In article ,
Mxsmanic wrote:

Steve Foley writes:

No, there is not.

Unless the engine is weightless and frictionless, it will exert torque
on the airframe whenever it is turning, even if there are no props.

No, that's not true. If there is no prop, the engine will only exert
torque on the airframe when its rotational speed is changing.

My mom used to have a 1960-something Buick with a big-ass V8 and a mushy
suspension. You could set the thing rocking just by revving the engine in
neutral.