[HN Gopher] XTS-210 25hp rotary engine; 1/5th size/weight of die...
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XTS-210 25hp rotary engine; 1/5th size/weight of diesel piston
engines
Author : mpweiher
Score : 24 points
Date : 2023-04-29 19:59 UTC (3 hours ago)
(HTM) web link (www.greencarcongress.com)
(TXT) w3m dump (www.greencarcongress.com)
| [deleted]
| toss1 wrote:
| This is more hype than performance.
|
| When I worked on a hybrid-power multirotor drone about eight
| years ago, I was checking out Wankel engines for their power-
| weight ratio, and also came across this Liquid Piston crew. They
| were supposedly ready to ship Real Soon Now. But worse, their
| power-weight just didn't compare to Wankel options available
| then.
|
| Liquid Piston still do not compare on their headline power-weight
| ratios. They make a lot of claims about 25 HP (18.6kW) and light
| weight, but don't actually mention the weight, which is down in
| their spec sheet - 21.2kg dry [0], which is about 0.877kW/kg.
|
| By comparison, just a quick search of small Wankels turns up
| these:
|
| -- AIE model 225CS outputting 40 bhp / 30kW weighing 10kg = 3.0
| kW/kg[1]
|
| -- AIE model 80S outputting 15 bhp / 11.2kW weighing 5kg = 2.24
| kW/kg [2]
|
| -- Sorrel Hiperlight Wankel outputting 75 hp / 56 kW weighing
| 52kg (fully wet with all electric start, reduction drive, and
| exhaust system, etc. = 1.07 kW/kg [3]
|
| -- Crighton CR700W motorcycle engine puts out 220 hp / 164 kW
| weighing 43kg = 3.8 kW/kg. [4]
|
| -- Small Nitto NR20-EP puts out 2.24kW / ~3hp weighing 1.466 kg =
| 1.53 kW/kg. [5]
|
| In short, this is a lot of marketing hype for low pefrofrmance,
| and they've been working on it since 2003 according to their
| website.
|
| The sole advantage this engine might have is running on a broader
| range of fuels including JP-8, but I've seen Wankels setup for a
| wide fuel range also. If I had a funded task to develop a high
| power-weight engine, I'd start with the Wankel design, not this
| one. It is already WAAAY ahead, and there's still a lot of
| performance left on the table.
|
| [0] https://uploads-
| ssl.webflow.com/5f6086e9bbbabd41a20f2984/642...
|
| [1] https://www.aieuk.com/225cs-40bhp-wankel-rotary-engine/
|
| [2] https://www.aieuk.com/80s-15bhp-wankel-rotary-engine/
|
| [3] http://www.ultralightnews.com/sunfun99/hiperlight.html
|
| [4] https://newatlas.com/motorcycles/dual-rotary-crighton-
| cr700w...
|
| [5] https://barnardmicrosystems.com/UAV/engines/wankel.html
| decafninja wrote:
| Haven't rotary (Wankel?) engines proven to be unreliable?
|
| I love the RX-7 (my dream is to own a FD one day), but IIRC even
| the more refined Renesis engine on the RX-8 seems to have been
| proven to be ornery.
|
| I think Mazda has a rotary acting as a range extender in their
| MX-30 EV. I wonder how that will fare.
| joecool1029 wrote:
| I wish they had video of the two-stroke design in operation.
| There's a bunch of their 4-stroke engines being demonstrated by
| this youtube channel: https://www.youtube.com/watch?v=TDFAjCOM3iQ
| This one is interesting as it shows difference between their
| 4-stroke design and a standard wankel rotary in operation,
| wondering if the two-stoke variation looks like a combination
| between the two?
| prottog wrote:
| Surprising that there's still that much efficiency to be squeezed
| out of internal combustion engines!
| Animats wrote:
| Yes. Makes you wonder how real this is. And how long it lasts.
|
| The military might want it for drones. Even if it's only good
| for an hour, that's a good survival time in modern combat.
| smcleod wrote:
| I think it probably is real, Mazda has a new single rotor
| engine they've got in the new MX30 hybrid, it's used to
| extend the range https://www.drive.com.au/news/2023-mazda-
| mx-30-r-ev-revealed...
| wongarsu wrote:
| They mention "the XTS-210 engine addresses the fuel
| efficiency, lubrication, and fuel type limitations of the
| traditional Wankel rotary engine", but while they quote great
| fuel compatibility, don't waste more words on efficiency and
| lubrication. So just based on the marketing fluff I expect
| those two points to still be worse than traditional diesel
| engines, just good enough for military applications. And
| given the other advantages the military might be completely
| ok with a fuel-guzzling hard-to-maintain engine for certain
| applications, wouldn't be the first time
| inferiorhuman wrote:
| Dollars to donuts the rotary will be easier to manufacture
| and maintain than the diesel. It's got fewer parts and the
| parts themselves are way simpler. Lubrication's easy if you
| don't care about efficiency or emissions, which the
| military doesn't.
| Phlarp wrote:
| Adding in the 2 stroke design and wide ranging fuel
| compatibility to the above military centric specs, I have
| to imagine the emissions profile is truly stunning.
| IronWolve wrote:
| My twitter ads have been flooded by this company liquid piston,
| it looks cool, but if the use case is to replace small engines
| also, I need to see a drop in crate replacement for a honda or
| cheap chinese motor for a generator/atv/scooter.
|
| I love tote-goats, they use the old 5hp engines, if I could get a
| diesel version that I could use (for farm use and cheap diesel),
| count me in if it works.
| Zak wrote:
| Do the ads want you to buy engines, or invest in the company?
| Last time[0] I saw this on HN, it appeared very targeted toward
| military UAV applications rather than anything most consumers
| would have a use for.
|
| [0] https://news.ycombinator.com/item?id=35455286
| IronWolve wrote:
| Just got one NOW, yes invest. They are still paying to
| promote their product.
|
| 630.7K views,
| https://twitter.com/LiquidPiston/status/1625932968865693718
| Zak wrote:
| "The first major innovation to the internal combustion
| engine in over 100 years" claimed there suggests they're
| not familiar with the Wankel rotary engine upon which their
| design is based; the modern eccentric shaft version first
| ran in 1958.
| huijzer wrote:
| So the big question is: what's the fuel efficiency of this thing?
| atlex2 wrote:
| For things that fly, what I've seen be more significant is the
| weight savings (as long as you're not running too rich).
| throw2awaymay wrote:
| [dead]
| metadat wrote:
| Also discussed 24 days ago:
|
| _" Inside-out Wankel" rotary engine delivers 5X the power of a
| diesel_
|
| https://news.ycombinator.com/item?id=35455286 (203 comments)
| thomasjb wrote:
| This would be great for making a light sporting cyclecar around,
| a category of vehicle that's been sadly neglected this last 100
| years.
| ChuckMcM wrote:
| This is a pretty cool engine. 25hp is about 18.75 kW so a really
| good fit for a 15kW generator (sometimes marketed as "whole
| house" generators) its high RPM (typical of rotary engines) makes
| it a good match foundation for a turboprop engine. A pair of
| these driving ducted fan turboprop engines would give you an
| excellent long duration drone platform with good payload
| capacity.
|
| My guess is the Army might be considering them as APUs (Auxiliary
| power units) on armored vehicles as this would give them long
| duration "sitting" capability without running the main power
| plant (but using the same fuel). Similarly bus style RVs could
| use them to run their in-vehicle electric gear (not a lot of bus
| RVs are designed for the "dry camping" or boon docking market but
| it would definitely work well for that.
|
| The next thing they have to figure out I'm guessing is how to
| make them inexpensively (the Army won't care so much but I don't
| think the company would survive on just Army contracts).
| inamberclad wrote:
| Nit: it's not a turboprop if it's no longer using a turbine.
| magila wrote:
| It's also not a turboprop if it's using a ducted fan. Chuck
| keeps using that word, I do not think it means what he thinks
| it means.
| skykooler wrote:
| This would definitely be interesting in an RV, it's way more
| compact than engines in similarly powerful generators in a
| vehicle where space is at a premium - and the ability to run
| off the same diesel fuel as the main engine is a huge plus.
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(page generated 2023-04-29 23:01 UTC)