Some notes on the factors influencing the possible damage to buildings due to the passage of shock waves from aircraft flying at supersonic speeds

The purpose of this note is to discuss, from the limited information available, the order of magnitude of the strength and the configuration of the shock waves, close to ground level, generated from aircraft flying et supersonic speeds. The level flight case is the only one considered in detail but brief reference is also made to other manoeuvres such as the supersonic dive of limited duration. The alterations in path and strength of a shock wave in passing through the heterogeneous atmosphere are shown to be very important. For normal temperature variation with altitude the attenuation of shock strength, with distance downward from the aircraft, will be decreased. A similar effect will occur when shock waves are propagated against a wind, whose velocity increases with height.. These results should be of interest to civil engineers and others making estimates of the possible damage to buildings due to the above cause. A preliminary, mainly qualitative discussion of this part of the problem is included, which although not complete should at least give some idea of the damage to be expected. In this connection it is found that for aircraft flying at and above 5000 ft. at Each numbers up to 2 the damage to buildings should be limited to a number of ‘freak’ cases of window breakage and similar minor damage. In the case of aircraft diving at supersonic speeds at a high altitude the excess pressures caused by the resulting shock waves and their time duration are so small that the chance of any damage occurring is almost negligible