GB390201A - Improvements in aircraft aerofoils - Google Patents

Abstract

390,201. Tail-less aeroplanes. LIPPISCH, A., Fliegerlager-Wasserkuppe, Post Gersfeld, Germany. Sept. 30, 1931, No. 27242. [Class 4.] An aerofoil for arrow-shaped tail-less aircraft has a section which varies over the span from a stable section at the root being merged gradually into sections having an inverse centre of pressure movement whereby the aerofoil has a substantially constant centre of pressure permitting the employment of a single spar. The aerofoil may be formed with a continuous small slot between a large fore part and a small rear part, and this rear part may be pivoted to form a control surface. Fig. 1 shows an aerofoil of the above-described type in which a main part 1 with a reflexly curved median line 7, 8, Fig. 2, is merged into a symmetrical section 12, Fig. 3, and finally into a reversed aerofoil section 17, Fig. 4. The small aerofoils 4, 13 formed by the division of the main aerofoil into two parts by an inclined slot are adjustably mounted on brackets arranged with pivots at or over their centres of pressure and are shaped so as not to close the slot in any adjusted position. Aerofoils 4 serve as elevators and aerofoils 13 as ailerons. A single spar 10 is fitted. Vertical aerofoils 19 with or without adjustable flaps 18 may be arranged at the wing tips 17 and are of a section such as to give an inwardly directed reaction. These surfaces may be adjustable oppositely to obtain greater directional stability or in the same .sense.