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Aerofoil theory for swallow tail wings of small aspect ratio
No full textA method is developed for the calculation of the aerodynamic forces acting on a ‘swallow tail’ wing of small aspect ratio. Lift, induced drag, and aerodynamic centre position of simple swallow tail wings (Fig. 1 (b)) are computed as an application. For a given incidence, lift and induced drag are, within the limits of the theory, proportional to aspect ratio and independent of speed. The chordwise life distribution rises linearly from zero at the apex, drops rapidly in the region of the root chord trailing edge, and then decreases gently to zero
Note on the efficiency of adiabatic shock
No full textThis note records some calculations of the efficiency of adiabatic shock in air (x=1.4); where the efficiency is defined as the ratio of the work used to compress the air in the shock wave, from the inlet static to the outlet total head pressure, to the work required if the compression were isentropic
Surface conduction of the heat transferred from a boundary layer
No full textThis note considers the effect of thermal conductivity upon the temperature distribution in the skin of a body (moving through air) due to the heat transferred from the boundary layer. It is found that the effects are of importance only very near the nose of the body, and that here the temperature reaches a maximum which, depending on the skin conductivity and thickness, may be appreciably less than the thermometer temperature, particularly at high speeds and altitudes of flight
Analysis of two-cell swept box with ribs parallel to the line of flight under loading by constant couples
No full textThe method of oblique co-ordinates is used to analyse the problem associated with the strength and deformation of a uniform, rectangular, two- cell swept box beam having ribs parallel to the line of flight. The case of loading by constant couples is considered, but no account of root effects is taken. Continues
Optimum climb technique for a jet propelled aircraft
No full textThe present method for obtaining a climb technique for jet propelled aircraft do not include the effect of kinetic energy variation with height. By introducing the concept of ‘energy height’ to include the geometric height and the height equivalent of the kinetic energy, a more exact treatment of the optimum technique has been possible. A new method has been suggested for obtaining the energy height climb function. Continues
Note on the development of a trailing-edge flap as a stall-detector
No full textA trailing-edge flap protruding slightly outside the wing profile has been developed as a stall detector and flight trials on “Anson” and “Provost” aircraft have proved successful. The device gave an adequate stall warning for all conditions of power and landing flaps and operated satisfactorily prior to stalls from steep turns. It was easily adjusted to give any desired warning speed to an accuracy of 1 m.p.h. and gave a two-stage warning, a preliminary warning preceding the final warning by about 3 m.p.h. Continues
Measurement of the derivative zw for oscillating wings in cascade
No full textExperimental results are reported of the damping derivative zw. for rigid rectangular wings of various aspect ratios in cascades having gap-chord ratios of 2, 1,1/2, 1/3, 1/4. The results show fair agreement with two-dimensional theory. The ranges of Reynolds numbers and frequency parameters were 0.8 to 2.5 x 10) and 0.1 to 0.45 respectively.
The results show a strong dependence on Reynolds number which increases with decrease in gap-chord ratio. This effect was eliminated by transition fixation by wires placed at suitable positions down-stream of the wing leading edge
The air resistance of racing cyclists
No full textTests in the closed-section wind-tunnel on three different cyclists mounted on a racing bicycle are described, and figures quoted for the recorded air resistance. Some comments are also included on the implications of the results concerning the power-output of racing cyclists
Ablation studies of low melting point bodies in a pre-heated supersonic air stream
No full textThis report is an investigation into the melting of axi-symmetric
and two-dimensional bogies at a Mach No. of M[infinity] = 1.78 and stagnation
temperatures up to 550 [degrees]K. In this temperature range, the most suitable
material for the models was found to be an eutectic tin-lead alloy
a melting point of 456 [degrees]K.
For the cone and hemisphere-cone models two distinct modes of melting
were observed. In cases where the estimated equilibrium surface temperature
(Tw)o was approximately equal to the material melting temperature Tm,
melting occurred only at the stagnation point of the model and was such
that a flat surface normal to the gas stream always resulted. If the
average rate of heat transfer at the air-liquid interface be defined as
qi = LmPm x, where Lm is the latent heat of fusion, Pm is the density of
the material and x is the rate of recession of the flat surface, it is
found that qi decreases with increase of the radius of the flat nose. A
very approximate theory is found to show some agreement with the experimental
rates of heat transfer. When (Tw)o was considerably greater than Tm the flat surface was no longer preserved and the resulting steady ablating
shape was paraboloidal in nature. When this occurred x was usually
constant. This allowed some average steady state heat transfer rates to
be evaluated and compared with theory.
Preliminary tests were also made with a two-dimensional wedge model
