LANDING DANGERS

Waikato Times, Volume 120, Issue 19984, 7 September 1936, Page 2

LANDING DANGERS

“ANY FOOL CAN FLY.”

80ME BAFETY DEVICES. AVOIDANCE OF CRASHES. “Any fool can fly,” states an English aviation writer. He affirms that the most dangerous thing about flying is not flying, but landing. Four out of five crashes occur in landing. “One reads a lot in newspapers about cruising speeds, much less about landing speeds, and still less about speed range, actually one of the major problems of aeroplane design.” He continues: The average landing speed is still around 50 m.p.h. for aircraft with a cruising speed in the neighbourhood of 100 m.p.h. And the problem has boiled itself down to keeping landing speeds near that level in spite of increased maximum speed, he says. Slotted Wing. If no artificial devices had been invented to reduce landing speed, ’planes like the “Comet,” flying at 250 m.p.h., would be completely unmanageable to all but a few pilots, for they would come in at over 100 m.p.h. As it is their landing speed is near about 70 m.p.h. and they take outsizes in aerodromes. To keep fast ’planes down to this level various devices, extraneous to the actual design of the aircraft, have been invented. The most common is what is known as the slotted wing. “Slotted wing,” is really a misnomer, for actually there is no slot in the wing. The slot is formed by a narrow winglet on the front edge of the wings.

When the ’plane approaches the stall this winglet automatically lifts, leaving a slot between itself and the edge of the wing. By canalising the air stream this slot smoothes out the eddies and gives more “lift” to the ’plane. This additional lift at the psychological moment prevents the ’plane from falling into tiie uncontrolled spin, or stall, which nearly always means a crash. Another device that is helping considerably to keep landing speeds down to a safe level is the wing flap, which acts as an air-brake. In normal flight this flap, hinged to the rear of the wings, follows the general camber of the wing. But for landing the pilot releases it until it drops to an angle of 60 deg. to the wing. This flap not only checks the speed of the ’plane, but by giving the wing a greater camber aiso gives it greater

“lift”—which means to say that it can fly more slowly without danger of stalling. Moreover, it increases the ’plane's angle of descent. To the layman this may appear a strange way of making landing safer—bringing the airplane to the ground at a sharp angle. Actually this is a most desirable feature, and one which is becoming increasingly difficult to achieve as aircraft become more streamlined. Floating for Miles.

’Planes like the Comet and the Schneider Cup seaplane are so beautifully streamlined that they will "float” fur miles. They are extraordinarily difficult to bring in to any normal sized landing ground, and in the event of a forced landing where the pilot must get his ’plane to earth rapidly within a given, and usually small space, they become extremely dangerous. Without slots or flaps, these fast, highly streamlined aircraft would be impossible for practical purposes. Most ’planes to-day are fitted with both slots and flaps—and slotted flaps. This combination has been found to increase the “lift” of a ’plane by 100 per cent. And it is through them that the new 150 m.p.h. air liners will be able to glide in safety at a nice steep angle at the comfortable speed of 55 m.p.h. All the same, you may say, 55 m.p.h. is still fast enough to hit the ground at if something goes wrong. It is, and that is why the number of landing crashes remains high compared to the other causes of accidents.

But beyond some highly efficient oilcompression shock-absorbing undercarriages, and the new stainless steel fuselage and wing construction, little has been done to minimise the dangers of a bad landing. And aircraft constructors will tell you that there is little that can be done. You can build an all-steel crash-proof railway coach, and an all-steel crash-proof car. You can build an all-steel ’plane, too, but it will not be crash-proof. While the strength and thickness of steel are depended upon it will never be possible to guarantee a plane as crash-proof, even for landing crashes. For the designer would have to take into consideration such factors as speed, height, and manner of falling, which are all variable unknowns. And if he tried to prepare for the worst contingency he would have to build a ’plane so heavy that it would never be in danger of crashing, because it would never fly. The Egg Trick. There is only one way in which a nearly crash-proof or landing-proof fuselage might be desgined, and that is by making physical laws co-operate with man-made materials. That is the way one Albert Sauvant tackled the problem. Albert Sauvant is a young Frenchman made of the stuff of which inventors and other martyrs are made. When he was a boy he was fond of “messing about.” And one day his messing about led him to place a hen’s egg inside an ostrich egg, seal up the hole in the larger egg and throw it hard to the ground. The ostrich egg was smashed, but the hen’s egg was not even cracked. This unwitting demonstration of the shock-absorbing qualities of a cushion of air was forgotten until ten years ago, when, while training to be a seaplane pilot, Sauvant witnessed a mortal accident—a seaplane crashed while flying over land and the occupants were crushed to death among the debris. This reminded him of his eggs, and he forthwith set about designing a fuselage on the air-cushion principle. In 1929 he tried out his first model with a specially designed steel fuselage. In the enclosed cockpit he strapped a three-days-old lamb and then let his model fall from a height of 450 feet. To everyone's surprise and his satisfaction, the lamb was uninjured. A year later he dropped a perfected model containing six eggs from 650 feet. One cracked, the remaining five being intact. Then lie designed a 'plane which he claimed would be both fireproof and crash-proof. It had double steel walls (Continued hi next column.)

and the cockpit closed automatically on impact. He's Still Waiting. He was so confident in his invention that he applied to the French Air Ministry for funds to convert a service ’plane and permission to crash it from 2,500 feet. The Ministry refused, and when Sauvant raised the necessary to buy and convert ail antique 80 h.p. army biplane, they had the Gendarmes chasing- him all over France to prevent him testing it. They would have none of this Death or Glory boy. He did nevertheless, in spite of their vigilance, eventually crash his crock, and crawled out shaken but triumphant. Unfortunately the enforced secrecy surrounding the crash, when it did happen, did him out of' the glory. ( And no Air Ministry being willing to assist at what they refuse to believe would be anything but sucide, he has not so far obtained official recognition. However, three years is not long for an inventor to wait before someone borrows his idea, and his day may yet come. But it is probable that before that day comes, the true helicopter, which goes one better than the autogyro, in that it goes up and down just like a lift, without any forward speed at all, will have solved the problem of landing speed and make crash-proof ’planes an obsolete superfluity. A ’plane of the true helicopter type is nearing perfection in England and may very shortly startle the world by making back garden landing and aerial traffic cops a possibility.