Here is another more serious attempt to go mach 1.0 with a piston AC:

http://renaissance-research.com/company/

By Eric Ahlstrom who was also designing the last Steve Fossett carproject.

Ahem…

Does that mean that the jets provided some of the power, or was it flown solely on the turboprop?

If the latter, fair enough. If the former….

Here is the world second fastest single engine prop plane F-84H Thunderscreech;

http://en.wikipedia.org/wiki/XF-84H

I must point out that cleaniness and supersonic prop alone won’t make a plane go fast…it is the power to weight ratio. F-84H has worse power to weight ratio than a standard P-51H ( 487 mph mover ).

My fantasy racer has over 1.5 hp/kilo power to weight ratio ( 3 x F-84H ) and cleaniness number of wetted area drag ( 0.0015 ) is 1/3 of the Mustang one ( 0.0040 ).

Problem in going supersonic with a prop plane is that prop has to be well beyond mach 1.0 and the noise is awful…even devastating.

Here is more of xf-88b going supersonic ( F-88 was not supersonic ).

http://en.wikipedia.org/wiki/XF-88_Voodoo

The speed of sound varies roughly from 767 mph ( sea level ) to 660 mph ( 20 000 ft ).

http://www.rogerdarlington.co.uk/Mach.html

Not correct DazDaMan !

John Fitzpatrick went supersonic with a prop plane already in 1953:

http://www.aviastar.org/air/usa/mcdonnell_xf-88b.php

John’s e-mail; jmfitzp(@)aol.com ( if you doubt it ).

Enclosed Sleek Streak II ( above ) is 3 x cleaner than a Mustang.