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Aviation History
1951
1951 - 0639.PDF
6 April 1951 397 Sesirable in this country. Rightly, in my view, the British have in general adopted some form of the wing-float arrangement. The critics of this method contend that wing floats are necessarily somewhat fragile and very liable to damage; and they are the weak link in the flying-boat chain, invariably getting knocked off in the event of a forced landing in a rough sea, thus greatly increasing the risk of a total loss. That, because of their size and situation, they cannot reasonably be retracted and so cause a loss of performance under all conditions. I suppose there is some measure of sense in all these arguments but they are all, I think, grossly exaggerated. Stabilizing wing floats can be positioned almost anywhere along the wing span. I personally favour the extreme wing-tip float because in this position, to satisfy any given stability requirement, it can be of the smallest dimensions. This is all in the interest of weight, air resistance and structural strength. In this position it can be not retracted inboard but raised to the wing tip, where it may well be that its drag is more than compensated by a reduction in induced drag of the wing itself, a phenomenon found in fighter aircraft to which long-range jettisonable wing-tip tanks have been fitted. After a considerable study of the subject, I have come to the conclusion that wing floats are seldom lost or damaged as a direct result of rough seas. Indirectly sometimes, yes. For instance, when a boat has been badly landed or has been bounced off again at a stalled speed, and falls back again wing-tip first. More often the loss of a wing float has followed an alleged good landing on a smooth sea, a glassy smooth sea, and probably in poor visibility. I cannot conclude on such a disturbing note and so claim indul- gence once more to digress awhile. No, I do not believe that waves knock floats off, as is generally supposed, either at moorings, adrift, or when taxying fast. Waves are not what they seem; except when breaking on a shore, the water composing them has no velocity. Though waves can vary much in shape, they are usually much flatter than they look and they do not contain much energy. How could a small ship create such big ones if there were ? The mass is great but it moves slowly. If enough water gets on a ship's deck the deck will collapse, but it is not, I contend, wave energy but just plain weight of water that does the damage. A properly shaped wing-float at the proper incidence will stand an amazing amount of collision with waves. Its very shape is its own shock absorber, but no float can stand being propelled at high speed through the water submarine fashion. Try to imagine the resistance of such a body at a mere 80 knots. It is quite impossible to stress for. Here, I think, lies the answer to the mysterious loss of wing floats in the past. Too high a landing speed and/or too fine an incidence, an improperly shaped float, and it is under and off. I hope I have not implied inadvertently that I consider there is a limit to the practical landing speed of a flying-boat, for I do not. Provided the hull contacts the water at the correct attitude, I see no practical limit to speed such as, in the case of a landplane, might well be wheel r.p.m. There were innumerable cases on record in the last war where Sunderlands survived rough seas, sometimes without suffering any damage at all. There was the famous occasion where a Sunder- land, its petrol tank holed by enemy action, alighted in a big sea and was towed by a corvette for 74 hours to base. Despite storms and a big swell, it suffered no damage. Perhaps the epic was when a Sunderland, patrolling some 400 miles south-west of Iceland, was forced down in a full gale as a result of a defect in the fuel system. The seas were terrific, and the captain, fearing the boat would founder before they could be rescued, invited the rest of the crew—the defect having been rectified—to take the risk with him of attempting a take-off. They all agreed, for, although they knew the odds against them were great, they felt it was their only chance. After one false attempt, out of wind but along the waves, they had another go and this time, aiming straight at the seas, they succeeded. It was a terrifying experience; they hit the waves a number of resounding cracks before finally getting clear. The hull was severely damaged, the airscrews bent to an incredible shape, the whole ship was almost a "write-off", but they flew home with the wing floats still in position and doing their job. That sort of story helps to confirm my faith in the type and in the future of the flying-boat. In conclusion, I am going to have the audacity to offer a word of advice to the flying-boat designers of the future. Do not risk the many brilliant qualities inherent in the type too much in an effort to surpass landplane performance, and avoid at all costs the trend to develop on lines being pursued by some foreign countries particularly America, at least until their boats are as good as our own. Let us continue to have courage to carry on in our own way. Short Sunderland (Great Britain) with lateral stabilizing floats. Dernier Do 24 (Germany) with "sea wings," or sponsons. Consolidated Catalina (USJL.) with floats retracting at the wing-tips. Savoia-MarchettiSM twin-hull flying-boat. Machines of this same general type, with two or three engines, were widely used by the Italians before the war.
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