Crusade and the 54-inch Black Knight

RAE had plans for yet another set of re-entry experiments after Dazzle, which were code named CRUSADE (derived, apparently, from ‘Co-operative Re-entry Undertaking, Signature and Discrimination Evaluation’). RAE also wanted to improve the performance of Black Knight still further. The Gamma 301 motor had been used at thrust levels of 21,600 lb, but up to 25,000 lb was quite feasible. Increasing the thrust meant that a bigger vehicle could be designed. Thus was born the 54-inch Black Knight6.

The original 36-inch Black Knight had been a long and slender vehicle – increasing its weight without increasing the diameter would have made it rather too long. The new vehicle would have tanks of 54 inches diameter, which made it shorter than the original vehicle, despite being heavier.

Saunders Roe produced a variety of schemes (Figure 103) presenting to them to the RAE at a meeting in July 1962. The first ideas were to keep the engine bay at 36 inches, and taper the HTP tank, although the result looked distinctly inelegant.

It was decided to change to a 54-inch bay and thus a parallel sided vehicle relatively late in the design process, and for aerodynamic rather than structural reasons. The parallel sided tank would have been marginally heavier, according to Saunders Roe’s calculations.

It was not only the main stage that could be enlarged: keeping the Cuckoo motor meant that despite the increase in size, performance was not that much better. Instead, a new motor was designed – the Kestrel. This was 24 inches in diameter – the first Westcott motor to exceed 17 inches diameter.

And comparing the two first stage configurations:

Weight empty Fuel Capacity Total 36 inch 1,380 lb 11,600 lb 12,980 lb

54 inch 1,480 lb 15,600 lb 17,080 lb

The last Dazzle flight took place in November 1965. The first flight of the 54- inch Black Knight was still some way away – perhaps 12 months or so – but the intention was to use BK22 for the first experiment in the Crusade programme. This was one of the last of the Gamma 201 engined vehicles, and had been an ELDO experiment back-up, upgraded to a two stage vehicle. Seven firings had been pencilled in, which included much heavier (250-300 lb) re-entry vehicles, and some decoys. Construction of a new engine bay and tank structure for BK26 had begun when RAE was given the choice between Crusade and Black Arrow, and Black Arrow won. Further re-entry experiments were dropped, although the US carried out further flights using old Redstone missiles, in a programme codenamed Sparta. One Redstone was left surplus to requirements at the end of the programme, and adapted to launch an Australian satellite.