From: Michael Lorrey (retroman@tpk.net)
Date: Sat Jul 12 1997 - 14:57:04 MDT
Michael M. Butler wrote:
>
> >Man
> >made air vehicles have always had maintenance requirements of between
> >20-100 man hours per flight hour.
>
> I'm not sure that your low end number is literally true. I'm going to
> visit my local F.O.B pretty soon, and I'll try to get their numbers
> for the low end. It may (in fact, I expect it will) depend on the
> timescale you measure.
The low end number applies to several WW I & II military craft that were
rugged and reliable. Most of their additional maintenance had to do with
battle damage.
>
> >higher maintenance requirements, with the exception of some of our new
> >military planes like the F-22, but vehicles like the space shuttle and
> >the stealth bomber are still way up above the top of the range.
>
> Bzzzt! Have you further considered that that's because they're absurdly
> specified and designed, by political and pocket-lining
> creatures?
By what basis do you make this assertion? There is no politics in
engineering. The more complex a device, and the more severe its
operating environment, the greater its maintenance requirements.
You do know the story of the B-1 and of F-111s, right?
> To take the latter example, suppose I insisted on fielding a full
> complement of F-111s (the B variant, I think) fully loaded with Phoenix
> on an aircraft carrier. You're going to have hella high maintenance
> if you really want to keep everything flying; in fact the carrier may
> never be the same, either:). Those tubs land *hard*.
F-111s have been flown on carriers, and were originally supposed to be a
multiservice platform. The naval version was going to have several more
struts in the fuselage, a sturdier wing, and heftier landing gear.
>
> MTBF very much depends on how rich you are, how carefree you are (i.e.
> "what's a failure?"), and how superior your tech is to the requirements.
> I suspect strongly that the maint-to-flight hours ratio (whatever that's
> called in aero, I forget) is, too.
No matter how steep a difference between tech level and operating
regieme, higher tech always has higher maint time. There is a difference
between tech level and the quality of construction. A crappy Edsel of a
flying saucer will still be more likely to crash than a hot air balloon.
>
> The long term data isn't in for things like composites and the Zoche
> turbo diesel, but I suspect they, or what comes after them, will
> start stretching those numbers out into the sub-1 range.
The trouble with failures in composites is that there is not usually a
soft failure. You can't detect cracks until it gives way under strain,
and when it does, it shatters. This is why new composite wings are
stress tested on the ground far in excess of their operating margins.
This does not mean that they will not fail over time.
You think that there will be less than 1 maint hour per flight hour? It
hasn't happened yet, and the curve averages upward over time, so I doubt
that it will happen for anything but the most low stress flight regeimes
for quite a while.
>
> <snip>
> >As for your assertion of any visitors not being detected, this goes
> >against logic. Given that some group, corporation, or government on
> >another planet would have shelled out billions if not trillions of
> >EBE-bucks for such an expedition, the idea that they would not try to
> >wring out the maximum PR, scientific, or economic value from that
> >investment is ludicrous.
>
> Ah, but why is this a given at all? And who says they'd derive any
> benefit from being seen? How can you (or Hara Ra) be sure you know
> what their payoff matrix is for be3ing seen? What if their motto
> really is "Primum non nocere (at least at first...)"?
>
So your beleive in alien abductions?
Because Occams razor tells me if screwed up creatures like us with our
screwed up ways of doing things can make it, then any visitors are just
as likely to come from screwed up planets as well, and just as likely to
have short sighted, self centered, idiotic politicians and bureaucrats
in charge of things on their home planet. The ideas that people get from
Star Trek are much more unlikely than things continuing much as they
are now.
Read Scott Adams new book, Dilbert Futures, in which he states "The
future will NOT be like Star Trek." because people will still be as
screwed up as they are now, they'll just have cooler high tech toys to
be screwed up with.
--
TANSTAAFL!!!
Michael Lorrey
------------------------------------------------------------
mailto:retroman@tpk.net Inventor of the Lorrey Drive
Agent Lorrey@ThePentagon.com
Silo_1013@ThePentagon.com http://www.tpk.net/~retroman/
Mikey's Animatronic Factory
My Own Nuclear Espionage Agency (MONEA)
MIKEYMAS(tm): The New Internet Holiday
Transhumans of New Hampshire (>HNH)
------------------------------------------------------------
#!/usr/local/bin/perl-0777---export-a-crypto-system-sig-RC4-3-lines-PERL
@k=unpack('C*',pack('H*',shift));for(@t=@s=0..255){$y=($k[$_%@k]+$s[$x=$_
]+$y)%256;&S}$x=$y=0;for(unpack('C*',<>)){$x++;$y=($s[$x%=256]+$y)%256;
&S;print pack(C,$_^=$s[($s[$x]+$s[$y])%256])}sub S{@s[$x,$y]=@s[$y,$x]}
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