Re: engine question [TANKS]

["jon s kowitz" <jonskowitz-at-hotmail.com>]

  I didn't say that they didn't really make sense (it's what I'm going to 
try using) but I'm simply pointing out the potential difficulties I see from 
thier use.  At 150 rpm, you need an overdrive ratio of about 1:3 to produce 
the 400 rpm sprocket speed needed for 4 - 5 mph (assuming a 4" / 10cm 
sprocket).  This will decrease sprocket torque to 1/3 of motor torque (which 
is why you need to keep the tank as lightweight as possible), though using 
multiple motors to drive each track may help (which will up the amperage 
your relays will need to carry, don't have any data on amp draw yet though).

  Of course, the motors are very lightweight and compact, plus it's a lot 
more appealing to try over-volting a pair of motors you picked up for $5 at 
a junkyard than it is a $150 DeWalt or a "soon-to-be-priceless" Warrior.  
I'll have some more data available on overvolting these motors in a couple 
of weeks (need more $$$ for batteries to test with).  Also, if the amp-draw 
turns out to be significantly less then you might be able to get away with a 
smaller battery (further lightening the chassis).

  BTW- another advantage of these motors is that they seem to be extremely 
plentiful.  I noticed today that a '95 Ford F800 medium truck uses the exact 
same motor, which means finding matching copies will be very simple to do.

  Hopefully I'll have a rolling chassis finished by the end of March or 
April and we can get some "real-world" testing done on them.