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Aviation History
1938
1938 - 0269.PDF
JANUARY 27, 1938 THE AIRCRAFT ENGINEER SUPPLEMENT TO FLIGHT 960 "I 20x10* 10X10* / 9x 4 •A (it c 3cgy 9;/ 1 IO3 20xlO3 FIG.6 i~" 2 Thus equations (9') and 9") become = .21 — gv = -2i ro - J — k" (10') (10" gx, gv are found graphically by determining the point or the points of intersections of (10') and (io"), (see Fig. 6). The shape of these curves is easily recognised, ^g* = k gives the equation to an asymptote, and g „ cc gx for §g2 >>k gives the limiting value of the other branch of the curve as a straight line. The theoretical distinction between the three points of intersection, ABC and the choice of the required point giving Gx and G, is still a problem to me. However, by applying "common sense," one can determine the required point as follows : Since it was, say, A times as difficult to twist the bar through 6 with the lamination || to b than with the lamination J_ to b. .-. Gx ^ To ascertain the breaking shear stresses of the material, the test specimens were twisted until rupture occurred. They are given by the evaluated formulae ; . M 3/ c M 3 Rupture occurs in theory and practice at the centreline of one of the faces of the rectangular prism and for sufficiently elongated rectangular cross-sections alwayson the longer side. The general stress-strain relation of material of three planes of symmetry as in the case of laminated wood are given by «M.= p- PxT — VsyPvv— V*< Pzz) 1 - x *.. = -Jf P»v-Vll<Ptl-Vllxp,r) FIG. 7 u(x) Summary of Test Results on " Jablo" ImprovedLaminated Wood. Specific Gravity Gx Gy Px Py ... P*i Pyi .8 1.96 x 10s 1.0 X 10s 2210 3100 1930 131 1 1.2 3.12 xlO5 . 1.58 X105 5360 7730 4560 3150 1 •/»« C*v = -7T Pxv with three different moduli of elasticity RXE,K, with three different moduli of rigidity GxG,,Gj with three different Poisson's ratios vxavvzvzx For pure bending, the stresses are in the same way related to the curvature — and the moment of inertia I as lor K > isotropic material = ASrfF P = u = M XV R The approximate determination of the shear stresses is the same as for isotropic material and St. Yenant has shown that also the exact theory of this problem may be transformed from the isotropic to this kind of acolotropy. AERONAUTICAL PATENT SPECIFICATIONS 17213. 18000. 23658. 2101). «8G. 10802. U5«2 1771L (The numbers in brackets are those under which the[Published January 20, 1938.) WILSON, W. K., THOMAS, F. M., and DE HAVILLAND AIRCRAFT CO. Ltd.: Colouring of metal surfaces (477,280). AUTOMOTIVE PRODUCTS CO., Ltd., and GATES, G. R. G.: Servo-brake mechanism (477,173). AUTOMOTIVE PRODUCTS CO.. Ltd., BROCK, D. T., and GATES, G. R. G.:Servo-brake mechanism (477,170). JUNKERS FLUGZEUG-UND-MOTORENWERKK AKT.—GES. : Locking thecontrol surfaces of a parked flying machine (477,194). CIBIE, P.: Projectors for automobiles, aeroplanes and the like (477,072).opAs PATENTS, Ltd.: Aeroplanes (477,238). AVIATION CO., Ltd., BRAV, F. C, and BODDY.C. S.: Coverforhandholes, inspection or servicing openings, and the like (477,200). Published January 27, 1938).BILLOQUE, E. J. H.: Stabilising devices for aeroplanes (477,395). r\SBOTn HELICOPTERS, LTD. : Wing arrangement for rotary-win^1 aircraft Specifications will be printed and abridged, etc.): 17838. MARCONI'S WIRELESS TELEGRAPH CO., LTD., DAVIS, N. E., GREEN, E., andHALL, A. W. : Thermionic valve apparatus for use on very short waves (477,362). 17973. HAMILTON MOTORS (LONDON) LTD., and THEED, YV. D. L. : Control appa- ratus for aircraft with autorotative wing systems (477,369). 18158. NORMAN, H. N. ST.-V., and VULLIAMY, A. T. : Wind-direction indicators for aerodromes (477,527). 18353. SUPERMARINE AVIATION WORKS (VICKERS), LTD., and MITCHELL, R. J. : Construction of wings and other aircraft bodies or parts (477,541).9641. AKTIEBOLAGET ATLAS DIESEL : Scavenging pumps of two-stroke internal combustion engines (477,505). 9677. MERCIER, P. E.: Device for limiting the aerodynamic efforts on aircraft (477,506). 12851. CIBIE, P.: Projectors for automobiles, bicycles, aeroplanes and the ike (477,575). 22178. HANSEN-, L. : Screw propellers (477,514).
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