utube rotary engine (not wankel)
 

http://www.youtube.com/watch?v=0jHRuEkvO8E

regards
Mech

Looks like an aircraft radial engine.

It is an old aircraft engine. The LeRhone goes back to the early 1900s.

I'm trying to remember the engine where the shaft was actually fixed to the firewall and the engine spun with the prop. I imagine overheating wasn't a big issue on that one. Can anyone tell me what that was?

That is the one, crank bolted to air frame prop to engine block. Radials had spinning crankshafts, like every other reciprocating piston engine.

http://www.youtube.com/watch?v=-UBAukXPD-0

regards
Mech

I image getting the plane to turn could be tricky with the torque from that heavy block spinning around.

Turned twice as fast one way as the other. Those kites could do 6 g's in a turn. The spinning engine provided 90% or the valve spring tension dueto centrifugal force and the Le Rhone with intake runners was also a centrifugal supercharger. I think it was 80 HP at 1200 RPM and weighed around 325 to 250 pounds. Took something like 80 man hours on a lathe to machine each cylinder jug. 100 pounds of steel finished to something like 7 pounds and a lot of cuttings on the floor!

regards
Mech

That was why the Sopwith Camel was so dangerous to fly.Many pilots were killed in training.An experienced pilot used this to his advantage in combat, it would turn slower to the left but could "Right hand you to death" .:eek:

How did the carb/fuel delivery work?

Fuel was mixed with castor oil, and delivered through the fixed crankshaft. Late in WW1 they even developed a carb that would work inverted, something the early Spitfires did not have in early WW2. Gnomes went through a valve the piston crown, LeRhones and most of the others had intake runners for each cylinder.

Pretty sure they controlled speed by selectively shorting the plugs out, plugs fired once per revolution but they were 4 stroke.

regards
Mech

Combustion pushed the cylinder head away from the piston, Con rods rotated around the crankpin, unlike any others that only oscillated on the journal. Very similar to the modern rotary vane pumps use in air tools except reversed. Originally built to provide good cooling when air speeds were 45 MPH in 1908 they jumped to 120 MPH in 1912 at the Rheims air races.

regards
Mech

Here you go mid 1920s front wheel drive rotary engined motorcycle.

The Megola motorcycle.

http://www.youtube.com/watch?v=qAQuljp-atA

regards
Mech

http://www.osengines.com/engines-air...307/index.html

Just add bike :)

You must mean the Bentley BR2 Rotary Aero Engine.

Yeah, I just wrote "Airplane" and copied and pasted your description into Google! :D

Radials are reciprocating engines. Rotaries are not. The action of the connecting rod in a radial is the same as any other engine, the difference in a rotary is shown in the first post. That design, although ancient, is the only engine where the con rods orbit the crankpin. That is not a reciprocating action. If the cod rod rotated one time around the crank pin in a radial, or any other reciprocating engine, you have a blown engine with internal parts possibly sticking outside of the destroyed engine block.

regards
Mech

The "radial" vs. "rotary" description is what keeps tripping me up. And the Wankel kind of blurs the lines too, as its described as a rotary but the engine block stays still.

That motorycycle is amazing. It would take some serious cojones to drive that, can you imagine hitting a pothole with that front wheel? You'd knock your own teeth out. Also: no clutch.

My understanding is that the main advantage of the rotary engine was that it did not need a flywheel, because almost all of the mass of the engine itself acted as a flywheel. So it could be a lot lighter than the engines that needed a flywheel--which most did, because early on they didn't have very smooth-running engines. Especially if you controlled your power by killing the ignition to some cylinders.

The term "rotary" is a bit overloaded. But the engine shown in the first post is definitely an aircraft rotary engine. The crank was bolted to the firewall, and the prop was bolted to the engine block.

-soD

Man, those guys had it all figured out. Beautiful engineering!

I think most airplanes use the propeller as the flywheel...

Perhaps they do these days, but back in the 1908-1914 time frame a propeller wasn't nearly enough weight to be as effective a flywheel as they needed.

Mixture control on the early radials (especially the Monosoupape) was horrible. Throttling the engine was basically impossible, and the valve timing was rather suboptimal as well. But they had good power-to-weight for the time--which made them among the best aero engines just then.

They were able to make incremental improvements to the basic rotary, which improved things like carburetion and valve timing, but other layouts improved even faster. It is likely that improved carburetors and ignitions resulted in engines that didn't need an immense flywheel, so the major advantage of the rotary was gone.

Plain radials could separate out the intake air from the crankcase air, which only helped with the power and mixture. And the inline (or vee) water-cooled engines had much less frontal area, making it easier to streamline the aircraft--plus they were able to extract similar power from rather less displacement. Though the radials could be (and were!) built to massive sizes (3000+ cubic inches!) for massive power, and were much more damage-tolerant than the water-cooled engines.

-soD

These radial engines look cool. Well, maybe the aircraft engines closest to the concept of a Wankel are the turboprop ones.

I just got here from the thread in General Efficiency.

In this case I'll point to the Chrysler A57 Multibank
http://upload.wikimedia.org/wikipedi..._multibank.jpg