RE: New video of my Centaur [TANKS]

["Carioti, John" <john.carioti-at-sensis.com>]

Title: Message

Well...it was a little tricky.

 

Basically, I bought a #40 hubless sprocket from McMaster Carr and then just matched the bolt pattern on the face of the 64038 and drilled four  5/16" clearance holes in the sprocket.  Not exactly precision machining going on here, but it did work.  One of them is slightly off center, but fortunately roller chain is very forgiving.

 

One word of caution: if you do use these motors, you have to bolt them down with more than just the two 5/16" mounting holes in the bottom.  The motor has so much torque that it will rip the threads out very quickly.  It's a little hard to explain, but I added a steel right angle piece to the bottom of the motor to help strengthen the mount.  There are 2 additional holes above the bottom mounting holes, and that is where I attached the steel angle.

 

When I had these in my 220 lb bot, I had even more structure to hold them.  The motors have sort of a "diving board" effect because the heavy magnet part is unsupported and is far away from the mounting holes.  So I made a support for the back also.  But I don't think you need to worry about that part because the Tanks aren't crashing into each other at 15 MPH!

-----Original Message-----
From: tanks-admin-at-rctankcombat.com [mailto:tanks-admin-at-rctankcombat.com] On Behalf Of Derek Engelhaupt
Sent: Monday, August 28, 2006 10:31 AM
To: tanks-at-rctankcombat.com
Subject: RE: New video of my Centaur [TANKS]

John,

 

I have a couple of these NPC 64038 motors and I was wondering if you had any pics of how you mounted the sprocket on them.

 

Derek

"Carioti, John" <john.carioti-at-sensis.com> wrote:

The drive motors are NPC 64038.  These are 2 hp wheel chair motors that I had previously used in my 220 lb Battlebot.  They have the gearbox built in. 

 

I'm running them at 24 volts. And I am actually gearing them up a little to get more speed.  The motor has a voltage constant of 10 RPM/volt, so with my gearing the drive sprocket is turning at about 325 RPM.

 

The chain is #40, and the drive axle is 1" steel.  All of this stuff was scavenged from my Battlebot material.

 

I used EV warriors on a 120 lb Battlebot that I built last year.  They worked OK and gave pretty good speed, but they really aren't robust enough in the Battlebot world for a speedy 120 lb bot.  Especially if you use 4 wheel drive skid (or tank) style steering.  The motors are working really hard when you have to drag one side through a turn. After a 3 minute match, the things were red hot!

 

It seems like the EV warrior would work OK for a 100 lb Tank, with the right gearing and with a little less duty cycle. In the Battlebot world we are shooting for at least 10 MPH, I think in the tank world 5 MPH is pretty fast.  So maybe that's why the EV warriors seem to be so popular for the tank guys. 

 

What kind of motors do you have in your tank?  139 lbs seems very heavy! 

-----Original Message-----
From: tanks-admin-at-rctankcombat.com [mailto:tanks-admin-at-rctankcombat.com] On Behalf Of BrendanKotlanger-at-aol.com
Sent: Wednesday, August 23, 2006 4:46 PM
To: tanks-at-rctankcombat.com
Subject: Re: New video of my Centaur [TANKS]

I know about over kill in construction.  My tank was made out of 3/4 ply and the suspension is a rectangle made out of square aluminum tubing with 8 1/2 inch stainless rods 24 inches long going through it.  That part (plus drive system) was 30 lbs.  the wood hull is 10 lbs.  each of the 24 road wheels are 1.5 lbs each.  I saved some weight with conveyor belt tracks.  batteries are about 50 lbs total of 18 ah for the drive system and 7 ah for the electronics/sommer speed control.  the upper deck is 13 lbs for a grand total of 139 lbs.  I wish I had ev warriors.  It runs fast for a heavy tank after the poufs of smoke were fixed.

 

What motors and gear reduction are you using and at what volts do you run them at?

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