Wednesday, January 4, 2012

Silver Spur 3

I think there was a post about this rocket including the video below, but I can't find it right now. What is new to this blog are some of the images from before the flight. The Silver Spur 3 flight employed some interesting construction techniques, particularly the use of ablative leading edge material on the fins. This may be considered excessive, or nearly so at "just" mach 3.3, but that is around the threshold where severe composite delamination has been occurring. As always, I push for aluminum fins in these circumstances, but there are good reasons to test out the composite fins. It is taking on extra risk for the benefit of the community. It remains to be seen how far high temperature epoxy can go (that means above the 500 degree epoxy used to date) but I have reason to expect that really smart application of high temperature epoxy should be good for sustained flight over mach 3, and even short periods above mach 4 below 50,000 feet. Beyond this, ablatives or metal parts are required. I frequently wonder about either a metal leading edge, or even a thin sheet of titanium or aluminium attached with some high temp. epoxy. But at no time can the metal be below a composite layer because, obviously, that layer would fail anyway. The huge slug of titanium on the nosecone is certainly excessive, but very cool.

"Launch of USCRPL's Silver Spur 3 at Balls 19 in the Black Rock desert, Nevada. It features an all carbon fiber motor case, ablative fin leading edges, and a titanium nose cone tip. Flying on an O5000, it flew to about 50000 ft and reached a maximum speed of about Mach 3.3."






Images at Picasa

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