The hidden hinge has a uniquely shaped arm that allows the hinge to be mounted completely out of view to the underside of the cowling. The center hinge eye is removed for the custom made spring that loads the hinge to be full open when unlatched. If your oil door unlatched it will be full open, eliminating
accidentally taking off with the oil door unlatched. The hinge is aircraft quality extruded MS20001-4 hinge with a 3/32” steel hinge pin. One end of the hinge pin is flattened. When installed and closed the hinge pin is gripped tightly by the force of the spring.
Install the hinge so that the curved part of the hinge just misses the cowling when opening. We suggest you remove the spring to make it easier to see the range of motion during mounting. Mount the hinge to the cowling first; then mount the oil door to the hinge. Some builders may want to make an aluminum door instead of using a fiberglass door. Latching of the oil door can be accomplished with screws, camlock, dzus, hartwell latches, remote latches, etc. (available from aircraft hardware & aircraft supply houses).
Great little hinge for oil level stick inspection. It comes with a spare spring as well. I couldve made one. But, saved so much time just buying this one. Recommend.
Works well installed under a cowling door. Instructions are pretty clear.
works very good and I like that it pops open and stays that way until you close it.
Easy to install, looks and works great!