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Aviation History
1944
1944 - 0387.PDF
FEBRUARY 24TH, 1944 • FLIGHT 197 Fig. 2. Amphibian flying boat based upon the suggestion of a contributor to our Correspondence page. regarded as a refinement, yet it still remains an encum brance with a known capacity for wallowing, and when retracted it becomes but a second-rate wing tip devoid of any purity of form. ^ For my own part I am essentially unprejudiced, and I hold no brief for the landplane, but I am also not con vinced that the flying boat is the exclusive answer to transoceanic air transport. My views are based on observa tions going back to 1934 or so- At that time Deutsche Luft Hansa were operating Dormer " Wal" flying boats on the South Atlantic service between Bathurst and Natal, and during a period of two or three years it was only neces sary to make three forced landings at sea. ^~ In the ten years intervening, engine maintenance, over haul, and in consequence reliability, have improved to such an extent that I believe this record could be improved upon and the possibility of a forced landing almost discounted. Perhaps I am a little too optimistic, so for the moment I will accept Mr. Edmunds' sober warning to consider the psychological effects of a forced landing at sea. First of all, we must realise there is a danger that the false perspective encouraged by/persistent claims of the flying boat having a ready-made landing surface may prove misleading, and this goes for the forced-landing bogy also. In their comments on this point Mr. Kemp and Mr. Edmunds very aptly acknowledge the possibility of bad weather interfering with the process, and I am brought to wonder if it is realised what serious limitations are thereby implied. In certain parts of the globe the safety factor of the flying boat, i.e., its ability to land on water, is of little consequence and it is on a par with the landplane. 1 should certainly be very apprehensive at the prospects of a flying boat forced to land in the Mediterranean with a mistral blowing ; which serves to confirm my memory that off the West Coast of America the Pacific swell will produce 30ft. waves without there being a»y wind. Some "ready- made " surface! Moreover, the difficulty of clearing a seadrome of drift ing, and possibly submerged, iceflows would be a greater problem than clearing the concrete runways of a snow bound airport. Putting the matter in a nutshell, an airport is statically determinate ; a seadrome is not. Perhaps I may be permitted a guarded reference to what is surely the classic example of the landplane's aquatic aptitude. The well informed will recall that during this war certain of our bombers whose duties exposed them to long sea crossings were fitted with pneumatic flotation gear as a precautionary emergency measure. The purpose of this equipment was to keep the machine afloat long enough for t&e crew to abandon aircraft in the event of a landing at &a. There can be no finer testimony to the success of the idea than those reports which reveal that many of these aircraft, after having been abandoned for hours, had to be finally sunk by naval gunfire. Here is the mora!. With a heavy sea running a forced landing might tear the bottom out of a flying boat, and with subsequently fatal consequences. A landplane with carefully placed flotation gear could possibly suffer similar damage and still not founder. [ • Post-war Instrumentation What Mr. Knowler argues in regard to the effects of fog is, in the main, highly debatable. One must confess to batting on a sticky wicket when holding forth on tb^possi- bilities of post-war instrumentation for so much of its present development is correlative with military procedure and therefore highly secret. The view I take is that if seven or eight hundred air craft can rendezvous over a certain area of enemy terri tory, within the space of thirty rninutes or so and in infi nitely hazardous conditions, then modern instrumentation should ensure bringing a mere handful of, say, fifteen or twenty civil aircraft safely into a fog-bound airport. I make this assertion without any knowledge of the collision risks on these big raids but with the firm conviction that we have, even now, almost mastered the paralysis .pFtog. To compare a fog-delayed train service with a similarly handicapped air service is no criterion at all, for the two are worlds apart. A train can move only in one direction and in one plane and when brought to a standstill it will CENTRE OTGRAVITT q R ! i/n q A i A/ A '^••-^.^ O.A.B, ARC COUPLES ABOUT C.G CAUSING ROTATIONAL MOVEMENT Of HULL A» 1NDICATEO BT ARROWS Fig.3. Sponson location dictated by tricycle con siderations would introduce yawing moments on the water. inevitably cause a hold-up lor two or three miles down the line. Such a bottleneck can hardly occur with a num ber of aircraft stepped-up at various altitudes. Regarding Mr. Edmunds' proposal, which I have sketched in Fig. 2, the whole idea is fundamentally at variance with recognised practice and, far from having any saving grace, is actually full of loopholes. The first thing to be observed is that the fore-and-aft location of the sponsons is immediately affected, which is what Mr. Edmunds predicted. On dry land the machine would probably be safe enough, but in the water a very different state of affairs would prevail and the machine would be hard to handle. Obviously under the influence of moments mf^m Oi_JK^2L Fig. 4. Comparative lateral stabilities of boat and landplane at moment of touching down are determined by hull beam and wheel track, about the e.g. caused by the rearward disposition of the sponsons, the boat would have a pronounced tendency to yaw, as shown in Fig. 3. The great failing of the amphibian, however, is contained in the fact of it incorporating two landing devices, and if P
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