The American Aircraft Penetrator was modified from a helicopter produced by what nation's military?
Bell UH-1 Iroquois The Bell UH-1 Iroquois (nicknamed "Huey") is a utility military helicopter powered by a single turboshaft engine, with two-blade main and tail rotors. The first member of the prolific Huey family, it was developed by Bell Helicopter to meet a United States Army's 1952 requirement for a medical evacuation and utility helicopter, and first flew in 1956. The UH-1 was the first turbine-powered helicopter to enter production in 1960 for the United States military, and more than 16,000 have been built since.
Firestone XR-9 The Firestone XR-9, also known by the company designation Model 45, was a 1940s American experimental helicopter built by the Firestone Aircraft Company for the United States Army Air Forces. Only two (the military XR-9B and one civil example) were built.