earlwb

For Goodyear racing they use some sort of a fuel shutoff device on the plane so they can make the pitstops. In many areas they have evolved into just using diesel engines now for it though as the glow engines weren't as reliable with glow plugs burning out on you in a race. But a lot of local clubs have specialized rules that allow for most any 2.5cc engine to be used, and otherclubs may be more restrictive. One of the Australian Clubs was allowing for just about any 2.5cc engine to be used in their profile Goodyear class for racing.

I think it was the Bendix class of Goodyear racing where someone could use a .35 engine or thereabouts. The Vintage B class was the other one that used .35's or 5cc engines. A more modernClass 2 version exists or existed that used 5cc engines too.