Scale Models

WW1 Rotary Aircraft Engines lead to Brandy and Silk Scarfs for pilots

Build of the Cleget Rotary Engine & Propeller

Now I am onto the next none programming project, building a 1917 Sopwith Camel Fighter at 1:16 scale the SF Cable car was a little to easy. The first stage was putting together the Clerget Rotary engine.

There are a few interesting things about this design and the implications it causes, the engine operates by rotating around a fixed crankshaft. This is not normal for today”s engines to say the least, if you look at the scale model example I built in the picture here, the propeller turns along with the whole engine and the central crankshaft is fixed.

This has the benefit of improving cooling of the nine cylinders which was a problem for engines of the time, however it meant that oil used to lubricate the internals of the engine was thrown outward because of centrifugal force and would leak out of the valve/rocker assembles on top of each cylinder.

To overcome this issue they engine needed a constant supply of oil delivered with the fuel mixture, in comes castor oil the only oil of the time that was no soluble in petroleum fuel.

However as with most developments in the early stages this actually moved the problem to another location, the pilot. Castor oil has the wonderful property when administer to people of being a laxative, so imagine the effects of being behind an engine that just keeps on spewing out castor oil (burnt and unburnt).

The first line of defence is a silk scarf to wipe it from you face and goggles (you thought the dashing white scarf of the men in flying machines was for style!). However for the medicinal effects of caster oil the pilots would carry flask of Blackberry Brandy to stop things from loosening up to much.

Although it is debatable if the cowling over the engine was put there for aerodynamics or to divert oil away from the pilot and under the aircraft.

This a video of a Sopwith Pup the predecessor of the Camel but they had the same issue with the rotary engines, if you listen to the commentary you will hear details on how they needed to prime the engines to start, etc.

Sopwith Camel Engine Start