Chapter 9 - Step 3

This step involves the making of the attachment tabs on the strut. This is followed by the actual installation of the strut in the fuselage.

Measuring the Tab Location August 6, 2000. The strut is leaned up against the end of the worktable so the exact position of the attach tabs can be determined. Good use of levels, plumb bobs, and squares are needed to get everthing correct. The board under the strut was used to level the strut since the floor is crooked. The plywood behind the strut was attached using some spacers so when the strut is leaned against it, the trailing edges don't hit the end of the workbench.

Once all the measurements are made I will do them again to make sure I got it right. I don't want to make the tabs and discover they are in the wrong place.

Strut Box Part A August 7, 2000. Here is part "A" of the strut box cut to shape and in position.

Strut Box Parts B and C August 7, 2000. Here is the strut box with parts "B" and "C" glued in place on part "A".

Sanded Leading Edge August 9, 2000. As I was making strut box parts "D" and "E" I discovered that my strut was a bit too wide. The plans make it pretty clear that the box should be 5.75" wide. Mine would need to be 5.875". I posted a message to the mailing list and just about everyone said to sand the extra 1/8" off. A few people were concerned with the fact that this would result in sanding through the reinforcement layers. I was concerned as well but I figured the 45 layers of glass added to each side of the strut for the tabs should take care of that. I sanded a flat on the trailing edge a bit and took off the rest from the leading edge.

Test Fitting Strut Box August 9, 2000. Here I am test fitting the partially completed strut box. You may notice that this strut setup is different then in the previous pictures. I wasn't happy with the other layout so I moved to the front of my workbench instead of the end. I added some reinforcements to the plywood to keep it straighter than I had it earlier.

I ran into an interesting problem. I had (at least I thought I had) everything just right. The strut was level, the leading edge was 9.25" out, I had the strut centerline measured, and I had the 13" lines layed out. I then proceeded to measure the high point of the strut at the two 13" positions. I then measured up 0.75" and the extra 5". I then layed the level across the two 5" marks. Uh Oh! They are not level. One is 1/8" too high (or too low). I pondered this for a while and thought of several solutions. All were compromises. I decided to call Nat. Since the obvious goal is to get everything level we decided to just make one tab 1/8" longer. I thought of this earlier but drawing M-9 shows specifically that this dimension should be 0.7" min. to 0.75" max. Nat said it was OK to be 0.875" in my case.

As soon I we hung up I had a brainstorm and chose a different approach (sorry Nat). I shimmed the "low" end of the strut 1/8" by placing two stirring sticks under the strut end. This raised the low spot and the tabs would be just right. None of my other dimensions or reference lines changed. All I have to do later is either chop an 1/8" off the OTHER strut end or just mount that axle 1/8" higher. No big deal (I think).

Strut Box Complete August 11, 2000. After way too many hours of trying to get the strut box built, the strut sanded to size, and measuring the location of the tabs, I finally got the strut box built and bondoed into place. This took much longer than it should have.

Full Strut August 11, 2000. The same completed strut box showing it on the whole strut.

Checking Strut Position August 11, 2000. After the bondo dried I flipped the strut over and placed the whole contraption on the workbench. I had already drawn all the reference lines on the bench top. Here I am using a straight edge to make sure the strut ends are level. I placed two stirring sticks under one end to compensate for the adjustment I made earlier. The strut leveled perfectly first shot.

The next test was dropping the plumb line from the leading edge. One strut end was dead on. Unfortunately the other was 5/32" too far aft. I tried a shim in that corner under the box but the whole box tilted, not just that end. I decided to ignore it for now. I can adjust for it later with axle placement or maybe it will magically go away while putting the strut in the fuselage. I am annoyed this showed up because I measured everything thirty-seven times. Who knows where I went wrong.

Strut Close-up August 11, 2000. Here is a close-up of the strut in the box. The gray triangle on the right edge is actually bondo on part "D" of the strut box. Since the strut gets narrower toward the strut center, part "D" sticks out a bit here.

All taped up August 11, 2000. The last prep work was to cover the wood with tape. I also taped plastic down on the workbench to catch drips. The brown tape is thin enough that I can still see the tab layout lines I drew on the strut box.

UNI Tab Layup August 12, 2000. Here are 25 layers of UNI for the one of the tabs.

First Layup Complete August 12, 2000. Here is the tab with 25 layers of UNI and 20 layers of BID. The strip of peel ply is covering the ends of the BID. You can see the glass was a bit long. The BID could probably have been cut to 13" strips instead of 15" since it doesn't need to reach all the way across the strut like the UNI.

Tabs Being Clamped August 12, 2000. After doing the 45 layers of glass for both tabs I clamped a couple of boards in place. They bowed a bit so I drilled a quick hole through them and added the threaded rod with some washers and nuts to squeeze the bow out of the boards.

Drilling Holes August 19, 2000. After removing the clamped boards I made a drill jig from a piece of 2x4. I needed a longer piece with a gap underneath since all my tabs were so long. I used this jig to drill all four holes and everything lined up just right.

Drilled Tab August 19, 2000. Here is the other tab with the pilot hole drilled.

Drilled Tabs August 19, 2000. Here are both tabs after drilling the holes.

Rounded Tabs August 19, 2000. Here is one of the tabs after rounding and trimming. I used a sabre saw to cut the round part and some of the straight. I then used a hacksaw blade to trim the width of the tab near the strut.

Trimmed Tab August 19, 2000. Getting the tab width down to 3" wasn't going to happen. My compromise was to bevel the edge the best I could with a Dremel and sandpaper. I was real careful not to gouge the strut. Trimming both tabs made a huge mess of fiberglass dust. I had my respirator and goggles on for this job.

Completed Tabs August 19, 2000. Here is a shot of the trimmed and sanded tabs from underneath.

MG-1 and MG-2 August 19, 2000. I didn't have time for the next layup so I jumped ahead and made the four MG-1s and the four MG-2s. My drill press made quick work of all the holes and the countersinking.

Second Tab Layup September 2, 2000. Here is the second tab layup with a board clamped in place.

Aligning the Holes September 7, 2000. After I finished shaping the tabs I drilled out the holes and set the strut into position. After a bit of work I got the 1/4" drill bit through the holes on one side. The rod through the other set of holes is a touch off. It looks like I'll need to "move" a bulkhead hole about 1/8".

Strut in Position September 7, 2000. Here is the gear in position for the first time. The rods are holding the strut in place via the 1/4" holes. I dropped plumb lines off the leading edges of the strut. Both are too far forward. One is 7/16" off and the other is 11/16". The strut is level and centered so I'm not sure how I can get both leading edges even. Maybe I'll shoot for getting one 1/8" too far forward and one 1/8" too far aft. I'll think I will adjust the holes in the forward landing gear bulkhead since the tabs touch the angled part of the bulkhead. Time will tell.

Update May 26, 2001. After about 8 months hiatus I finally got back to this. I ended up doing what I thought so long ago. I elongated the holes in the forward bulkhead so the resulting hole was higher. I then elongated the holes in the aft bulkhead so the holes were a little lower. This combination gave me the best compromise. One strut leading edge is a bit too far aft and the other is a bit too far forward. The axle position will fix this.

MG-2 in position May 26, 2001. Once I had the strut aligned correctly (close enough anyway) it was time to get the MG-1s and MG-2s set. While the strut was in place in the proper position I slipped the four MG-1s onto the 1/4" rods and then hot glued them in place. I then pulled out the rods and removed the strut. I then put the 1/4" rods back in place along with the MG-2s. I then hot glued the MG-2s in place and removed the 1/4" rods. As seen in this picture I then used 1/4" hardware store grade bolts to hold MG-1 and MG-2 together in preparation for drilling the #10 holes. One problem I ran into was with the MG-2s on the forward bulkhead. The angled part of the bulhead was in the way of MG-2. I had to file down a little of MG-2 to get it to fit.

MG-2 holes in bulkhead May 26, 2001. Here is the bulkhead after drilling the four #10 holes. I didn't have a right angle drill so I went down to the local Home Depot and rented one. $12 for four hours. All they had was the heavy duty Milawaukee one. Heavy sucker. Anyway I put in my #10 bit and #$%@#^#$! It doesn't fit. Now what? Remove bit, dig out hacksaw. Put shortened bit back in. Barely fits but it will work. I drilled one hole and inserted a bolt and nut to hold everything in position. I then drilled the other three holes. Repeat four times. I now have 16 #10 holes. It appears my #10 bit was getting very dull. It took a while to drill all the holes.

The plans call for S60 bolts. Wicks sends you S58 bolts with the chapter 9 kit. Neither is long enough. Let's see: S58 bolts are 1" long. I have MG-1, 1/8", MG-2, 1/4", bulkhead, 1/4" foam and 3/8" fiberglass, nut, 1/8"+. This all totals 1 1/8+". Plus enough for threads to stick out past the nut. Let's call it 1 1/4". This is a S62 minimum. Looks like I'll be ordering some more bolts.

MG-2 screwed and floxed June 1, 2001. This took a lot of energy to do. I was soaked and my arms were tired. I must be out of shape. Those 16 little nuts take a lot of effort to put on in a tight spot. Especially when the flox is beginning to set up on you. Everything turned out fine of course but sheesh!

Completed Mounts June 1, 2001. The landing gear studs fit perfect in the MKMG-4 bushings. I'm quite pleased with how this has turned out. I'll find out real soon whether the main strut ends up OK or not but so far so good.

MKMGA Glassed June 16, 2001. Here is the landing strut tab with the MKMGA floxed in place with some foam underneath. There is a 2 BID layer over the whole thing.

Completed Tab June 16, 2001. This shows the washer under two layers of BID on the outside of the tab. At this point the strut attach tabs are complete.