From: nsmca@aurora.alaska.edu
Subject: Re: DC-X: Vehicle Nears Flight Test
Article-I.D.: aurora.1993Apr5.191011.1
Organization: University of Alaska Fairbanks
Lines: 53
Nntp-Posting-Host: acad3.alaska.edu

In article <C4zHKw.3Dn@zoo.toronto.edu>, henry@zoo.toronto.edu (Henry Spencer) writes:
> In article <2736@snap> paj@uk.co.gec-mrc (Paul Johnson) writes:
>>This bit interests me.  How much automatic control is there?  Is it
>>purely autonomous or is there some degree of ground control?
> 
> The "stick-and-rudder man" is always the onboard computer.  The computer
> normally gets its orders from a stored program, but they can be overridden
> from the ground.
> 
>>How is
>>the transition from aerodynamic flight (if thats what it is) to hover
>>accomplished?  This is the really new part...
> 
> It's also one of the tricky parts.  There are four different ideas, and
> DC-X will probably end up trying all of them.  (This is from talking to
> Mitch Burnside Clapp, who's one of the DC-X test pilots, at Making Orbit.)
> 
> (1) Pop a drogue chute from the nose, light the engines once the thing
> 	stabilizes base-first.  Simple and reliable.  Heavy shock loads
> 	on an area of structure that doesn't otherwise carry major loads.
> 	Needs a door in the "hot" part of the structure, a door whose
> 	operation is mission-critical.
> 
> (2) Switch off pitch stability -- the DC is aerodynamically unstable at
> 	subsonic speeds -- wait for it to flip, and catch it at 180
> 	degrees, then light engines.  A bit scary.
> 
> (3) Light the engines and use thrust vectoring to push the tail around.
> 	Probably the preferred method in the long run.  Tricky because
> 	of the fuel-feed plumbing:  the fuel will start off in the tops
> 	of the tanks, then slop down to the bottoms during the flip.
> 	Keeping the engines properly fed will be complicated.
> 
> (4) Build up speed in a dive, then pull up hard (losing a lot of speed,
> 	this thing's L/D is not that great) until it's headed up and
> 	the vertical velocity drops to zero, at which point it starts
> 	to fall tail-first.  Light engines.  Also a bit scary, and you
> 	probably don't have enough altitude left to try again.
> -- 
> All work is one man's work.             | Henry Spencer @ U of Toronto Zoology
>                     - Kipling           |  henry@zoo.toronto.edu  utzoo!henry

Since the DC-X is to take off horizontal, why not land that way??
Why do the Martian Landing thing..  Or am I missing something.. Don't know to
much about DC-X and such.. (overly obvious?).

Why not just fall to earth like the russian crafts?? Parachute in then...

==
Michael Adams, nsmca@acad3.alaska.edu -- I'm not high, just jacked

Please enlighten me... Ignorance is easy to correct. make a mistake and
everyone will let you know you messed up..
