It is November in Minnesota, and it has been a weird fall. Unfortunately, that means at least half the leaves are still in the trees, and we are forecast to get 4-7 inches of snow between tomorrow night and Wednesday morning. Of course it could be 60 and sunny too, lets hope. But I had to divert some of my attention today from the airplane to cleaning up leaves and the gutters.
Even with having to do that, I was able to make another set of hinge pieces for the other side of the gear doors. It was a simple process of just copying the pieces I already had.
Both of these aluminum anchor plates were prepped, drilled, and countersunk for nut plates. I had to use single lug nut plates due to the edge distances I was using for the screw holes. These single lug nut plates have both rivet holes on one side of the ‘nut.’
Lightning holes were drilled in the area of the anchor plate that is to be bonded to the gear well. Again, these serve dual purpose and are filled with flox to improve the bond to the fiberglass and provide “flox rivets” to further secure the piece. A little light sanding on the bond area, clean with acetone, and they were ready to be bonded in.
Then the attention shifted to the actual gear well. I had already modified the ‘aircraft right’ side of the gear well, so I did the same on aircraft left. Basically this involved cutting out a small piece of fiberglass (that I had done twice already). Then the area was sanded back to allow the plate to fit flush with the edge of the gear well.
I debated how to bond the anchor plate to the gear well. One option was bonding the entire length of the anchor plate and creating a pocket behind it. I decided against this due to the complexity. Instead, I am leaving 1″ of the anchor plate cantilevered to provide a clear area where the pivot hardware will go. There is still 4+ inches of bond for the anchor plate, and that should be more than sufficient.
In order to do this, it was necessary to add a bit of foam back at this point to increase bonding area and minimize cantilever for the anchor plate. A small area was dammed off with aluminum tape, foam was cast, and then sanded to shape.
After that was all done, it was time to layup 2 ply bid over the foam. Then the anchor plates were floxed to the 2 ply BID and jigged into position. Lastly, 2 plies of BID were laid up over the bond area of the anchor plate. It is currently under a heat tent, and left to cure.
Tomorrow will be a big day, either third time will be the charm for the gear doors, or I will be severely disappointed. If it doesn’t work, I will admit defeat and do it the way everyone else does, with piano hinges. But I am fairly confident, that this is going to work. (I know, you have heard that before.) Hopefully tomorrow will start with adding the question mark pieces to the gear doors, and a successful test of the actuation. We will find out tomorrow.
4 thoughts on “Third time is the charm?”
Hey Joe, what’s the purpose of the rivets on the anchor plate?
They hold nutplates in place so you don’t have to get a tool back there.
The “single lug nut plates”… I should have known. Thanks Joe.
Yup! You bet.