Servo - November 2008

The wheels from Banebots get fantastic traction, but they are very soft rubber and wear quickly. Buy spares!

A more close-up view of the speed controllers. I have used some zip strips to try to manage the mess of wires that invariably comes from wiring a bot. Don’t be afraid to tie down everything that you think will move around. Nobody will ever give you a bad time after you’ve won a match and tell you that you have too many wire ties!

been avoided if needed. You could simply use 1.5” tall aluminum for the frame rails, and made the top

and bottom plates match the exterior dimensions. The only critical dimension was to make sure the distance from the top to bottom plates was 1.5” to correspond to the height of the motors and bearing blocks. Available on the SERVO website

( www.servomagazine.com) are the AutoCAD drawings (and PDF files for those without access to AutoCAD) with the specifications on Mitch’s construction, not including the wedge mounts. With 1” thick aluminum across the front and sides, there is plenty of opportunity to mount a wedge in almost any fashion you would like. I am

For a simple, quick, and cheap locating method for the wheels, I simply stacked washers on each side of the wheel. This kept the wheel centered in the wheel opening, but allowed some side to side movement of the wheel on the axle.

ITEM

• Drive motors

• Wheels

• Bearing blocks

• Batteries

• Speed controllers

• Power switch

• BEC

• Radio

Parts List

SUPPLIER LINK

http://banebots.com/pc/MP-36XXX-545/MP-36020-545 http://banebots.com/c/WHB-KS3-298 http://banebots.com/pc/MOTOR-ACC/PB-S3751-BB www.hobbycity.com www.robotmarketplace.com/products/IFI-V883.html www.teamwhyachi.com/MS1.htm www.robotmarketplace.com/products/0-PBEC1.html www.robotmarketplace.com/products/0-SPM6600.html

providing these as a guide to making a simple and effective combat robot which you can copy exactly or modify as you see fit. The frame and drivetrain minus the wedge weighs in at about 15 pounds, giving plenty of weight for any extras you may feel like adding. Our wedge weighed in at 12 pounds, giving us a combat weight of slightly less than 27 pounds. The wedge on Mitch is constructed of . 25” 4130 steel, which was cut and welded into the final shape. A big part of Mitch’s success is due to the shock mounting I used for the wedge. A wedge that is more than 1/3 the bot’s weight is obviously substantial for the class, but the shock mounts really helped isolate the chassis of the bot from the big hits from all the nasty spinners in the 30 pound weight class. The rubber isolators are the only item I cannot find you a link to the exact part I used. I bought these surplus years ago and like most surplus items, once they are gone you can never find them again. McMaster-Carr sells many rubber isolation mounts though, so you can find similar items, such as their part #9376K39. Mitch proved to be a tough little machine, and was a blast to build and drive. Top speed was manageable at around 8 mph, and was easily controlled. If you have any questions on the parts and materials used, I can be reached at ray@hardcorerobotics.com. SV