The Gun Counter

Parts 1 & 2:

https://www.youtube.com/watch?v=qjnQKXNPsk4

https://www.youtube.com/watch?v=R71Xhrkc3EQ

Fascinating! Seems like it would produce a lot of torque. Shamelessly stolen from an arfcom thread.

That is awesome. I mostly understood the concepts from my reading, but I am a visual learner and that helps to put it together. Thanks for sharing.

Certainly interesting, I had always thought that the outer part with the pistons was what rotated.

mekender wrote:Certainly interesting, I had always thought that the outer part with the pistons was what rotated.

Nope, that's a Rotary engine (not to be confused with a Wankel engine). Rotaries are what you saw on most of the WW1 fighters. A lot of the mechanism is the same, but a rotary has the crankshaft bolted to the airplane and the propeller bolted to the crankcase, which turned with the cylinders. This allowed for adequate cooling at very low airspeeds, but was apparently a pain in the behind to throttle and has massive gyroscopic torque.

Certainly interesting, I had always thought that the outer part with the pistons was what rotated.

Well, you're not completely wrong. The Fokker DR1 Triplane used a rotary engine that the cylinders spun and the crank shaft was stationary. The major problem with this was that there was no throttle control. It was either on or off. The pilot slowed the airplane down by switching off the magnetos momentarily until he reached his desired speed. Not very efficient and it was one of the leading causes why the DR1 was replaced by the DR7 as the frontline scout of WWI

Yeah, word is that with a rotary if you want to turn left you're better off making a 270 to the right. Those were fed a fuel/oil mix thru the crankshaft (to deal with fuel delivery/plumbing challenge I imagine). Forget your dry sump, those were total loss oilers.

Interesting wiki on rotaries here: https://en.wikipedia.org/wiki/Rotary_engine

Captain Wheelgun wrote:

mekender wrote:Certainly interesting, I had always thought that the outer part with the pistons was what rotated.

Nope, that's a Rotary engine (not to be confused with a Wankel engine). Rotaries are what you saw on most of the WW1 fighters. A lot of the mechanism is the same, but a rotary has the crankshaft bolted to the airplane and the propeller bolted to the crankcase, which turned with the cylinders. This allowed for adequate cooling at very low airspeeds, but was apparently a pain in the behind to throttle and has massive gyroscopic torque.

Apparently there were a few different ways to modulate power output, but none of them was particularly satisfactory.

Also getting fuel and air into the cylinders is an issue, requiring the crankcase to serve as intake manifold. That has problematic consequences of its own, oil loss being only one of them.

Just as a side note, rotary engines are spectacularly loud for their power output.

blackeagle603 wrote:Interesting wiki on rotaries here: https://en.wikipedia.org/wiki/Rotary_engine

The animation on the right is what I remember seeing years ago that made me think that radials were like that... I never put 2 and 2 together to realize they were different designs.

Thinking about it logically for a split second, it makes total sense to do it the radial way, but it was not something I had ever really given a ton of thought to.

And I believe that there were some cars that had a rotary engine too...

mekender wrote:And I believe that there were some cars that had a rotary engine too...

"...but the Mazda goes mmm..."