A was amazed at watching the guys at Alamogordo set up a rocket sled test run. They were testing
a new ablative coating for the radome of a high mach missile. Think about that. This was, IIRC, the AIM-54
being tested for the Navy. It has an active radar seeker, so needs to send and receive throught the nose,
and is running above Mach 3. So it can't be an ordinary fiberglass radome like on an aircraft.
In any case, I asked about the really crude looking supporting struts holding up the test article to
the sled chassis. Literally railroad rails cut up and welded together. Seemed ultra crude and really,
REALLY aerodynamically bad. They laughted and said, "Yeah they are crude, and definitely not
aerodynamic, but if we need more speed, just add another rocket motor, we have warehouses full
of them for nothing. And the RR rail is so thick and heavy that it will only melt a little bit at Mach 4
or even up to Mach 6 by the time the test run is over." Typical test runs are only a few seconds, since
the rail is only 10 miles long and at high mach that doesn't take long. They use old, timed out rocket
motors from military inventory. After a solid fuel rocket motor has reached a certain age, it cannot
be trusted, but will likely still work, so they get them and use a bunch to power their sleds.
Aerodynamic heating was something I was generally familiar with, but that two weeks spent there was
a real eye opener. Cool stuff. And they had all these cockpits of varous jets on sleds just sitting out
there baking, so I played jet pilot in some of them, of course. They had all sorts of cool stories. It
turns out that testing ejection seats ( major portion of what they do) is a REALLY good idea. They do
not always work the way intended the first few times. The said the first 4 seat B-52 test was the absolute
definition of a cluster eff----. All four chutes tangled, and four seats smashing into the fuselage and
splattering across the desert at 400 mph. It got better after that, until it actually works wonderfully now.
Bill