Re-engining the Camel with a rotary Gnome

I finally found some drawings that I did for Air Trails in 1970. They should explain a few things about the operation of a rotary engine.

 

Trying again to get things to download.

 

Keep working...I for one am fascinated by this subject...my understanding was that they had overhead valves driven by pushrods off a cam on the crankshaft.

Yes, I was aware of the Oberrusal type which had the prop connected to the engine block and the crankshaft stationary to the airframe -- but still had never heard of your inertial intake valve in the center of the pistons.

 

Third try. Looks like it worked finally and I hope the drawings are good enough to show the valve-piston arrangement
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James, I found and posted my drawing of the valve in piston arrangement. Crazy design.

 

Yup - pretty far out there. How many cubic inches did this have - and how much horsepower? It doesn't really look very efficient to me...

 

James, the valve in piston engine was in the early Gnome. After many failures the design was abandoned and resulted in the new Gnome Monosoupape design.

 

That smell is alive and well at Sprint kart tracks across the country, many engine builders still recommend 50% pure castor. When my kid was racing I'd use left over fuel mix in the weed wacker and instantly be transported to the racetrack.

Anyhow: watching the thread eagerly for updates. An amazing project and fascinating comments already. I'm a longtime fan of 'first decades' autos and vulnerable to the allure of same period aircraft, I fear...

 

Russ-

Do you know Andrew King? He rebuilt this one.
That's me getting the castor oil bath.

[ame=http://www.youtube.com/watch?v=CYc-H8Wg-MQ]1918 Gnome rotary engine running - YouTube[/ame]
Tom B

 

Yes - I've actually met him twice. I have watched these videos about a thousand times. Great job - I think the plan is to put the 9N on a Nieuport 28C.
Very cool.
Any advice?

 

Advice from me?
The only advice I can give is to send all questions to Andrew. He's obviously very knowledgable and a tremendously nice guy.
The only part of this I'm useful for is working on his worn out Toyota.
I just happened to be at the airport when he was firing this thing up.
It was a memorable day and the castor oil bath did wonders for my dry skin.

Cheers,
Tom B

 

Tom- Inhale too much of it and there can be other problems that can cause you to love the porcelain throne.

 

Yes, Taz. I have read that their were no constipated pilots who flew behind a rotary.

 

I shared Mr. Parks' drawings with my friend Jim and he sent me a link to an animated Gnome:

Animated Engines - Gnome Rotary

--Carter

 

I read in the Road&Track article that diets of Brandy & Milk were not uncommen.

 

On Friday the 31st January 2014 at 3 pm the smell of burnt castor oil wafted over the Omaka Aerodrome as the newly manufactured 100 hp Gnome filled the air with that unmistakable sound that only a rotary engine does...
Totally built from scratch.
A remarkable achievement.
We are in line for engine #2.
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Russ- Pretty amazing. They are also making Oberursel Ur.II, Mercedes D.IIIa, and even Simens Halske Sh.III engines. Quite an enterprise. I cannot wait for Peter Jackson to make the definitive WW-I aviation movie. He is building the AF to do that.

 

The use of cowlings on tractor rotaries had nothing to do with aerodynamics; it was done solely to try and contain the castor oil as much as possible. You'll note that pusher rotaries were always uncowled.

When radials came along, they were usually uncowled as well (except for possibly a "helmet" over the core of the engine that left the cylinders out in the breeze) until someone discovered the aerodynamic advantages of cowlings, but that didn't happen until around 1930 or so.

 

Now if they were really clever they could have engine mounted the cowl and trapped the oil to recycle it.

 

I can imagine. I rode in a Waco on floats with a high time radial and that was bad enough.


I think round motors were built to leak oil. Like a BSA motorcycle. If it isn't leaking it is out of oil.

 

You should also notice that most rotary cowls were open at the bottom or had slots in them so that the castor oil would be blown out underneath the airplane.

 

And, the cylinder is in it's exhaust stroke in and arc around the bottom every other revolution.
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The blue plastic thrones on the trailers must have been placed for a purpose!
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Beautiful illustration of the rotary's cycle, thanks! I also remembered that some times fuel would collect in the bottom of the early cowls and ignite if there was a back fire or some other ignition.

 

Bob- That usually happened on the Gnomes during a descent if the pilot forgot to shut off the fuel valve with the coupe switch depressed. On restart, this fuel would often ignite. Most of the cowls for the early aircraft that used Gnomes were completly open for this reason, like the early Fokker and Pfalz Eindeckers, but still did not completely solve the problem. The Oberursel U.0 and U.I were license built Gnomes, although I doubt the French got any royalties after 1914.