Meet Republic XF-84H Thunderscreech, The World’s Noisiest Aircraft

We have all seen jet planes in movies or in real life. There are several such planes in the world that produce a lot of noise. Do you know which is the noisiest jet plane? According to reports, it is said that when this jet plane took off, even the ground staff were forced to cover their ears. In fact, its sound was never recorded at any decibel because there was a fear that the measuring instrument might break. The jet plane was none other than the Republic XF-84H Thunderscreech. It was an American experimental turboprop aircraft based on the F-84F Thunderstreak. The XF-84H was powered by a turbine engine which was connected to a supersonic propeller. It had the potential to break the unofficial air speed record for propeller-driven aircraft, but it was unable to overcome aerodynamic deficiencies and engine dependability issues, leading to the program’s abandonment.

The XF-84H was probably the loudest aircraft ever built, gaining the nicknames Thunderscreech and Mighty Ear Banger. The prototypes were allegedly heard 25 miles (40 kilometres) distant during ground run-ups.

Unlike ordinary propellers, which revolve at subsonic rates, the outer 24-30 inches (61-76 cm) of the XF-84H’s propeller blades flew faster than the speed of sound even at idle thrust, resulting in a continuous visual sonic boom that radiated laterally for hundreds of yards.

The shock wave was indeed strong enough to knock a man down; one unfortunate crew chief who was inside a neighbouring C-47 was seriously debilitated during a 30-minute ground run.

Although the Guinness Book of World Records recorded the XF-84H as the fastest propeller-driven aircraft ever built, with a design top speed of 670 mph (1,080 km/h) (Mach 0.9) and 623 mph (1,003 km/h) (Mach 0.83) during tests, this claim has been disputed.

The unofficial record speed also contradicts statistics from the National Museum of the United States Air Force, which estimates a peak speed of 520 mph (840 km/h) (Mach 0.70), nonetheless making the XF-84H the fastest single-engine propeller-driven aircraft until 1989, when Rare Bear – a highly modified Grumman F8F Bearcat – reached 528 mph (850 km/h) (Mach 0.71).