We're planning on putting a featherweight together for Motorama 2011, and we wanted a design that would (a) have a large weapon; and (b) look good :-) so here's what we're going to build - Formidable Fustigator 0.9. Click Back after viewing an image.
Starting out with the baseplate - 3/16" polycarbonate should suffice, as there's not a lot mounted to it except the drive train.
We're using a mix of half-inch 6061 aluminium and polycabonate. The inside walls are aluminium and the outside walls are polycarb. The rounded ends over the wheels are half-inch 6061 aluminium tube.
The drive train will be either DeWalt 18V drill motors or Craftsman 19.2V drill motors - we haven't decided yet. The DeWalts are a little heavier, but the mounts for them are pre-made. We'll have to see how we're doing for weight as we go through the build. The wheels are 4" omniwheels recovered from our middleweight we never finished building: Epitomic Expletive 0.9.
To try and stiffen the weapon mount we're putting in two quarter-inch 6061 aluminium braces that bolt to the baseplate, the front wall, and the weapon mount.
The weapon mount comprises a pair of 6061 aluminium rings, with nylon bearings between the blade and the rings. That's a 1" steel shaft in the middle.
Passing through the middle of the weapon shaft is a threaded tube that bolts on top and below to keep the weapon mount together. Here you can see the 24" steel blade, and the bearings/bushings for the weapon.
This render shows the 'bot coming together, with the weapon motor and timing pulleys installed, along with the braces. The weapon motor is a Turnigy G110 which we will run from an 8S LiPo pack.
Assembling more of the 'bot, and the upper blue object is the 8S battery for the weapon motor, and the one on the right is the 6S pack for the drive motors. Not rendered are the receiver or speed controller.
A final render with team colours applied - black and purple. We're ready to send DXFs off to our friendly water-jetters for the base and top plates. Watch for this one to come together quickly!