ANtweight POKE OF DOOM

[bob=)]

well, i have an idea for a really fast thwacker bot...but im not completley sure that it will work...any help would be extremely appreciated :D

Beetle B16 Gearmotor 16:1 // (2) for two wheels

GWS 1050mAh LiPoly Triple Cell 3S 11.1V Pack // (2) so i wont be caught with a dead battery

Spektrum DX6 6-channel 2.4Ghz Radio System // because its awesome

Ant 150-02 Dual 5A plus 15A AUX Speed Controller with connectors // controller for robot

Spektrum BR6000 6 channel Bot Receiver

Hitec/JR Switch with charging plug // switch to turn robot off

are the beetle motors good for a 16 oz (1 lb) robot? will they be too weak?

here are their stats:

http://www.robotmarketplace.com/marketplace_ant_motors.html

scroll down a little, they're called:
B-Series Beetle Gearmotors

thx for help in advance:cool:

[Kevin Berry]

Hey Bob -

First a digression on those B series motors. I actually "discovered" them, from a Chinese hobby company, and turned Jim (robotcombat) onto them. The B-62's were the first model. I tried them but bailed because they were too slow. The B-16's were Jim's remedy for that. They are quite popular, and well worth it for a non-weaponed ant.

I would suggest you start a spreadsheet and figure the weight. Those are a bit heavy for an ant, but your battery selection is excellent, offsetting that quite a bit.

"Weak" is a factor of delivered torque, which is a factor of wheel diameter. You are always trading torque for speed and vice versa. So figuring a "fast" ant at about 100 inches per second, you'd back out wheel diameter from that, then figure torque. I use a factor (unscientific but proven) of 6:1 for an unweaponed bot. So for a 16 oz bot, you'd want at least 96 oz of "push".

So, do the math, post your results, and we'll talk more. I've never used the Spectrum, but many combat builders are in love with it.

[bob=)]

umm...what if i am not sure how to do those calculations?:confused: :oops:
I know that bigger wheel means more top sped, less torque, and that smaller wheels lead to les top speed, but more torque...but i beleive thats the extent of my knowledge considering actauly toque because of motor power and wheel diameter...i dont know how to acutally calculate the real numbers..so...help anyone?:confused:

[bob=)]

im thinking about using the b16's for direct drive straight to some 1 3/4 inch wheels for a thwack bot...im thinking the arm length should be around 6 inches...any thoughts?

[Kevin Berry]

Sorry to be away so long, should have responded weeks ago.

Take the torque spec of the motor, say 50 in-oz for example. If you use 2" wheels, the radius is 1". So the wheel will exert 50 oz on the floor. Assuming perfect traction, which there isn't, but thats another problem.

Lets say our hypothetical motor runs at 360 RPM. That's 6 revs per second. A 2" wheel, Pi times diameter, runs about 6 1/4" in circumference. So every second, the bot will go about 37". For a 6 foot arena, you'd get across in 2 seconds. Thats a bit on the slow side, especially since for a thwack you've got to CATCH them first?

Looking at the B16 specs it would depend on the voltage you're going to run at.