Brief Description: Internal hinge pin removal system
The hidden cowl hinge pin is not my idea, but the implementation is. I was going to use Sky-Bolt fasteners but after looking at price and the advantages, I decided on the totally invisible hinge pin system. The top hinge pins are removed through the oil door and the 2 side hinge pins get removed from inside the cockpit. The beauty of this system is the “beauty” of no external fasteners. The bottom attachments are not the hinges shown in the plans, rather platenuts and screws. The reason for this is strength and to hold tight against the buffeting of the exhaust. This is the one area the hinge pins wear very quickly and the platenut / screw attachment handles these loads well. The guide tube for the side hinge pins is standard 3/16” aluminum tube lined up through the firewall to the hinge. It is held in place using AN832 bulkhead fittings and then I bent the wire to go into a stay made out of a piece of hinge. This locks the pin in place.
AN fitting and hinge pin lock
3/16 tube through the firewall lined up with hinge
