Gadgetopia

XF-84H Thunderscreech :  I love this plane.  I totally want one.  It appears to be the most ridiculous experiment in aviation history.

The engine was […] an Allison XT-40-A-1, capable of 5,850 hp (4,362 kW). An afterburner was installed though never used, which could increase power to 7,230 hp (5,391 kW). The propeller consisted of three square-tipped blades turning at a constant 3,000 rpm, with the tips travelling at approximately Mach 1.18.

[…] It flew a total of 12 test flights. One test pilot flew in it once and refused to ever fly in it again. Test pilot Hank Baird took the craft up 11 times, with 10 of these flights ending in forced landings.

The XF-84H was quite possibly the loudest aircraft ever built, earning the nickname “Thunderscreech” as well as the “Mighty Ear Banger” On the ground, they were reportedly audible 25 mi (40 km) away. Unlike standard propellers which turn at subsonic speeds, the outer 24–30 inches of the blades on the XF-84H’s propeller traveled faster than the speed of sound even at idle thrust, producing a continuous visible sonic boom that radiated laterally from the propellers for hundreds of yards and was reportedly strong enough to knock a man down