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Aviation History
1929
1929 - 0142.PDF
What is remarkable, assuming the account sent to us to be reliable—and we see no reason to doubt this—is the fact that the machine should have survived the pounding she must have received while lying for two days in the surf, and later as she was being left high and dry by the tide. Not only survived it but without springing a leak. In this connection it may be recalled that the Short " Singapore," during Sir Alan Cobham's African flight, got into difficulties during a gale at Malta. Although the lower wing of the " Singapore " was damaged, the metal hull itself remained intact, and these two experiences rather seem to indicate that the strength of a modern flying-boat hull is something out of the ordinary. The hull of the " Romar " is of very peculiar shape, being characterised by very narrow beam, perfectly flat sides, and a fairly pronounced rounded Vee to the planing bottom. Doubtless, the shape and con- struction of the Vee bottom were mainly responsible for the fact that the hull remained watertight. What seems, perhaps, more remarkable is the fact that the wings were not damaged. With outboard engines and a fairly heavy wing structure, it is to be expected that the stresses set up every time the hull grounded in the breakers would be severe, and it is, at any rate, possible, although our correspondent does not refer to the fact, that the breaking later, during the sea- worthiness trials, of the diagonal strut which braces the wing float in a fore-and-aft direction, may have been due to undetected damage sustained during the stranding. As for riding out gales at moorings, both the Blackburn "Iris" and the Short "Calcutta" have done this very successfully, the " Iris " at Felix- stowe and the " Calcutta " at Southampton. Their moorings held (even if only just), and thus they were not called upon to lie in a breaking surf for two days, but their seaworthiness while afloat at moorings was amply demonstrated. As regards the actual trials of the " Romar," dealt with in the article, these appear to have been entirely successful. To British flying-boat designers and students, the main feature of interest in the Rohrbach " Romar " is the extremely narrow beam of the hull, and in view of certain developments in this country the behaviour of a machine of this type while on the sea is a matter of very considerable interest. We have had no definite statement on the subject from Dr. Rohrbach, whom we did not have the pleasure of meeting during the Berlin Show, but a close examination of the " Romar," its wing loading and power loading figures, no less than its lines and construction, leads one to the conclusion that, for this type of flying-boat, the narrow beam hull is the only satisfactory solution. The " Romar" has a very high wing loading. Even with a high-lift wing this must necessarily mean a high take-off speed. And with a hull of more normal proportions there would appear JANUARY 24, 1929 to be a likelihood of the lift from the steps raising the machine before the wings are able to take the lift, and the controls capable of giving sufficient power. Consequently, a more beamy hull would probably give rise to difficulties in handling during the actual take-off. To obtain a nice balance between wing lift, planing and control is one of the problems with which the designer of a flying-boat is faced, and it may be imagined that this problem does not become any easier as the take-off speed increases. If the problem can be successfully solved, and the " Romar " appears to show the possibility of doing so, the narrow beam probably has considerable advantages. The inevitable corollary of high take-off speed is high alighting speed, but the pronounced vee bottom and narrow beam should provide shock- absorbing qualities of a very high order, and if, therefore, the take-off problem with a narrow beam can be overcome, the alighting and seaworthiness should not really present very great difficulties. Taxying on the surface in a rough sea, the narrow- beam hull will probably give smoother and easier movements than would a more beamy hull, but on the other hand, as the beam is reduced so the problem of lateral stability on the water becomes more difficult. It is- interesting to compare the three "schools" which may be said to exist as regards this subject. The British " school " favours biplane arrangement of the superstructure, and wing floats placed under and near the tips of the lower wing. Herr Dornier, on the other hand, uses the monoplane wing, coupled to a hull of fairly wide beam, and relies for lateral stability on the water on wing " stumps " projecting from the sides of the hull. Dr. Rohrbach, also a monoplane exponent, uses an extremely narrow beam, but places his wing floats under the wing engines, i.e., farther outboard than the wing " stumps" of the Dornier boats, but not at the extreme tips, as is British practice. Which of the three systems is likely to prove the best—if indeed there is very much to choose between them, has not yet been conclusively proved, and the seaworthiness tests of the " Romar " have contributed but little towards a settlement of the question. What they have, apparently, done is to prove that the Rohrbach system does give a very good degree of seaworthiness. But they have not, of course, proved that the other two schools are " wrong." To us, the great interest of the " Romar" trials lies in the fact that a type of boat which differs so materially from those produced on this side of the North Sea should, during its early trials, have proved not only seaworthy with a total weight of 32.0C0 lbs., but able to get off repeatedly in a heavy sea. As yet we have no information concerning the ability of the " Romar " to get off in a calm from a smooth sea. It is just possible that this may prove somewhat difficult for the narrow-beam boat, which may be assumed to be at her best in.a seaway. Air Adventures of Sir Sefton Brancker ON January 16, Sir Sefton. Brancker, Director of Civil Aviation, returned to London from the Mediterranean, having encountered one or two air mishaps. Whilst he was flying by seaplane on the Italian Tripoli-Syracuse line the machine was obliged to return to Tripoli owing to engine trouble. Taking another route, Sir Sefton reached Rome and then flew by the regular air service which operates between Rome and Barcelona and calls at Marseilles. The mistral was met which blows with such force in the Marseilles region, and the seaplane was forced down in a small harbour. about 20 miles from the Marseilles seaplane base. Sir Sefton was then obliged to reach Marseilles by land and go on to Paris by train. From there he flew on the air line to London. High-Speed Flight THE R.A.F. High Speed Plight, which will provide the pilots for the British machines entering the Schneider Trophy Race, has been strengthened by the posting of Sqdn.-Ldr. A. H. Orlebar, A.F.C., to the Felixstowe Seaplane Station. The other officers who have already joined the flight are Flight-Lieut. D'Arcy Greig, Flight-Lieut. G. ih Stainforth and Flying Officer D. F. W. Atcherley.
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