[HN Gopher] NASA Whoosh Rocket
___________________________________________________________________
NASA Whoosh Rocket
Author : speckx
Score : 149 points
Date : 2025-03-18 17:23 UTC (3 days ago)
(HTM) web link (www1.grc.nasa.gov)
(TXT) w3m dump (www1.grc.nasa.gov)
| AStonesThrow wrote:
| Two or three drops of fuel! That's a very counterintuitive
| contraption! I would really be reluctant as a teacher to bring a
| flame near something made entirely of plastic... and with no fins
| or guidance control on a ballistic trajectory? I mean it's an
| air-filled soda bottle, but still.
|
| I also seem to recall a type of toy vehicle that was propelled by
| some compressed gas as it slid, suspended along a horizontal
| wire/string, but I'm drawing a blank regarding the type of
| propellant right now. It seemed safe enough to use indoors,
| especially considering the constrained pathway.
|
| I loved water rockets as a kid and I also enjoyed actual model
| rocketry, except they seemed too hazardous for me to find a
| launch area where bystanders felt completely safe. Model rocketry
| is sometimes 90% modeling, and 10% launching them. Estes can make
| some really precious designs that fly horribly but look great in
| a Plexiglas cube on your shelf.
|
| I lost most of the ones I built due to poor launch conditions,
| and while I chose deserted school campuses during vacation or
| weekends, I didn't make any friends with security patrols there!
| kelseydh wrote:
| It looks like a pretty fun demo to do for students:
| https://youtu.be/xZ3hRrdj7Y0?t=445
| tbrownaw wrote:
| > _I also seem to recall a type of toy vehicle that was
| propelled by some compressed gas as it slid, suspended along a
| horizontal wire /string, but I'm drawing a blank regarding the
| type of propellant right now. It seemed safe enough to use
| indoors, especially considering the constrained pathway._
|
| I've heard of using ordinary rubber party balloons for this.
| userbinator wrote:
| _Two or three drops of fuel!_
|
| The stoichiometric AFR for isopropanol is 10.4:1 according to
| the sources I found. For 1g of fuel you need 10.4g of air which
| at SSL[1] corresponds to around 8.5L. One drop of fuel does
| consume several liters of air to burn. The volume difference is
| really that huge --- and the higher the AFR, the bigger the
| difference; gasoline engines are around 14.7:1, and diesels go
| much higher when idling or under light load.
|
| Relatedly, fuel economy expressed as an area:
| http://theskepticalzone.com/wp/weirdly-fuel-efficiency-can-b...
|
| [1] https://en.wikipedia.org/wiki/Standard_sea-level_conditions
| timewizard wrote:
| > WARNING - Extreme care must be exercised in flying a whoosh
| rocket and students must be supervised when using this type of
| rocket.
|
| Only surpassed by the time I tried to grab a falling soldering
| iron by the tip this is the source of the worst burn I've ever
| received. I cannot stress how vicious an ignited alcohol mixture
| in a container can be.
| maccam912 wrote:
| What went wrong?
| timewizard wrote:
| Something in my childhood I presume. In this specific case,
| you see how they depict the long necked "BBQ" style lighter?
| That's a /really/ good idea.
| kbenson wrote:
| > Something in my childhood I presume.
|
| LOL, I can empathize quite a bit, as someone that has a
| nasty burn scar on my hand caused by a glob of melted
| saltpeter and sugar from an accidental ignition of a
| concoction I was cooking one fourth of July in my youth.
| s1artibartfast wrote:
| A lot of good lessons to be learned from KNO3. An early
| lesson was not to melt it and incorporate fuel on a
| kitchen stove. Next lesson was how to build a outdoor
| brick stove. Then we learned a couple pounds would fill
| up several square blocks with dense smoke and burn a hole
| through blacktop.
|
| Not sure how we made it through our youth without
| learning what the inside of a jail cell looked like, but
| I suppose things were different before 9/11.
| kbenson wrote:
| > An early lesson was not to melt it and incorporate fuel
| on a kitchen stove.
|
| That was, indeed, an aspect of the problem I alluded to
| before. I have made it a few times before, and I was
| going to use the gas grill outside, but it seemed to be
| acting up, and I didn't trust it, so I thought it would
| be "safer" to move inside.
|
| Combine that with me iterating on a few different batches
| with "improvements", such as lining the bottom of the pan
| with tinfoil so I could lift it out, and then next making
| an extra large batch... well multiple lessons were
| learned that day, including how to deal with insurance
| companies from some shrewd negotiating from my parents,
| given most the entire kitchen needed to be replaces and
| the entire house needed to be scrubbed floor to ceiling.
|
| > Not sure how we made it through our youth without
| learning what the inside of a jail cell looked like, but
| I suppose things were different before 9/11.
|
| Ha, probably true, especially since my recipe came from a
| copy of the anarchist cookbook my older brother happened
| to have (and I wouldn't be surprised if you happened upon
| it the same way). It's got a lot of dangerous stuff in
| it, but honestly, as a tool for sparking curiosity it
| works pretty well.
| dhosek wrote:
| I grew up with a (stolen, of course) copy of _Steal this
| Book_ in the house.
| dhosek wrote:
| As a grade school kid, I was taken to the police station
| for making a bomb with a couple friends. Fortunately for
| us, no charges were pressed (presumably because we didn't
| manage to ignite the bomb and it was the 70s).
| hermitcrab wrote:
| I met someone on holiday whose brother has been blinded
| for life by a pipe bomb he and a friend made. So the
| risks of messing around with that sort of thing are very
| real. Better to couple youthful enthusiasm with some
| adult oversight. It can still be a lot of fun (see my
| comments on youth rocketry competitions elsewhere in this
| discussion).
| dmd wrote:
| Is this you? https://i0.wp.com/makezine.com/wp-
| content/uploads/2016/03/Sc...
| qoez wrote:
| HN is turning into reddit/twitter
| latchkey wrote:
| https://news.ycombinator.com/newsguidelines.html
|
| Please don't post comments saying that HN is turning into
| Reddit. It's a semi-noob illusion, as old as the hills.
| qoez wrote:
| I'm aware of this rule but I think it's clearly not true
| that quality hasn't degraded over time. Look at any pg
| thread from 2014
| https://news.ycombinator.com/item?id=21233848 Anyway I
| get that commenting this isn't the best use of space but
| I still think it's true (I also suspect not being allowed
| to call this out is not helping the quality).
| HeatrayEnjoyer wrote:
| Thank god.
| nickmcc wrote:
| For the latest in multi-stage high pressure, high altitude water
| powered rockets, this group is paving the way:
| https://youtu.be/xm-tGJxepUw?si=uGA--H1kPgBCVREd
| hermitcrab wrote:
| That is pretty impressive. Large empty spaces like that are a
| bit hard to come by in the UK.
| thih9 wrote:
| Video demonstration (Whoosh Bottle Rocket by RamZland):
| https://youtube.com/watch?v=Lq_6-0Ra4Hk&t=55s
| michaelmior wrote:
| My high school chemistry teacher did this a few times with a
| water cooler bottle. In fact, the morning of our graduation, we
| were having breakfast at the school when he walked on stage
| holding a water cooler bottle and a lighter. I think he must
| have used too much alcohol that time because it blew out the
| bottom of the bottle and the rest of it shot several feet in
| the air.
| Retr0id wrote:
| "too much alcohol" tends to make it _less_ explosive because
| the oxygen ratio becomes suboptimal.
| hermitcrab wrote:
| I'm not sure it is a good idea to do that indoors.
| blacksmith_tb wrote:
| Possibly not, though that larger polycarbonate water bottle
| is quite heavy, compared to the 2 liter PET soda bottles NASA
| is suggesting for outdoor firing, and it looks like the
| "nozzle" is the uncapped mouth, which would also help to keep
| it from hitting the ceiling.
| hermitcrab wrote:
| I would be more worried about setting fire to the building.
| Just seems like a totally unnecessary risk. But I have been
| called a 'safety Nazi'.
| nealabq wrote:
| Could you do this with dry corn starch? Shake it up in the bottle
| and light it before the dust settles.
| huhtenberg wrote:
| I wonder if adding a static charge to the dust would help it to
| stay airborne longer.
| hermitcrab wrote:
| I'm not sure that corn starch would stay as a fine powder long
| enough for that to work.
|
| However, if you have a long cardboard tube:
|
| * place the tube vertically with an ignition source at the
| bottom (small candle perhaps)
|
| * pour fine powder in the top (may need a step ladder if the
| tube is tall enough)
|
| * satisfying _whoosh_
|
| Don't look down the tube as you are doing it and don't do it
| indoors, obvs!
| pbhjpbhj wrote:
| A common science demo in UK used to be exploding a cloud of
| custard powder - ostensibly powdered sugar and cornstarch.
|
| https://youtu.be/aGBT5pwxThU?si=ay9fm_ZaYImIeNK8 is similar to
| how it was done.
| rkagerer wrote:
| Could a 3D printed nozzle of some sort improve its
| characteristics?
| hermitcrab wrote:
| Almost certainly. But it might need to be printed out of
| something with moderate heat resistance.
| Eduard wrote:
| > soda bottle
|
| The article never states that the bottle should be made of
| plastic. Or glass.
| fuzzylightbulb wrote:
| Please go find us a 2 liter soda bottle being sold in the
| United States in 2025 that is made of glass.
| nancyminusone wrote:
| I don't think a glass bottle would break at this scale, but it
| would be too heavy to fly
| k7sune wrote:
| Humm the next logical step would be to pressurize the rocket
| before igniting it. Or maybe to add some water in the bottle to
| increase the propelled mass. They just need a way to ignite the
| alcohol fume from the top......
| neuroelectron wrote:
| I would think the next logical step would be pressurizing a
| stainless steel thermos with liquid methane and mating it to a
| 3d printed copper prototype manifold and turbine pump.
| DeathArrow wrote:
| Can't we just have reusable space ships with engines that burn
| some kind of fuel and we just replenish that fuel?
|
| It seems a waste to use rockets and replace the whole rocket or
| most parts of it after each flight.
| actionfromafar wrote:
| This is exactly what the article describes. Only the fuel and
| oxidant need replacing.
| DeathArrow wrote:
| Yes, I know. I am only asking why we don't do it and why we
| didn't do it until now.
| actionfromafar wrote:
| I think the reason can be the industry incumbents - there
| just isn't much money to be made with such a simple design,
| only a nozzle and combined fuel and oxidant tank in PET
| plastic which can be recycled, no moving parts.
| gus_massa wrote:
| It's a toy that can go up 50 feet or less. You can't scale
| it too much. To get to space you need like 100km (x6000)
| and then a lot of speed sideways to get to orbit.
|
| This model works with a drop of fuel that evaporates and
| mix with the air. In a real rocket you most inject the fuel
| and oxygen from the tanks into the very hot and high
| pressure burning chamber, so you need pumps.
| Sharlin wrote:
| Heard about the Space Shuttle? Or the SpaceX Falcon 9?
|
| The reason it hasn't been done in scale before SpaceX is that
| reusability is a _hard_ problem to solve and it is /was more
| economical to use expendable launch vehicles than to develop
| recoverable and refurbishable stages.
|
| You might also like to read about single-stage-to-orbit (SSTO)
| which is something of a pipe dream. The rocket equation is a
| bitch.
|
| https://en.wikipedia.org/wiki/Single-stage-to-orbit
| philjohn wrote:
| The shuttle was a re-usable ship, the rockets used to get it
| into space were not reusable.
| skissane wrote:
| That's not true... both the RS-25 SSMEs and the SRBs were
| reused - however, the extent of refurbishment required
| between flights was so extensive, time-consuming and
| expensive, that it erased much of the benefits of
| reusability
| Sharlin wrote:
| Not so. The solid rocket boosters were reused, as were the
| three SSMEs bolted to the orbiter itself. The only part
| that wasn't reusable was the external fuel tank because
| bringing it back intact from almost orbital speeds would've
| been hilariously uneconomical.
|
| That said, refurbishing both the SRBs and the SSMEs after
| each use was labor-intensive and as such expensive.
| usrusr wrote:
| The SRBs were collected from the sea for reused and the
| upper stage was reused after landing horizontally. The only
| thing not reused was the upper stage drop tank. That single
| use drop tank was rather big, true, but not a rocket, not a
| rocket at all.
|
| The Soviet lookalike did use a single use rocket as its
| second stage, with the reusable part just being an orbiter.
| Sharlin wrote:
| Interestingly, the Buran's Energyia launch vehicle could
| possibly have been made reusable exactly because the tank
| and the engines were one unit. At the expense of payload
| capacity, of course. And anyway the Soviets were confused
| about the whole shuttle concept because it didn't seem to
| make economical sense, reusable booster or not - but they
| assumed the Americans knew something they didn't.
| usrusr wrote:
| How would Energyia become reusable? Tail landing? Is
| there more to this, something specific that would make
| Energyia a candidate for tail landing other than just "if
| F9 can do it, in theory every liquid fueled rocket could
| do it"?
| vpribish wrote:
| all the concepts i've seen were horizontal landing mostly
| with fold-out wings
| usrusr wrote:
| Wow, that's ... ambitious. I'd imagine the extra mass to
| make an energyia-size tank+engines able to land
| horizontally to be enormous. It's not just wings (plus
| folding mechanism, if you believe that's worth saving a
| bit of drag on the way up) but also landing gear plus all
| the structural strengthening required.
|
| Sounds suspiciously like one of those projects you
| propose when you want something finer short term but
| assume that they never survive to the point where they
| actually need to deliver?
| Sharlin wrote:
| Ah, no, I was mostly just idly speculating that at least
| it could've been possible in principle, but there in fact
| were _some_ (possibly unrealistic) plans to make it fully
| reusable, see https://en.wikipedia.org/wiki/Energia_(rock
| et)#Energia-2_(GK...
| inglor_cz wrote:
| "Refurbishable" would be a better term than "reusable".
|
| Refurbishment of the shuttle orbiter took months and tens
| of thousands of work hours before it could fly again. It
| was pretty far from what ordinary people understand under
| "reuse", though not completely outside the meaning of the
| word.
| numpad0 wrote:
| Earth's gravity is too strong and human energy exploitation
| isn't large enough to allow for such reusable rockets. The
| rockets we humans fly look massive and shame to discard, but
| they're more like liquid fueled balloons than proper spaceships
| for their scales.
|
| e.g., the Al-Li metal layer of Shuttle ET was 0.1" thick at
| thinnest points yet those ET were 150ft+ tall. iPhone back
| covers are thicker than that. Rocketry gears are infuriatingly
| flimsy relative to their size, but they have to be because
| that's what it _currently_ takes to fly to space.
|
| If we could build ships on the Moon from Lunar rocks out of a
| grinder, or if we could build an all-fusion spaceships, we can
| (relatively)easily have 2m thick radiation shielding, or 8km
| wide hulls, or anything we want.
|
| But we're not doing it, but are stuck with lox-fuel chemical
| propulsion, so we can only make them so durable.
| marsovo wrote:
| More context on the external tank: https://archive.is/2017.03
| .30-030831/https://www.nasa.gov/mi...
|
| > The common soda can, a marvel of mass production, is 94%
| soda and 6% can by mass. Compare that to the external tank
| for the Space Shuttle at 96% propellant and thus, 4%
| structure. The external tank, big enough inside to hold a
| barn dance, contains cryogenic fluids at 20 degrees above
| absolute zero (0 Kelvin), pressurized to 60 pounds per square
| inch, (for a tank this size, such pressure represents a huge
| amount of stored energy) and can withstand 3gs while pumping
| out propellant at 1.5 metric tons per second. The level of
| engineering knowledge behind such a device in our time is
| every bit as amazing and cutting-edge as the construction of
| the pyramids was for their time.
| MarkusWandel wrote:
| The (early) Atlas ICBM was even less substantial than a
| soda can. There used to be one parked on the front lawn of
| our local science museum. It had to be kept inflated with
| pressurized air. When the time came to retire it and they
| let the air out...
|
| https://ottawacitizen.com/news/local-news/museum-shrugs-
| as-a...
|
| In service, of course, the necessary pressure would have
| been maintained by propellant boil-off.
| chipsa wrote:
| In service, it was pressured with nitrogen, just like it
| was while not in service. RP-1 is not an especially
| volatile fuel.
| bityard wrote:
| I don't think NASA is having any problem finding room in their
| budget for soda bottles.
| snickerbockers wrote:
| not sure what this has to do with the middle-school science-
| fair project in the OP, but the whole "reusable shuttles" idea
| hasn't really panned out that well. The Russian Soyuuz rockets
| haven't changed much since the 70s and they have an excellent
| safety record compared to the space shuttles.
| trhway wrote:
| >Flying model rockets is a relatively safe and inexpensive way
| for students to learn ...
|
| according to the current laws - it isn't, and may be even more
| dangerous than walking to the school on your own.
| Liftyee wrote:
| Reading this in the UK, I'm not sure if "walking to school on
| your own" is supposed to be a safe or unsafe reference point.
|
| I thought that children walking to school is unthinkable in the
| US because everything is designed for cars and public transit
| is inadequate/nonexistent. Made worse by endless suburbia
| stretching for miles. Someone please prove me wrong...
| boutell wrote:
| I could say a lot, but I'll just point out that most American
| school districts provide school bus transportation.
| Nextgrid wrote:
| > children walking to school is unthinkable in the US because
| everything is designed for cars and public transit is
| inadequate/nonexistent
|
| The hysteria around it is even worse than any of the actual
| dangers.
| jebarker wrote:
| I live in the US and my daughter has/will have less than 1
| mile to walk to every school she'll ever go to before
| college. Just an existence proof though!
| dhosek wrote:
| And if she goes to a small residential school, she can keep
| that up at college. I attended the Claremont colleges where
| all six campuses (there's a seventh now) of the schools lay
| within a one square mile area and if you were silly and
| only attended classes at your own school, your longest
| distance between dorm and classroom might be half a mile or
| so.
|
| Even a sprawling area like Tucson has a public elementary
| school in each square mile of residential neighborhood. I
| live in an inner-ring suburb of Chicago (Oak Park) which
| has 8 elementary schools (plus two middle schools) serving
| an area of 4.5 square miles. The middle schools require the
| longest travel distance of about 2.5 miles (taxicab
| metric). The high school serves a broader region, but
| that's fairly typical in the Chicago area but the furthest
| students travel is about 4 miles (which is a bit less than
| the commute distance for the most distant students at the
| high school I attended as a kid one suburb to the south).
| My own grade school walk was less than half a mile. High
| school was three miles away for me, and I would get a ride
| or take the bus in the morning, but often walked home when
| there was less of a time pressure (sometimes I would walk
| with friends who lived in the opposite direction from me
| after school and then back to my own home which made my
| walk home five miles).
| SamBam wrote:
| Depends very much where you are. In a medium city many/most
| middle schoolers are walking to school.
| ggm wrote:
| Nearly took out a <5yo kids eye with a bottle rocket showing off.
| Not my kid either. (he was safely out of distance a bit wiser)
| Haunts me still.
|
| Rockets are fun. With one remaining eye explain to mummy and
| daddy how this happened again.
| hermitcrab wrote:
| Water bottle rockets have a surprising amount of energy. I
| managed to hit myself in the chest with one, after only a
| couple of pumps, and it fair knocked the wind out of me.
|
| We also did some messing around with coke/butane rockets. These
| could easily knock teeth out and I made my son wear his full
| face cycling helmet before handling them.
|
| Model rockets with solid fuel motors obviously require an even
| greater level of respect.
| Loughla wrote:
| Solid fuel at least is more controlled. You can ignite them
| from a very safe distance.
|
| I've never been hurt by an actual rocket motor, but I thought
| I lost a finger with the woosh rocket that exploded. . .
| Luckily just a cut and some burns and not on my face.
| hermitcrab wrote:
| Solid fuel motors are quite hard to ignite. So they are
| pretty safe from that point of view. But:
|
| Once the motor is ignited, nothing will put it out. Not
| even immersion in water.
|
| The motors are not made to NASA standard and don't always
| do the expected thing.
|
| Model rockets with solid fuel motors can go 1000s of feet.
| If they come down in one piece without a parachute (which
| does happen). You don't want to be under it.
|
| They can set fire to dry ground. I've seen it happen.
|
| None of the above are an issue if you are being sensible,
| following guidelines and paying attention.
| TeMPOraL wrote:
| Also: solid fuel motors may be quite hard to ignite for
| launch, but solid fuel _itself_ is damn easy to ignite
| _when you 're making it yourself_. Take care, keep
| containers pointing away from your face at all times, and
| generally _FIRE HAZARD_.
|
| Also: a bad fuel mixture will clog your nozzle with
| "solid combustion residue", as we called it with my
| friend, leading to the infamous rapid unplanned
| disassembly (the motor will promptly explode), so if you
| value your life and not being in prison, _never ever use
| metal containers_ for it. Thin PVC pipe dangerous enough
| in case of RUD, but is much less likely to kill you.
|
| (Obviously, I too somehow survived childhood unharmed...)
| hermitcrab wrote:
| Bear in mind that making solid fuel motors without a
| licence is also illegal in some countries (such as the
| UK).
| finghin wrote:
| I have never been to the US, but I wonder if this is equally safe
| in the EU where plastics regulations appear to have changed the
| density and feel of drinks containers over the past half-decade
| or more. They're obviously fine for carbonated drinks, and
| probably bottle-rocket use too, but I wonder about their
| structural integrity as a receptacle for alcohol combustion.
| 4gotunameagain wrote:
| Only one way to find out !
| vvchvb wrote:
| I think so:
|
| 1. It's only a drop out two of alcohol
|
| 2. Carbonated drinks are at a very high pressure already.
|
| I could, if I wasn't feeling lazy right now, do the math to
| compare the two pressures. Its easy stuff - two drops of
| alcohol combusted + assumption all the combustion products are
| ideal gases vs Henry's law for CO2. This last one will require
| looking up how much co2 is dissolved in the product, but thats
| not too hard.
|
| But, like the other commentator pointed out.... there's only
| one way to find out.
| hermitcrab wrote:
| Soda bottles are surprisingly strong. Even if one fails, I
| think it would probably split, rather than creating dangerous
| shrapnel (citation needed).
| PaulHoule wrote:
| The patent for the PET soda bottle was granted to one of the
| Wyeth brothers!
|
| https://patents.google.com/patent/US3733309A/en
|
| The patent says they are good to 100 psi for regular
| operation and people pump them up to 2x that when they shoot
| them up as rockets.
|
| It's fun to make a "chemical pressure bomb" out of that kind
| of bottle, the classiest way to do that is to use liquid
| nitrogen, the second classiest way is to put in a pellet of
| dry ice, if you have no class at all you put in some aluminum
| foil and either a strong acid ("The Works" drain cleaner) or
| a strong base (Lye/Sodium Hydroxide) which in either case
| will evolve hydrogen. [1]
|
| The dry ice version goes off in 30-45 minutes if you put in
| just the pellet, if you add some hot water it works like a
| hand grenade and will explode less than a minute, cold water
| is intermediate. These are dangerous at point blank range
|
| https://www.youtube.com/watch?v=ZygYNfAKjNs
|
| but in my experience harmless 10 feet away. [2] [3] When I
| was in college my friends and I made a bunch of them and
| threw them into a vacant lot at night and thought 30 minutes
| later that we'd failed, but soon we heard a series of loud
| explosions which caused the neighbors to call the police. The
| cops drove by and shined a spotlight into the area and we
| were worried that the last one would go off when he was there
| but it exploded just after he drove off.
|
| See also https://en.wikipedia.org/wiki/Boiling_liquid_expandi
| ng_vapor...
|
| [1] ... and spray dangerous chemicals. Don't do it.
|
| [2] had one blow the bottom out of a small plastic waste
| basket though and read a report which I couldn't find this
| time about a high school chemistry teacher who tried this in
| class and it blew up in a student's hand, blinding him
|
| [3] usually the bottle is torn up such that most of the
| plastic is in one big piece with jagged edges, today people
| would worry about microplastic generation
| bityard wrote:
| TFA warned against using bottles other than soda because soda
| bottles are made to withstand a lot of pressure. Others may or
| may not.
|
| I don't imagine ANY plastic bottle survives too many lift-offs.
| PaulHoule wrote:
| See https://waterockets.com/ for commercial kits for making
| really fancy pressurized water rockets, even 3-stage rockets!
| You can get many many uses out of a bottle.
|
| In Larry Niven's _Known Space_ books, rockets are launched
| from earth using some kind of super-compressed material
| encased in tanks made of some unobtanium, a vastly improved
| version of those water rockets.
| hermitcrab wrote:
| Model rocketry is a gateway drug for STEM. I bought my son an
| Estes model rocket kit when he was about 11. Now he is studying
| aerospace and astronautic engineering at university.
|
| There are some fantastic model rocketry competitions for
| youngsters. There is one running in the UK right now (Google
| 'UKROC') and equivalent ones in the USA, France and Japan. Plenty
| of guidance is available and it isn't dangerous if you are
| sensible. We entered a team into UKROC 2 years running and had an
| amazing time.
| bayouborne wrote:
| I'm 66, and when I myself was 10 or 11 my friends on my street
| and I were completely obsessed with the Estes rocket and Cox
| .049 U-control scenes. Most of us were lucky enough to have
| engaged fathers and once the standard craft were assembled and
| flown, we all browbeat them mercilessly for more information
| for mods, shortcuts, hacks etc. My dad grew very wary of the
| 'Why can't we' type questions. I had modified a C-type engine
| Big Bertha rocket with an extra long transparent payload module
| which set the stage for various kidnappings of lizards, frogs,
| praying-mantises, eggs, multiple 1 and a quarter inch sockets,
| etc (all returned to earth unharmed, if not un-rattled). The
| nichrome wire igniters were troublesome for most of the kids.
| Bulky and expensive (for 4th graders) lantern batteries were
| hard to come by. We found we could steal D-cells from
| flashlights, hack cardboard tubes from paper towel rolls,
| reinforce with electrical tape, and make passable energy
| sources from that, etc. But all of that required questions from
| the closest available parent about voltage and series/parallel
| connections, as well as other questions about CG when modding
| the rockets themselves, etc. I think your STEM comment is very
| much on-point. None of my friends thought we were learning
| anything at the time. We were mostly just jazzed about doing
| fun stuff that had the potential for tearing itself apart in
| mid-air. I know the advent digital everything makes modeling
| systems for kids [Kerbal,etc] probably pretty trivial now, but
| actually crashing things in spectacular fashion IRL had/has
| it's own visceral rewards.
| hermitcrab wrote:
| My son enjoyed Kerbal Space program. But, fun[1] and
| educational as that is, it couldn't match the thrill of
| launching a real home-made rocket to ~1000 feet.
|
| [1]Not for some of the developers, apparently.
| https://mcvuk.com/development-news/squad-devs-blast-
| kerbal-s...
| desertmonad wrote:
| Mentos and cocacola or maybe vinegar & baking soda variant could
| be safer. I'm sure kids would have fun with this. Loved launching
| bugs(unharmed) in my nova payloader as a kid :-)
| krunck wrote:
| When I was a kid I used to do this with propane. I'd fill it with
| a propane torch - which is set t mix the C3H8 and O2 to the right
| proportion - and light it. I would not use a restrictor/nozzle
| cap because it had plenty of thrust without it.
|
| I survived my childhood unscarred, somehow.
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