SPECS: Tank Technical Data
SolidWorks Render
All wood construction with a steel powertrain.
Deviations from the Design during Build:
- Each wheel pack has two extra 1/8" discs. These are used to capture the nylock nuts on the underside of the belt to help with tracking, they were not a part of the original design
- The belt tensioner was also added later as it was discovered that the belt was too loose and climbing over the discs in the wheel pack and falling off.
- The underglow in the turret was a last minute addition because, why not?
Update: 8-31-18
- The nylock nuts on the tracks have been replaced with nylon acorn nuts. During use the tracks were continuously walking off the wheels. It is suspected that the tracks have stretched since they were first installed and were no longer maintaining sufficient tension. The apparent failure mode was the flat nuts catching on the side of the entrapment groove, creating a larger diameter. This caused an effect similar to a crown pulley which further pulled the belt out of the groove. The acorn nuts have solved this problem. The nuts still catch on the side of the groove but due to the round shape of the nuts they slip and fall back into the groove instead of walking up onto the discs.
- We finally have remote control!!! After multiple attempts and failures I finally bought a model airplane controller. Simple plug and play installation for all of my existing PWM cabling. I did have to wire in a 12v to 5v power adapter for the receiver on the tank, however installation still was under an hour. In hindsight I was just being stubborn (also penny-wise/pound-foolish) and should have bought the airplane RC in 2016.
- Additionally, my dad asked if the tank could climb the deck steps, they are fairly shallow. After testing my conclusion is that the tracks have enough grip but the motors are stalling out. Possible solutions include converting the two CIMS to four AM Redline motors, using a DeciMate Gearbox to combine them into pairs and install them in the toughboxes. This would also require redoing the motor controllers and in total would be approx. $320. The cheaper solution would be increasing the size of the driven sprocket in the chain portion of the drive. Most likely it could be done for free to $20.
Update: 9-17-18
- Splurged a bit this weekend, we now have the second battery!
Update: 12-27-18
- Finally got some time to put together a video from the footage this summer.
Update: 4-22-19
- AndyMark was having a sale on gearboxs/motors so I was able to get my upgrades really cheap, plus free shipping to the FIRST Detroit Championship so I spent some money on the necessary things. Because of the sale I was able to afford the 4 AM RedlineA motors in DeCIMate gearboxes like I wanted, total cost of about $110. I still have to acquire some motor controllers for the extra two motors but I think I have a lead on some old Victor 888s that I can get for free. I'll definitely get a video posted once the upgrade is installed. The tank should have a lot more zip. Full specs of the upgrade here.
Update: 5-19-19
- Installation of the upgrade was completed this weekend. So we took the tank out for a spin. We now have plenty of power for driving around and climbing; however, we don't have enough traction to climb the steps. The treads slip as they are only contacting the stairs on two edges of the stair tread due to the curvature of the tank treads. The speed and acceleration improvements were as anticipated. One unfortunate side effect of the upgrade is that the Redline motors obstruct the back battery bay. For the time being we will be limited to the front battery bay while we search for an alternative battery, or a way to modify the back bay to gain the needed clearance.