Here are a couple shots of our belly pan. We used the belly pan as the main design element to hold the frame together. We use rivets to join the pieces together and once joined the frame is lightweight, very stiff and strong. The material we used was .090" 5052 aluminum. The frame is 12 lbs total. No welding required.
We used a CNC punch press to cut the metal. Notice the basic shapes circle and square. The punched frame takes only minutes to produce but requires a bit of up front programming. The tolerances for the frame are very high. Hole to hole tolerance is +-.010" . We used a staggered perforation pattern to lighten the belly pan. A staggered pattern can reduce the weight by 50%-60%.
We laid out our electronics prior to punching. By taking the CAD model of the the electronics and extrude the mounting holes through the belly pan we come up with all the mounting holes. We used a 10-32 .250 thk. Pem standoff, a plastic isolator and a nylon screw to mount the electronics. Once installed we cut off the remaining thread and makesthe bottom surface smooth.
The proper use of the belly pan can reduce your build cycle considerably. It can be used to fixture other parts of your frame. It can be used to mount electronics. It can be used to strengthen and stiffen your frame. It can be bent up in the front and rear to allow the wheels to climb over field elements.
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