From:      skunk-works-digest-owner@harbor.ecn.purdue.edu
To:        skunk-works-digest@harbor.ecn.purdue.edu
Subject:   Skunk Works Digest V3 #72
Reply-To:  skunk-works-digest@harbor.ecn.purdue.edu
Errors-To: skunk-works-digest-owner@harbor.ecn.purdue.edu
Precedence: bulk

Skunk Works Digest          Sunday, 4 July 1993        Volume 03 : Number 072

In this issue:

	Re: Terminal velocity
	RE: Terminal velocity

See the end of the digest for information on subscribing to the skunk-works
or skunk-works-digest mailing lists and on how to retrieve back issues.

----------------------------------------------------------------------

From: agbrooks@teaching.cs.adelaide.edu.au (Zoz)
Date: Sun, 4 Jul 93 0:47:25 CST
Subject: Re: Terminal velocity

|> > |> Well, just what is terminal velocity for a streamlined shape that's
|> > |> roughly 3 feet long and one inch thick?  Weighing in at 10-12 pounds?
|>
|> > Should your Brilliant Crowbar (tm) be accelerated to Mach 20 in the
|> > vacuum of space, it should retain a goodly percentage of that velocity
|> > by the time it reaches the ground as it will not be in the atmosphere
|> > long enough for the relatively weak deceleration of air resisitance
|> > to slow it down much.  Especially as it is a very streamlined shape.
|>
|> But you're assuming that it's going to be coming straight down through the
|> atmosphere upright.. It would be tumbling all the way down, greatly
|> increasing the resistance.

When I originally heard of the concept (THOR) the crowbars were to be
positioned "vertically" in space with a guidance package and rocket motor
on the "away" end.  When employed, the rocket motor was to drop it out
of orbit with the guidance package keeping it vertical and on target.  The
front end was naturally expected to ablate on re-entry heating but there
was still supposed to be a fairly large chunk of metal left to land on
something.
- --
     ______        _____________    ______________________          ______
    /\####/\      /            /   /                     /         /\####/\
   /  \##/  \    /_______     /   /    _     ______     /         /  \##/  \
  /____\/____\          /    /   /    / \    \    /    /         /____\/____\
  \####/\####/         /    /____\    \_/    /   /    /_______   \####/\####/
   \##/  \##/         /                     /   /            /    \##/  \##/
    \/____\/         /_____________________/   /____________/      \/____\/

                     agbrooks@teaching.cs.adelaide.edu.au

------------------------------

From: beede@SCTC.COM (Mike Beede)
Date: Sat, 3 Jul 93 14:58:47 CDT
Subject: RE: Terminal velocity

> 
> > |> Well, just what is terminal velocity for a streamlined shape that's
> > |> roughly 3 feet long and one inch thick?  Weighing in at 10-12 pounds?
> 
> 
> > Should your Brilliant Crowbar (tm) be accelerated to Mach 20 in the
> > vacuum of space, it should retain a goodly percentage of that velocity
> > by the time it reaches the ground as it will not be in the atmosphere
> > long enough for the relatively weak deceleration of air resisitance
> > to slow it down much.  Especially as it is a very streamlined shape.
> 
> But you're assuming that it's going to be coming straight down
> through the atmosphere upright.. It would be tumbling all the way
> down, greatly increasing the resistance.

I presume that someone who invested enough money to get the sucker up
would have invested enough to make it a shape that was stable in a
(relatively) low-drag orientation.  

Don't know what that would be--probably that's what those ones that have
the little claw-shaped fin angled out of the back are for--they're sure
overkill for pulling nails.

	Mike


------------------------------

End of Skunk Works Digest V3 #72
********************************

To subscribe to skunk-works-digest, send the command:

    subscribe skunk-works-digest

in the body of a message to "listserv@harbor.ecn.purdue.edu".  If you want
to subscribe something other than the account the mail is coming from,
such as a local redistribution list, then append that address to the
"subscribe" command; for example, to subscribe "local-skunk-works":

    subscribe skunk-works-digest local-skunk-works@your.domain.net

To unsubscribe, send mail to the same address, with the command:

	unsubscribe skunk-works-digest

in the body.

Administrative requests, problems, and other non-list mail can be sent
to either "skunk-works-digest-owner@harbor.ecn.purdue.edu" or, if you
don't like to type a lot, "prm@ecn.purdue.edu".

A non-digest (direct mail) version of this list is also available; to
subscribe to that instead, replace all instances of "skunk-works-digest"
in the commands above with "skunk-works".

Back issues are available for anonymous FTP from harbor.ecn.purdue.edu, in
/pub/skunk-works/digest/vNN.nMMM (where "NN" is the volume number, and "MMM"
is the issue number).