Bulkhead Reinforcments

Step 1 LANDING GEAR BULKHEAD REINFORCEMENTS

In preparation for installing the bulkhead reinforcement layups, I did a ton of sanding with 36 grit. This shot shows the right side of the fuselage with the three places extra layups will be applied with their surfaces sanded and ready for layups.

This shot shows the left side forward face of the landing gear bulkhead with the layup complete and peel ply laid over it, ready for cure. I used a bunch of separate pieces of peel ply to get the whole layup but prevent any wrinkles caused by curves and bends in two directions.

The right side again after the layup has cured and the peel ply has been removed. These are pretty tricky layups to do correctly without bubbles. The glass likes to slide around a lot when you squeegee. I use a squeegee in the corner then a second squeegee to pull the glass and extra epoxy out of the glass and that helps. It also helps to put a generous coat of epoxy down before the first layer goes on or you'll get a lot of bubbles under the first layer. Get those out first or subsequent layers will make the problem worse.

Between bulkheads was just as much "fun" as the other places. This was a pretty tricky layup to get installed, squeegeed and peel plied without it moving, pulling out of the corners and so forth. I did lay up several layers on the workbench, on plastic, then transfer them to the fuselage once squeegeed. This works pretty well, but again, make sure you have a pretty decent coat of epoxy under the multi-layer layup or you'll get bubbles that are really hard to get out. I might try letting the multi-layer workbench layup cure just a little before installing it into the fuselage - so you can work the bubbles out easier from underneath it - let you know how it goes.

I used plastic for the other side vice waxed paper. Each has its advantages; the plastic is more sturdy and doesn't rip like the waxed paper, but, seems to stick to the layup much more and ends up pulling some of it off when you remove it. The waxed paper doesn't stick as much, and pulls off easier, but can rip if you have to squeegee.

Here's the other side peel plied after finishing. The trick with these layups seems to be in how you first lay it on there. Using the waxed paper or plastic, use your gloves and squeegee to remove most of the air. If you have to squeegee after removing the waxed paper (or plastic) use a second squeegee in the corner to avoid pulling the layup out of of the corner and making a bubble.

In order to do the layup over the NACA scoop in between the landing gear bulkhead and the firewall, you have to micro the foam. This was a pain. I hooked my light up to the clamps holding the rotisserie to the firewall (after moving the clamps to make for more room.) There wasn't much room to work and I ended up with a ton of epoxy on the insides of my arms.

Here's another shot of the foam microed and ready for the layup. I made some big micro fillets, per plans, along the edges to avoid having a problem getting the glass to go into the corner.

A syringe is the easiest way for me to do micro fillets like these. I use the syringe (I have cut off the plastic point on the end to make a bigger hole for easier flow) to get an even rope of micro along the corner, then, use a stir to get a nice radiused edge.

Here's the top of the scoop laid up and peel plied. I realize that peel ply is not really necessary on parts like this, but, it sure does a good job of smoothing off the surface and absorbing any epoxy drips or extra that might have been left on the edges. Keeps the edges down and smooth, too.

Another shot of the layup after extensive peel plying. I like to use several smaller pieces and even double it up if there is a spot that looks like it has a ton of extra epoxy. Yes, I squeegee the extra but occasionally there are corners that can't be squeegeed well without disturbing the layup.

These are shots of the last four layups between the aft landing gear bulkhead and the firewall. These, too, were a pain. I decided that I liked waxed paper better (even though it rips) because it pulls off and folds easier than the plastic. I usually do the layup, on a piece of waxed paper, over a piece of plastic that protects the work bench. One you have laid up and squeegeed all the layers, I add another sheet of waxed paper over the top (extra long) and squeegee the extra epoxy off the layup on onto the extra waxed paper or plastic underneath.

Cut the waxed paper and layup just around the layup (leaving the extra epoxy lumps on the waxed paper) then pull off the top waxed paper. Transfer to the spot it's to be installed, in this case folding in half to make it easier to place. While the waxed paper is still on (this method is only slightly different than the plans) squeegee and press the bubbles out. Remove the wax paper, touch up squeegee and brush/stipple, you're done.

These layups were a pain! I am very glad they are done!

Next step is preparing the landing gear strut for installation.