Re: quick BT-7 [TANKS]

["Stacy Hilton" <stacyj-at-defnet.com>]

Chrys,

 

I simply can not let this stand.  Let's look at .25 pitch chain drive first.  If you use two 14 tooth sprockets you get a 1:1 ratio, meaning that if you turn the input gear one time, the output gear also turns one time and torque remains the same.  If you use one 7 tooth sprocket and one 14 tooth you get either a 2:1 ratio or a 1:2 ratio depending on which sprocket is used as the input. So, if you use the 7 tooth sprocket as the input (2:1 ratio) the output speed is reduced by half and torque is increased X2.  If you use the 14 tooth sprocket as the input, speed is increased X2 and the torque is reduced by half.  The length of chain doesn't matter.  This is the simple version by far, but as you gain a bit more confidence, you can delve a bit deeper.

 

Paul Hilton.

----- Original Message -----

From: Chrysanthos Kanellopoulos

To: tanks-at-rctankcombat.com

Sent: Monday, October 22, 2007 12:08 PM

Subject: quick BT-7 [TANKS]

 

I know Paul, only pulleys and gears are above my skills level.

 

Chrys

 

OK, that's better.  So, as you can see there isn't any room for a direct drive.  the gears for the final drive shafts are housed in those disk shaped housings.  The final drive shafts are mounted in the tube that connects the two housings.  The relationship between the tube, housings and drive cog are such that it isn't really possible to "fake" the rear of the vehicle and move the drive cog forward.  I would think that it would resemble a pickup truck with the rear wheels right behind the cab.  Just not quite right.  I've decided to simply accept the structure and use it pretty much as it was originally, with sprockets for chain drives inside the two housings and either a pair of live shafts or a long continuous dead shaft inside the tube.  The dead shaft would offer more stability, the live shafts are simpler to construct.

 

Paul Hilton.