Military History Monthly
Just over 75 years ago, the world’s loudest ever aircraft took to the skies for its first test-flight. When the US Navy voiced its need for a carrier fighter that did not require catapult assistance, Republic Aviation started experimenting with the USAF/Republic XF-84H experimental turboprop fighter.
A variant of Republic Aviation’s F-84 Thunderstreak, this novel aircraft used an Allison XT40-A-1 turboprop engine which drove the propeller at 3,000 rpm. Thrust level was changed by varying the blade pitch. However, there was one immediate drawback which gave rise to the aircraft’s nickname: the shock-waves created by the prop engine were so powerful and the sound level so extreme that it induced intense nausea and raging headaches among the ground crew. The ‘Thunderscreech’ was born.
Two XF-84H prototype aircraft were built by Republic Aviation. The use of a T-tail was required to keep the horizontal tail and elevator in clean air flow. In flight, they were destabilised by the powerful torque from the propeller, hindered by problems with the supersonic propeller blades, and plagued by engine-related glitches.
https://www.military-history.org/articles/back-to-the-drawing-board-the-republic-xf-84h-thunderscreech.htm
