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Subject: 
Re: rubber band power
Newsgroups: 
lugnet.technic
Date: 
Thu, 9 Dec 1999 14:50:10 GMT
Viewed: 
963 times
  
"Rick Kirkwood" <dynamics@mediaone.net> writes:

I've seen the picture of the Blast-off Dragster 8205, but the connection
mechanism between the long rubber band and the wheels is not obvious, at
least to me.

Sorry, I don't have a scan of the instructions.

The design is very simple, but still very well done.

The rubber band basically drives the rear wheels.  But imagine
connecting the rubber band-driven spool directly to the rear axle: When
the vehicle has traveled for the full duration of the band's length, it
would simply brake.

So the extra gears you see are there to ensure that the car does not
brake when the rubber band has done it's work.  It's sort-of a one way
switch, the rubber band can drive the wheels around in one direction,
but not the other.

This is achieved in a very simple way: The rearmost 16t gear cog you can
see in the image is connected to the rubber band spool.  There is an
additional gear hidden behind the left rear wheel.  The third wheel is
allowed to "flip" up, since it is connected to a lever, and hence the
spool can only drive the wheels the correct way.

Keeping in mind that there is a hidden gear behind the left rear wheel,
you may be able to build the model from this image:

    http://www.lugnet.com/pause/search/?query=8205

I have a similar setup on my homepage, although the aim of that
contraption is different: To discard the direction of an axle's
rotation:

    http://www.math.uio.no/~fredrigl/technic/direction-unifier/

Fredrik



Message is in Reply To:
  Re: rubber band power
 
I've seen the picture of the Blast-off Dragster 8205, but the connection mechanism between the long rubber band and the wheels is not obvious, at least to me. Is there a scan of the instructions for this one available? Its not on Brickshelf. Its (...) (25 years ago, 9-Dec-99, to lugnet.technic)

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