exhaust as heat shield

Has anyone tested the idea, for an SSTO, of running the engines at a
low level at re-entry, thus using the engine exhaust as a heat-shield?

As a related question, do bench tests exist that simulate the
environment a ship (or a part thereof) would see on re-entry, perhaps
using super-sonic, super-heated air?

wrote:
Has anyone tested the idea, for an SSTO, of running the engines at a
low level at re-entry, thus using the engine exhaust as a heat-shield?

As a related question, do bench tests exist that simulate the
environment a ship (or a part thereof) would see on re-entry, perhaps
using super-sonic, super-heated air?

Not really well.
You can get the temperature, the velocity, the gas mix, the heat flow,
the pressure, or the sustained heating effect.

Getting one or two is almost trivial.
Getting more than about three of these is really challenging, getting all
of them isn't possible to bench test.

You can use various gas-expanding-into-vacuum chambers that attain a
reasonable velocity, but these are essentially pulsed.

In article .com,
wrote:
Has anyone tested the idea, for an SSTO, of running the engines at a
low level at re-entry, thus using the engine exhaust as a heat-shield?

It's been suggested. I don't think it's actually been tried. Bear in
mind that the engine exhaust is still pretty hot.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

On 21 Mar 2005 11:39:33 -0800, in sci.space.tech wrote:

As a related question, do bench tests exist that simulate the
environment a ship (or a part thereof) would see on re-entry, perhaps
using super-sonic, super-heated air?

Depends upon what exact part of the trajectory you are interested in and
what exactly do you wish to simulate.

Blowdown facilities such as the NASA LaRC 8-Ft HTT and GRC HTF can simulate
true enthalpy conditions up to ~Mach 7 at ~100,000ft.,max test times can
be on the order of a min. If you need faster than that you have to go to
shock or gun tunnels that go to ~ Mach 12 or so and have test times in the
msec range. To go faster than this you need expansion tubes such as the
NASA Hypulse or UQueenslandX2 facilities and you are down to microsec of
test time.
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Ed Ruf Lifetime AMA# 344007 )
http://EdwardGRuf.com