Re: OT interesting find


OTOH they aren't a serious challenge to the absolute land speed record
of Mach 8.5.http://en.wikipedia.org/wiki/Land_speed_record_for_railed_vehicles

Your link says unmanned! well Mach 50 is easy.

Actually, barring some calculations that would give me a headache on a
nice Saturday morning, I guess that Mach 50 is ludicrous per se for
propelling a macroscopic object through any reasonable value of
"atmosphere." Orbital re-entry occurs at about half that (and of
course the spacecraft must be heat-shielded in one way or
another). Light-gas guns can be used to simulate astronomical
impacts (e.g., meteorite impact cratering, debris encountered in
orbit, etc.) but I think the barrel and target chamber are usually
pumped down to at least rough vacuum.

Pondering the Space Shuttle's mission profiles -- "max Q" on the way
up and braking on the way down -- gives some interesting insight into
speed, altitude, pressure, etc. So does what happens when meteors of
various sizes and speeds enter the atmosphere (e.g., http://tinyurl.com/meteorspeed).

The unmanned rocket-sled test at Holloman was quite an engineering
feat in its own right, as detailed on
http://www.rdecom.army.mil/rdemagazine/200401/itl_amrdec_roadrunner.html
(executive summary: this wasn't even your ordinary rocket-sled track,
let alone your ordinary train.)

As for Stapp's rocket sled work, the point was not how fast he was
going but how quickly he stopped (with a side interest in what happens
when you step outside at slightly supersonic speeds). I mean no
deprecation of him whatsoever -- from everything I've read, his
aeromedical science was pioneering, influential, and above-and-beyond
brave -- but neither sheer speed nor manned control of the vehicle was
the main issue.

Cheers,
--Joe
.

Relevant Pages

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  • Re: OT interesting find
    ... well Mach 50 is easy. ... various sizes and speeds enter the atmosphere. ... As for Stapp's rocket sled work, the point was not how fast he was ... done 1st with an FBW inertial guidance system to keep on or near ...
    (rec.aviation.military)
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