🚀 go-pugleaf

In article <1993Jan12.171525.7437@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes:
>Even the SR71 uses fuel to help cool it's titanium skin, and it travels
>more than four times slower than a re-entry vehicle...

However, it does it for a much longer period.  I don't claim to be a
hypersonics guru, but my understanding is that you get *very* different
design solutions for a "hypersonic accelerator" and a "hypersonic cruiser"
(where the former is at hypersonic speeds only briefly, accelerating
towards orbit, and the latter spends much of its operating life there).

The X-20 Dyna-Soar's heat protection was mostly refractory metals, as
I recall.

>The only practical
>metal more refractory than titanium is tungsten...

A curious claim.  The X-15 used titanium only for its *low temperature*
structure, and did not use tungsten at all.  Most of its hot structure
was stainless steels of various types.  They are heavy, but not impossibly
so.  The B-70's wing and main body was stainless-steel honeycomb.
-- 
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  henry@zoo.toronto.edu  utzoo!henry