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What motor should I get? PLEASE HELP? Answered

For science fair,  i need to make a car for a 'king of the hill' type thing
I need 2 motors (one for each back wheel) that can get me up the hill relatively quickly.
The maximum power source i'm allowed is two nine volt batteries at one time (i can switch out dead ones in between runs)
The hill is 40 inches in height and the ramp leading to the top of the hill is eight feet long
The motors need to have a driveshaft sticking out about 1-2 inches
I'm not allowed to use remote control but i've devised a way so that the car will stop, regardless of what the motor is.
A link to a website where i can buy the motors or where i could get them would suffice (please below $15 per motor)
Help would be GREATLY appreciated

edit: my car will weigh about 1 -1.5 pounds
edit: i dont know a whole lot about which motor to get so if someone could (not to sound helpless) pick one for my situation that'd be great



8 years ago

if your allowed to have 18v of power, then you will need minimal gear reduction as long as you keep the machine pretty light. unless it needs to steer, then just ose one motor to drive both wheels. or even have one big drive wheel. servos are painfully slow, but will work. you could get a cheap rc car, gut it, and run 18v directly to the motor. dont expect the motor to last very long tho lol.


8 years ago

What's the weight of the car?


8 years ago

Hobby servo motors might be a good choice. These are normally used to position the ruder and alerons on model planes. They ordinarily don't rotate continously, they are instead commanded to a certain position. However, there are many good guides on the web, including this site, on how to modify them for continous rotation so that they can be used as drive motors on small robots.

The good thing about these is that they are small, inexpensive, and have a built in gear reduction.

A good source for Tower Hobbies, at www.towerhobbies.com. There should be some within the $15 price range. You could of course check ebay for possibly better deals still. They typically run off of about 5 to 6 volts. I think they should run off your batteries long enough to get up the incline you describe.