RotoRocket

iTrader: (1)

I'm not trying to to change the subject, but the future of the Renesis in light aircraft looks very promising from some of the things I've been reading lately.

If one can pinpoint the reasons why this is the case, I think you will highlight all the unique attributes where a Rotary has certain advantages over a piston motor, even if we're discussing a different application.

From what I can gather, it boils down to fewer moving parts, less weight, more compact size, and a biggie in the avaiation world: reciprocating losses (or lack thereof).

Paul_in_DC

I'd bet that power-to-weight ratio has a lot to do with it.

daisuke

ppl have been saying that for a long time, the power-to weight ratio is good, but you need a gearbox to reduce the RPMs for the prop to run at the right speed which cancels the advantage of it's lighter weight.

where it DOES shine is in the fact that it can't fail catastrophically like with a broken rod or crankshaft in a reciprocating engine, which can mean the difference between life and death, even if it overheats it won't seize up and fail. durability under failure is it's true strongpoint.

the true realm of the rotary is aviation use, not automotive.

Raptor75

I have also read that it has a longer service interval between tear downs then a piston aviation engine.

Paul_in_DC

People with real-world experience in rotary engine aviation say that the high power-to-weight ratio is a major factor in using rotaries for aircraft:

daisuke

you're quoting a website dedicated to installing rotaries in aircraft, of course they're going to say it's an important factor, and I couldn't agree with them more, but I maintain that there are other advantages to the rotary that far outweigh that one. If you put one in your plane, the lower weight of the engine allows for more fuel and therefore more range, which is nice... but when you're flying your conventional engined plane and the engine tears itself apart, and you realize you're probably going to die... I think you'll be really sorry you didn't get that wankel.

I have a very strong interest in aviation and the rotary engine and have spent many many hours doing research on the subject so I'm not just pulling stuff out my ***.

dmc27

I once pulled a wankel out of my ***. But that was a different threadjack.

flomulgator

sorry I'm continuing deviation of thread. This post has been dead for some time though so who cares. Anyways, I took a flying lesson and on that first lesson I had to deal with the airplane wanting to roll counterclockwise during a change in throttle (if i remember correctly) because of the prop mass rotating clockwise (to the pilot's view). I was told at the time that small planes are "tweaked" to handle this in normal flight. Could a rotary be set up to rotate both rotors in the same direction in such a way that it's rotating mass equally opposes the mass of the propellor thus no longer causing this minor roll issue and smoothing out the tweaks in aero for greater efficiency and stability?

Side note: Do rotors rotate opposite or same direction to begin with?

flomulgator

thx! Always good to know. So that at least could potentially offset propeller spin. Any aviators wanna pipe in?