[net.space] Gyroscopic reels

@S1-A.ARPA,@MIT-MC.ARPA:king@Kestrel (07/03/85)

From: king@Kestrel.ARPA

As the fullness of a reel increases its moment increases and its
angular velocity decreases.

We have two degrees of freedom: hub diameter and moment of an empty
reel.  It seems likely to me that e can make any variations in the
angular momentum third-order.  I'll do the math when I'm less busy...

rivero@kovacs.UUCP (Michael Foster Rivero) (07/10/85)

In article <2498@mordor.UUCP> @S1-A.ARPA,@MIT-MC.ARPA:king@Kestrel writes:
>From: king@Kestrel.ARPA
>
>As the fullness of a reel increases its moment increases and its
>angular velocity decreases.
>
>We have two degrees of freedom: hub diameter and moment of an empty
>reel.  It seems likely to me that e can make any variations in the
>angular momentum third-order.  I'll do the math when I'm less busy...


	Of course, there's the problem of mass  leaving  one  rotating
	tape reel and moving to the other on a continuous basis. That
	makes the math more interesting!


					Mike

spangler@kvue.UUCP (Lance Spangler) (07/11/85)

There are motion picture cameras which should solve the problems 
associated with one reel being fuller than the other...and the inertia
problems associated with the speed involved. 

Most everyone remembers the film magazines shaped like mouse ears.  Most
film cameras (16 & 35mm) still use something like that.  But years ago, a
16mm sound camera called a (sp?) Belieau used what was termed stacked 
loading.  That is, the feed reel and the take up reel literally sat on top
of each other, with a small hub between each to take care of the difference
in reel speed. 

While I haven't picked up a camera in years (anyone want to buy a complete 
Bolex 16mm outfit? <:-)) I know the technology still exists.  We presently 
use a RCA portable 1" vtr that uses the same type of stacked loading.  

Would this sort of setup solve the inerta problems which seem to be  
creating problems in a weightless environment?  I'm not sure, but after 
reading the hack about opposing reels traveling in opposite directions, 
I thought I'd throw the idea out.  I'm sure Arriflex or who ever is making
the motion picture cameras for NASA these days could whip one out.  Or 
for that matter, check with Belieau in France to see if they make a unit
suitable for the shuttle.  I know the Belieau was a beauty of a camera back
in my news photographer days...power zoom...auto iris...a battery that lasted
for ever...etc. 

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