robert lamont
3 inch quad arms 3mm. tpu canopy
upperplate 2mm suits 16x16 and 20x20mm stacks.
upper and lower plates sandwich the arms held in with one 2mx10mm nut and bolt.
four 2mx14mm bolts go through all plates and screw into tpu canopy.
there is a 3mm gap between upper and lower plates for battery strap.
cut outs added to stop strap moving when using narrow batteries