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)
XTS-210 25hp rotary engine; 1/5th size/weight of diesel piston engines
21–30 of 56 posts
Re: XTS-210 25hp rotary engine; 1/5th size/weight of diesel piston engines
#22This would be great for making a light sporting cyclecar around, a category of vehicle that's been sadly neglected this last 100 years.
Re: XTS-210 25hp rotary engine; 1/5th size/weight of diesel piston engines
#23This 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 considerin…
Nit: it's not a turboprop if it's no longer using a turbine.
Re: XTS-210 25hp rotary engine; 1/5th size/weight of diesel piston engines
#24This 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 considerin…
Nit: it's not a turboprop if it's no longer using a turbine.
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.
Re: XTS-210 25hp rotary engine; 1/5th size/weight of diesel piston engines
#25That would make cool small dual-sport/dirtbike, super-light and "put anything flammable in the tank".
Re: XTS-210 25hp rotary engine; 1/5th size/weight of diesel piston engines
#26Surprising that there's still that much efficiency to be squeezed out of internal combustion engines!
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Re: XTS-210 25hp rotary engine; 1/5th size/weight of diesel piston engines
#27Earlier quoted context omitted.
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 ot…
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.
The military does care about efficiency: higher efficiency means longer range, as we seem to be talking about aircraft / rotocraft applications.
Higher wear is what they care less about: at peacetime, parts can be replaced more often, and at wartime, many will be destroyed before spending up the spec-dictated operation hours.
Re: XTS-210 25hp rotary engine; 1/5th size/weight of diesel piston engines
#28Earlier quoted context omitted.
Just got one NOW, yes invest. They are still paying to promote their product. 630.7K views, https://twitter.com/LiquidPiston/status/1625932968865693718
"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.
It's not just another wankel engine tho, it's significant modification to the idea and comes with few interesting improvements (and some other drawbacks).
Basically, the intake and exhaust is delivered thru the rotor, not ports on the sides, and the seals (the achilles heel of the wankel engines are on the outside of it which in theory would make it possible to both replace them without taking apart whole engine, and oil them directly, without putting oil into fuel.
The bad part of it is that it would probably be pretty hard to make multi-rotor one
Re: XTS-210 25hp rotary engine; 1/5th size/weight of diesel piston engines
#29This would be great for making a light sporting cyclecar around, a category of vehicle that's been sadly neglected this last 100 years.
The problem of (very) light cars is that they can't be strong enough to pass crash tests. 100 years ago regulations around that barely if at all existed.
Re: XTS-210 25hp rotary engine; 1/5th size/weight of diesel piston engines
#30Haven'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.
Kinda, kinda not, they have been proven to be vulnerable to mishandling. They have few quirks and require a bit different handling than normal engine, which means that someone treating it as any other car. But at some point it will need to have engine out job and replace apex seals.
In motorsports it proven to be very reliable for example.
> IIRC even the more refined Renesis engine on the RX-8 seems to have been proven to be ornery.
Renesis was evolution in performance but IIRC had some quirks that weren't solved because the car stopped being produced. IIRC the modern apex seals with modern materials do a pretty good job. It also have oil metering pump which just...stole the engine oil and put it into fuel (which was required to oil the seals), which means if you were not on top of filling oil up, you could end up starving the engine. It wasn't a good idea either as 2 stroke oil was better for that use case, so many people removed the metering pump and just added some 2 stroke to the fuel tank every time they filled up