Republic XF-84H Thunderscreech

Republic Aviation Corporation · United States · first flew 1955 · fighter

The Republic XF-84H Thunderscreech was an American experimental turboprop fighter that attempted to combine jet-era performance with propeller efficiency, but became notorious as the loudest aircraft ever flown — its tip-supersonic propeller generated continuous sonic shockwaves that caused nausea, headaches, and hearing damage in ground crew.

Recognition (WEFT)

W — WingsMid-mounted, swept
E — Engines1 × turboprop, nose-mounted
F — Fuselage15.67 m fuselage
T — TailConventional

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Appears as a standard swept-wing jet fighter of the F-84F family from a distance, but the enormous four-blade (or three-blade) supersonic propeller immediately identifies it — the only turboprop aircraft of the era with a swept transonic wing.

Specifications

Figures are for the representative variant described above; marks differ. See how AircraftIQ sources figures.

History

Developed from the F-84F Thunderstreak, the XF-84H replaced the jet engine with an Allison XT40 turboprop driving a three-blade supersonic propeller. First flown in July 1955, it suffered catastrophic vibration, handling problems, and the infamously destructive noise environment. Only twelve flights were made before the programme was cancelled; at least one crew member reportedly suffered a seizure from the sound.

Variants

Two XF-84H prototypes were built; both are now preserved in museums (USAF Museum and Planes of Fame).

Where you'll see it

Never entered service; the XF-84H is remembered as one of the most problematic and physically dangerous test aircraft ever flown in the United States, as much an audiological hazard as an aeronautical one.

Related aircraft

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