According to the Standard Aircraft Characteristics sheet for the F8F-2 with full internal load but no external stores the maximum allowed positive acceleration is given as 6.2 g only (being inferior to the A6M and the comparable figure for the F4U-4 being 7.25 g) . In addition, the pilot manual for the F8F has many more warnings regarding structural strength than any other contemporary fighter manual I have read. So, how did it fare in service as far structural failures go?
Potential F8F-2 structural strength problems
- Thread starter Trilisser
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Some Bearcats have an external reinforcing strap along the lower wing spar. First photograph id of the Woods Family F8F-1 Bearcat, N2209. Underside of port wing, nose to left at 11 o'clock of photo, landing gear bay @ 8 and 11 o'clock. Dive flap with interdigitated hinge to left of antenna, spar strap to right of antennae. The second pic is the starboard wing of John O'Conner's F8F-2, N68RW, nose to the right at 2 o'clock,, which has the dive flap, but no spar strap.
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GregP
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Most U.S. fighters at the time were designed for 8g with a 50% safety factor. You could pull up to 8 g's with no danger. You could pull up to 12 g's and expect wrinkles in the wing / fuselage / tailplane. You could expect failure at 12 g's and over, though some WWII fighters came home with a few more degrees of dihedral than they took off with.
The A6M series was designed for 6 g's with a 100% safety factor. You could pull 6 g's with no damage, and up to 12 with expected wrinkles. You could expect failure at 12 g's and over.
So, the failure point was the same for the A6M and for U.S. fighters, but normal rating for the A6M was 6 g's.
The Bearcat was a U.S. attempt at a Zero-like fighter without the Zero's flaws. The break-away ailerons (supposedly at 7.5 g's) were never a success, though they were tested, and were actually tested asymmetrically, too. In most combat situations in WWII, there was precious little difference between a 6 g and an 8 g airplane because the planes didn't have the power to generate 8 g for anything but short-duration direction changes ... maybe a 30° - 45° turn. After that, they bled speed and were down to sustained turning g-loads, which were almost all 6 g's or less at any altitude, with the power available at the time. The Bearcat may have been a bit better-prepared for more sustained g than other due to the power-to-weight ratio at combat weight, which was about 4.6 pounds per HP for the F8F-1 and about 4.3 pounds per HP for the F8F-2 at a combat weight of about 9,700 pounds. Wing loading for boith at this weight was just under 40 pounds per square foot, making them quite maneuverable.
The only real issues were with the break-away wing tips. They went from squibs, to explosives with a cockpit trigger, and then away from explosive disconnect when a maintenance tech was killed from an inadvertent firing during maintenance. Later, they abandoned the break-away wing, added external structural straps, and limited the aircraft to 7.5 g's.
I can attest that the Bearcats that have been operated by the Planes of Fame have universally been quite reliable, though they are not exactly getting standard military handling by a wide variety of pilots who don't care about the engines or airplanes. Today they are operated by dedicated owners and pilots who know how to care for the engines., and they only see 2,000 HP for a short time at takeoff before being throttled back to economy cruise. Probably the worst they see is when flying aerobatic demos at airshows, and they seem to shrug off any issues in that mission.
Yes, things go wrong. Mostly very minor.
The A6M series was designed for 6 g's with a 100% safety factor. You could pull 6 g's with no damage, and up to 12 with expected wrinkles. You could expect failure at 12 g's and over.
So, the failure point was the same for the A6M and for U.S. fighters, but normal rating for the A6M was 6 g's.
The Bearcat was a U.S. attempt at a Zero-like fighter without the Zero's flaws. The break-away ailerons (supposedly at 7.5 g's) were never a success, though they were tested, and were actually tested asymmetrically, too. In most combat situations in WWII, there was precious little difference between a 6 g and an 8 g airplane because the planes didn't have the power to generate 8 g for anything but short-duration direction changes ... maybe a 30° - 45° turn. After that, they bled speed and were down to sustained turning g-loads, which were almost all 6 g's or less at any altitude, with the power available at the time. The Bearcat may have been a bit better-prepared for more sustained g than other due to the power-to-weight ratio at combat weight, which was about 4.6 pounds per HP for the F8F-1 and about 4.3 pounds per HP for the F8F-2 at a combat weight of about 9,700 pounds. Wing loading for boith at this weight was just under 40 pounds per square foot, making them quite maneuverable.
The only real issues were with the break-away wing tips. They went from squibs, to explosives with a cockpit trigger, and then away from explosive disconnect when a maintenance tech was killed from an inadvertent firing during maintenance. Later, they abandoned the break-away wing, added external structural straps, and limited the aircraft to 7.5 g's.
I can attest that the Bearcats that have been operated by the Planes of Fame have universally been quite reliable, though they are not exactly getting standard military handling by a wide variety of pilots who don't care about the engines or airplanes. Today they are operated by dedicated owners and pilots who know how to care for the engines., and they only see 2,000 HP for a short time at takeoff before being throttled back to economy cruise. Probably the worst they see is when flying aerobatic demos at airshows, and they seem to shrug off any issues in that mission.
Yes, things go wrong. Mostly very minor.
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