Question on Rotary Wankel Engines

[kilo delta]

The engine seals were with the early versions. That was long since fixed and improved, perhaps 15+ years ago.



Bill

I'm not sure that the rotor tip issue was ever fixed on the RX-7.....the RX-8,however doesn't suffer from this particular problem.

 

[Ferry_vO]

IIRC Diamond has made some aircraft with a Wankel engine? (I believe it was a version of their Katana)
Torque isn't much of an issue with Wankel engines, as the rotating mass is relatively small, I don't think the diameter of a Wankel rotor is much bigger than the diameter of a rotating crankshaft.

 

[Ken Stallings]

Because the effect is minimalized like many other forms of propulsion such as jet engines.

But jet engines rotate in a circular motion with the weight evenly distributed over the perimeter of the circular motion. Therefore, the jets engines are smoother than horizontally opposed piston engines. The firing sequence of piston engines are designed to attain a more symetrical sideways force, with each piston cancelling out the sideways torques of the previous firing piston. Further, each piston in effect becomes a somewhat circular rotation of its own.

The rotary engine has one piston so to speak with its triangular shape providing three separate burn chambers.

You may be right, the displacement in any direction may be small enough as to be insignificant. I just don't know. But my biggest concern is that a car sitting on the ground has its weight resting on the ground and that can dampen the oscillating forces. An aircraft in the air enjoys no such natural dampening force and therefore if an oscillation starts to take place, if the rotary engine's piston was set up at a certain RPM, it could cause a harmonic type of oscillation in which a small oscillation builds upon itself and eventually could overcome the control surfaces' ability to maintain stable flight.

Cheers,

Ken