Main Gear Mounting

Time: 6hrs

Well this has been very challenging. I think mounting the gear with the fuselage upside down was a good decision. It’s been very easy to check the fitment of the gear and accessing the bolts has been somewhat easy… though working inside the fuselage is a bit of a pain and somewhat cramped. The main issue is that I can’t seem to get two bolts (one on each side) in at the same time. Once I put one bolt in then the other side is a fraction of a millimeter off which makes it impossible to push the other bolt in. There is really no room to tap the bolt with a mallet. I did find a way to push the bolt in using a piece of wood placed between the bolt head and the main spar. After some research in the manual it appears that the bolts are to be installed with the head facing aft, but that’s not what the FAA says. I’d really like to install them in the correct orientation. 

As far as fitment I’ve had the gear on and off a multitude of times. The top of the gear hits the rivnuts and also interferes with the rivets that will be installed to hold the rear seat floor panels on. Also the gear is a bit too wide at the bolt locations so that needs to be sanded down as well. 

Some photos and a bit more narrative below. Even after working in this for many hours I have not yet been able to get the bolts in… so the work will continue. 


This was a good method for me to allow placement and rough fitting of the gear. You can remove the wood block and check the fitment and then sand as needed. 


Here I thought I had the fitment right so I put some grease at the bolt area location as instructed by Jean from Torrance TAF. He said that this will minimize any creaking in the gear. It turned out that the top of the gear needed to be sanded as well so the gear was removed and sanded multiple times since this photo. 


I put a bevel on the top edge of the gear. This was done to get the gear to fit down without putting pressure on the rivnuts. Also it helped give some room to where the rivets will be installed for the rear floor panels. After this photo was taken I ended up taking out the belt sander with some 60 grit paper and sanded down the bevels even more. 

I think the fitments is good now and the gear seems to fit down into the channel without needed to be held into that position. This may help with the installation of the bolts which so far has been impossible to do. I spent nearly 4 hours trying to get two bolts in. The first bolt is fairly easy to install since you can get perfect alignment of the metal spacer in the gear and the holes in the gear channel so the bolt can be pushed in by hand or by using some wood to pry it in. The problem is the insertion of a second bolt on the other side. The top to bottom alignment can be tuned by pushing down on the gear and holding it with some clamps. The left to right positioning is really the problem. There’s not too much you can do about it and even if you have a small misalignment the bolt will not go in. I have tried to round off the edges of the metal spacers in the gear so that there are no hard edges for the bolt to catch on, but it only helps minimally. I’m thinking I may need to widen the hole in the gear channel just a small bit to get the bolts to fit. If you had room to tap the bolt in it would probably go, but there really isn’t much room. Hopefully I’ll get some time to work on this again in the next few days. 

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