FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1945
1945 - 0123.PDF
JANUARY I8TH, 1945 upon which to build. The fuselage of the Bristol Beau- fighter is built up on two substantial keel members, which result in a centre section of very great strength. The underside will be prone to damage in " wheels-up " belly landings, and it mighjtroe wise to reinforce certain stringers to act as skids should such an accident happen. The rocket-propelled, tailless Messerschmitt 163b fighter is reported to jettison its undercarriage after taking off, and to land upon a skid member built into the underside of the fuselage. This scheme, in a modified form, might be applied to very large landplanes in the not so distant future. The rear end of the fuselage has to carry the tail loads. These will be vertical from the tailplane, horizontal and torsional from the fin and rudder, and vertical and often torsional from the tail wheel while taxying. On many modern aircraft it is the practice to " bury " the fly- ing controls in this part of the fuselage, allowances for the operating cranks being made early in the design stage. A good example of this practice is given by the Hawker Typhoon, which has an exceptionally clean tail eiKfT especially now the rudder mass balance is housed inside the fin shroud. The housing of the identi- fication lights in the rear of the tailplane fairing is also a particularly ingenious feature. The duties for which the type is intended should be considered. A high-speed fighter, which will become obsolete after a few hun- dred flying hours, is in a different class from a com- mercial air liner that may still be operating after several years, • as in the Douglas Dakota. In the case of the fighter, weight and performance are both more important than cost. In the past the view was often held that in the case of civil transports it might be worth while sacrificing ultimately worth literally just over twice its weight in gold. The problem of serviceability—the criterion by which aircraft are largely judged in the R.A.F.— should receive special attention. Vf^ not much good to have some of the finest aircraft in he world if most of the time they are "U/S" on the ground. This problem is likely to be of great importance on transport aircraft in the future, and should be carefully considered in the designs now '' on the board." Finally, there is the all-important question of replace- ments, which is of exceptional importance in modern war- fare. Special parts should only be used sparingly, and when there are very definite reasons" for not using a '' stan- dard " part, in order to ease the vital problem of replacements. In the early days many aircraft designers considered metal stressed-skin fuselages as impracticable. Nowadays, however, there is no doubt that the problem of rapid and cheap manufacture can be solved largely in the drawing office. In the past these consideratidns were often left to the works, who devised ingenious and costly jigs, tc^make parts elaborately designed. ^" The fuselage of the Avro Lancaster is an excellent example of the way in which production problems can be solved in the drawing office. The fuselage is split up into several sub-assembly units, some of which are further split down the centre line. Stressing1 Considerations Another example is the fuselage of the de Havilland Mosquito, which is built in halves, the split being along the top and bottom from nose to tail. Many advantages can be claimed for this method, and there appear to be no corresponding disadvantages. It is possible to employ many more on the work at the same time without undue congestion, and thus increase the rate of production. The interior is completely accessible for riveting and for the installation of some of the equipment, besides most of the plumbing and electrical wiring circuits. The problem of '' stressing'' a stressed-skin fuselage is not easy, for it is not generally possible to take any success- ful short cuts in problems of this nature. To obtain a satisfactory analytical solution, it is necessary to accept certain fundamentals, and then work out mathematically the appropriate stress distribution. A stressed-skin fuselage is really a hollow beam which must be capable of transmitting bending, torsion and shear stresses. It differs considerably from the usual engineers' idea of a beam, which may be described as " a member in which the flanges take the bending moment and the web the shear force." The stringers ta^e the bending moment stresses, and the flow of shear forces must be maintained entirely by the skin. Much research work has been done ith a wooden monocoque fuselage some of the pay-load to in- crease robustness. This was confirmed by Chief Engineer Guilonard, of the K.L.M. Air Lines, who claimed that their Fokker equipment was still satisfactory after many years' service. More recent experience, however, has shown that, providing the safety of the aircraft is not endangered, the maximum payload possible is desir- able. To substantiate this an American has produced figures showing how every extra ounce of payload is The fuselage of the Deperdussin •• Seaguii •' monoplane, 1913, was a true wooden monocoquewithout internal stringers. The term is really a misnomer as applied to modern construction, with its numerous frames and stringers. A return to true monocoques by using magnesiumwas advocated by Mr. Digby in our issue of July 6th, 1944.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
