SummaryRecords of the behaviour of aluminized grenade glow clouds at twilight and at night were obtained using cameras and photometers. From these records the radiance, radiant p~wer, and radiant energy have been deduced for the altitude range 100-200 km. The twilight observations show that the absorption cross section of aluminium monoxide is about 3 X lO-14 cm2• From the night-time results it is concluded that the glow probably arises from a chemiluminescent reaction with atomic oxygen. A set of reactions consistent with the observations above 120 km altitude is AI02 +O -+ AIO+02, AIO+O -+ AI02+hv, AIO+O -+ AI+02, with the rate constants being 5 X 10-12, 1 X 10-13, and 4 X 10-13 cm3 molecule-1 sec-1 respectively.

During 1961 preliminary consideration was given by the Weapons Research Establishment to the possibility of measuring the structure of the upper atmosphere by pressure probes on sounding rockets. A similar technique had been used with success in the USA. It was proposed that velocity be measured and that an incidence meter be used to measure pitot and static pressures, from which atmospheric pressure and density could be calculated. There was available at the time comprehensive calibration information on hemispherical-headed incidence meters at Mach numbers below 3. Since the sounding rocket would be flying within the Mach number range 3 to 6 there was a need to extend the existing calibrations to higher Mach numbers. At first it seemed that the results of Baer would do this, but a closer examination showed that his results did not agree with the incidence meter calibrations.

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This Note Gives a simple relationship between the zero-lift wave drag of the wing of a rectangular wing and body combination and the wave drag of the portion of the gross wing blanketed by the body, both evaluated as if isolated (i.e.ignoring the interference of other parts of the combination). The result is valid only when the tip Mach cones of the wing lie downstream of the blanketed wing. Detailed results are given for the case of wings with double-wedge section, the maximum thickness being at mid-chord.

SummaryRecent free flight tests have provided information on the applicability of the sonic area rule to non-lifting configurations. An analysis of results for the sonic wave drag of swept-back, tapered wings has suggested that the sonic area rule is applicable to thin wing and slender body combinations provided that the product of the wing span/length ratio and the cube root of the thickness /chord ratio is less than unity. The wing span/length ratio was found to be a much more useful slenderness parameter than the aspect ratio.When the wing has a round-nosed section, theoretical considerations predict the existence of a so-called leading edge drag force varying with Mach number. One would expect such a wing to have the same sonic drag-rise as the equivalent body with an identical cross-sectional area distribution. Some test results do not confirm this drag-rise equivalence. It appears that the transonic drag-rise of the leading edge force is much greater than that predicted by theory.Tests on one basic wing-body combination, with different body cross-sectional shapes of the same area, suggest that the cross-sectional shape, of a smooth slender body, has no influence on the transonic wave drag of a configuration.