Negative vs. positive G's What say you?

[Patco Lch 1,465]

Just read "Never Call Me A Hero" by Jack "Dusty " Kleiss. At the Battle of Midway he scored hits on Kaga,Hiryu and Mikuma. He tells of puling 6G's out of a bomb dive. I was surprised those old birds could stand that. My thoughts wondered to the guy in the back seat facing rearward. If the aircrafts roll axis went between the front and back seat would the back seat gunner not experience negative G's? If so, seems this would be much harder on your body. Not only would it pull everything in your stomach up, but think of the blood pressure in your head with the strong risk of a stroke. We owe those WW2 guys so much!

[skelsey 765]

19 minutes ago, PATCO LCH said:

would the back seat gunner not experience negative G's?

Not unless he was upside down!

I see what you're thinking about the pitch change: however the rate of pitch change is relatively small compared to the overall trajectory of the aeroplane. Both crew members were travelling downwards a significant speed and by virtue of the pull up are now being forced to start travelling back upwards again, hence will be being pushed down in to their seats (or, more accurately, the seats are pushing them upwards).

However, I can't disagree with your last sentence!

[scottb613 1,188]

Hi Folks,

Another good example - The Great Waldo Pepper - wasn't the main competition in the movie was who could do an outside loop first ? All negative baby...

Regards,
Scott

[Patco Lch 1,465]

2 hours ago, skelsey said:

Not unless he was upside down!

I see what you're thinking about the pitch change: however the rate of pitch change is relatively small compared to the overall trajectory of the aeroplane. Both crew members were travelling downwards a significant speed and by virtue of the pull up are now being forced to start travelling back upwards again, hence will be being pushed down in to their seats (or, more accurately, the seats are pushing them upwards).

However, I can't disagree with your last sentence!

I see your point. But think of the poor guy in back that while the g"s are pushing the pilot down and back he is pushed down and forward against shoulder straps. Ouch. during climb out anyway. Dawg on officers always get the best .

[Chock 17,769]

I should think that you'd be more bothered about getting out of the concussion blast radius, the flak and MG fire which was coming up at you etc, than bending the airframe a bit from a high-G pullout if you were dive-bombing a warship. I would would certainly put up with a few Gs if I knew it would help throw an enemy gunner off his aim. I daresay that's infinitely preferable to having a 57mm cannon shell hit your cockpit!

Certainly it would be expected that a warplane would be pulling a lot of Gs anyway, so it's no real surprise that a WW2 combat aeroplane might pull 6Gs and would likely be stressed for that and probably more. Even a lot of the gliders I've flown have been stressed for +4/-2 Gs; pulling 4 Gs is not all that uncomfortable in them so long as it isn't for a long period and I've done that plenty of times when doing things such as low altitude practice spin recoveries, steep turns and such.

Most of the time, it was expected that warplanes which indulged in skip and dive bombing warships, such as the Vought F4U Corsair, Douglas SBD3/5 Dauntless, Curtiss SB2C Helldiver etc, would be lost through attrition after less than 50 hours of operation, either by enemy action, sustaining uneconomically repairable battle damage, or damage through landing accidents and carrier deck collisions during wartime operations. We've all no doubt cringed at the period footage of what look like reasonably intact classic warbirds - which would be worth millions nowadays - being unceremoniously dumped over the side of carriers to clear the decks; that sort of thing even happened in the Vietnam war, with many perfectly serviceable Bell UH-1 Hueys being tipped over the side of carriers to make room for others which were landing during the final days of evacuating personnel from Saigon. So nobody would be too bothered about overstressing an airframe and popping a few rivets on any of those venerable warbirds when they were operational warplanes, especially when factories were churning them out at the rate of one every couple of hours or so, which indeed they were during WW2's fevered production.