Team MedBots

[Max]

Started work on making a mockup of my new pneumatic flipper but it seems very large.
Here are some pics to show you the shape/size:
[attachment=1:1yhvlgju]flipper photo 1.jpg[/attachment:1yhvlgju]
[attachment=0:1yhvlgju]flipper photo 2.jpg[/attachment:1yhvlgju]

the dimensions are 550mm long, 300 wide (excluding the wheels) and 200 high.
i was thinking of making all those bulkheads out of 15mm hdpe (it wont be against spinners) or possibly having middle 2 bulkheads as wood then hdpe for the other ones; then i thought a 3mm aluminium lid.

Do you guys think thats sound ok and in the weight limit? also what do you generally think of the design?