1/4 Scale Bentley BR2 Rotary Engine

[Jim Tremble]

http://www.rjdunn.co.uk/tony/aero/thumb0001.htm

This is a well done job. And it runs.

Jim

[Forrest A]

Not a dig, I was just expecting to see a rotary engine from the title of the thread.

For those unfamiliar with this type of engine it is actually a radial type. A rotary engine is quite different. See the link below.

http://auto.howstuffworks.com/rotary-engine.htm

Forrest A

[Alan New]

Actually, the Bentley BR2 IS a rotary. It was and improved version of the Clerget rotary. Many aircraft, as well as some automobile engines built before and during the World War 1 era were rotaries or rotating cylinder engines, as opposed to fixed cylinder "radial" engines. They felt that the air cooled cylinders had to rotate around the crankshaft for effective cooling. the early radials were liquid cooled. These came many years before Wankel developed his "rotary".

[W.B.Lewis]

A member of New England Model Engineering Society in Mass. has one which he shows regularly at shows in the Northeast. Nicely done model.

[maryjane30]

hi all

if you want to see a full size pre ww1 rotary engine running, there is on on youtube I saw..

http://www.youtube.com/watch?v=R_JMGO5NzuI

should find it. the engine is definatley a rotary, the Bentley was the last form as fitted to the sopwith snipe right at the end of the war. the torque of the spinning engine was what made the sopwith famous for its "immellman turn". the bently however was as big as they got,(200hp) they became too hard to fly straight, basically.. the gnome as in the video link was 50hp, and the first aero engine in 1909 to fly more than 1 hour, loop the loop, and fly upside down, as well as numerous other achievements!

the crank was bolted to the firewall, and the prop to the engine crankcase.

nice work though.

M-J

[John Davidson]

FYI, the true rotary engine where the crankshaft is stationary and the cylinders revolve was developed in 1898 by Fay Oliver Farwell. It was a 3 cylinder engine. In 1903, working at the Adams Co. of Dubuque, Iowa, the ADAMS-FARWELL car was produced with the 3 cylinder rotary engine. In 1906, a 5 cylinder model was produced. Production lasted till 1913. There exist one 1906 5 cylinder car. The horizontal cylinders were mounted directly over the rear axle. No flywheel need or cooling. It was in the Harrah collection. I saw it running in 1968. An amazing thing to see and I will never forget it.

[Andrew Mackey]

The Gnome engines actually ran too cool! They used to foul plugs like mad. The cowl was designed to cut down airflow, so the engine would actually run hotter!
Andrew