Castor Oil

[Pips]

Camel pilots often mention the Camel's notorious habit of spewing out copious amounts of castor oil, leading to some very uncomfortable problems for the pilots.

Yet all rotary engine used castor oil as the mix with fuel (although the Germans late in WWI had to resort to an ersatz version, once supplies ran out). So why doesn't the same problem crop up in biograpies of pilots who flew the E.III, Dr.1, various Nieuports and so on?

[GASML]

The legendary Prussian military discipline perhaps?

[MilesC]

I read one modern report of a chap flying a Nie 10 with a rotary engine using castor oil. He stated the darned thing was literally coated in oil inside and out to the point where the rudder bars were slippery.

"After chocking the brakeless wheels, I climbed in around the wires and struts, slipping on a film of castor oil, which lubricates the engine. Palen primed each cylinder using a squirt can while I turned the gas valve on, pushed both throttle and mixture controls forward, then called "Contact " With one pull on the prop the Le Rhone sputtered to life, spraying castor oil all over the place, including the windshield and me. A quick reduction of throttle and mixture kept the tiny fighter from jumping the chocks, but there is no such thing as bringing the power back to idle. Instead there is a coupé, or cut-out button, on top of the stick. Press it down -"blip" it - and the entire ignition system shorts out, leaving nothing but whistling prop and cylinders. Release it and the engine roars back to life.

The technique is to use fuel and air controls to idle the engine below 1,200 rpm and use the cut-out switch above that. With the switch pressed, unburned fuel and oil fill the cylinders and spray into the horseshoe-shaped cowling. If you blip the engine for more than four or five seconds and then release the switch, you can start a fire."

From: Air & Space Smithsonian. October/November 1991.

by Jeffrey L. Ethell