-09-01 20:50 UTC (1 days ago)
(HTM) web link (www.aopa.org)
(TXT) w3m dump (www.aopa.org)
| once_inc wrote:
| > The FAA signed on September 1 supplemental type certificates
| that allow ....
|
| As a non-native English reader, why is this not written as:
|
| > The FAA signed supplemental type certificates on September 1
| that allow ....
|
| The current sentence feels disjointed and doesn't '_flow_' like
| natural sentences normally do in English.
| kleiba wrote:
| This is so that the following relative clause is closer to the
| noun phrase it modifies.
| moffkalast wrote:
| Newspaper title text written stupidly for shorter headlines.
| supernova87a wrote:
| What was the innovation? A new different chemical additive to
| take the place of lead? Does it require any hardware changes to
| work right? (spark plugs, etc)
| outworlder wrote:
| The whole point is that it had to be a drop-in replacement.
| sokoloff wrote:
| Original headline seemed far less communicative (and was far too
| long to use in the submission), so I did the best I could to
| faithfully summarize.
|
| For the record, the original headline/subheadline is:
| GA moves closer to unleaded future FAA approves GAMI
| unleaded avgas STCs covering piston fleet
| [deleted]
| inamberclad wrote:
| Thank god, this is decades overdue. Seeing the white powder left
| on my fingers after I spilled some gas while sumping (to check
| for impurities, before every flight) always made me cringe. If
| the fuel is impure, standard procedure is to keep draining the
| impurities (water usually) out and just throw it on the ground.
| marcelo123 wrote:
| throwawayx134ax wrote:
| This is great! Expect the EPA and the FAA to finally ban 100LL,
| which will be a great boon for everyone. Note, you will require
| an STC, but not poising yourself with lead will probably net out
| the costs in the long run.
|
| * I am a pilot of piston engines, and I really don't like 100LL
| being the only option
| V-eHGsd_ wrote:
| ul94 has been around for a year or so (I've had the stc since
| last december), but yeah for high compression engines, it was
| 100LL or nothing. I'm hoping the stc is comparably priced, $100
| or so.
|
| this is really awesome.
|
| edit to add: for the non av geeks, an stc is a supplemental
| type certificate. it's basically an faa stamp that says, "this
| aircraft has been changed from when it was initially certified,
| but it's an approved change"
|
| https://en.wikipedia.org/wiki/Supplemental_type_certificate
| sokoloff wrote:
| George Braly in the video interview indicated it would be
| similarly priced to the Petersen STC, which used to be
| $1/rated HP and now appears to be $2/rated HP.
|
| In short: it's no barrier whatsoever to adoption.
| V-eHGsd_ wrote:
| so a little more expensive than the swift stc but yeah
| still totally worth it.
| mips_avatar wrote:
| I live by lake union in Seattle, and I love watching the
| seaplanes taking off and landing. It's high time that there's a
| lead-free option. Seattle doesn't need that kind of lead in its
| air.
| verst wrote:
| As someone who flies GA aircraft out of Boeing field (KBFI) I
| also welcome this change. I don't want more leaded fuel on my
| hands. The lead can be absorbed by skin.
| tffcccdredf wrote:
| blensor wrote:
| Have you seen this Veritasium video about the man who came up
| with adding tetraethyllead to gasonline and it's negative
| impact on humanity?
|
| https://www.youtube.com/watch?v=IV3dnLzthDA
|
| Given how dangerous lead is in even the tiniest quantities it
| is really surprising that there has not been more pressure to
| change that.
| flyinghamster wrote:
| Don't have time for the video, but if that was Thomas
| Midgley, he was quite the one-man environmental
| catastrophe.
|
| https://en.wikipedia.org/wiki/Thomas_Midgley_Jr.
| obituary_latte wrote:
| It is indeed. The video (which I just happened upon
| yesterday) does a great job of describing his impact on
| humanity and it was interesting to learn that prop planes
| were still allowed to use leaded gasoline--I had no idea.
| Ironic he died by strangulating himself in one of his own
| inventions.
| Klonoar wrote:
| Every time I hang out in Georgetown and a plane flies
| overhead I have this same thought.
|
| (ish)
| scoot wrote:
| tadfisher wrote:
| https://www.europarl.europa.eu/news/en/headlines/society/20
| 1...
|
| https://www.epa.gov/greenvehicles/fast-facts-
| transportation-...
|
| From those figures, the entire civil aviation sector
| accounts for 13% of European transport emissions and 8% of
| US transport emissions. I can't find a breakdown of GA vs.
| airline, but I highly suspect GA to be a small fraction of
| civil aviation emissions relative to airline.
|
| Be concerned about activities that make up the majority of
| emissions: passenger vehicles, electricity generation, and
| industry. Eliminating GA tomorrow would barely make a dent.
| disillusioned wrote:
| This article is specifically about _lead_, which is used
| (up until now, with very few exceptions like Mogas)
| exclusively in GA piston aircraft.
|
| In fact, leaded aviation fuel is the largest source of
| lead emitted to the atmosphere in the US.
|
| Eliminating GA tomorrow _would_ make a dent on the lead
| exposure of those who live near GA facilities.
|
| See this study that attempts to quantify the damage done
| to IQ because of this additional lead: https://www.ncbi.n
| lm.nih.gov/pmc/articles/PMC5338738/#:~:tex....
| tadfisher wrote:
| GP edited their post, but they were insinuating GA is
| still not safe because of carbon emissions.
| giantg2 wrote:
| I'm a bit skeptical of that claim, although I do agree
| it's a good change. It will prevent further lead
| emissions, but if it's as bad as they say, then it's
| likely they'll still feel the effects from the soil.
|
| I live in the flight path for a small field that had been
| a round for a long time. Soil lead levels are very low
| here. I have no concerns about the atmospheric amount
| either. The biggest source of exposure for most people is
| likely food.
| [deleted]
| fulafel wrote:
| Chopping CO2 emissions into tiny pieces of a pie and then
| making a point of how small any particular slice is a
| traditional way of fooling ourselves about it.
|
| Also, civil aviation emissions have larger warming impact
| than just the CO2 emissions would say, as the radiative
| forcing effect is dramatically multiplied due to what
| happens high in the atmosphere - see eg
| https://csl.noaa.gov/news/2020/287_0903.html
|
| (May not apply as much to GA due to lower altitudes
| and/or combustion properties of different fuels and
| engines)
| smaddox wrote:
| This isn't elemental lead. It's tetraethyl lead. Unlike
| elemental lead, it's readily absorbed through the skin.
| HPsquared wrote:
| It's not tetraethyl lead after the fuel has been burned,
| that's only the delivery mechanism to get it into the
| combustion chamber. It'd end up as some sort of lead
| oxide particulate after combustion.
| Justin_K wrote:
| Are you asking them to list off every concern so you are
| satisfied their list meets your standards?
| scoot wrote:
| djohnston wrote:
| Are you alluding that he has blood on his hands because
| he flies GA?
| tffcccdredf wrote:
| btilly wrote:
| Figures from
| https://journalistsresource.org/environment/plane-lead-
| fuel-...
|
| In 2008 there were 167,000 small planes. The discounted
| present cost of future lost productivity due to the lead
| in their gas in any given year is $1.63 billion. That's
| about $9760 of lost productivity per year you choose to
| fly that plane.
|
| Some models put the cost of lost productivity due to
| lowered IQ much higher, for about $11.3 billion. That's
| about $67,700 per plane per year of damage caused to
| others (mostly poor and often minorities).
|
| Do you think this qualifies as "blood on his hands"?
|
| People will differ in their opinions on that. Certainly
| if he was breaking into poor people's houses and trashing
| them, everyone will condemn him. But he clearly had no
| intention to do harm, and probably had no idea of the
| full extent of the harm that he has been doing. There is
| also room for people to argue with the assumptions in the
| scientific model.
|
| But the range of defensible opinions ABSOLUTELY includes
| his having the blood of poor people on his hands.
| outworlder wrote:
| That is just one article. It certainly provides a good
| model for follow up discussions, but take the absolute
| values with a grain of salt. For starters, they didn't
| actually measure the impact, they developed a model. It
| may be accurate, or it may be wildly off. Specially
| because it uses a bunch of other models.
|
| There are other issues. For example, they say that for
| children, the main exposure is through ingestion. How
| exactly are they ingesting the lead particulates?
| Unclear. They do say it's difficult to determine and they
| try to account for that (they spend several paragraphs
| discussing this).
|
| They also say that the contributions from planes in
| flight (as opposed to takeoff/landing) may be
| indistinguishable from background concentrations or lower
| than monitor resolution detection limits(!!!). So more
| modelling is used.
|
| > Research suggests that forest fires and lead re-
| emissions from soil are increasingly important sources of
| lead to the atmosphere.58,59 These sources, like
| aviation, were an insignificant source of airborne lead
| during the peak of leaded gasoline, but now may be a
| principal source of emissions in certain regions.
| Further, leaded paint and paint dust is expected to be
| the largest contributor to childhood lead exposure, with
| exposure risk being spatially and demographically
| heterogeneous.
|
| Lead paint is STILL the largest contributor.
|
| We need to get rid of lead as much as we can, true. But
| to go so far as say "blood of poor people" it's a step
| too much. Specially based on a single paper full of
| "models" (aka educated guesses).
| btilly wrote:
| You have demonstrated the truth of my statement that
| there is room to argue with the assumptions of the
| scientific model.
|
| But IF the model is correct, the impacts are severe.
| Doubly so if the upper range is correct. And so we have
| the ethical question of how we should progress in the
| event of uncertainty.
|
| On this question some hold the perfectly defensible
| position is that, when faced with such uncertainty, we
| should assume the worst until we have more information.
| That a person who is aware of the potential for harm and
| fails to act merely because they are not certain of it
| deserves the full blame for the harm that they are aware
| might have happened.
|
| For someone who takes this position, "blood of poor
| people" is definitely not a step too far.
|
| Note: I am very carefully not saying that this is a
| correct or universally accepted position. I'm merely
| saying that this is a position that some hold for
| reasonable reasons, and can be defended.
| bushbaba wrote:
| even without the lead, the CO2 impact of general aviation
| is pretty high. General Aviation is a rich-mans activity
| which the rest of society bears the brunt of. If you want
| to fly a plan for fun great, go to the countryside and do
| it and payoff the land-owners for the nuisance
| dreamcompiler wrote:
| Number of active GA aircraft in US: 220,000 [0]
|
| Number of cars on the road in US: 284,000,000 [1]
|
| [0] https://www.faa.gov/newsroom/general-aviation-safety
|
| [1] https://www.statista.com/statistics/859950/vehicles-
| in-opera...
|
| The CO2 impact of GA doesn't even rise to the level of
| "in the noise" compared to that of cars. This doesn't
| make it good, but it does make the problem low priority.
| dTal wrote:
| There's a social justice angle on that - cars are an
| essential tool for almost everyone to live in the US,
| while GA is an impractical rich person's hobby. Keeping
| GA convenient at the expense of the environment and
| public health should _also_ be low priority.
| p_l wrote:
| Rich person's hobby is a small slice of GA
| rocqua wrote:
| Given the toxicity of tetraethyl lead, and the (apparent)
| risk of spilling it all over you when refuling, I
| wouldn't be surprised if the personal risk to a pilot was
| comparable to the marginal risk to the wider public of
| whether one person flies with leaded gas or not.
| verst wrote:
| Of course I also don't want to spray aerosolized lead all
| over low income (especially) neighborhoods. I have always
| felt very conflicted about this. I think that point was
| adequately covered by other comments however.
| sergiomattei wrote:
| Lived there for a while as well. Didn't think about that...
| walrus01 wrote:
| The rotary engine tech in a DHC beaver is barely changed from
| WW2 era rotary piston engines... Assuming we're not talking
| about the more modern turbine beavers and otters.
|
| The turbine ones already run on Jet-A
| s800 wrote:
| Rotary or radial?
| repiret wrote:
| Radial.
| walrus01 wrote:
| My brain was clearly not working right when I wrote that,
| though the mental image of a Mazda RX-7 engine strapped
| to the front of a beaver is certainly amusing.
| alricb wrote:
| In the early days of aviation there were actually rotary
| engines that were like radials, but where the entire
| engine rotated:
| https://en.wikipedia.org/wiki/Rotary_engine
| dreamcompiler wrote:
| Wonder if anybody ever tried that. Somebody must have,
| decided the gallons per hour was ridiculously high, and
| abandoned the idea.
| hindsightbias wrote:
| There have been many attempts with the 13B. One I saw it
| all worked, except the exhaust system. Builder went
| through everything, built 3 or 4 of them. The last was
| made out of titanium welded by guys who worked for a
| defense contractor.
|
| Failed in flight like the rest of them. He ended up with
| a lycoming.
| buster3000 wrote:
| They're used in drones
|
| https://www.aieuk.com/wankel-rotary-uav-engines/
| mechanical_bear wrote:
| In a similar way, there are kit planes which use EJ and
| EA series Subaru engines. These tend to be a bit more
| fuel efficient than Mazda rotaries though.
| repiret wrote:
| Given that the DHC-2 Beaver was introduced in 1948, that's
| not too surprising.
| exmadscientist wrote:
| And I think that Kenmore Air is the main operator out of Lake
| Union, and they're mostly or all turbine.
| itslennysfault wrote:
| I used to live near there too. I was today years old when I
| learned those planes still use leaded fuel. Oof. Glad that's
| getting rectified.... finally.
| cibyr wrote:
| The piston engines still use "low lead" fuel. The turboprops
| run on jet fuel.
| outworlder wrote:
| Some piston engines use jet fuel too (Diamond planes in
| particular). Some use automotive gas.
| dreamcompiler wrote:
| Piston engines that run on jet fuel are diesels. Nothing
| wrong with that and diesels are very efficient. But
| diesel GA engines have a long history of problems.
| Diamond is rare in seeming to have overcome those
| problems.
| Tagbert wrote:
| I live near the south end of Lake Washington near Renton
| Airport and always cringe when those small piston engined
| planes take off over the lake and homes. I would be afraid of
| growing a garden in the homes around the airport. I see people
| fishing in the lake next to signs warning about the risk of
| eating too much fish from the lake. It is high time we got rid
| of this last remnant of leaded gas.
| btmiller wrote:
| I spoke with a coordinator at Kenmore Air about a private
| charter a few months back. Over 90% of their flights are on
| their higher capacity DHC-3 de Havilland Otters so that they
| can fill seats more efficiently. The Beaver runs on leaded gas,
| but the Otters do not.
| inamberclad wrote:
| The otters are all turbine now, which runs essentially pure
| kerosene.
| dfgert wrote:
| I am shocked to read this. Why are they still using leaded fuel?
| There are so many well known research that links lead in fuel to
| unstable mental health and crime in population.
| josephcsible wrote:
| Because they needed to be completely sure that they had a
| replacement fuel that wouldn't start making planes fall out of
| the sky.
| jillesvangurp wrote:
| That's the excuse. Basically the real reason is that they
| only care about safety of the planes, not of the people
| handling the fuel (e.g. pilots, ground staff), or breathing
| the toxic fumes (everybody on or near an airport). So, they
| only care about safety when it is a very narrowly scoped
| notion of that concept.
|
| Bureaucracies are weird like that. This is fundamentally not
| about people's safety but about covering their own safety
| (i.e. ass coverage). The problem is not something bad might
| happen but that they'd be held accountable for it.
|
| Never mind that something bad has been known to happen for
| the last half century or so that they are not being held
| accountable for. People actually get sick and die because of
| leaded fuel but it's not their problem. And never mind that
| the bad thing that might happen is basically some ancient
| engines not running that well with unleaded fuel. That's why
| certification processes exist for engines. You can test this
| and decide to not certify certain engines for unleaded fuel.
| Ensuring people fly around with certified engines definitely
| is their problem. Any modern engine is basically certified
| for unleaded fuel already.
| andrepd wrote:
| S201 wrote:
| Oh please. Single engine planes are far more than toys for
| rich people. General aviation is training new airline pilots,
| medical flights, aerial surveying, charter flights otherwise
| inaccessible areas, and a method to fly supplies to areas
| during emergencies. This level of ignorance is extremely
| frustrating.
| worewood wrote:
| Yeah, but what is the proportion of these flights relative
| to rich-people hobby flights? That matters.
| tjohns wrote:
| Quick napkin math here...
|
| The estimate is that about 65% of general aviation
| traffic is related to "business and public services".
| [1][2] The other 35% is personal in nature. From that,
| about 22% is flight instruction for new pilots - most of
| whom are trying to get into the airlines. [3]
|
| So that would mean about 13% of general aviation is
| recreational.
|
| (Also, for what it's worth, many general aviation pilots
| I know aren't rich by any stretch.)
|
| [1]: https://download.aopa.org/hr/Report_on_General_Aviat
| ion_Tren...
|
| [2]: https://www.govinfo.gov/content/pkg/GAOREPORTS-
| GAO-01-916/ht...
|
| [3]: http://www.dviaviation.com/files/45181042.pdf
| bushbaba wrote:
| Maybe in more rural areas. But are you really going to
| tell me that 65% of general aviation traffic in LA, SF,
| NYC,..etc is related to 'business and public services'.
| Do private jets for executives count as for 'business
| services'.
| sokoloff wrote:
| If someone's traveling to/from a work purpose, why
| _wouldn 't_ a corporate jet flight be categorized as a
| business service?
|
| Taking that same jet to ski in Tahoe?
| Personal/recreational. Taking it to a business meeting
| with a customer/prospect? Business.
| p_l wrote:
| A lot of what people think as "Silicon Valley" is
| actually centered around general aviation industry - for
| example San Mateo County at least in 2015 had majority
| share if its economy based on aviation, with majority of
| it being GA
| throwayyy479087 wrote:
| Going to need a source for that claim - generally the
| largest industry in a given area is government, then
| hospitals or schools, then some specific niche. I don't
| think there's any airplane manufacture in NorCal anyway -
| this would be a bit more believable about Wichita.
| p_l wrote:
| Because you're looking for "airplane manufacturer" and
| possibly large one. Though for example just a stolen
| throw from Google Mountain View campus you have Northrop
| and Lockheed-Martin.
|
| I can't find the original webpage after 7 years, but the
| source was San Mateo County page related to county-owned
| airports, and it included all sorts of aviation industry
| (both flying and ground side)
| tjohns wrote:
| The numbers I gave were national averages for the US. Of
| course those numbers will vary by location.
|
| That said... you'd be surprised how many flights out of
| the small GA airports in big cities aren't personal
| flights. Air ambulance, news crews, law enforcement,
| firefighting (usually more on the periphery of the city),
| utility companies doing inspections, and aerial
| photography all tend to operate from these locations.
|
| On the other hand, I'd certainly expect the number of
| flight school operations to be higher in areas with a
| large population.
| p_l wrote:
| Rural areas are more likely to be recreational plus
| agricultural, due to proximity of sophisticated clients
| in big cities.
| tekla wrote:
| I'm sure that they train wide-body aircraft pilots on the
| multi-million dollar planes rather than something cheaper
| p_l wrote:
| Usually they start on a plane like Cessna 152 that is older
| hab their parents. Even military pilots start like that,
| just tend to switch for newer turboprops sooner.
|
| For reference - considerable portion (possibly even
| majority, especially if you don't count USA due to
| different licensing) of airline pilots will have their
| first jet/turboprop experience when they will be training
| on airliner after getting their "frozen ATPL". In one
| airline it was common for chief of training to give every
| new trainee a copy of MSFS 2004 with professional addon for
| the first plane you'd graduate for, and the better trainees
| used that to become familiar with plane - cause usually the
| largest previous plane they flew would be a small twin
| piston plane like Piper Seneca.
| sokoloff wrote:
| Airline pilots in the US need 1500 hours of flight time to
| earn their ATP (airline transport pilot) certificate.
|
| For non-military pilots, most of those hours come from
| general aviation aircraft.
| [deleted]
| djmips wrote:
| All the piston engine aviation in my general vicinity is
| commercial paid transporting. I live in an area with a lot of
| islands.
| tjohns wrote:
| Every single airline pilot has had to train in a small piston
| aircraft that runs on leaded fuel. There simply has been no
| alternative if we want to have a supply of trained pilots.
|
| Not to mention medivac flights, overnight delivery of many
| laboratory medical specimens from doctors' offices, law
| enforcement, high-quality aerial imagery in maps apps,
| farming, access to rural communities in areas like Alaska...
| neximo64 wrote:
| Cessna's are used to access small regions in many countries
| can't even be accessed if it wasn't for a Cessna due to lack
| of funds, places that take up to 3 days by motorcycle. The
| fuel mix is basically copied worldover.
|
| I believe the typical American who sees the upper middle
| class, the same way the rest of the world sees america as.
| M3L0NM4N wrote:
| Some piston engines are really high compression and it's hard
| to prevent knocking without leaded fuel.
| tjohns wrote:
| And to be clear, "knocking" means engine detonation, which
| _very quickly_ leads to catastrophic engine failure. Which is
| something that you don 't want while in flight.
|
| Until now, the only alternative was to fly a turbine-powered
| aircraft that can run on Jet-A. The problem with _those_ is
| that turbines are far too expensive, and terribly inefficient
| at low altitude - both of which have kept them out of reach
| for most of general aviation.
| jsmith45 wrote:
| Admittedly Turboprops can be somewhat more efficent at
| lower altitudes than turbojet and turbofan engines. But
| still not terribly efficient at say sightseeing or
| cropdusting altitudes, and they are still a lot more
| expensive than avgas engines (and that is not even
| accounting for the fact that the aircraft designed to use
| them are bigger and more expensive than many avgas based
| prop planes).
| NikolaNovak wrote:
| Nice. I hope this ushers approvals across the planet. I am just
| starting the journey to private license in Canada and I kinda
| hate how inefficient, but also how primitive and unhealthy the
| engines and fuel are :-/
| samstave wrote:
| >> _Nice. I hope this ushers approvals across the planet._
|
| TBH - this will just shift sales of that fuel type to the still
| "dirty" countries fuel supplies where banning it will not
| happen, sadly.
|
| Oil companies are not our friends.
|
| -
|
| I was just thinking about this yesterday; the amount of human
| infrastructure built around the petro-chem industry:: Land use,
| pollution, corruption, just plain evil, etc...
|
| Along with the fact they lobby and get subsidies and everything
| where the Earth provides their raw input for "free" and the
| rest of the world suffers.
|
| /r/fuckcars, but seriously - Petro-chem, for all the great
| things industrial revolution has given us, is the most
| insidious industry on the planet. Look at fucking ARAMCO's
| cap/profits last year. Largest company on the planet. BigOil is
| a nightmare.
| p_l wrote:
| There's only one company legally producing TEL anymore plus
| few doing so illegally in China. If as GAMI claims all
| supplies to make G100UL are available in every refinery
| handling commercial fuels... That's going to be a possible
| investment goals for everyone across the world just to get
| rid of Innospec as supplier
| sokoloff wrote:
| 100LL is blended regionally to serve the piston engine
| demand.
|
| I expect that blending will switch to G100UL and there's
| nothing remaining to export to "'dirty' countries". As a
| consequence, the one remaining source of TEL in the world
| will close down within a decade. This is all overwhelmingly
| good as compared to yesterday's condition.
| shultays wrote:
| If that fuel type is banned in a country, wouldnt that also
| disallow planes to fly that country?
|
| I guess leaded fuel can still be used flying between (and
| within) the "dirty" countries
| samstave wrote:
| precisely...
|
| Look at the Philippines - a nation of >7,000 islands. They
| use Ferry, plane and boat... for all intra-national
| travel... and they pollute like mad (thanks Reagan Marcos
| ((I know a lot about the history of the CIA/Reagan/Marcos
| legacy...)) -- PH is a corrupt government. Or maybe I
| should just say Government...
|
| If you have coin...
| avalys wrote:
| The engines are actually fairly efficient. Unlike an automobile
| engine, they really only operate in a very narrow range and are
| usually run at a substantial fraction of full power (60% or
| more).
|
| Automobile engines are very challenging because the power
| demands are highly variable and they can't be optimized for any
| specific load.
| riffic wrote:
| that's what transmissions are for though.
|
| variable valve timing also helps.
|
| EDIT: This comment is about automobile engines.
| outworlder wrote:
| Transmissions == variable pitch in aircraft.
| worewood wrote:
| But until very recently transmissions worked on steps and
| could never keep the engine at peak efficiency.
|
| CVTs are fairly recent and people managed to stifle it by
| adding simulated gears.
| imoverclocked wrote:
| Transmissions also lose a lot of energy.
| bombcar wrote:
| Amusingly enough the Piper Cherokee I flew got better _ground
| gas mileage_ than the '66 Fury I had at the time.
| ketzo wrote:
| Wow, that's a hilarious stat. How is that even... possible?
| sokoloff wrote:
| 1960s cars were terribly inefficient is a big part of the
| story.
| NonNefarious wrote:
| It's quite possible for a plane to net higher mileage
| than many cars today, especially light-sport planes that
| only burn 5 gallons per hour or so.
| Filligree wrote:
| Yes, but this was _while taxiing_.
| NonNefarious wrote:
| No, not while taxiing. Who the fuck are you to
| misrepresent what I said?
|
| I said GALLONS PER HOUR. If you're taxiing for hours,
| you're doing it wrong.
| bombcar wrote:
| "Ground gas mileage" meant converting the KIAS to mph on
| the ground (while flying).
|
| I never checked mpg while taxiing but the motor would be
| almost idle.
| outworlder wrote:
| > Wow, that's a hilarious stat. How is that even...
| possible?
|
| There's nothing magical about flight. Take-off takes a
| bunch of energy. Maintaining that energy, not so much.
| Planes are pretty aerodynamic, imagine that :) Some are
| much lighter than cars since every pound counts. To the
| point that people often opt to not have AC (if it's even
| an option) to save a few pounds.
|
| They will cover a lot of ground in the same amount of
| time. That helps even more.
|
| Not all planes are that economical, of course. But some
| are indeed hilarious. Check ultralights (or microlights
| as they are known in Europe).
| midoridensha wrote:
| >There's nothing magical about flight. Take-off takes a
| bunch of energy. Maintaining that energy, not so much.
|
| Yep, take-off and ascent burns a lot of fuel, much more
| for the time duration than cruising. It's too bad there
| isn't a way of recovering some of that energy when
| descending, similar to how electric cars recover energy
| when braking.
| ryandrake wrote:
| > It's too bad there isn't a way of recovering some of
| that energy when descending, similar to how electric cars
| recover energy when braking.
|
| A descent is a pretty efficient conversion between
| potential energy (altitude) and kinetic energy
| (speed/horizontal distance) so you get it back. Your RPM
| difference between cruise and descent is a proxy for your
| recovered energy. An engine out glide/landing is the
| extreme demonstration of this.
| weberer wrote:
| >It's too bad there isn't a way of recovering some of
| that energy when descending
|
| But that's exactly what happens already. Point the
| aircraft down and it will pick up speed.
| thfuran wrote:
| But you don't tend to want to land at enormous speed.
| sokoloff wrote:
| That's not an issue. My typical cruise descent profile on
| a VFR flight is to roll in a small amount of nose down
| trim and fly at full cruise power around 300 feet per
| minute for most of the descent, using the stored
| potential energy to increase speed.
|
| Nearer the airport, I'll make a power reduction and
| continue to convert that potential energy to forward
| travel, eventually putting out gear and flaps.
|
| There's more than enough drag for any reasonable descent
| profile to allow the potential energy to be used to move
| forward without gathering excessive speed.
|
| Power off, I can glide around 1.5 nautical mile for every
| 1000' of elevation I have to use.
| bombcar wrote:
| A/C is amusing because it's only needed on the ground -
| once you're at cruise you can just open the window if
| it's too hot - the outside air temp will almost always be
| pretty Low.
| mschuster91 wrote:
| All kinds of planes have by necessity far better drag
| coefficients than cars. A truck, SUV, even a minicar is
| like a brick wall moving at high speeds while a plane
| essentially slices through the air like a knife.
|
| Additionally, planes tend to fly at constant and pretty
| high speed for most of their operation, while a car has a
| lot of acceleration and deceleration going on. Planes can
| also use wind thermals to change altitude (sail planes
| can _only_ use that!) or can stay at the same altitude
| while a car driving below it is stuck with the geography
| (i.e. it has to follow and climb hills).
| bombcar wrote:
| The '66 Fury weighs in at 3500 pounds and got about 10-12
| miles per gallon based on my pump-to-pump odometer tests.
|
| The Piper Cherokee PA-28-140 weighs a petite 2150 pounds
| (max loaded weight) and burns 10 gallons an hour and
| would do about 115 KIAS, which translated to roughly 130
| miles per hour ground speed, which is 13 miles per
| gallon.
|
| It would do even better if you flew for efficiency, but
| since rental was by hours of engine time wet (I didn't
| pay for fuel and would be reimbursed for fuel purchased),
| there was really no reason to not throttle that baby up
| to full rental power.
| Symbiote wrote:
| > there was really no reason to not throttle that baby up
| to full rental power.
|
| The reason is to reduce pollution, but that's obviously
| no concern at all for most GA pilots and passengers.
| NikolaNovak wrote:
| I guess it depends. I understand some ultralights and new
| airplanes may be efficient. But it is my understanding that a
| Cessna 172 lycoming is basically 50-70 years old, depending
| on how you count, and horribly inefficient, and completely
| prevalent. Faa certification for new engines is such that
| innovation is stifled. I mean it took the industry what, 3-4
| decades _and counting_ , to phase out leaded fuel which we
| all agree is God awful :-0
| avalys wrote:
| That's my point, the Lycoming (while an old design) is not
| all that inefficient.
|
| A Cessna 172 burns about 8 gallons per hour and travels at
| 125 knots, or about 140 mph. That's the equivalent of about
| 18 mpg.
|
| There's been an enormous improvement in automobile engine
| efficiency in the past 30 years, and most of that has come
| from optimizing engines and transmissions to minimize their
| fuel consumption under light load, while still giving them
| enough peak power capacity to accelerate quickly, tow a
| heavy load up a hill when needed, etc.
|
| In comparison, an aircraft engine spends very little time
| "idling" and sees very little change in load over the
| course of a flight. It just runs at a fixed speed and power
| setting for most of the time. There isn't that much to
| optimize or improve.
| conradev wrote:
| Aren't Cessna 172s and other small planes so efficient
| that the optimization strategy is to electrify them?
|
| It's still early days with short flying time, but
| electric planes are a thing:
| https://en.wikipedia.org/wiki/Pipistrel_Velis_Electro
|
| Flight training is seemingly the first market:
|
| "The eDA40 will compete with Bye Aerospace's new all-
| electric eFlyer 2 and eFlyer 4 aircraft, which have been
| securing significant preorders in the flight training
| market."
|
| https://www.futureflight.aero/news-
| article/2021-10-13/diamon...
| TylerE wrote:
| No. Energy density for batteries is at least an order of
| magnitude off where it needs to be for manned flight.
| outworlder wrote:
| Sort of. One feature of fuels is that the planes gets
| lighter as you burn it. You can also choose not to fill
| it up in order to have more cargo (or passengers).
| Batteries don't offer the same flexibility, so they will
| have to be pretty power dense to provide the same
| utility.
|
| I'm still rooting for electrification there too. I can't
| imagine an electric drive train to cost as much as a
| Lycoming/Continental engine overhaul.
| TylerE wrote:
| This is especially important in small aircraft, as many
| have ZERO cargo capacity (just enough for the pilot - no
| passengers) at full fuel load.
| maximilianburke wrote:
| There's tons to optimize!
|
| Timing is a big one; magento fired engines have fixed
| timing. The engines can't remove or add timing to get
| more power.
|
| Fuel ratios are determined by the pilot with current
| Lycoming and Continentals. Why should the pilot need to
| worry about this? EFI has been around for 40 years now
| and would help decrease the cognitive load on the pilot.
| Like, how many engines have cooked valves because the
| pilot (or student) forgot to richen the mixture before
| descending?
|
| Cooling is a huge one. There are a few liquid cooled
| aircraft engines and they just make everything easier.
| The engines are more reliable, and it also removes a
| carbon monoxide poisoning risk due to corrosion in the
| exhaust cuff.
|
| Yeah, a Cessna can get better fuel economy than a car
| traveling at 140mph but it could be _so much better_ than
| what it is. And not just better fuel economy, but better
| all around experience for the pilots (lower cognitive
| load), and owners (lower cost of living, more reliable
| engines).
| outworlder wrote:
| So what I'm hearing is... get a Diamond? :)
| avalys wrote:
| I'm not disputing that GA engines could be significantly
| improved and modernized in numerous ways. But none of the
| improvements you mention actually relate to efficiency at
| cruise power.
| maximilianburke wrote:
| I feel like I've said this already but carbureted and
| mechanical FI in aircraft often do not have even fuel
| distribution; that is not all cylinders receive the same
| amount of fuel. If you have an injector on (in) each
| cylinder, you do. If you have O2 sensors on each sensor
| the ECU can adjust mixture on the fly and ensure that
| each cylinder is running optimally
|
| The SDS EFI people claim up to a 20% fuel effiency gain
| by going to multipoint fuel injection on existing
| engines.
|
| If you have consistent cooling (hey, guess what, those
| rear cylinders on an O-540 are running hotter than the
| fronts), you can run more timing and more compression.
|
| More timing, more compression, less fuel = more
| efficiency. Basically everything I'm talking about is
| more cruise power efficiency!
| sokoloff wrote:
| The premise of GAMI injectors is that not all cylinders
| are _supposed to_ receive the same amount of fuel,
| because they don't all receive the same amount of air.
| The intent is to achieve the same air-fuel ratio, which
| means having different injector sizes for different
| cylinders.
|
| I have GAMIs; they are one per cylinder, just like the
| factory injectors were, but provide closer matched air-
| fuel ratios. I also have per-cylinder EGT and CHT
| instruments and have measured less than 0.3gph spread
| (about 2%) between the leanest and richest cylinder.
| Modern cars are rarely measuring per-cylinder fuel, but
| rather measuring the average of half or all the cylinders
| and using that to adjust short and long term fuel trims.
| sbaiddn wrote:
| Youve added a pretty sophisticated complication to that
| engine. What happens if the O2 sensor fails in flight?
|
| Also, I dont know that you want to increase the
| compression on the hot cylinder. If anything Id run rich
| to make sure it doesnt knock
| jdhn wrote:
| >better all around experience for the pilots (lower
| cognitive load)
|
| Can you elaborate further on this? Is this lower
| cognitive load because the engine is more reliable?
| NegativeLatency wrote:
| Lower cognitive load because you as the pilot wouldn't
| need to manually set the fuel mixture
|
| In the gallery here: https://cessnaowner.org/pilots-
| perspective-cessna-340/ The red controls are the mixture
| and have to be manually adjusted by the pilot, so you
| could potentially remove 1/3 of the controls from that
| area
| maximilianburke wrote:
| Plus the associated gauges too (cylinder head
| temperature, exhaust gas temperature, fuel flow).
| TylerE wrote:
| Absolutely not. Engine health is VERY important, even in
| a fully managed "one lever" engine.
| sokoloff wrote:
| Many racecars and boats also run fixed timing. Variable
| timing is needed when the load is variable. If the load
| is constant, the timing can be fixed.
|
| Modern engine monitors have given us more insight than
| ever into engine operation and I don't find the engine
| management particularly taxing.
|
| After initial takeoff, I'm likely to set the power
| (throttle, RPM, and fuel mixture) at 1000' above the
| ground and not touch it again for 4 hours (when it's time
| to transition to landing).
| maximilianburke wrote:
| That's still not particularly efficient. There's still
| variable load: circuit work, obstacles to climb over,
| flying around (or into) airspace. Air density isn't
| fixed, your engine may be running richer or leaner than
| you need to be. Pilots aren't nearly as efficient as
| setting the mixture as a computer, nor are the currently
| used single injector (or carburetor) as efficient as
| multi-point, or direct, fuel injection.
|
| GAMI got their start selling more balanced fuel
| injectors, but there's only so much you can do when you
| squirt gas into a tube and hope that it makes it equally
| to all cylinders.
|
| There's a _lot_ on the table in terms of efficiency and
| it puzzles me why there has been almost zero progress on
| this front.
| sokoloff wrote:
| The C172 (most common small airplane) has a Lycoming
| 4-cylinder engine of various sizes throughout the years. A
| representative engine, the O-320, is around 89% as
| efficient as traditional (non-hybrid, non-Atkinson) ICE
| automobile at turning gasoline into productive work.
|
| I don't view an 11% spread as "horribly inefficient" given
| the need for many redundant systems, air-cooling, high
| diameter pistons, and relatively low RPM.
|
| 0-https://michaelsoroka.com/2014/03/26/are-airplane-
| engines-in...
| nimish wrote:
| They lack a bunch of emissions control equipment like
| fuel injection, catalytic converters, and the like.
|
| They are 60's or maybe 80's car engines that are still
| made since nobody in GA wants to pay for better ones.
| laverya wrote:
| > since nobody in GA wants to pay for better ones.
|
| Since nobody wants _to pay to certify_ better ones.
|
| The engine in a Cessna 172 is going to run you $20-40k
| (20k rebuilt, 40k new afaict - check out [0]) - _far_
| more expensive than an automobile engine with
| 'equivalent' performance. The difference is that the
| Lycoming is certified by the FAA for use with your
| airframe. (And it'll work in whatever conditions you care
| to name, and with a car engine that's only a 'probably')
|
| 0: https://www.coronaengines.com/In-Stock
| jcoby wrote:
| > They lack a bunch of emissions control equipment like
| fuel injection, catalytic converters, and the like.
|
| Yeah unfortunately the weight and size of those systems
| is prohibitive for most light aircraft. Plus catalytic
| converters and oxygen sensors for closed loop efi can't
| be used with leaded fuel.
|
| > They are 60's or maybe 80's car engines that are still
| made since nobody in GA wants to pay for better ones.
|
| The Lycoming and continental engines in most of the fleet
| were certified in the early 50s. A few were in the early
| 60s. That means they were designed in the 40s and 50s!
| martincmartin wrote:
| Wait, airplanes don't already use unleaded fuel?
| dreamcompiler wrote:
| Nope. Not piston engines anyway. Airplane engines have to be
| much more reliable than car engines in a much harsher
| environment, and until today leaded fuel was the only solution
| that produced the requisite level of reliability.
| lbriner wrote:
| Thanks. This was the question I was looking to answer, "if we
| did it in cars seemingly easily, why not planes!)
| doliveira wrote:
| Was it easy, though? We already knew it was a bad idea to
| start with, and yet it took almost a century to phase it
| out.
| dreamcompiler wrote:
| It's always been trivially easy to replace lead in car
| gas if you don't care about cost. There are a thousand
| chemicals that will increase octane levels and prevent
| knocking, and some of them can be bought at your local
| hardware store.
|
| But none of them were as cheap as tetraethyl lead in the
| early 20th century, so TEL won.
|
| (This argument doesn't apply to avgas, where TEL did/does
| more than just prevent knocking.)
| doliveira wrote:
| I know that, and if monetary cost is the only thing
| you're measuring it's a perfectly good explanation and
| it's totally worth it to knowingly poison people for
| that.
| sokoloff wrote:
| It was introduced into auto fuel in 1921 and phased out
| in autos in the US from 1976 to 1996 (with the phase out
| being heavily front-loaded).
| doliveira wrote:
| I would count from the very introduction, because
| everyone knew from the start it was a bad idea but
| profits spoke louder.
| sokoloff wrote:
| When do you think TEL was introduced to auto fuel?
| doliveira wrote:
| > It was introduced into auto fuel in 1921
| sokoloff wrote:
| OK, so maybe the question then is "how many years is
| 'almost a century'?"
| doliveira wrote:
| That was also the argument for putting lead in fuel for cars
| in the first place.
|
| The answer just seems "not enough political pressure to phase
| it out".
| skimo8 wrote:
| Thats true, but aircraft engines also run harder, must be
| lighter, and more reliable. It has been discussed
| elsewhere, and is a technically harder problem.
|
| On top of that, general aviation makes up a much smaller
| part of the population motoring around every day, so
| probably less of a priority to gain political traction
| (until now).
|
| That being said, I'm very happy to see an unleaded
| standard. It was my understanding that 100LL was not able
| to be transported via pipeline, which was part of the
| contribution to its higher cost.
| Gordonjcp wrote:
| What do they run 2-strokes on in the US then?
| FourHand451 wrote:
| Oil/gasoline mixture. No requirement that there needs to be
| lead in the gas, as far as I've ever heard.
| Gordonjcp wrote:
| Well, I know it's got oil mixed in. Presumably the leaded
| fuel requirement is only for four-strokes though, since
| two-strokes can't run on leaded?
| jabl wrote:
| It's kind of an orthogonal issue. Oil is needed in the
| fuel for two-strokers with crankcase ventilation for
| lubrication. Lead is needed to boost octane. But your old
| outboard engine is most likely a very simple low
| compression engine that doesn't need particularly high
| octane, so can run just fine on regular car gasoline
| (preferably without ethanol, but again a slightly
| different issue) mixed with the two-stroke lubricating
| oil.
| skykooler wrote:
| Jets do (as well as turboprops), but piston-engine planes (aka
| almost all general aviation aircraft) currently burn leaded
| gasoline.
| midoridensha wrote:
| Jets and turboprops do not use "unleaded fuel", they use jet
| fuel (which is basically kerosene).
|
| "Unleaded fuel" doesn't mean any fuel without lead, it
| specifically means gasoline (petrol) without lead. Hydrogen
| gas (or liquid) can be used as a fuel, but no one would call
| it "unleaded fuel".
| throwthere wrote:
| Reminds me of the xkcd comic--
|
| https://xkcd.com/641/
| moffkalast wrote:
| Yeah, my reaction to this isn't "oh hey about time" but more
| "WHAT THE ACTUAL FUCK HOW IS THIS STILL A THING"
| codalan wrote:
| https://www.faa.gov/newsroom/leaded-aviation-fuel-and-enviro...
| kurupt213 wrote:
| How do they replace the lubricating function of the triethyl
| lead?
| orangepurple wrote:
| I hope not by burning PFAS (lol)
| kurupt213 wrote:
| You jest but a fluorinated hydrocarbon is probably
| particularly well suited for the task
| orangepurple wrote:
| I think they worked around the detonation problem by using
| massive concentrations of MTBE, methanol, and an organic
| manganese aromatic compound to keep corrosion at bay
| kurupt213 wrote:
| MTBE...something else absolutely horrible for you when
| the leaking underground storage tank (LUST) contaminates
| the water table.
| someweirdperson wrote:
| Does anyone have a link to the STC? FAA stc search didn't return
| anything new for GAMI.
| bmismyname wrote:
| Fun fact: many major US cities still have lead pipes[1]. It costs
| about $20,000 to replace a lead service line from the water main
| to your home if you live in an older home/building, and the
| cities are not exactly working hard to replace lead mains.
|
| The cheapest way to lower your risk of lead exposure is to
| install an RO filter if you believe there are lead pipes (there
| are many different brands, but the one from APEC is popular and
| affordable). It has the added benefit of reducing exposure to
| other nasty things which have pretty much contaminated all the
| drinking water on earth like PFAS.
|
| I have an unsubstantiated pet theory on correlation between lead
| poisoning and crime in poorer neighbourhoods due to landlords
| refusing to replace these (why bother if you don't have to drink
| the water? landlords have no incentive so long as they can
| extract rents).
|
| In many cities you can get your water tested for free by the
| city, just do some searching. They've usually got an online form
| you can fill out and they'll send you a kit that you have to send
| back.
|
| [1]: https://www.nrdc.org/resources/lead-pipes-are-widespread-
| and...
| amluto wrote:
| > The cheapest way to lower your risk of lead exposure is to
| install an RO filter
|
| That's much more expensive than the average NSF-listed filter.
| I believe most of them work by ion exchange, and they are a
| _lot_ simpler and cheaper than RO.
|
| Get RO if you have serious hardness issues or taste issues that
| are not mitigated by a good NSF-listed filter with a carbon
| stage.
|
| https://www.nsf.org/news/concerned-about-lead-drinking-water...
|
| > if you believe there are lead pipes
|
| Just test your water. Even without lead pipes, lead _solder_ on
| copper pipes can be a problem. Or lead in city pipes. Or
| anything made out of non-"lead free" brass or bronze. (Some of
| the latter has a shockingly high proportion of lead in the
| alloy.)
| Spooky23 wrote:
| Lead pipe risk is dramatically overstated. It's the new
| asbestos, lots of noise and bullshit and little reality.
|
| What happened in Flint, MI was criminal negligence - literally.
| That system was operated safely for decades and started
| poisoning people because of political conditions in the state
| and incompetence/dereliction.
| AngryData wrote:
| I agree. It should be phased out, but there is no reason to
| do it until you have to work on those pipes and disturb them.
| They are safe while they are calcified and are sending water
| that is suitable for metal pipes in the first place. Flint
| was sending basically acid down their pipes because of
| intervening incompetent and corrupt state officials. It made
| stainless steel sinks start rusting for gods sake. Even if
| the system was pure iron pipe that shit would have opened up
| like swiss cheese into the dirt and ground. Im not even sure
| if plastic water pipe would have been totally immune to such
| shitty and prolonged pH levels.
| bmismyname wrote:
| Do you really trust the people running local governments to
| not mess things up? I certainly don't. I wouldn't trust them
| to look after my house plants.
| Spooky23 wrote:
| The engineer in charge is usually competent and has the
| prospect of losing his PE at stake.
| [deleted]
| Dylan16807 wrote:
| At least you can prevent leeching from lead pipes. Can't really
| stop the lead from getting out of an engine.
| [deleted]
| nawgz wrote:
| Finally
| clamprecht wrote:
| How will California cities justify closing general aviation
| airports now?
| NonNefarious wrote:
| Sadly not just CA. Another favorite lie is "safety." Despite
| the fact that the road going past any given airport has
| suffered more fatalities in a few years than the airport has
| seen in its history, land-speculating trash love to trot out
| the "safety" excuse.
|
| Take the current poster child for corrupt destruction of our
| airports: Santa Monica. Not one neighbor of that airport has
| been killed by an aircraft IN A CENTURY. But the street going
| past it kills a person per year.
|
| And rich, white people who want to goose their property values
| come out not only to regurgitate discredited FUD, but to
| complain that the airport is used by rich, white people.
| Meanwhile they're just fine with a golf course operating next
| to it during a permanent drought and a "housing crisis."
|
| BTW, Ann Heche crashed her car and burned down a house not far
| from Santa Monica... where are the calls to shut down that
| street?
| NonNefarious wrote:
| S201 wrote:
| Easy: "We need that land for more strip malls, box stores, and
| overpriced condos."
| GoOnThenDoTell wrote:
| Noise
| V-eHGsd_ wrote:
| noise.
|
| "the airplanes landing at this airport that was here when I
| moved are very loud and should not be allowed to land here
| anymore."
| shitlord wrote:
| They could also argue that the airplanes will cast a shadow
| on neighboring parks/houses.
| ajsnigrutin wrote:
| This is a standard in my country but with farm smells and
| noises. People buy a house "in the country", then they
| complain about manure on fields, cows mooing and tractor
| noises.
| Rebelgecko wrote:
| Considering that FAA lowered a bunch of flight paths over the
| last ~5 years, kinda feels like a bait and switch. My
| parents' place was always pretty quiet since it's 20+ miles
| from the nearest major airport, but after FAA Nextgen was
| implemented it got fairly noisy from all the airliners
| passing over.
| clamprecht wrote:
| I'm curious, where did this happen?
| toomuchtodo wrote:
| Previous: https://news.ycombinator.com/item?id=30943466
| humanwhosits wrote:
| I sure hope they ban the leaded fuel soon
| tjmc wrote:
| If this prevents spark plug fowling as claimed it will be great
| and brings back a fond memory. During the Sydney Olympics in 2000
| I flew a Piper Warrier over the Hawksbury River north of Sydney
| and the engine started missing - quite possibly due to this
| issue. A bit of a nervous prospect as there is basically nowhere
| to land there. At the time there was a huge air exclusion zone
| over the Olympic Park and there was excited talk of how quickly
| jets would be dispatched to shoot you down if you violated the
| airspace. Anyway, the moment we reported engine trouble we were
| given clearance to head straight back to Bankstown - pretty much
| right over the top of the games. Good times!
| londons_explore wrote:
| What are the chances some airports have signed 20 year fuel
| supply contracts with some leaded fuel supplier?
|
| I think for this to have much traction, some carrot and stick
| needs to be applied... A $1/gallon tax on leaded fuel that
| doubles every year ought to be a good incentive to start using
| lead free stuff.
| sokoloff wrote:
| I think you'll see the fuel supplier unable to supply 100LL
| somewhere between 10 and 20 years as this rolls out.
|
| The critical element is this is miscible fuel. It doesn't need
| new tanks, new pumps, airplane mods, or any big-bang adoption.
| It takes refineries licensing the formulation and individual
| airplanes to spend around one fillup's worth of fuel on a piece
| of paper.
|
| That's a 5-10 year process, not a 20. Once the volume drops
| off, the one plant making TEL will plan to shut down I think.
|
| I'd expect to see an EPA Clean Air Act update to ban 100LL in
| the 10-20 year timeframe as well.
| shultays wrote:
| What makes lead such a magic substance that makes it used in many
| places and hard to replace?
|
| I know leaded solder wires have lower melting temp. What else?
| _s wrote:
| Cheap, abundant, easy to acquire, easy to transport, inert,
| mostly harmless if left alone, maintains its properties in
| harsh conditions over extended periods of times, mixes well
| with some other chemicals.
|
| Very harmful if ingested or absorbed, directly or indirectly.
| sv123 wrote:
| Wow, I can't believe they got it done. After watching all the
| Paul Bertorelli videos on it I assumed it would be stuck in
| bureaucracy from here to eternity. Incredible work by the whole
| team, very exciting.
| NonNefarious wrote:
| Agreed, but sadly it's still a niche fuel. Although I have to
| admit that for a (hopefully) brief time, we've seen airplane
| gas and corner-gas-station gas the same price in California!
|
| I think that unless a large number of GA airplanes can run on
| true automotive gas (which means gasohol now) in the near
| future, GA is doomed. This is something the industry should
| have been tackling with abandon for the last 20 years. But they
| failed to take lead seriously for the last 50, so can we expect
| better?
|
| Maybe. I think there is one Rotax engine that can run on
| gosohol (10% ethanol). We need much more of that, and
| widespread adoption of fuel injection and electronic ignition
| ASAP.
|
| Oh, and we need more people to stand up for their local
| airports. Corrupt local politicians, developers, and fake-NIMBY
| land speculators are all arrayed to destroy our nation's
| aviation infrastructure for personal profit. Even airlines are
| in on it. Innovations like this unleaded fuel and
| electrification will cease if there's no place to deploy them.
| dreamcompiler wrote:
| And turbochargers. Cars benefit from turbos and they don't go
| from lean to rich to lean every day. Planes do that several
| times on every trip, and can benefit from turbos much more.
| jabl wrote:
| The logical conclusion of that argument is to scale up the
| turbo, rip out the big chunking reciprocating mass of metal
| and just inject fuel directly in a can ahead of the turbo.
| ;)
|
| (Oh, and since your gas generator no longer has a prop
| shaft sticking out of it, you need to mount the shaft on
| the turbo instead. Possibly on a separate turbine wheel.)
| dreamcompiler wrote:
| Hey, I seem to recall somebody tried that :-)
|
| The distinction of course is about reliability and cost.
| If a turbo quits, your piston engine can probably still
| limp along. But if your tur _bine_ quits, the houses are
| gonna get bigger...
| cossatot wrote:
| _Oh, and we need more people to stand up for their local
| airports. Corrupt local politicians, developers, and fake-
| NIMBY land speculators are all arrayed to destroy our nation
| 's aviation infrastructure for personal profit. Even airlines
| are in on it. Innovations like this unleaded fuel and
| electrification will cease if there's no place to deploy
| them._
|
| So, I think GA is great in principle, and I use some products
| from it (mostly digital elevation data from airborne lidar,
| which is amazing). But it seems to have a very large
| component of taxpayers footing the bill for rich guys'
| toys/playgrounds (particularly for the infrastructure, not
| for planes themselves); this opinion has been influenced by
| talking with people I consider honest who have worked in
| municipal/county government, but I don't have any numbers.
| Can the many GA enthusiasts here give provide some insight
| into the public benefit from GA? Please note that I am sort
| of asking to be convinced and am not being antagonistic.
| Spooky23 wrote:
| When I worked retail a long time ago, one of the assistant
| managers flew every weekend.
|
| He wasn't rich. Now he's making a good living flying for
| Southwest iirc.
| outworlder wrote:
| > But it seems to have a very large component of taxpayers
| footing the bill for rich guys' toys/playgrounds
|
| Eh, most are not that rich. There's a wide range of plane
| prices. From Honda Civic money, to millions of dollars.
|
| GA encompasses a whole bunch of activities. You do have the
| rich doctors flying in twins, yes. You also have Angel
| Flights, Pilots N Paws providing volunteer assistance for
| people and animals. You have flight training (we are going
| through a pilot shortage). Aero(photography/grammetry).
| Sightseeing flights (tourism industry). Transportation of
| people and cargo to remote areas. Etc.
|
| In some cases the revenue generated doesn't pay for the
| infrastructure. That's why so many airports have closed in
| the last couple of decades.
|
| There are also people just flying for fun. Usually in very
| cheap and economical planes burning single digit gallons
| per hour. Their gallon/mile figure can be pretty good even
| compared to cars (let alone SUVs).
| mschuster91 wrote:
| Lot of the aerophotography stuff is switching to UAVs
| these days though, it's easier to obtain pilots and the
| capability of modern UAV platforms is just amazing.
| snowwrestler wrote:
| AFAIK no privately available UAV system can match the
| range and flexibility for GA aircraft. For example
| photographing things that are dozens of miles from any
| road or airport. If I'm wrong I'd be interested to learn
| more.
| mschuster91 wrote:
| A DJI Matrice 300 can fly for an hour, at a distance of
| up to 15km [1]. Agreed, it's not going to be useful in
| the extreme outback, but enough to cover a lot of use
| cases in areas near civilization.
|
| [1] https://www.dji.com/uk/matrice-300/specs
| p_l wrote:
| Generally there are different classes of aerophoto ops
| and most UAVs so far seem about opening up markets that
| were previously closed due to high prices
| reaperducer wrote:
| There are places in America that are a hundred or more
| miles away from the nearest hospital. These small airports
| are vital to rural healthcare.
|
| Sure, all those people could move to more populated places,
| but then you'd have nothing to eat.
|
| Source: The company I work for is slightly involved with
| air ambulances.
| AYBABTME wrote:
| For one, there's no country in the world where the GA scene
| is like it is in the US. There's airports everywhere and
| flying is mostly accessible. As such, like US universities
| attract the world's students, the US GA airports attract a
| _ton_ of foreign pilot students.
|
| That's just one angle. Another angle: the US is a lame duck
| in term of mass transit infrastructure like trains. So
| development and advancements in those fields occurs
| elsewhere, like in Europe and Asia. But in the case of
| aviation infrastructure, US is miles ahead. And as a
| result, a lot more aerospace stuff happens in the US than
| anywhere else. It's not as directly useful to the general
| public as inter-city trains, but it does have a lot of
| positive side effects for the economy and industries.
|
| Perhaps one day, flying will simplify and become
| commonplace for the average person, like cars that were, as
| an industry, born in the US. And then on that day, it'll
| seem pretty smart to have nurtured general aviation and
| allowed aerospace to germinate.
|
| GA looks like a rich people's hobby, and it sort of is. But
| it's not "10M$ in the bank" rich. The middle (as a treat)
| and upper class can afford to fly GA. In most other
| countries, that's just too out of reach for most people,
| it's not realistically in the cards unless you want to have
| a career in that field.
| NonNefarious wrote:
| The people making these claims typically don't know anyone
| in GA or anything about their local airport. The taxpayers
| footing the bill for GA are GA USERS. GA pays way higher
| fuel taxes than the AIRLINES do.
|
| A large proportion (the majority?) of the people in GA are
| not rich. They simply choose to spend their money on
| flying, instead of on leasing a new giant SUV every three
| years. My flight instructor had to SAVE UP to buy a crummy
| portable GPS... and 15 years later he still doesn't own a
| plane.
|
| And that's not counting the entire industry's worth of
| people whose living depends on servicing aviation.
| Mechanics, painters, upholsterers, you name it. And this is
| a mostly DOMESTIC industry. It's despicable that GA doesn't
| enjoy more support from everyone, from legislators on down
| to Joe Plumber.
|
| "You're posting too fast. Please slow down. Thanks."
|
| Oh yeah, Hacker News? Then WHY IS THE REPLY BUTTON ENABLED?
| Why do you allow people to waste their time typing out a
| question or comment and THEN say, OH NO YOU CAN'T POST?
| Then you jerks "shadow ban" people who point out your
| offensive behavior.
| sokoloff wrote:
| In addition to air ambulance/medevac, aerial firefighting,
| overnight package intake and delivery, and medical lab test
| samples are all things that I think have fairly broad
| benefit if not widespread support and rely heavily on
| airports other than the 100 largest in the US.
|
| In times of natural disaster, GA airplanes are often
| delivering support and supplies using these non-primary
| airports. This often happens before the larger agencies can
| spin up and post-hurricane can often reach areas before the
| roads are fully open.
|
| In rural areas, like Alaska, they're even more utilitarian.
|
| Most of the commercial pilots now got a lot of their 1500
| required hours in some of the activities around these small
| airfields.
|
| And of course, there's all the use of private aviation in
| support of businesses (logistics to prevent line shutdowns
| or move urgently needed repair crews to a factory).
|
| It's not just rich folks buzzing around to kill time or
| flying around in their private jets. (Neither is that zero
| of it.)
| dreamcompiler wrote:
| People from the lower 48 can't seem to conceive how
| important GA is to Alaska. If you grounded all GA planes
| in Alaska, thousands of people would start dying of
| starvation within a couple of weeks. There are simply no
| roads to most of rural Alaska.
| mschuster91 wrote:
| At that point the question does arise: is it long-term
| sustainable to keep such communities artificially alive,
| or would it make more sense to pay off their residents to
| move somewhere where they can be supplied with resources
| way more efficiently?
| snowwrestler wrote:
| GA in Alaska requires less public infrastructure than
| elsewhere because there are more planes that can land on
| and take off from water, snow, and unpaved surfaces.
|
| Also Alaska can easily afford basic infrastructure, heck
| they pay an annual stipend to permanent residents.
| mschuster91 wrote:
| > Also Alaska can easily afford basic infrastructure,
| heck they pay an annual stipend to permanent residents.
|
| The question is not if they can afford it because they
| obviously can, the question is if this is long-term
| _sustainable_ - not just from a CO2 emissions point, but
| you also need pilots, the planes or boats themselves, and
| all of that to supply cities that don 't even manage to
| get 100 residents [per 1, at least 23 fall below that
| limit]?!
|
| Maybe just accept for once that there are areas so remote
| it isn't worth the effort to supply them. We should
| return these areas to nature.
|
| [1]
| https://en.wikipedia.org/wiki/List_of_cities_in_Alaska
| snowwrestler wrote:
| You're not going to save the world by kicking a few
| hundred Alaskans off their property.
| mschuster91 wrote:
| It's not (just) about saving the world. It's actually the
| ability to keep them supplied that is at question, given
| the current immense shortage on labor and fuel prices
| that are _not_ going to go down.
| josephcsible wrote:
| What's "artificial" about using planes to transport food
| instead of trucks?
| dreamcompiler wrote:
| Many of these communities have been there for hundreds of
| years. It was their homeland long before the United
| States existed. Do we force them off their land because
| it's more convenient for us? Do we force them to revert
| to a primitive lifestyle with no access to modern
| conveniences like medical care, a good education, food in
| lean times, electricity, or communication?
|
| Or do we let them continue to have the best of both
| worlds at the cost of an airplane once a month? I vote
| for option 3.
| sv123 wrote:
| I imagine the idea is now that it is approved for every
| piston engine then the EPA can ban 100LL and airports
| everywhere can switch to 100UL instead.
| maxerickson wrote:
| Ethanol free gas is widely available (In Michigan stations
| call it Rec fuel).
|
| Are you concerned about cost, availability, some other
| factor?
| NonNefarious wrote:
| I disagree. I haven't seen alcohol-free gas in decades, in
| Los Angeles, Chicago, or anywhere else that I can remember.
| Spooky23 wrote:
| Availability is limited in many places. California,
| Massachusetts and New Jersey have very few stations.
| sokoloff wrote:
| "George Braly, chief engineer at GAMI, said the fuel can be
| made with components "that are found inside the fence of any
| refinery.""
|
| Now, that quote comes from the principal at GAMI and in a
| GAMI newsletter, but over the last decade and a half of
| following this, I've found him to be pretty damned
| straightforward.
|
| https://gami.com/g100ul/AvGas0211.pdf
| jabl wrote:
| > Agreed, but sadly it's still a niche fuel. ... I think that
| unless a large number of GA airplanes can run on true
| automotive gas (which means gasohol now) in the near future,
| GA is doomed.
|
| There are several problems with gasohol outside the core
| engine, from compatibility with fuel systems (bladders etc.),
| to phase separation, to vapor lock, to hygroscopicity. I'm
| sure that can be designed around, but it's not a drop-in
| replacement in planes designed for avgas.
|
| If you want an abundant and affordable fuel, in the aviation
| world that's Jet A(-1). There's some limited success with Jet
| A burning diesel engines for the GA market (Thielert (or
| whatever they're called today) and Austro mainly).
|
| Personally I think it would be cool if turbines suitable for
| GA would be developed. Currently turbines cost an arm and a
| leg, but I think partially that is an effect of development
| focused on power/weight and fuel efficiency, cost be damned.
| That might suit commercial and military use, but not GA. And
| yes, turbines don't scale down very well either. Still, a
| turbine that would have an upfront cost competitive with
| current GA engines would be very attractive, even if it would
| come at a cost in fuel efficiency. That would be, I think,
| more than compensated by the power/weight and safety
| advantages, as well as fuel availability and affordability. I
| think there are a couple of companies working in this space
| (TurbAero and Turbotech that I'm aware of, maybe others as
| well), we'll see if any of them ever come to fruition.
| p_l wrote:
| A big problem with turbines is overhauls and how they are
| calculated.
|
| For piston engines, overhaul time is calculated from amount
| of hours operated. For turbine engines it is calculated
| from _amount of hours and amount of start-stop cycles,
| whichever is reached first_. And in GA, you have short
| flights and many cycles, which results in overhauls being
| much more common and expensive.
| NonNefarious wrote:
| Yep, I wouldn't expect the transition to have occurred
| overnight. But after several decades of experience in
| automotive applications, I'd think the GA fleet could have
| been adapted by now if the industry had taken it seriously.
|
| I also realize that the regulatory regime has stifled
| progress. It seems a bit better now, but it may be too
| late.
| boppo1 wrote:
| Lowering the financial barrier to entry would help. Idk how,
| but part of the industry's problem is that people who want to
| learn to fly can't afford to.
| NonNefarious wrote:
| Fuel costs are a huge part of it.
| LadyCailin wrote:
| I don't want more incompetent people flying planes, so I'm
| content to keep it expensive enough to keep out people that
| aren't going to take it deadly serious - because it is.
| Expense doesn't guarantee that, of course, but it limits
| the collateral damage.
| sv123 wrote:
| There might be a correlation in the other direction.
| Successful and wealthy people have a propensity to buying
| more expensive and flashier planes, which generally
| equates to faster, which is something an inexperienced
| pilot should always try to avoid.
| dzhiurgis wrote:
| Wait until you hear how much eScooters cost
| sokoloff wrote:
| I've been flying for almost 25 years. I haven't seen much
| correlation between income/wealth and how seriously
| pilots take aviation.
|
| I've seen rich people take it extremely seriously and
| with great attention to detail and safety, just the same
| as I've seen people who struggle to get the money
| together to go flying do the same.
|
| I've also seen a lot of rich, successful, type-A people
| just not have the mindset of "Oh shit, this could easily
| kill me" because they've been successful at some other
| aspect of life.
| blitzar wrote:
| You fly jets long enough, something like this happens.
| dahdum wrote:
| > Oh, and we need more people to stand up for their local
| airports. Corrupt local politicians, developers, and fake-
| NIMBY land speculators are all arrayed to destroy our
| nation's aviation infrastructure for personal profit.
|
| I'm skeptical the public will stand up for GA. At least from
| my perspective, progressives and much of the left would
| prefer the industry fade away entirely. It's been in decline
| for decades and with the new trend of public carbon shaming I
| don't think you'll get many who come out in support of it
| beyond rural conservatives.
| NonNefarious wrote:
| I share your skepticism, but will still work to oppose what
| contributes to it.
| p_l wrote:
| Not all of us are unknowing of how interconnected GA
| capability is to many other areas of economy, even if we
| live in countries with less such impact.
|
| Now, landlords looking for more land (especially well
| communicated) for apartments are very happy to push for
| everything that removes airports so long as they can reuse
| the land afterwards...
| mschuster91 wrote:
| Airports consume an awful lot of land directly, cause
| severe pollution issues for even more land (by noise,
| mostly) and severely limit land use in the flight paths
| due to safety concerns.
|
| Building out actually capable high speed and regional
| rail infrastructure is the way forward.
| sokoloff wrote:
| If you get high-speed rail to be competitive with flying
| a 175 knot piston airplane, piston GA travel will fall
| off a lot. I love flying, but I'd switch.
| mschuster91 wrote:
| French TGV routinely has service speeds of 320 km/h [1]
| which is about the same as your plane, same for the
| Japanese Shinkansen [2]. Technically, speeds exceeding
| 500 km/h on close-to-stock rail are possible, the French
| have done that as well [3].
|
| [1] https://de.wikipedia.org/wiki/TGV#Allgemein
|
| [2] https://en.wikipedia.org/wiki/T%C5%8Dhoku_Shinkansen
|
| [3] https://www.hsrail.org/worlds-fastest-trains
| sokoloff wrote:
| I've ridden the TGV and Shinkansen. They don't go to my
| kids' grandparents' house, but when they do (or hell,
| even something like the German ICE does), I'll use them.
| I'm not anti-train; I am anti-impractical-train.
|
| Today, Amtrak takes 22.5-27 hours to go 642 miles Boston
| to Columbus, OH. I can drive there in around half the
| time (likely less once you add the time to/from train
| stations) or fly there in 1/4 the time.
|
| That's a perfect distance for _actual_ high-speed rail.
|
| To the other grandparents, Amtrak can get me 657 miles in
| 18.5 hours to a place about 100 miles from their house.
| That leaves once per day at 9:30 PM and still leaves me 2
| hours drive from their house (which is in a tourist area
| near the ocean, not some unpopulated area). Another
| perfect distance for HSR where I can drive there in less
| than half the time or fly there in around 1/4 the time
| Amtrak takes today.
| mschuster91 wrote:
| > Today, Amtrak takes 22.5-27 hours to go 642 miles
| Boston to Columbus, OH.
|
| Agreed, which is why I said that building out such
| infrastructure is the way forward. A lot of countries,
| particularly Spain, France, China and Japan, prove that
| this is possible and that people actually use this kind
| of rail service if they are provided and affordable, the
| US just doesn't manage to build the infrastructure
| required out of a toxic combination of NIMBYs, ignorance,
| incompetence and utterly absurd construction
| requirements.
| p_l wrote:
| GA doesn't handle mass transport that can switch to
| railways, so it's a bit moot point.
|
| So GA infrastructure and railway infrastructure is
| effectively orthogonal and you need both (passenger/cargo
| airports also greatly benefit from having rail links!)
| jimnotgym wrote:
| So when are we seeing the sunset date of leaded fuel? The
| government should step in and set it to help the industry move
| along
| unglaublich wrote:
| It will stay around as long as it's free to poison the
| environment with lead.
| stevage wrote:
| Huh. I had no idea leaded fuel was still a thing in aviation.
| mmaunder wrote:
| Jet fuel is unleaded. It's also pretty close to diesel, and
| some aircraft manufacturers have diesel piston engines that can
| use JetA. The leaded culprit is AVGas aka 100LL which we use in
| piston general aviation aircraft.
| na85 wrote:
| It lets you run comparatively higher manifold pressures than an
| otherwise identical but unleaded fuel.
| bombcar wrote:
| More importantly most aviation engines were designed in the
| 50-70s and need the lead to keep the valves happy.
| jabl wrote:
| Post-WWI aviation engines overwhelmingly have hardened
| valves (and valve seats) which work fine with unleaded
| fuel.
| NonNefarious wrote:
| It's about detonation; I don't think it's about the valves.
| throwaway0a5e wrote:
| It's about the valves.
|
| Plenty of 100+ octane unleaded fuels out there.
| bombcar wrote:
| The 100 octane is about detonation; the lead is about
| lubricant for the valves.
| outworlder wrote:
| And the spark plugs unhappy?
| p_l wrote:
| Another issue is that replacements for TEL that were fine
| for cars had issues with high altitudes (and high ambient
| temperatures)
| maximilianburke wrote:
| Only because the engines themselves haven't evolved to handle
| higher manifold pressures. Lots of advancements in internal
| combustion engines, like combustion chamber and piston shapes
| that help manage the flame front, direct injection, wideband
| O2 sensors, are entirely unknown in certificated aircraft and
| still on the periphery even in experimental aviation.
|
| Like, Mazda is running 14:1 compression ratios in gasoline
| engines, but 7:1 is considered normal for a naturally
| aspirated Lycoming and it'll often dip into the 6's for
| turbocharged versions.
| throwaway0a5e wrote:
| They were designed in the 60s and the FAA certification
| process makes designing a replacement cost prohibitive with
| current and future sales volumes.
| p_l wrote:
| It's not just engine evolution, but TEL was replaced by
| non-lead additives, not removed. And the fuel mix impacts
| values critical for aviation but mostly irrelevant to cars,
| like fuel vaporisation for given temperature/pressure (this
| is AFAIK major issue with ethanol added to fuel and source
| of limits on use of MOGAS in aircraft) as well as impact in
| performance which are pretty much impossible to notice for
| a car (except maybe if you have engine with sparkplugs
| designed for leaded fuel) but matter of life and death in
| airplane.
| sokoloff wrote:
| Mazda sold 332,756 vehicles in 2021.
|
| Cessna has the best selling model of airplane of all time,
| the 172, which has sold around 45K units _since its
| introduction in 1956_.
|
| Mazda sells that many cars in a typical 2 month period.
| It's no surprise that there's more non-recurring
| engineering investment in car engines than airplane
| engines.
| maximilianburke wrote:
| I mean, okay? I get that. But it's not like the Cessna
| 172 is a $25k item either, it's now over $400k.
|
| There have been tons of advances in general aviation,
| look at panel technology between now and 15 years ago.
| That's awesome! Let's do the same thing but for engines
| now. But it isn't going to happen as long as no one is
| pushing for it; we have the efficiency in automobiles we
| do now because regulators have been pushing for better
| fuel consumption and lower emissions for decades. It'd be
| great if there was similar pressure applied to aviation.
|
| I'd love to have a 172 that had no mixture knob and no
| issues with hot starts. Man, wouldn't that be awesome?
| This is what we should be asking for, not apologizing for
| why we're stuck with mechanical FI, carb heat, and shock
| cooling worries.
| sokoloff wrote:
| And Cessna sold 166 of them last year, a figure that
| Mazda probably refers to as "Saturday morning".
| maximilianburke wrote:
| So, because Cessna isn't moving many aircraft we
| shouldn't ask / hope / demand / lobby / regulate for
| technology improvements in aircraft engines?
| sokoloff wrote:
| If Mazda spends $25M in NRE on a new engine program and
| sells that design for 8 model years, the amortized NRE is
| around $10 per car or about 3 basis points of the
| product.
|
| If Lycoming or Continental spend $25M on a new engine
| program and sell them for 15 years in all 172s, it's
| around $22K per airplane or around 550 basis points. When
| investments in engine development are over 180x more
| expensive on a percent of sales basis and over 2000x as
| expensive on a per-unit basis, it's unsurprising that few
| companies are stepping up to do that development.
|
| I don't mind at all if you want to lobby for it; I think
| there are improvements that could be made, but I think
| you'll find the economics daunting and the current engine
| tech to be pretty well matched to the application.
| outworlder wrote:
| Regulation is exactly the reason why there are few
| technology improvements. Improving the engines is pretty
| trivial. Heck, Diamond adapted car engines for their
| aircraft.
|
| _Certifying_ them is hilariously expensive for the
| manufacturers _and_ users.
|
| One can certainly fix that, but that's how it is. Main
| reason why the planes that consume automotive gas the
| most are in the 'experimental' category.
| tialaramex wrote:
| For cars, the argument was, if you used unleaded fuel and (as
| it might because the engine was designed for leaded gasoline)
| this causes engine damage, your engine is broken, which is sad,
| but you can just repair it. The failures are annoying, but
| they're unlikely to get anybody killed. You can just walk from
| the broken-down vehicle to somewhere with food and shelter and
| call a rescue truck.
|
| Even in countries like the UK which offered limited exemptions
| for "classic" cars, the fuel companies don't care, selling a
| few thousand litres per year of this weird special fuel makes
| no sense at their scale, so even with a regulation allowing
| this, it quickly died out. It was (maybe even still is?) legal
| to buy leaded gasoline ("petrol") in the UK for a really old
| car, but that's useless because nobody will sell it to you,
| it's just not profitable at the incredibly low volumes. Classic
| owners who run with leaded fuel these days buy their own
| additives and mix it at home, but also these cars are getting
| fragile, they probably belong in a museum anyway, not clocking
| up miles driving around, and in a museum display they don't
| need fuel.
|
| However if an aircraft engine dies, even though pilots of
| single engine piston aircraft are trained to assume that will
| happen in any phase of flight (because it can) that's extremely
| dangerous, complete engine failure over mountainous terrain
| could mean that your _best case scenario_ becomes trying to
| land your plane (well, now glider) in some untried clearing and
| if you survive then maybe needing to walk out because in some
| cases nobody is looking for you. So engine failures translate
| into fatalities at a significant rate.
|
| Planes are very expensive, and so they have long lives, which
| means many aeroplanes built long before leaded fuel was
| prohibited are still flying.
|
| On the other hand, notice this is about piston planes. So,
| you're mostly talking about smaller planes for personal use,
| and maybe some agricultural or business purposes but less
| often. For scheduled aviation, you're never going to be on a
| piston plane. To a layman it's less obvious because although
| they don't have piston engines lots of smaller or shorter range
| planes have propellers like an old-timey plane. But their
| propeller is driven by a jet engine, and that runs on JetA -
| kerosene fuel not leaded gasoline:
| https://en.wikipedia.org/wiki/Turboprop
| sokoloff wrote:
| What you said is overwhelmingly true, but there are some
| scheduled flights in piston twin C402s and the like (Cape Air
| being one of the larger operators of piston scheduled airline
| flights).
|
| https://www.capeair.com/
| tialaramex wrote:
| Thanks! I was not aware that existed. It's surprising to me
| how affordable their ticket prices are, and how many places
| they're operating. I think I'd imagined anywhere you
| couldn't justify coming in and out once per day with a Twin
| Otter there'd be nothing scheduled at all.
| rektide wrote:
| I want to fly in to Rutland VT (RUT) again sometime just
| to have the experience again. I got to fly in a personal
| aircraft once or twice as a kid, but my couple Cape Air
| flight still stand out as awesome experiences. And crazy
| crazy crazy convenient for some of my travels.
| Spooky23 wrote:
| It's subsidized by the federal government... a really
| cool program.
| throwaway0a5e wrote:
| Seems like every discussion about anything slightly
| environmental had some lead related low effort comments about
| "it's 202x, why is leaded avgas still a thing?".
|
| I won't miss those.
|
| I won't miss the lead either.
| panzagl wrote:
| I'm sure the 'problem X only exists because America doesn't
| have walkable cities' crowd will take up the slack.
| NonNefarious wrote:
| TedShiller wrote:
| We live in an age where "less terrible" is sold as "great".
| bmismyname wrote:
| It'll keep working until it stops. You'd think that with
| Wikipedia and all the information at our fingertips people
| would be able to tell a sheep from a wolf, but instead they're
| more likely to believe the authoritative talk show host because
| that person makes the tribal signals they like the best.
| missedthecue wrote:
| I'd hate to live in a world where no achievement is worthy of
| celebration unless it passes all your purity tests
| TedShiller wrote:
| You do
| Linda703 wrote:
| watersb wrote:
| Only 30 years!
|
| I trained in a Cessna 152 that was certificated to run on high-
| octane unleaded auto gas. No modifications, the EAA just
| demonstrated that it would run fine like that.
|
| But my 172 had to use Aviation gasoline. Until now.
| aaaaaasss wrote:
| ramesh31 wrote:
| >FAA approves unleaded fuel for piston fleet
|
| Yay! Primary flight training costs will come down 20-30%!
|
| >While the cost of the fuel has not been determined, Braly said
| the small-batch production process that will initially earmark
| the arrival of G100UL at airports means that the fuel will cost
| slightly more than leaded avgas. "Small volume batches cost
| money," he said. "Until we can get [production] revved up that
| we're making millions of gallons at a time, there will be an
| incremental [additional] cost," he said.
|
| Oh.
| outworlder wrote:
| Give it time.
| londons_explore wrote:
| Is the full composition of this fuel public knowledge?
|
| Or is there some secret ingredient that acts as a lead
| replacement?
|
| Some PTFE precursors would be a really unfortunate choice for
| example...
| [deleted]
| spaghettiToy wrote:
| Didn't expect to see good news today! Talk about making my body
| fill with happy chemicals!
| spitfire wrote:
| So this is a 100octane fuel? Can it be sold through regular
| retail chains?
|
| Since avgas is such a small market I'm thinking that might raise
| its TAM as a "premium plus" sort of product.
| NelsonMinar wrote:
| Congratulations to GAMI. They are a really interesting and
| innovative small company. Their calibrated fuel injectors are a
| great upgrade for many planes letting you save 5-15% of fuel.
| They make an innovative turbo system for the Cessna Cardinal that
| is quite a challenge. But taking on the task of creating an
| unleaded avgas and shepherding it through an arduous approval
| process for literally decades.. Good for them.
|
| (GAMI is still independently owned, right? Sometimes it feels
| like the last American GA company that wasn't bought by a Chinese
| aviation company.)
| greggsy wrote:
| I recall watching a YouTube video a little while back that went
| into the modern history of light aircraft engines, and how
| there have been several failed attempts at redesigning existing
| technology over the past 20 (40?) years.
|
| Is it genuinely workable? Or is there some weird edge case that
| makes it completely impractical from a maintenance or
| reliability perspective?
| Scoundreller wrote:
| Maybe this guy's video:
|
| https://www.youtube.com/watch?v=_k1TQGK3mZI
| sokoloff wrote:
| There were several failures from converted ex-automotive
| engines. Some of those were related to vibration; others to
| the much higher percentage of power that an airplane engine
| runs for hours on end.
|
| My engine might last for only 2000 flight hours between
| overhauls. In those 2000 flight hours, it's likely to burn
| ~30K gallons of fuel. Taking that as a proxy for the total
| energy generated, 30K gallons of fuel will take a typical car
| almost a million miles. How many cars reach 1 million miles
| without major engine work?
|
| There were also a bunch of (IMO misguided) attempts to fit
| liquid cooled engines into aircraft. What do you have
| absolutely no shortage of in flight? Fast moving, cool air.
| What do you have no tolerance for in flight? Loss of coolant.
|
| It's not impossible to improve upon them, but aircraft
| engines have gotten to a local maximum of sorts where they're
| pretty darn good at what they do and the maintenance needs
| and failure modes are pretty well understood.
| verelo wrote:
| I'd agree with most of this but frankly when was the last
| time your car engine stopped on the highway? Or was hard to
| start because it was hot, or cold, or just because? These
| problems are solved in cars. The old Cessna 172 models I've
| flown all continue to have these issues, even a friends
| SR22 from the mid 2000s was a nightmare.
|
| Plane engines are well understood, but they are old and
| clumsy designs that could be drastically improved upon.
| hef19898 wrote:
| Aircraft engines are running on full load for almost all
| the time, with added load during take off. Car engines
| are not, a modern car engine would blow up running under
| the same load patterns then aircraft engines.
|
| And sincr ICE engines are dying bread when it comes to
| aircraft, why bother if the current ones work perfectly
| fine for what they are supposed to do?
| Gordonjcp wrote:
| And yet many light aircraft are powered by very simply-
| adapted car engines.
| hef19898 wrote:
| And those are following totally different certification
| requirements.
| eru wrote:
| > And since ICE engines are dying bread when it comes to
| aircraft, [...]
|
| Are they actually? I'd expect air-travel (and rockets) to
| remain the last holdouts for combustion engines for quite
| a while to come.
|
| Cars will definitely move to being electric.
|
| Big ships, maybe too?
| jabl wrote:
| Wouldn't surprise me if aviation engines would move to
| turbines (see TurbAero and Turbotech for turboprops
| designed for the GA end of the market), and electric for
| short range. Leaving little if any space for piston
| engines. Though of course existing planes aren't going
| away for a long time.
| eru wrote:
| Turbines are internal combustion engines. But I guess the
| comment I originally replied to meant non-turbine ICE
| only?
| jabl wrote:
| > But I guess the comment I originally replied to meant
| non-turbine ICE only?
|
| I would guess that yes, otherwise the comment would be
| pretty outlandish if the poster is predicting the
| imminent death of turbine powered aircraft.
| hef19898 wrote:
| Obviously claiming turbine powered aircraft are a dying
| breed would be outlandish. I wrote ICEs, and meant piston
| powered aircraft... my bad...
| hef19898 wrote:
| Modern aircraft use turbines, either as turboprops or jet
| engines. Those burn kerosene.
| SlickNixon wrote:
| Turbines are ICEs.
| cush wrote:
| I can't remember the last time I commuted and didn't see
| a car broken down on the side of the road.
| TedDoesntTalk wrote:
| Not necessarily engine problems.
| ThePadawan wrote:
| That is freaking wild to me.
| dzhiurgis wrote:
| Hmmm. Something to do with lack of state warrant of
| fitness in US?
| elmomle wrote:
| But thousands of cars pass that way each day, and one
| breaks down. The (admittedly anecdotal) issue rate
| described for planes sounded much higher.
| iancmceachern wrote:
| It's more to do with the relative consequences. A car
| engine goes out and you cal AAA, an airplane engine goes
| out and you have a serious problem.
| eru wrote:
| If you have at least two engines on your plane, one
| failing ain't so bad?
| jabl wrote:
| As the saying goes, when you have an engine failure in a
| twin, the remaining engine takes you to the crash site
| faster. ;)
| cush wrote:
| I was responding to "when's the last time your engine
| gave out"
| sokoloff wrote:
| The anecdotes above I read as difficulty getting an
| airplane engine started, which is definitely true
| compared to a modern car engine. Even using proper
| technique, mine can be frustrating to get and stay
| started after a fuel stop. (It's a vapor lock issue that
| arises from heat-soaking while stopped for fueling, not
| something that makes for a safety-of-flight issue.)
| code_duck wrote:
| The most frequent problems I've had with cars in the last
| 20 years have been engine cooling systems and battery
| charging.
| iancmceachern wrote:
| When was the last time an issue with the car engine
| caused you to fall out of the sky?
| throwaway0a5e wrote:
| >How many cars reach 1 million miles without major engine
| work?
|
| I can think of about a dozen engine platforms off the top
| of my head that would reliably get there or damn close if
| they got the same kind of maintenance/inspection schedule
| that a GA aircraft gets.
| eru wrote:
| > My engine might last for only 2000 flight hours between
| overhauls. In those 2000 flight hours, it's likely to burn
| ~30K gallons of fuel. Taking that as a proxy for the total
| energy generated, 30K gallons of fuel will take a typical
| car almost a million miles. How many cars reach 1 million
| miles without major engine work?
|
| I guess you could still take car engines, but overhaul them
| more often? Might still come out cheaper in the end?
| wil421 wrote:
| If you wanted to use an auto engine it would probably be
| a truck engine. Most car engines aren't designed to be
| run at lets say 5,000rpms for an hour or so at a time.
| It's the same reason inboard/outboard engines in boats
| use big and small block GM designed truck engines (Merc
| and Volvo).
| wolrah wrote:
| A truck engine is a great comparison point, because you
| can look at modern trucks for a perfect example of this.
|
| A Ford F-250 through F-450 pickup truck with the 6.7L
| "Power Stroke" diesel is rated for 475 HP and 1050 lb-ft
| of torque.
|
| The same engine in the same basic truck, but in
| commercial chassis-cab form, is rated for 330 HP and 825
| lb-ft of torque.
|
| Step up to the medium duty F-650/750 chassis with a much
| larger cooling system and that engine is now rated for
| 270 HP and 700 lb-ft of torque, with optional software
| upgrades available for 300/725 or 330/750 configurations.
|
| The same applies to their gas motor, the pickup trucks
| get the 7.3L "Godzilla" engine with 430 HP and 475 lb-ft
| where the chassis-cabs and medium duty trucks get a 335
| HP/468 lb-ft tune.
|
| The harder and more consistently the truck is expected to
| be worked the less power the engine is rated for.
|
| This isn't just a Ford thing either, GM and Ram also
| derate their commercial chassis compared to the pickups
| and the multiple power level thing on the medium duty
| diesels is common industry practice. Often the highest
| horsepower packages on larger diesels will be restricted
| to RV and/or emergency response applications where short
| bursts of power are more important than the ability to
| run hard for hours on end.
| sokoloff wrote:
| As a point of reference to airplane engines, my first
| airplane made 230 HP @2700 RPM from 470 cubic inches (7.7
| liters). My current airplane makes 325 HP @2700 RPM from
| 550 ci (9 liters).
| hnuser123456 wrote:
| How fast does it go?
| sokoloff wrote:
| First was a Skylane (fixed gear, fairly draggy) and would
| do 135-140 knots on 12-ish gallons per hour.
|
| Second is an A36TN (retractable gear, turbo-normalized)
| and will do 185-ish knots (215-ish mph) on 15-16 gph.
| eru wrote:
| Yes. I was being a bit lax when I said 'car engine'. I
| basically meant any land transport engine with a large
| production run.
|
| (Though looking at ship engines might also be
| interesting. I assume they are heavier and bulkier than
| car or truck engines, but they probably can also run at
| high load for a long time? I don't know anything about
| them..)
| wil421 wrote:
| You wouldn't want to run them wide open throttle for a
| long time but usually they give you a cruise RPM
| suggestion for optimal gas/speed. People make 20-30 miles
| runs offshore in smaller boats running them close to wide
| open for hours at a time.
|
| Yes I think they are heavier than their truck
| counterparts. Most are raw water cooled so they have
| intakes/risers and shoot water out the exhaust.
|
| The diesel ship engines are beasts, can take a beating,
| and run for 10x as many hours as a gas engine. It looks
| like they are too heavy for aircraft but there are some
| Diesel engine manufacturers listed on Wikipedia.
| cardiffspaceman wrote:
| Diesel engines on large ships typically work as diesel-
| electrics, the way railroad locomotives do. For example,
| Celebrity Solstice[1] uses diesel generators and azimuth
| thrust pods which contain electric motors. Celebrity
| Millennium[2] uses gas turbine generators and azimuth
| thrust pods. The electricity is also used for the rest of
| the electrical needs on the ship. The cruise industry is
| adopting LNG fuel, and hybrid power plants, gradually.
|
| [1] https://en.wikipedia.org/wiki/Celebrity_Solstice [2]
| https://en.wikipedia.org/wiki/Celebrity_Millennium
| scarier wrote:
| Ooooohhh, the air-cooled vs. water-cooled argument is a
| great one. The mechanical simplicity of air-cooled engines
| is a very strong point in their favor, but it's arguably
| the only one. Water-cooled engines can be run leaner (i.e.
| more efficiently) because they don't need to run rich to
| keep cool, don't have uneven cooling issues, aren't
| susceptible to thermal shock when going to idle during a
| cruise descent, have better power-to-weight ratios, and
| don't have as big of a problem dealing with the dilemma of
| having the slowest/warmest airflow when the most engine
| power is needed (during takeoff and go-around
| conditions)--all for the relatively modest risk of a pump,
| radiator, or hose failure. In an alternate reality where we
| had seen the same amount of R&D go into general aviation
| piston engines as automotive ones, I wouldn't be surprised
| if nearly all light aircraft used hybrid-electric liquid-
| cooled engines with reduction gearboxes.
| raverbashing wrote:
| I think people are trying to balance in a false dychotomy
| here
|
| You could have liquid cooling, but it could be different
| from a car liquid cooling. For example, maybe you don't
| need pumps and could rely on a sturdy passive convection
| system. (Also include some fail-safe aspects)
| upsidesinclude wrote:
| The concept doesn't need to be married to modern
| automobile design, agreed.
|
| Much like the transition motorcycle engine manufacturers
| made, moving away from air cooling in the late 70's. The
| first innovation being under piston oil jet cooling and
| then moving progressively to water cooling.
|
| Oil cooling offers little additional risk or complication
| over air cooled designs, but there are limitations on
| liner/piston temperatures and additional vapors which
| increase maintenance that don't exist with water cooling.
|
| It really comes down to whether it seems reasonable to
| trade on some risk for economy, but ultimately recip
| engine flight isn't efficient anyway
| manholio wrote:
| Unless you build a rocket or submarine, all engines are
| air cooled. Using an intermediate transfer medium with
| high heat capacity seems like a design tradeoff, it helps
| you achieve higher power density in the combustion
| chamber at the expense of total mass of the propulsion
| system and some extra complexity.
|
| Given the specifics of aircraft operation, large amounts
| of available coolant air, extra mass of cooling gear with
| available materials etc., I wouldn't be surprised if the
| result of that optimization problem is always against
| liquid cooling; at least for ICE engines where you can
| only achieve limited efficiency gains with higher
| temperatures and power densities.
| jmvoodoo wrote:
| Most (perhaps all) marine engines are water cooled, not
| just submarines.
| eru wrote:
| > [...] at least for ICE engines where you can only
| achieve limited efficiency gains with higher temperatures
| and power densities.
|
| More generally: all heat engines need high temperatures
| for efficiency. By Carnot's Theorem the best energy
| conversion efficiency you can hope for is (T_hot -
| T_cold) / T_hot
|
| Where T_hot is the temperature of your combustion, and
| T_cold is the lowest temperature you can cool it too, ie
| ambient temperature at best.
| HPsquared wrote:
| Engine temperature effect on efficiency is about heat
| loss, which isn't accounted for in the Carnot cycle (it
| assumes perfectly reversible cycle, and heat conduction
| across a temperature difference is not reversible: it's
| heat bleeding from one point to another and averaging
| out, kind of like mixing two substances).
|
| If the metal walls of your combustion chamber are cold,
| there will be more heat transferred and more entropy
| generated. Looking more physically, heat lost after
| combustion reduces the temperature and therefore pressure
| of the gas on the power stroke, reducing power output for
| a given heat input (i.e. less efficient).
| eru wrote:
| Yes. Carnot's Theorem gives merely an upper bound on the
| efficiency you can achieve.
|
| In practice, you can easily do much worse. Eg via
| heatloss as you say.
|
| However, you can never do better.
| manholio wrote:
| Sure, in principle, but in practice you are limited by
| the actual fuel you need to burn, and it seems the
| existing designs get close enough to those limits and do
| not stand to gain significantly from higher energy
| densities. Fuel efficiency and range is a primary target
| for optimization for decades, I doubt there are vast
| reserves of untapped efficiency just waiting for a hotter
| engine.
| jabl wrote:
| I don't know. If you look at the swan song of big
| aviation piston engines just before turbines took over
| (immediate post-WWII era), it was all air-cooled radials.
| If the WWII experience would have proved liquid cooled
| engines to be superior, I guess all those Convairs,
| Constellations, DC-6's etc. would be using Griffons,
| Sabres or such.
| samatman wrote:
| I worry about people who use a word like 'superior'
| without any dimensions.
|
| I can think of plenty of reasons the simpler design with
| one less failure mode might dominate production during
| the war, without being the obviously better choice given
| peacetime applications and seventy years of technical
| advances.
| jabl wrote:
| > I worry about people who use a word like 'superior'
| without any dimensions.
|
| Well, let me clarify that as "superior in whatever
| dimensions the designers of those post-WWII piston
| engined planes considered important". Hope that helps.
|
| > I can think of plenty of reasons the simpler design
| with one less failure mode might dominate production
| during the war, without being the obviously better choice
| given peacetime applications and seventy years of
| technical advances.
|
| To be clear, I was writing about the immediate post-WWII
| environment before jets made piston engines obsolete
| except for the lowest end of the market. Aviation piston
| engine development pretty much stopped then.
|
| Sure, a "modern" aviation piston engine for the GA market
| will quite likely be a water cooled design, if for no
| other reason that there is so little R&D money available
| for piston aviation engine development that most likely
| it's going to be based on a car engine.
| Gibbon1 wrote:
| I worry when there is a hidden assumption that people
| were dummies for the choices they made. That tends to be
| more true for policy than engineering.
|
| Distilled impression.
|
| Water cooled inline engines. Small frontal area means
| lower drag. Water cooled provides a forgiving flexible
| operating envelope. What you want in a fighter. Downside,
| more complicated. Upside better performance means kill
| enemy better.
|
| Air cooled radials. The drag penalty is less as the
| engine size increases. More reliable as long as you stay
| inside the design envelop. Scales up better than inline
| water cooled engines. Better suited for multi-engined
| bombers with a well defined mission profile.
|
| At the end of the war though it was obvious that
| turbojets were the future for fighters. Which is why
| water cooled engines went away. Radials though are more
| efficient at lower speeds than early turbojets which is
| why they persisted.
| jabl wrote:
| I don't think it's that simple. Inline engines have less
| frontal area, yes, but then you need a radiator which
| will add back quite a bit of drag. Further, as Kurt Tank
| demonstrated with the, at the time, revolutionary FW 190,
| it's possible to make a very low drag radial engine
| installation. These ideas were then used in the Tempest
| II and Sea Fury, which were among the fastest piston
| engined planes ever made.
|
| Further, I'd say in history there's a lot of path
| dependence here (in aviation engine development as well
| as elsewhere, obviously) as well rather than 'pure'
| arguments based on the best option for a from scratch
| design. As it wasn't clear at the time which engine type
| would 'win', major powers developed both lines in
| parallel, if for no other reason but to not be so much
| behind their competitors in case some development would
| cause one of the engine types to clearly pull ahead.
|
| WWII showed that both air cooled radial and water cooled
| inlines could be used for top of the line fighters for
| the entire conflict. After the war, it was clear that for
| speed jets were going to be the future and there wasn't
| the wartime pressure to keep any and all production lines
| going at maximum capacity, so aircraft designers had more
| leeway in choosing powerplants. Perhaps it was because US
| multi-engine aircraft designers were familiar with
| radials and it was clear to them they were plenty good
| enough, perhaps it was better reliability, but radials
| they chose (with some exceptions, obviously).
| p_l wrote:
| Funnily enough from RAS (Reliability, Availability,
| Serviceabilty) British liquid cooled engines beat
| American radial engines so hard it wasn't funny.
|
| Mostly it was due to end to end design of entire engine
| pod which made all operations better. Meanwhile USA had,
| well, a lot of radials and radial making manufacturing
| lines and people who had experience with radials but
| little idea about much more complex liquid cooled
| engines.
| jabl wrote:
| > Funnily enough from RAS (Reliability, Availability,
| Serviceabilty) British liquid cooled engines beat
| American radial engines so hard it wasn't funny.
|
| Presumably you mean the Merlin and not, say, the Sabre?
| :)
|
| But anyway, that's interesting, haven't heard of that
| before. Do you have some more information on this topic?
|
| From what I've read Americans were shocked to find out
| how 'hand built' the Merlins were, with pretty large
| differences between each engine, engines being delivered
| with metal filings in the crankcase requiring inspection
| and cleaning and whatnot. So a large part of the work
| Packard did for the license produced Merlin was
| tightening up the design so it could be mass produced
| much faster on production lines. Of course this doesn't
| prove the RAS point you made one way or the other, but it
| seems strange that if Americans put so much more emphasis
| on efficient production that they wouldn't have put
| similar effort into serviceability?
| p_l wrote:
| The issue with Merlins was that Rolls Royce was
| manufacturing them whenever and by whomever by the time
| war got into full swing, which easily explains the
| differences between individual engines.
|
| As for serviceability, the difference was in design -
| American engines were effectively "thrown over the wall"
| to airplane designers, resulting in such beautiful
| designs like B-17, where IIRC inspecting or changing a
| sparkplug started by removal of propeller because
| apparently even good idea fairy was out drinking when
| they designed it.
|
| In comparison Rolls Royce designed a standard "pod" for
| the engine that would be then minimally adapted by plane
| designer, with an eye towards servicing and commonality.
|
| So the tolerances might have been tighter on US
| production lines, but little thought was placed at least
| in some designs on how to support operations on the
| planes instead of just building them. (Something that
| arguably is present today with F-16 at least, and
| possibly F-35 too)
| jabl wrote:
| > So the tolerances might have been tighter on US
| production lines, but little thought was placed at least
| in some designs on how to support operations on the
| planes instead of just building them. (Something that
| arguably is present today with F-16 at least, and
| possibly F-35 too)
|
| Not too familiar with the maintenance requirements of the
| F-16, but admittedly having a hydrazine powered APU is a
| pretty WTF design choice.
| samatman wrote:
| Generally engineers don't make dumb decisions, there are
| exceptions, they make plenty of hard ones.
|
| The difference between the Thompson M1928 and the M1A1
| isn't that the M1A1 is superior, and yet they cranked the
| handle on the latter as hard as they could during the
| war.
|
| So "If something were better than something else, why did
| they make more something else during WWII?" doesn't
| persuade me. Nor does it eliminate other arguments which
| would make sense.
| VLM wrote:
| Classic scalability issue, those engines were HUGE
| compared to general aviation so all the rules about shock
| cooling and surface area to volume ratios don't apply
| unchanged to engines a thirtieth the size.
| jabl wrote:
| I'm not sure. Surface vs. volume is certainly and
| interesting thing that explains many scaling phenomena,
| but in this case, those huge radials had huge fins as
| well (correspondingly huger than fins on smaller engines
| in order to cool the much higher mass) to cool them under
| normal operations. So those same fins would equally
| rapidly cool the engine when descending quickly at idle
| power. So shock cooling is certainly an issue with big
| radials as well. Now I don't know the exact scaling
| relation, but I'd guess it's more similar to a smaller
| engine than a straightforward surface/volume scaling
| would imply.
|
| Or to put it another way, the surface area of the cooling
| fins is not proportional to the surface area of the
| cylinders without any fins, but to the power output of
| the engine.
| dTal wrote:
| A) the highest performance aircraft were all liquid
| cooled
|
| B) combat aircraft have to deal with bullet holes
| jabl wrote:
| > A) the highest performance aircraft were all liquid
| cooled
|
| Well, how do you define high performance? Judging by
| speed at least, Tempest Mk II, Sea Fury, Bearcat, and
| P-47M are among the fastest piston engined planes ever
| made.
|
| > B) combat aircraft have to deal with bullet holes
|
| Sure. But an engine that lacks a critical subsystem by
| design (say, a liquid cooling system with pumps, pipes,
| radiators etc.), all else being equal, is less failure
| prone than an engine that has it. Whether that failure
| happens due to shells or mechanical failure.
| consp wrote:
| That's survivor bias and sheer production numbers of us
| bombers, only the us models mainly used air cooled radial
| engines (bombers and carrier fighters), neither the
| german nor the UK ones did (mostly, exceptions always
| exist).
| jabl wrote:
| > That's survivor bias and sheer production numbers of us
| bombers
|
| To an extent yes, but the US certainly produced liquid
| cooled aircraft engines as well, like the Allison's and
| Packard Merlins powering many famous WWII aircraft. If
| they would have considered liquid cooled engines
| obviously superior, I'm sure they would have preferred
| those in post-WWII piston aircraft.
|
| > neither the german nor the UK ones did (mostly,
| exceptions always exist).
|
| The UK produced nearly 60000 Bristol Hercules radials,
| practically all used in multi engined aircraft
| (Beaufighter, Wellington, Stirling, Halifax being the
| major ones AFAIK). Sure, a much lower production numbers
| than the famous Merlin at 150000 engines, but far from
| insignificant.
|
| Similarly, Germany produced over 60000 BMW 801 radials,
| mostly used in the FW190A fighters but some were also
| used in some Ju88 variants. In comparison the DB 600
| engines powering mostly Bf 109 was about 60000 as well,
| and about 70000 Jumo 21X series used mostly in bombers.
|
| So very broadly speaking, of total aircraft engine
| production, both UK and Germany produced about 1/3
| radials and 2/3 liquid cooled.
| p_l wrote:
| Allisons and Packard Merlins happened IIRC due to RAF
| orders and were at least partially related to British
| Merlin engine.
|
| Briston Hercules was fitted to sever plane types due to
| lack of production capability for the more complex liquid
| cooled engines, this was specifically a case with
| Beaufighter which suffered badly for it.
| jabl wrote:
| The Packard Merlin was a license produced version of the
| Rolls-Royce Merlin, famous for powering the P-51. The
| Allison, OTOH, was AFAIK an entirely US design.
| [deleted]
| p_l wrote:
| Allison was produced for P-51, which was designed to
| specification done by RAF and designed around Merlin
| engine. The reasons for existence of Allison engine were
| iirc part political part practical (second sourcing, low
| spin up of license production as Packard team learnt
| Merlins, low amount of British Merlins available)
| jabl wrote:
| The Allison was much older than the P-51 airframe, it was
| used earlier e.g. for the P-39 and P-40. My memory of
| Mustang history is a bit hazy, but IIRC the Mustang was
| originally meant to use the Allison and later they
| switched to the Merlin to get better high altitude
| performance as the Allison lacked a two-stage
| supercharger. But maybe you're right that it was
| originally meant for the Merlin and the Allison was a
| stopgap until Merlin production ramped up in the states.
| p_l wrote:
| Ah, I forgot about P-39 and P-40. Pretty sure Merlin was
| present in the design from start, or at least
| consideredin contract if not manufactured from start with
| it (I somehow doubt the RAF would have accepted the high
| altitude performance of Allison engine)
| jimnotgym wrote:
| Indeed the liquid cooled Rolls Royce Griffon engined Avro
| Shackleton was in service until 1991 with the Royal Air
| Force
|
| https://en.m.wikipedia.org/wiki/Avro_Shackleton
| Gordonjcp wrote:
| > How many cars reach 1 million miles without major engine
| work?
|
| Every old Mercedes taxi.
|
| Every Skoda Octavia taxi.
| bluGill wrote:
| Problem is it is a niche too small to support the
| customization needed. There are plenty of engines that are
| better in one aspect and we know that all needed aspects can
| be combined into one, but the engineering cost to do that is
| so high that you couldn't charge a reasonable price for the
| engine and still break even on R&D.
| feb wrote:
| Impressive work by GAMI who are working on it since decades.
| AVWeb made 2 videos on the subject of leaded avgas and on how
| hard it is to get it approved. In addition, the FAA launched
| several failed attempts with the industry at large.
| * https://www.youtube.com/watch?v=9F-WngVMJBQ The Long, Twisted
| And Slightly Ridiculous Story of Avgas Part 1 *
| https://www.youtube.com/watch?v=Mvse4Xhzwuk The Long, Twisted
| And Slightly Ridiculous Story of Avgas Part 2
|
| When reading the announcement, it looks like some
| municipalities in California started banning the sale of leaded
| avgas and I suspect that helped to push the FAA to finally move
| in approving G1000UL. Not surprisingly, they will start
| providing it to the California market before the other states.
| In the announcement on avweb.com
| (https://www.avweb.com/ownership/fuel-news/gami-unleaded-
| avga...), they also credit Mark Baker from the AOAP to
| encourage the FAA to complete the project.
| davidwihl wrote:
| I took their in-person class in Ada, OK back in the day. Highly
| recommended the training material.
| https://www.advancedpilot.com/
|
| They have a great test bed for validating their science.
| IncRnd wrote:
| When I read your comment too quickly, I saw Ada training. [1]
| Of course, you meant what you wrote, Ada, OK! [2]
|
| [1] https://en.wikipedia.org/wiki/Ada_(programming_language)
|
| [2] https://adaok.com/
| sokoloff wrote:
| I took that same course (in Fall 2013 I think); it was
| excellent.
|
| Sadly, both John and Walter have passed away, leaving only
| George as the last amigo standing.
| londons_explore wrote:
| It's a shame that it took some districts fully banning leaded
| fuel to force this change through.
|
| The wheels of American bureaucracy don't move without some
| serious outside forces!
| lbriner wrote:
| I don't think the wheels of any bureaucracy turn quickly.
|
| There are two fallacies in bureaucracy:
|
| 1) With enough organisation, we can please all parties 2)
| Process can solve all of our problems
|
| My experience (and I suspect others) is an enormous budget of
| people paid to have meetings, not making much headway, if any,
| but not being held accountable for outcomes. Imagine a
| Department having paid a team of people for 30 years to make
| this happen!
| salawat wrote:
| > 2) Process can solve all of our problems
|
| I'm gonna have to stop you right there, if only because
| process gets a bad rap from people who have never tried to
| implement systems in which more than a handful of parallel
| agents can safely work without stomping on or interfering
| with one another.
|
| Process is critical to coordination. You cannot "thread-safe"
| without the right process primitives. While I'm using the
| computing term, I'm using them in a non-computing/abstract
| system way. Information doesn't magically communicate to the
| parties who need it. Process gives you the blueprint to
| quickly create an environment whereby people can do their
| thing, but information still propagates to those who need it.
|
| _If people follow it._
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