>>2408174 Basically a roll top bag i had sewn out of 210 robic (just copy modern packs. 7.5 inches of depth, frame length 26 inches (not counting roll top collar) 13.5 inches wide. 1inch seam allowance so the cuts will be 8.5 and 14.5
Seek outside talon and load shelf compression system
Sew loop to run the one end through and loop around the vertical parts of the frame to connect it to the frame
You can use any type of bag or sack at this point just cinch it down
https://seekoutside.com/backpack-accessories/ 