There was an article in last month's Aviation Week & Space Technology (Feb 19, 2007 page 46) on a new engine design called the Legacy Powerplant. It is composed of three small rotors driving a central rotor/driveshaft. It is still under development. I thought people on this forum might be interested as they even mention the Wankel engine and Mazda in the article.

I have included a picture of the engine and the text of the article.

 

I know people are getting creative but I just look at that and think about the flow aspects of the wankel and how it's an issue and then see this and suddenly think that air has an easy trip in our engines. That's an awful lot of surface area and complexity for air to flow around. I just can't see this idea going very far in the longrun. The wankel may not be the most efficient engine out there but it's beauty is in its simplicity. I have yet to see another rotary concept as simple and consequently also have yet to see another successful one.

 

I know they need to generate publicity in order to raise capital for development. But I do get tired of various revolutionary engine designs which always seem to have been fired up exactly once, and never in a practical application -- yet predicting use an adoption in a wide range of vehicles and applications. Yet, Wankel took decades to bring his dream of a rotary engine to fruition. So I wish them luck.

 

Without an animation, I can not wrap my mind around how that thing would work.

 

looks like maybe the three rotons spin inside the spinning rotor, like three wankels in a wankel. maybe not though. the rotons maybe can't move. i dunno.

 

no they look like they are the seals. but insted of apply in pressure to the walls they just adjust by moving left to right

 

If I understand the article, the three rotons are concave rotors and move with a planetary motion like a normal Wankel rotor. The roton forward motion drives the "rotor" which just spins the central drive shaft.

In a way you could consider this a three rotor or 9 combustion chamber engine (3 per roton).

Yes, a video would be great and would explain much.

 

all I see is a huge intertia mass ...

 

Looks like someone with a Spirograph decided that they could design an engine.

 

Damn, Good luck with *that* design.

 

There is a disturbing lack of spark plugs in that engine.

 

lol there IS an animation, and it has plenty of spark plugs... check it out:

http://www.aviationweek.com/media/flash/

legacyanimation.mov -> right click -> save as

save it to your hard drive before you watch it... only way it worked for me

 

That animation shows all chambers going through the 4 strokes at the same time. Is it just me or is that a little flawed?

 

hmmmm

http://www.aviationweek.com/media/fl...yanimation.mov

 

That engine's got to have more seals than the Arctic Ocean.

 

You forget each roton has three surfaces so, while all the rotons are in sync, there are three combustion cycles per roton (per engine revolution) to drive each roton through the intake, compress, combust, exhaust cycle. A roton's intake, compress and exhaust cycles are driven by its own combust cycle, not the combust cycle of the other rotons.

Unlike the Mazda rotary, the rotons are symmetrically placed around the center of rotation so no cycle offset, is required. I believe the Mazda two rotors are physically offset to counter balance each other on the eccentric shaft but I don't think that is required for the engine to work. I believe a one rotor configuration will also work (again combust driving the other three cycles).

Also I was wrong, with this design no planetary motion is needed. Both the central rotor and the rotons just spin with compression being supplied by the shape of the housing (very cool). However, as Nubo noted the engine must have a ton of seals.

And, of course, it sounds like this engine is a long way from ever running in a vehicle of any type, if ever.

 

3D nuclear waste warning sign?

 

is it just me or was there some intake/exhaust timing overlap there?

seems like a lot of added complexity for a step backwards in 'rotary' tech.
what could be the advantages of this setup? (even less vibration?)

i just took a quick peak.

 

lol!

 

Ever see a new business open up and think what a bad idea and that it will shut down in a matter of months like an apple butter store. Wish them the best but don't see this going anywhere except to the patent office cellar.

 

I saw that too, the animation show the exhaust vents and the inlet vents being exposed at the same time during the expulsion of the spent fuel.