Mach 1 in its own length … no way!

Brian Blestowe set out to debunk the urban myth that a Mk2 Bloodhound missile reached Mach 1 (speed of sound) by the time it had cleared the launcher; he was successful!

The Mk 2 missile was only stressed to 35g in the longitudinal axis so Zero to Mach one in its own length (around 1700g) was a bit of Newton BS. Actual acceleration at launch was 19 to 21g dependent on the ambient temperature of the boost rocket motor propellant charge. Actual specs for the Gosling XV motor were 23,000 lbs for 3.8 seconds at -25°C to 31,500 lbs for 2.8 seconds at +40°C. The only firing that I do have information about in the UK was the Singapore round fired in 1980. It was fired at a sea level temperature of 12.6°C and an atmosphere pressure of 1007.3 millibars.

Boost motor separation was at 3.803 seconds after first movement at which point the missile was 1332.6 m (4536.1 ft) from the launcher in ground distance and 795.0 m (2608.3 ft) above the launcher at a speed of 701.0 m/sec (2299.9 fps) (1568.09 MPH, 1362.63 Knots, Mach 2.04373). At that point the missile angle to the ground was 29.060° and it had rolled to starboard 15° off the line of fire (which was 328°), which wasn’t a
surprise seeing that the Wind velocity was 5.182 m/s (11.59 MPH) from a bearing of 250° (almost side on to the line of fire). For hotter (and colder) temperatures, the Swedes fired one at -25° C from Vidsel, while all of the hotter ones would have been from Woomera.

The problems getting figures from those firings is most of them were done with the original Gosling IV motor planned for BH2, which only produced 22,000 lbs at -25°C and because of that was not capable of accelerating the missile to a speed where the ramjets could produce enough thrust to accelerate the missile post boost separation on a really cold day (which was bad news for sales to Sweden and Switzerland!).

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Brian is a BMPG member and the volunteer at Aerospace Bristol who has redied the Bloodhound Mk2 missile for exhibition. This is the only fully operational example that is complete; the only missile in UK to have fuze aerials and in every respect is the National Standard.

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