Problem Of Pilot "Blackout

Auckland Star, Volume LXXI, Issue 225, 21 September 1940, Page 1 (Supplement)

Problem Of Pilot "Blackout

FIGHTER aircraft are becoming so fast that greater attention will Have to be paid to the pilot's physiological limitations; Now that speeds are going up to 400 miles an hour and more, the ability to manoeuvre ■' rapidly will not be determined so much by the machine as by the human body; by how much centrifugal force, or "g," the pilot can stand in a turn without "blacking out." This point in fighter design may be looked on as one most curious yet reached, states the aeronautical correspondent of "The Times" (London). The barrier to progress seems suddenly to be shifting; and the next steps in effective speeds may depend not upon the designer alone but upon his collaboration with the physiologist. Means must be discovered, if possible, for enabling a human being to retain his faculties while turning his aeroplane on a small radius 'at high speed. Centrifugal loads may multiply his effective weight eight or nine times that of gravity. Blacking-out does not harm the pilot, but it momentarily destroys his fighting efficiency. There is a limit to what the aeroplane can stand in the way of centrifugal loads; a limit also to the smallness of the radius of turn which an aeroplane with a given wing loading can make. But it remains true that, with high-speed machines and with the pilot sitting upright, tho aeroplane can generally stand more than the man. The pilot himself sets the limit -to his aeroplane's powers of manoeuvre. His aeroplane may be faster than his opponent's, but that may mean that it is slower in manoeuvre. The extraordinary position may arise when the slower aeroplane will be able to get ' round a turn more quickly than the faster, because its pilot can hold it on a smaller radius. It is when the pilot is sitting upright in the customary attitude that his ability to retain his, faculties during big centrifugal loads is so restricted. It ht; been found if he Ikg vn

his back he can take without blackingout about twice the "g" as when sitting upright. If he crouches down he can take slightly more "g" than when sitting upright. German experiments with monkeys have been instructive. Together with experience in England and in the United State's, they suggest that about 6 "g" is the ordinary limit when sitting up, that about 8 "g" can be taken when crouched, and about 12 "g" when iving down on the back (the prone position will not do). A long period of 15 "g" seems to be lethal for monkey and probably also for man. He Would Fmd If a seated pilot in some hypothetical new fighter should approach his enemy at 400 miles an hour, and if the enemy turned and the fighter pilot wished to turn too as quickly as possible, he would still have to go round on a diameter of more than a mile if he were to iemain in full possession of his faculties. If he let his enthusiasm to put the enemy in his gun-eights get the better of him, and if the wing loading of his aeroplane permitted, be might tighten the turn by pulling in the control stick until the turn's diameter was less 1000 yards. Then the loads would go up with a rush. The pilot's body weight would soar, to six, eight, or more times normal At 8 "g" he would black-out, and at 10 "g w faint. In a recent paper Mr. Brian Worlev t pointed out that an aeroplane loaded ' at 201b a square foot, flying at 200 ; miles an hour, at 4 "g" would com- | plete a turn in 15 seconds, while at 400 miles an hour an aeroplane loaded ( at 401b a square foot would take nearly j 30 seconds for the same turn at the j same "g." The extra speed is there- . fore of no advantage during the turn unless the pilot of the faster machine m can take more "g." If the pilot of the ' second machine happened to be a man with a cast-iron stomach who could i stand 8 "g" he could get round the 1 turn in about the same time as the slower machine. u s At first sight these things seem to Z suggest that human limitations in the loads which can be taken without i blacking-out will set a boundary to

speed development. . Bat that is not so. Straight speed has no effect whatever on the pilot, and is always of use to. an aeroplane. Interceptor* must have straight speed; the more they have the better, because their first task is to catch the enemy. But when they meet other fighters their powers of manoeuvre come into play; then It would be a great advantage if the aeroplane eonld be so arranged that its pilot could stand enough "g" to enable him to use all the handling powers his machine possessed. , - - So we turn to the doctors to ask what can be done to fit the man for the modern machine. They are working on this subject and have been for some time, but so far the lying down theory seems the only useful one. It is not quite so impossible as it seems at first to arrange a pilot in the. lying-down position. The drivers of some sports cars are nearly lying down. But the first thing is to determine exactly what blacking-out is, and"on that there is no unanimity. Lyiag Down T« It! It is not a grievous sensation, though sustaining big loads in a turn is never pleasant. The head seems to weigh a ton and to be forced down between the shoulders. The actual black-out the Germans aptly call the "curtain." There is no loss of consciousness, no pain, none of the bleeding at the nose which the American films like to show; merely this "curtain" of black before the eves. And so soon as the turn is eased "and the "g" brought down, sight returns. Causing the pilot to lie down seem? the only way yet discovered of retard ing a black-out and so allowing the powers of manoeuvre of high-speed machines to be used. But whether so unorthodox a position would ever be accepted —supposing it could be arranged in a practical way with good outlook —is doubtful. Yet it would allow a 300 m.p.h. aeroplane, which could not turii on a smaller radius than 1000 yards wilh the pilot seated, to turn on a radium of half that distaooQi