What is the ability to roll and the ability to turn????

[cheddar cheese]

That would make more sense to me yes.

 

[the lancaster kicks ass]

you realise most aircraft would break up under that stress?? modern fighter pilots in mach 2+ jets suffer 8-9G..............

 

[Anonymous]

you realise most aircraft would break up under that stress?? modern fighter pilots in mach 2+ jets suffer 8-9G..............

Most WWII fighters had operating flight limits (ie: recommended maximum) G tolerances of at least 6 G's. The P-51 was rated at 8 G's sustained, and pilots took it as high as 10+ G's on occassion (we are talking bumps here, not sustained).

G-tolerance varies greatly from pilot to pilot. In general, we can assume fighter pilots were in good shape, so lets assume that is a constant. Another factor is build - short stocky men handle G forces better than tall or thin men. High blood pressure helps too. Robert Johnson was supposedly able to handle very high G-loads even w/o a G-suit, he was built like a beer barrel.

Generally speaking, people can withstand only about 2G's if sitting vertically for any period of time. At 2-3G's, even a person in good shape will usually start to grey out within about 5 seconds pass out within about 10 seconds. As G forces increase, tolerance goes down and the onset of greyout and blackout come faster. By 5G's only a couple of seconds will pass before greyout and blackout usually occures by 5 seconds. Interestingly, at higher G's the greyout timing seems to get shorter but the blackout timing seems to remain about the same, probably because the eyes are effected by lack of O2 quicker than the brain.

One way that G-tolerance can be improved is to tilt back the pilot's seat and raise his legs. The downside is this makes it harder to apply force to the stick. The FW190 had a fair incline to the seat, the Spitfire and many other allied planes had a second set of rudder pedals above the main pedals the pilot could use to raise his legs.

Well trained pilots are able to push their tolerance to G-forces up a little through what is know as Anti-G techinques. Basically this consists of bearing down hard like your trying to pass a huge one and grunting out a word (different pilot groups use different words). This can buy a pilot perhaps another G in tolerance and delay greyout and blackout by several seconds - if they don't blow a blood vessle and "strokeout".

The British introduced a G-suit in about 1943, but it was not well liked and most pilots refused to use it. It was basically like wearing two pairs of rubber pants comming up to a few inches below the armpits, one pair inside the other, filled with water in-between. When the plane pulled G's, the force of gravity on the water increased the pressure on the legs and torso of the pilot, helping to push the blood back up into the head. The problems were several:

1: folds in the suite could result in very high pressure against one leg only - pilots claimed the felt like their leg was being cut off.

2: the suit was very uncomfortable and tended to fill with sweat.

3: it was almost impossible to bail out if wearing one.

The Berger G-suit was much more successful. It was invented by a Canadian WWI pilot who'd been working on how to improve G-tolerance since that war. Unfortunately he was unable to get funding from the Common Wealth. So he decided to try his luck with the Americans after they joined the war on the side of Britain. After a couple of years he designed the pnematic G-suit which is, for the most part, what has been used ever since. It consists of inflatable cuffs (very much like blood pressure cuffs) sewn into the trowsers and around the mid-section of the flight suit. When a sensor detects increasing G's, compressed air is used to inflate the cuffs which squeeze the legs and torso driving the blood up to the brain. It was introduced into US service in mid-spring 1944, and very quickly installed on almost all front line high performance fighters. I believe some Spitfire units also got the Berger-G suit, starting in fall 1944.

Through a combination of the Berger G-suit and the Anti-G grunt, pilots could handle sustained loads of about 4.5 G's, 4.5-6 G's for about 10+ seconds, and 6-7 G's for 5+ seconds, depending on the individual.

Most modern G-suits are very similar to the Berger G-suit, except that they often use bio-sensors and computer controls to provide only what assistance the pilot actually needs. This, in combination with more selective fighter pilot screening and better training for G-tolerance, have increased fighter pilot G-tolerance only a little.

There are also some cutting-edge "hydrolic" g-suits in the works (I don't know if they've reached deployment yet), which use a large number of "cuffs" and very precise computer control to allow even higher G tolerance.

=S=

Lunatic