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Aviation History
1921
1921 - 0026.PDF
JANUARY 13, 1921 THE H.R WING AND GERMANY FROM an article which appeared in the German aviation jour- nal Flugsport it seems that Mr. Handley Page is not the only designer to arrive at the slotted wing as a means of obtaining increased lift. It appears, however, that the German inventor was refused a patent because, in the opinion ot the German Patent Office, there did not appear to be any reason to suppose that sxich a wing would give greater lift than the orthodox aerofoil. Following is a translation of the article in Flttg- sport :— " We learn that already in February, 1918, the same idea (as the HP. wing. -—Ed., FLIGHT) was placed before the Patent Office by Herr Otto Kattler on behalf of the inventor Herr G. Lachmann, of Darmstadt. The specification is as follows : ' Aerofoils whose profile consists of several separate staggered elements, arranged in the form of a Venetian blind.' The claim was founded on the following considerations : ' The lift of a curved plane moving through some medium is com- posed of a positive pressure on the lower surface and a negative pressure on the upper surface of the flane. The present inven- tion has for its object an increase in the lift of an aerofoil. FK5.1 To achieve this the thick aerofoil F is divided into auxiliary sections f1( f2, f3. Fig. 1.' " ' The spaces between the auxiliary aerofoils have the appearance, in section, of nozzle-shaped channels, with their narrow ends on the upper surface of the main aerofoil. The air rushing past the narrow nozzle openings on the one hand, and the suction of the negative pressure on the upper surface of the aerofoil on the other, result in sucking air past the cambered auxiliary aerofoils, thus causing the new pressures Pi. PJ. P:t•' " ' The total air resistance W of the aerofoil is therefore composed of the sum of the pressures p,, p,, p^, etc., on the small aerofoils f,, fj, f3, etc., and of the total resistance P of the larger aerofoil F respectively.- These will naturally be somewhat smaller than the resistance P of a solid aerofoil/ " ' In Fig. 2 is shown diagrammatically the constructional application of the invention to a modern aerofoil. In the space between every two ribs are arranged two plates of ply-wood, sheet metal, Cellon, or some similar material, shaped to conform to the aerofoil section. By suitably shap- ing the plates a smooth run into the lower aerofoil surface is possible.' " The Patent Office has refused the application, the reason stated being that it was not necessarily to be expected that the lift of the aerofoil would be increased by the arrangement of slots. It was pointed out that, although the negative pressure on the upper surface is constantly being built up, it is being reduced by the air streaming up through the slots. To this the inventor replied in a further application :—' The vacuum over the upper surface is not stationary, as a space from which the air has been exhausted and which can be filled again by letting in air. The negative pressure above the upper surface of an aerofoil is caused by the rapid forward motion of the machine, and is built up anew every moment. It cannot, therefore, be equalised through the slots, as the air rushing over the upper curve of the aerofoil at once re-establishes the original condition of rarefaction. By way of a practical example it is pointed out that the aerodynamic efficiency of an aerofoil depends to a minor extent only on the airproofness of the fabric covering. It is quite possible to fly with fabric which lets the air through, if only the surface is smooth. According to the objections raised this should not be possible, since an equalisation of pressures would occur.' " A complaint has been lodged, and the matter is now in the hands of the Appeal Department of the Patent Office." No. XI Squadron R.A.F. A RE-UNION dinner for officers of the above Squadron will be held at Kettner's Restaurant (behind Palace Theatre) at 7.30 p.m., on Friday, January 28. The price of the dinner will be 12s. 6d., exclusive of wines, etc. Those wishing to attend are requested immediately to inform R. E. Dangerfield, Mount Avenue House, Ealing, W. '5. *' A " Naval and 216 Squadron R.A.F. IT is proposed to hold a re-union dinner of all officers and men of the above squadron on April 2, 1921. Those interested are asked to communicate with Capt. E. D. Harding, 5, Belsize Square, London, N.W. Martlesham Heath R3union Dinner A REUNION dinner for officers of the Aeroplane Experi- mental Establishment, Martlesham Heath, will be held in London on Friday, February 25, 1921. The time and place will be announced later. Will any old members of the station please communicate with Captain P. G. Robinson, Room A. 139, Air Ministry, London, W.C. 2. The N. Ontario Balloon Adventure FURTHER information regarding the experiences of the U.S. Naval Airship officers, who on December 14 were driven in their free balloon into the, wilds of N. Ontario under storm stress, has been obtained by the New York World from the wife of Lieut. Hinton. An Indian runner brought in a letter from Moose Factory, where the balloonists found refuge after four terrible days of wandering. It describes how after every ounce of available ballast was expended the balloonists descended in a fog and abandoned the balloon. They eventually came across an Indian who led them to a trappers' camp. On the way they ate moss. The men were so exhausted from the cold—there were 40 deg. of frost—and the absence of food that Lieut. Stephen Farrell, according to Lieut. Hinton, " fell several times and wanted us to cut his throat and use his body for food." ««. Lieut. Hinton tells his wife that he succeeded in cheering the despairing man, and that they decided to stick and die together. The three men who for the last 11 days have been travelling homeward in snow shoes, accompanied by Indian guides, have arrived at Mattice, on the Nail Trans-Conti- nental Railway, the nearest railway station, 200 miles from Moose Factory, a journey of about 12 days in a dog sledge.
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