In article ,
Vincent Cate wrote:
*That* part is not particularly novel. The power wires to the
solenoid valves of the shuttle RCS engines wrap around the
combustion chambers, for the same reason.

Because SS1 has a composite chamber they could put the fiber inside
as they made the chamber and so detect when things were going bad
before burning all the way through. Do the RCS ones trip before the
chamber has burned all the way through?

Nope, it has to be a complete burn-through. But in the case that mostly
worried their designers -- combustion instability -- that happens very
quickly, and there is no useful advance warning to be had by detecting a
partial burn-through. That can also happen with hybrids, in slightly
different ways; the casing of Amroc's first 250klb motor went from intact
to massively ruptured in under 20 milliseconds, due to a hot-gas leak in
the insulation.

Also, is this the first time a nitrous-oxide/rubber engine of
this size (or larger) has been used?

Depends on what you mean by "used". Considerably bigger hybrids have been
fired, although I think they may have all used LOX rather than N2O. I'm
not aware of any previous use of hybrids to propel a manned aircraft,
however.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |