I am going to say something that I do not want anyone to construe in any way that I would condone or even consider a prop driven land speed car, BUT if you apply a propeller properly and allow it to be mounted to allow good clean air from a properly designed body to be fed to it, I am talking about a pusher configuration, the prop can be as high as 85% efficient. Now this is pretty good probably not that far off of a transmission,differential, drive wheel combination for efficiency, plus the prop will accelerate the air over the body and can actually assist the aero. There have been small single seater planes, pusher prop configuration that have gone over 300 mph with 100 real horse power. Pretty impressive.
I will not accept any correspondence addressed to "Propster II"
Rex