Let's start posting some CAD pictures:

Overall appearance
blastoff1.jpg
Chassis: I'm aiming for 10mm bolted aluminium alloy, preferibly 7075 series. Will have to be strong enough to contain a pair of springs each capable of 1000kg.
blastoff2.jpg
Drive train and cross section view. The motor is housed in a hub inside the drive wheel, with a reduction gearbox outside. A fair amount of machining will be involved but I think it's doable.
For tracks I'm going to use a poly V belt 45mm wide. The drive pulley will be machined to match the groves in the belt - I have high hopes this will be a final solution to solve the track alignment problems on previous builds
blastoff3.jpg blastoff4.jpg
Weapon system:
Main supply is Co2 from a paintball bottle (9oz for now - might get larger). From the bottle through a custom FP valve which will mount directly onto the bottle pin valve.
It consists of an on/off valve and a 2 position 2 way valve, solenoid operated normally closed. When energized air will pass through the valve to a QEV mounted on the ram inlet and retracts the ram, which in turn compress the spring.
When the valve is de energized air is exhausted through the QEV and the spring forces the flipper arm up.
blastoff5.jpg blastoff6.jpg