Speed Controllers

The original plan was to build our own speed controllers thus saving quite a bit of cash. The controllers were designed around standard speed controller/servo chips as used in smaller RC cars with a modified output stage using a MOSFET bridge to provide high power fully proportional forward and reverse. That was the plan ! Of course anyone who has got involved with high power speed controllers will tell you that they have a tendency to blow themselves to bits if not exacly right. Howard spent many joyful hours replacing blown MOSFETs and trying to figure out why 100 amp devices blow up with 5 amps flowing through them. Anyway, with the rehersals just a week away and no working controllers it was out with the plastic and of to see the man at 4QD in Burwell (about 15 miles from us).

We opted for NCC60 24 volt controllers, these can handle 100 amps. The interface to the radio gear was via 4QDs own joystick interfaces with a mechanical interface to the servos. We used one 50 degree pot interface per controller rather than the sum and difference interface to give us track style steering.