I normally leave my oil door open for cooling, one day the wind blew it closed and I missed that it was not latched on the preflight. Just as I was lifting off the door started flapping, I had enough runway left and landed so no harm was done but it made me think.
I have added a spring to the door to hold it open. The pictures are self-explanatory. I wound the spring 4 coils out of .045 music wire. The spool is aluminum and I used a longer bolt to put it all together.
The stock right side hinge.
Parts to do the mod, the spring and sleeve I made.
finished with spring in place.