Check out this footage featuring the sound of the XF-84H Thunderscreech, the loudest aircraft ever built that Made Ground Crews Throw Up

Check out this footage featuring the sound of the XF-84H Thunderscreech, the loudest aircraft ever built that Made Ground Crews Throw Up

By Dario Leone
Jan 1 2024
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The XF-84H Thunderscreech, a turboprop plane with a supersonic propeller

The footage in this article post features a recording of the Republic XF-84H Thunderscreech, a turboprop plane with a supersonic propeller. This sound (when played at its original volume) caused people to faint, vomit, become slightly deaf, and reputedly soil themselves.

It was the first US aircraft built with a Ram Air Turbine (RAT) which provided emergency electrical and hydraulic power in subsequent US aircraft, but provided needed power for the XF-84H when landing. Another novel feature was a “take-off fin” or “vortex gate” aft of the cockpit to overcome the effects of the propeller torque.

The XF-84H – a joint Air Force/Navy project – was derived from the RF-84F as a supersonic propeller test vehicle driven by an afterburning Allison XT-40 turboprop engine.

Sickening noise

Two aircraft were built and briefly tested as noise produced by the propeller even at idle was too severe for safe ground crew activities. The sickening noise gave the aircraft its nickname “Thunderscreech.”

According to, ‘the XF-84H was riddled with problems from the start. For starters, the supersonic propeller created enough torque and propeller wash to destabilize the plane in flight. Even Republic Aviation referred to the engine as “a monstrosity, a mechanical nightmare.”

‘It would have been useless as a fighter aircraft, because despite its powerful acceleration, it took 30 minutes to prepare for flight. In that time, the ground crews servicing the plane would have their work cut out for them.

‘XF-84 ground crews nicknamed the plane “Thunderscreech,” a play on the nickname of the operation F-84 fighter bomber, because it was so loud. The propeller tips of the XF-84 traveled at Mach 1.18, faster than the speed of sound, producing sonic booms that could be heard some 25 miles away.

‘The noise combined with the shock waves of the booms were enough to effectively cripple the area and any crewmen who might be in it. Crews would have to endure while the XF-84 was powering up for 30 minutes before takeoff.

‘One unlucky C-47 Skytrain crew chief who happened to be in the area while a Thunderscreech was powering suffered a seizure in the back of his aircraft due to the intensity coming out of the XF-84.’

The loudest aircraft ever built

The flight program lasted from June 1955 until October 1956 with the program being taken over by the McDonnell XF-88B which flew until January 1958. The XF-88B had both turbojet and turboprop engines and could taxi and take off without the turboprop operating, thus without subjecting the ground crew to the painful noise.

The first of the two prototypes produced by Republic is currently on display at the National Museum of the US Air Force (USAF). This aircraft flew 8 of the 12 test flights.

The XF-84H remains the loudest aircraft ever built.

H/T Earl Belz

Photo credit: U.S. Air Force

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Dario Leone

Dario Leone

Dario Leone is an aviation, defense and military writer. He is the Founder and Editor of “The Aviation Geek Club” one of the world’s most read military aviation blogs. His writing has appeared in The National Interest and other news media. He has reported from Europe and flown Super Puma and Cougar helicopters with the Swiss Air Force.
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