Fwd: [AR] Honda Engineering, on Failure
Bryan Bishop
From: Dave Klingler <da...@commercedata.com>
Date: Mon, Jan 26, 2009 at 11:48 PM
Subject: Re: [AR] Honda Engineering, on Failure
To: aRocket List <aro...@exrocketry.net>
On Jan 26, 2009, at 2:46 PM, Randall Clague wrote:
> At 04:45 PM 1/25/2009, Dave Klingler wrote:
>
>> I was going to mention this in private to Randall, but the topic's up
>> so I'll comment. After having made a second pass at the Columbia
>> Investigation report, I've developed a strong, grim appreciation for
>> vehicles without wings, at least on orbital reentry.
>
> I blame Challenger and Columbia on the same fundamental design
> flaw: they put human beings on a "stack" in which four different
> vehicles fly, not stacked one atop another, but in very close
> formation. Any one of those vehicles breaks formation, the whole
> stack comes apart and the humans die, thus Challenger. Any one of
> those vehicles sheds FOD onto the brittle heat shield of the
> vehicle carrying the humans, the heat shield breaks and the humans
> all die, thus Columbia.
Tsk. :)
Pilots often read the NTSB report on the latest accident and comment,
"You see? It was pilot error! What an idiot!" The above paragraph
carries a whiff of something similar.
I dunno, Randall. I'm not at all sure that I could agree with you
regarding horizontal stacking; it's too common. Horizontal stacks
have flown many successful launches. Any sort of staging whatsoever
has its advantages and disadvantages. To blame Challenger on
horizontal stacking seems like suspicious reasoning to me.
I would blame Challenger on a much simpler explanation: the vehicle
was flown outside its design envelope. Several times. It eventually
did what one would expect.
Columbia was an educational experience in aerospace engineering and
also a demonstration that the shuttle is an experimental vehicle. It
proved (at least) three things: that you can dislodge tiles with ice,
that you should listen to your engineers when they decree that
something new has occurred and they should therefore study it, and
that the titanium in the shuttle could sustain combustion in reentry
conditions and in so doing cause a lot more failures. The first and
last were both totally unexpected lessons for the highly-experienced
Apollo engineers that designed the vehicle, and for damned near
everybody else.
The common theme between the two accidents, rather than any
fundamental design flaw, was irascible human nature. Sometimes it
takes too long for the politics to catch up with the facts. That
problem is not going away any time soon, horizontal stacks
notwithstanding.
>
> The lesson here isn't, don't use wings. The lesson is, if the
> wings are brittle, don't drop things onto them. Columbia was a FOD
> accident.
What I took from the CAIR was that during reentry I'd like to be in
the most fundamentally simple and stable vehicle possible, one that
would respond stably to some of what befell Columbia. Call me a
nancy boy, but my brain and spine don't take well to being whirled
around at high Gs. Columbia was a compromise design but she was NOT
a bad one, and the fact that she lasted as long as she did with a
missing left wing reminds me of a B-17. The Challenger and Columbia
accident investigation reports have actually inspired my grudging
respect for the shuttle design, not eroded it.
During suborbital reentry, the issue is more of a wash to me, but the
reading I've done on hypersonic vehicles during the past twenty years
has led me to believe that I'd rather reenter the atmosphere inside a
large rock, as symmetrical a large rock as possible
A long time ago now Max Hunter threw me up against the wall of a
plastic latrine and gave me a stiff lecture on what he thought about
rocket design. His opinion was that if you left your spars and
landing gear at home, you'd save enough weight for a lot of fuel and
extra engines. I listened to him then, and my reading of the CAIB
report seems to add to that belief. Wings on a rocket are right up
there with chrome differentials and power windows.
>
> Making a reentry vehicle out of aluminum also wasn't the most
> brilliant decision in the history of engineering.
The titanium combusted, the Inconel melted, and the aluminum actually
in many cases did better because of its heat-sinking capability. The
conclusion of the CAIB was that had the wings been made of titanium,
the shuttle might have lasted an extra 13 seconds maximum.
> To be really robust, a reentry vehicle should be able to survive
> reentry even if the heat shield is grossly compromised. It doesn't
> have to be flyable afterwards, but it should get the humans into
> the sensible atmosphere safely.
Many people have uttered similar words. :) A stout slightly
aerodynamic boulder is the only vehicle I can formulate that fits
your above description.
Of late I've wondered about the possibility of using CVD to grow a
thick layer of graphene on a metal-composite matrix. If I'm
understanding what I read, the result would be a very strong,
incredibly effective heat sink comparable in robustness to a General
Products hull.*
And you could grow wings on it if you wanted to. I would ride in one
of those.
Dave Klingler
* Offer subject to all the usual high-temperature ionic oxygen
disclaimers.
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