Just finished up the work from yesterday on the channel cut into the main gear for the brake lines. I filled a few spots where the router bit hit the edge of the channel with some fiberglass epoxy and primed it. Not perfect but looks good. When the brake line goes in it will look even better. I also found these polyester UV resistant clamps that would be good to use on the top and bottom of the gear to hold the brake line. The RTV will hold the line in fine along the back of the gear, but it may not be enough to hold it where it makes the bend into the brake caliber and at the top where it bends into the fuselage. I guess I’ll have to see when the time comes for that.
Now to cook some turkey.
Time: 2 hrs
I wasn’t looking forward to this so it was hard to get motivated. Since I’m using stainless steel covered teflon brake lines I needed to widen out the channel that runs along the back of the main landing gear down to each wheel. I purchase a 9/32″ straight router bit (I couldn’t find a round nose one in that size). I put a block of wood on the router as a guide so that I couldn’t accidentaly slip out of the groove too much. I had to make three passes (probably could have done it in 2) down to a little over 1/4″ depth. It came out pretty good. There are a few spots that I have to fill because the bit knicked the edge of the channel. Also I had a quickly caught slight disaster that caused a few inches of the left side channel to be a bit deeper then wanted (the router bit started to move out of the chuck… got to make sure the chuck is tight ).
In other news. I’m still waiting for my GMU mounting bracket. It seems like everyone else got there’s but mine is still being shipped. I hope by next week or so. I real am not looking forward to installing that, but Peter was successful so it gives me hope that it may be doable. I also contacted California Power Systems and the lead time on the 914 is only 2 weeks so maybe January or so I’ll order the engine. I’d like to get the canopy and install that, plus any firewall forward parts I may need before the engine is ordered so that I’m ready to put it on the plane soon after it arrives. Additionally I verified that the fuel pumps and oil tank come with the engine so those don’t need to be purchased separately. I will need to get the oil cooler, radiator, and alternator.
Did a quick test in a block of wood. The brake line fit in nice and tight. Should be good to go.
Router bit set to a little over 1/4″. Didn’t get a photo of the wood block guide. Basically I just cut a small 1-1.5″ pieces of 1×1 wood and clamped it to the route base with a C-clamp on one side so that I could rest that on the edge of the gear and keep the router stable.
Came out pretty good. A few little knick to fill. This makes a mess.
The brake line fits pretty tight in the channel, you have to tap it with a rubber mallet to get it to seat. There’s a few spots where it’s not super tight though, but I’ll use some RTV when I install the brake line (after painting) that should keep it in place. Also I’ll probably use some kind of clamp on the bottom because it’s a fairly hard bend into the caliber. The clamp will be hidden inside the wheel pants. I was also looking at a way to use some adel clamps to hold the brake line down but I can’t really figure out a good way to install them. I don’t want to drill any holes in the gear for rivnuts.
Well I guess a day makes a big difference. After failing to get the bolts installed a few days ago I had much better success today. I used a little different technic then previous and maybe this the reason for the better outcome. I started by lining up the gear the best I could and then checking the alignment of the metal spacer and hole in the gear channel. Once it was close I used a large punch in the hole and pushed it into the hole using wood as a pry bar against the main spar. Now rather the clamp that in place I did the same on the other side. Once both punches were in place I then clamped the gear in place. I removed the punches and used a small half round file to file down any burrs in the hole. Starting on one side I inserted one bolt, pushed it as far as I could by hand (which was only about 1/4″ – 1/2″ and then used the wood to slowly pry on it. To my surprise the bolt slowly moved in. I was able to pry it in until it hit the other side of the gear channel. Then I had to tap in it with a mallet. Now on to the other side. Same method and the bolt went right in. Prying the bolts in was the same as what I tried to do the other day, but bolts just wouldn’t budge. It must have been the tecnique of using the punches to line things up first that really helped. The next set of bolts went in using the same method. I’m so happy that this worked out. I was so frustrated the other day and just couldn’t see how this was going to work, but I guess a small change in process did the trick.
Using the main spar and a long piece of wood to put pressure on the bolt to push it in. It didn’t require too much pressure, but I would have never been able to push them in by hand. Note: I flipped this image so that it’s a little easier to see where things are. I’m actually working upside down)
Bolt on the left and one on the right are in… making progress.
The tool that saved the day. I used one on each side to line the gear up.
So next is to rivet the gear channel skin then fill and sand the bottom fuselage rivets.
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.
Time: 4.5 hrs
Things done today:
- Fill primed and sanded main gear
- Fit back of main wheel spats to wheel spat brackets on left and right main wheels
- Filled unused holes and blemishes on back part of main wheel spats
- Mounted axle to main gear
- Moved brake bleeder on left caliper to bottom
Finished up priming and sanding the main landing gear. I used a fill primer and did about 3 or 4 heavy coats. I then sanded with 320 grit paper. The sanding paper gets clogged a bit, but worked well. Only a few small blemishes in the gear now and the ends are all primed. I also primed a bit more on the top side as well since it looked like they didn’t paint enough there either.
All nice and smooth and can’t really see the seam where they stopped painting.
I also did some work fitting the rear part of the wheel spats to the brackets on the main gear. This ended up being a lot of work and more work still needs to be done after I mount the gear and get the wheels on. I had to bend the tabs on the brackets in a bit to get the rear spat piece to sit a bit closer to the landing gear. There’s still about 1/2-3/4″ of a gap, but I think it will get pulled in a bit when the front part of the spat goes on. One thing to note is that you shouldn’t use the pre-defined indents on the spats to drill the holes because they don’t really line up. I was lucky with the left one, but kind of messed up the right one (am going to try to fill the part of the hole that’s not needed). If you are using the newer spat bracket (the one that lets you remove the brake caliper) then you definitely won’t use one of the pre-defined holes because one of the screws is in a completely different place. So just pick one of the two front pre-defined holes and drill it out. Get the screw in and mount it to the bracket, then set the part the way you want and mark the location of the new holes from the back of the spat (through the back of the rivnuts). The holes will be close to the pre-defined ones, but off enough). You can only get the top of the rear spat piece so close to the gear because the piece hits one of the bolts ends that holds the axle onto the gear. I tried using a shorter AN4-21 bolt and a thin AN4 washer but it was just a bit too short (you should have at least one thread after the nut).
Outside of the left spat mounted to the gear (upside down). You can see the unused hole just to the bottom of the bump out (to the left of one of the mounting screws) on the spat. This would normally have been used with the older style mounts, but I have the newer spat mounts. The rear part if the spat is mounted using 5M screws and 222 loctite. I purchased 5M X 12mm Class 12.9 Alloy Steel screws from Bolt Depot since I didn’t have any screws with the kit.
Inside of the rear spat. It’s a very close fit to the brake caliper.
The axle went back together pretty quickly since I had test fit everything before. The only change I made was I used thick AN4 washers rather then thin ones called out in the manual because the nuts were bottoming out on the non threaded part of the bolt.
All primed, axles mounted and bolts torqued to 7ft/lbs. I’m wondering though if this will all have to come apart when the gear gets painted.
Close up of the left axle mounted to the gear. I had to remove and reinstall the bleeder valve on the left caliber so that it was on the bottom. Also the caliper is only in the top hole. The pins should go in the two holes in the axle.
The garage is a disaster. I need to move the tables out and build some saw horses. I’ll then get some friends over so we can flip the fuselage upside down. Then I’ll fit the main gear, install it and rivet the gear skin. Lastly I’ll fill and sand the rivets. I’m hoping the plane will fit with the engine mount. I think it will 🙂
Time: 4.5 hrs
Finally was able to get back to working on the plane after some family events. Today I filled and sanded the right fuselage side. Now that the fuselage is on the ground it’s very easy to move it from side to side to fill the rivets. The tough part will be to turn it upside down so that the bottom rivets can be filled. I’m still not totally sure how I will do that.
I also worked on the main landing gear a bit. The factory didn’t prime all the gear and there were some spots that need some filling and sanding. I still need to do a bit of work on it. After it’s primed I’ll put the axels on and get it ready to mount in the plane.
The ends weren’t primed so I need to clean them up and prime. This part is under the wheel spats, but it will eventually get painted so it needs to be primed now.
Time: 1.75 hrs
Wow I figured I’d quickly put the axels on the main gear… well it took a bit longer then anticipated. There was one bolt on each side that seemed to have been drilled out a little off in the main gear (at the factory) so that made putting the wheel spat bracket on very difficult. I did manage to get everything together after some gentle hammering. It should be fun taking it apart again. Also it seems that the factory didn’t prime the whole gear so I’m thinking I should prime everything.
Note: I assembled this with the main gear upside down… which makes it even more fun :-). I flipped the photos over so that it’s a little easier to get the orientation. If you notice things hanging from the ceiling that shouldn’t it’s because of that.
Everything assembled looking from the axel side.
Assembled looking from the wheel spat bracket side (inside). finally got that sucker on. Also you can see the M5 rivnuts installed in the wheel spat bracket. This is the newer bracket which gives you access to remove the brake pads without having to pull the whole wheel apart. The old bracket is wider in the back and covers part of the caliper.
You need to align the axel and brake caliper bracket so that one of the holes for the brake caliper bracket lines up with the cut out in the gear (top right of photo) otherwise the brakes won’t fit back on.