- Ant Weight (1lb)
- Four-wheel drive
- Vertical spinner
- Titanium plow
- Carbon fiber and TPU construction
- Four cell lipo battery
The intent is to keep the weapons system simple and easy to maintain while still having enough kinetic energy to send an opponent flying. I believe with some slight modifications and attention to detail, the fingertech clamping weapon mount can achieve this.
The fingertech mount weighs in at 42 g and the 2822 weapon motor is 45 g. With a KV rating of 1100 and a cell count of four, the weapon should spin around 16,000 RPMs when at max throttle. They should put the weapon tip speed at roughly 116 mph, which is a bit slow, but this can always be corrected with additional cells in the battery if needed.
The 2822 motor will need to be battle hardened with epoxy. The epoxy is there to prevent magnets from becoming dislodged and jamming up the weapon. The motor shaft may also need to be replaced to help retain the weapon in the robots frame.
The base impactor teeth on the fingertech weapon system are squared off at the end. By beveling these by at least 60° the weapon sends a higher chance at getting underneath opponents. These will have to be ordered after the fact, since the stock ones will not be long enough.
Brushless repeat MK3 motors will be utilized to directly drive the rear wheels. The front wheels will be mounted on repeat ant weight dead shafts. A belt will transfer power from the rear wheel to the front wheel, most likely an S3M or a GT2 belt.
The wheels will be small diameter for this robot, so utilizing foam would have minimal benefits. Silicone wheels over TPU hubs will probably be the most durable and cost-effective method. McMaster car 35A silicone tubing has worked well in the past and will most likely be the wheel of choice in this case.
The rear wheel can utilize an aluminum shaft collar with an oversized set screw to retain itself in the hub. The front wheels can utilize nylon or PTFE bushings with sewing machine oil as lubricant.
The motor should be driven with AM32 ESC's.
The repeat MK3s have a motor with a 3500 KV rating. The gearbox is 28.5 to 1 gear ratio. The wheels on this robot will be around 1 in. Based on these assumptions, we can assume with a four cell lipo that the output at 100% will be roughly 1800 RPM. 1800 RPM with a 1-in wheel is roughly 5.5 MPH. The speed is adequate and will serve its purpose, although additional speed maybe needed in the future.
Frame and armor construction
All horizontally orientated panels should be 1 mm carbon fiber, anything thicker than that is wasted weight. The primary reason is that if the bot is getting hit on the underside or on the top panel, we probably have larger issues than the thinness of the material.
The vertical panels should be constructed out of 2 mm carbon fiber. These panels will be the two weapon uprights and the two drive sides. 2 mm carbon fiber might be overkill for this weight, class and design, but will serve as a good starting point. This may have to be reassessed in the future.
A series of tabs and slots as well as TPU mounting points will serve to hold the frames together. There will be approximately four unique TPU components. The center mount of the weapon uprights, the front armor mounts, the side armor mounts, and the rear panel will all be constructed out of TPU.
Number four plastite screws will hold the carbon fiber to the TPU. These may be larger than what needs to be utilized, but this can be reassessed in the future. Ideally each of these screws would be no longer than 8 mm into the TPU, this would allow for the top and bottom panel screws to be the same as the side screws to minimize hardware. Screw holes could be offset though to allow for longer hardware through the top and bottom panel.
The front armor should be between 1.5 and 2 mm titanium. Titanium is a great choice in this case due to its rigidity, toughness, and is lightweight. The armor will need to be bent into L shapes to conform around the front and sides of the robot. By mounting to both the front and side the armor will be much harder to remove by opponents.
Flathead plastid screws should be countersunk into the titanium wedge to hold it to the TPU mounting points. No part of the head of the screw should be exposed, this will reduce the likelihood that a weapon will catch it.