I dont know when my obsession with tanks and tracked vehciles started but I have always wanted to build a tank. Problem is they are very big and heavy so the only real option I have is a scale model, a big scale model. The T1 was my first go at building a tracked robot and it turned out ok, however, it was not a tank as such.
Inbetween other comercial projects I have decided to build a 1/6 scale model of a tank, which will be just for me. It will not be a copy of any existing tank, more a mix inspired by several different models, but the aim is to make it look very futureistic.
To power it I will use a couple of wheelchair motors, which I must admit might be slightly overkill as each is rated at 650w but there is nothing like exessive power. Dimensions, I am thinking around 100cm long by 60cm wide and probably 30cm high, although this will probably change.
Either Cytron or Sabretooth ESC to control the motors, 2x12v 20Ah batteries running 24v. It will be a full metal build so probably massively heavy.
When I built the bogies I was in two minds as to whether they should have suspension or not. I have decided to not have suspension but keep the wheel mounting solid like I did with the T1. It makes life much easier and to be honest I cant see any advantage the suspension will add given the relative low speed of the tank and that it is a model. I decided on 90mm wheels with an M12 bore arranged in a row of five doubles. This gives a track width of 11cm. My overall track will be 15cm.
The motors will be mounted at the back of the tank giving roughly 30cm between tracks. It will be direct drive through the gearbox to the drive sprocket. I will keep the wheelchair gearbox mechanical disengauge system to make it easier to move the tank around when not powered up.
The drive sprocket is fairly simple. A dual gear which will engage on the chains. Every other tooth of the drive gear has been removed so it will not impact on the bolts which bolt through the chain and secure the track plates.
I will need to fabricate a flange system to securely mount the drive sprocket to the motors, this will be fun.
The Tracks
I came up with an idea of using heavy duty 530 motorcycle chain and bolting the track plates through the chain with modified M6 bolts. It will mean removing every other tooth on the drive sprocket so it engages correctly. The M6 bolts will not be tightened but will allow play so the track can flex and move which will help keep it secure on the drive sprockets. The track plates are 3mm aluminium 25mm x150mm. It does mean each M6 bolt has to be ground down to correctly fit the chain and there are lots.
To secure it all I will eventually use M6 nylocs with thread lock.
The tensioner wheels will use the same tensioning system I used on the T1. It worked really well so I dont see why it wont work on a smaller scale.
This is it so far. Basic frame is made of steel and at the moment it is spot welding it together before final fabrication.
No idea what this thing is going to weigh but it is heavy already.
No comments:
Post a Comment