The RP-4, the fastest piston-powered plane that never flew, built in 2005 by David Rose

 

But is it a plane if it never flew, and if it never flew, how can it be said to be "fast?"

Intended to compete in the Unlimited Class at the Reno Air Races, work began on the David Rose RP-4 project in 2005. Designed by Mr. Rose and built primarily be Eric Hereth, both of San Diego, at slightly over 4,600 pounds, 100 more than the minimum allowable, it is estimated that the racer would tour the course at upwards of 600 miles per hour (mph), at least 100 mph faster than the current record holder.

Power is provided by two 600 cubic inch displacement V-8 engines designed originally for drag racing and, in that configuration, each is capable of producing as much as 2,500 horsepower (hp).Detuned to approximately 1200 hp. each, the engines were expected to withstand the rigors of running at full throttle for eight minutes, the time required to complete each heat at Stead Field in Reno. 

The engines are mounted in tandem, each with its own independent systems, and each driving its own propeller. The engines are pressure-fed by two Pro-Charger F3-R centrifugal type superchargers with refrigerated intercoolers. The induction system is custom made from the 6” diameter throttle plate, to the attachment at the cylinder heads. The fuel is delivered by an electronic fuel injection system, also custom made for this application. Two-inch diameter stainless steel headers converge into collectors at the bottom of the fuselage exiting rearward and providing additional thrust in the process.

Somewhat odd appearing contra-rotating propellers are reflective of those used in a ducted-fan experiment in the 1960s. Very efficient, but noisy, they split the job of delivering thrust and also cancel the negative torque reactions resulting from the P-factor, making such a high power aircraft of small dimensions much more easily controlled.