During the final stages of the XPF-67, the designers of AAD and PAD attempted to create a varient propelled by simple jet engines, still unsure of the reliability of the Atomicly Accelerated Propulsion engines that were in development at the time. After conjuring up multiple designs that derived from the original airframe, the designers went back, replacing the pair of twin push-pull engines with intake vents and quad fighter-JS250's. The end result was an airworthy airframe capable of speeds exceeding the design it was based upon. Although it sacraficed agility for speed, it ended up in the aircraft's favor, gaining an additional 100+ mph in speed at 1000 ft.