27-02-2007 23:57

seinchin

Re: pic: 379's transmission

Are you using a tread drive?

28-02-2007 00:41

Re: pic: 379's transmission

280 foot pounds... I'm slightly tempted to doubt this number, as a racing mustang I work on with a fully aftermarket engine, and all performance parts puts out 298 at 2100 rpm... Where did you get this number?

28-02-2007 01:00

gburlison

Re: pic: 379's transmission

Well,

If I did the conversions right, the small CIM puts out about 1.27 foot pounds of torque at stall or 0 rpm. That means that a 221:1 gear ratio would equal about 280 foot pounds of torque at 0 rpm (stall). I have no idea if this transmission has a gear ratio near 221:1
How much torque does that Mustang motor put out at 0 rpm?

28-02-2007 01:04

Re: pic: 379's transmission

0 rpm doesn't happen in a internal combustion engine, as the motor is not turning. I have a feeling they did their calculations based on the max rpm of the motor, or 5200 rpm.

28-02-2007 07:39

robostangs548

Re: pic: 379's transmission

Wow... 280 thats intense.... We are pushing around there, but in order to do so we had to do a serious friction increase project. Have you found out if you have any slipping going on or are you alright in that area? Other wise that is a SERIOUS gear system and looks great. We have a shifting mecognism that we think will really impress some people. But all in good time right . Other wise this looks like a great drivetrain that I am pretty sure will work very good. From experience I can say that being able to push 280 means pushing someone sideways wich translates into a HUGE advantage in the game. If you have designed this bot as a great bully bot then you did a great job! If you dident you still did a great job. One more question that I have to ask though is how fast does this drivetrain go? Usually with low gearing and not being able to shift you have high torque and low speed. Is the same true with your bot? Thanks, and I wish you and your team the best of luck at regionals.

28-02-2007 11:45

kevin.li.rit

Re: pic: 379's transmission

So 24 RPM for the output?

How much do your gearboxes weigh?

28-02-2007 20:05

gburlison

Re: pic: 379's transmission

Sorry, but my odd sense of sarcasm doesn't come across well online. Specs for internal combustion engines usually quote a torque and speed so that you have a better idea of what the engine is capable of. I assume that these claims are all based on calculations and are not actual. The point is that PM electric motors and internal combustion engines are very different and most of the time comparisons are not very usefull. I agree that the probably used 5200 rpm and their highest gear ratio to calculate the 15 fps. But they probably used stall torque and the lowest gear ratio to calculate torque not realizing that at stall the CIM draws 133 amps, so they will not produce 280 ft-lbs of torque for very long.

01-03-2007 12:29

Hadi379

Re: pic: 379's transmission

I'm not exactly sure about the calculations, but from my experience, this transmission is very powerful. I cannot recall a time that this Drive system has lost a pushing match. It is a 3 speed transmission that weighs a total of 25-30lbs, it is also combined with the traction of treads and slippage is not an issue.

01-03-2007 21:14

kevin.li.rit

Re: pic: 379's transmission

Yes but how fast do you move with that 221 reduction?

05-03-2007 08:48

Hadi379

Re: pic: 379's transmission

I believe its fastest speed is about 15 fps