Modified Canopy Lock and Installed One Cowling Hinge

Leave a comment

I found a great lock online that can be flush mounted against the side of the plane.  Most camlocks mount through the hole, but this can be mounted from behind so that it doesn’t protrude beyond the skin.  This is apparently the baggage compartment lock for a Lambretta/Scooters India Limited motor-scooter.  You can find them on eBay for about $5.

The problem is that the lock is designed so that the key will only come out in the locked position as seen here.  I didn’t realize this when I ordered the lock, but it obviously won’t work since I want to be able to unlock the plane and remove the key.

I disassembled the lock and modified it so that the key will also come out in this position.  This was easier than I thought and probably took no more than 15 minutes.

Afterward, I got started on the cowl again by riveting one of the side hinges on with epoxy/flox.  This was substantially easier than the other hinges because the eyelets protrude beyond the edge of the cowling.  This made it far easier to clean up the excess epoxy since it didn’t squeeze into the area between the eyelets.

More Plenum Work and Fuel Lines

Leave a comment

I added more glass to the front edge to bring it out past the face of the template.

While the fiberglass was curing, I got started bending the fuel lines that go from the fuel selector out to the wings.  Each side will be done in three pieces, a piece from the fuel selector to between the support brackets (as seen here), a second piece from between the support brackets to just outside the fuselage, and a third piece from there up to the fuel outlet on the tank.  Each section will be joined with an AN815-6D union.  This is necessary because it’s essentially impossible to maneuver longer pieces through the holes in the support brackets.

Worked on Fuel Lines

Leave a comment

I fabricated the other short fuel line up to the fuel selector as a mirror image of the right side.

I then fabricated the line up to the union that passes through the side of the fuselage.  I don’t have the unions yet, but they should show up tomorrow.

On the outside of the fuselage, the line turns forward.  There will be another union here and a short line from the fitting on the fuel tank.  It’s unfortunate to have this many fittings, but the only other reasonable option is a flex line from each tank all the way to the fuel selector.  That would be heavier and would require periodic replacement.  As long as I don’t have any leaks, these are a much better solution and will last the life of the plane.

Added Lock to Canopy Latch

Leave a comment

I drilled a hole in the side of the fuselage skin for the canopy latch lock.  Getting this hole positioned correctly required numerous measurements and calculations to ensure that the lock wouldn’t interfere with any part of the latch.

I fabricated a 0.063″ doubler plate to position the lock so that the face is flush with the skin.  The plate will be centered over the hole, so I added some layout marks to help center it.

After drilling the plate to the skin and drilling out for the lock, I installed everything to see how well it lines up.  The lock is almost perfectly flush with the skin.

Next, I needed to mill out the slot for the cam.  I headed to the Tech Shop and quickly milled out a slot in the lower mounting angle.

I then milled out a corresponding slot in the latch handle.

The cam is only about 0.080″ thick, but my smallest mill was 3/16″.  Because of this, I had to offset the slots so that the cam would just fit.

After reinstalling the components in the plane, I tested it out and everything works perfectly.  Here’s the latch in the unlocked state.

And here’s the locked state.  With the latch locked, the handle is completely immobilized.  I’m super happy with how this turned out.  Everything about the latch and lock is flush with the fuselage skin.  I’m sure I’ve picked up a huge amount of speed without the handle and cam lock sticking out from the fuselage :-).

Further Work on Cowl Joint, Started Gear Leg Fairings

Leave a comment

I popped the two cowl halves apart again.  The epoxy/flox filler worked perfectly and there’s a nice smooth that perfectly matches the outside of the lower cowl.  The end of the flange was a little epoxy starved, so I mixed up some lightweight filler and buttered it up.  I’ll sand this flush tomorrow.

I had a bunch of excess lightweight filler left over, so I covered the last of the fiberglass strips on the left side of the upper cowl.

Since I need the filler to cure before making any more progress on the cowl, I decided to get started on the gear leg fairings. I lined up the fairing with a couple of squares to ensure there is absolutely no twist.  Any amount of twist is added drag, and can act like a rudder to yaw the plane.  After I was sure it had no twist, I taped the trailing edge together in a few spots.  This not only keeps it straight during the next couple of steps, but the tape strips will act as a indicator to ensure I don’t introduce any twist later.

I cut out the gear leg fairing template and lined it up with a line I drew on the leading edge, making sure to make the leading edge of the template 3 7/32 back from the scribe line.

I then taped up the rest of the template and marked all the way around.

Here’s the marked fairing.

After a few minutes with tin snips and a sanding block, here are the trimmed fairings.

Installed Left Inboard Wheel Pant Bracket

Leave a comment

I fabricated the spacers that position the inboard wheel pant bracket.  The plans call for 13/32″ (about 0.406″), but I have the Grove wheels and brakes which have a thicker brake rotor, so I ended up having to make them about 0.540″ in order to get the recommended 1/16″ clearance between the bracket and the rotor.  This is not the stock Van’s aluminum bracket, but is the fairings-etc.com stainless steel one.  While this is heavier than the stock bracket, there have been a number of instances of the stock bracket cracking due to rough fields or ground handling.  Hopefully these will be quite a bit more durable.

The bracket required about 1/4″ to be trimmed off where it passes over the caliper.  This has about 1/8″ clearance all around to allow the caliper to move.

Wheel Pants, Plenum and Cowl Work

Leave a comment

I trimmed the right wheel pant bracket to match the left and fabricated three more spacers.

I then fit the outboard wheel pant brackets, but the attach point on the axle nut was rocking slightly which would have let the wheel pant move up and down a bit.  I used a few layers of aluminum tape to make the bracket fit much more tightly on the axle nut.

Here’s what it looks like installed.

I’ve never been very happy with how uniform the spinner to cowl gap was.  The way the cowl was formed, the center of the ring where the upper and lower half join was slightly recessed and had a larger gap than the upper and lower portion of the ring.  To fix this, I mixed up some lightweight filler and spread it around the ring.  I then covered it with saran wrap.

I put a flat board over that and pressed down firmly until enough of the filler squeezed out that I could see the pink part of the cowl around most of the ring.

In addition to the bug which landed in my paint job, there were a bunch of scratches and pinholes visible in the finish.  Since this will be very visible with the cowl off, I decided to try out a new technique for surface finishing.  I sanded the surface with 80 grit and then spread raw epoxy over the surface.  After it kicked, I squeegeed as much off as I could and then spread on another coat.  After that kicked, I squeegeed it off as well.  That should fill all of the pinholes and scratches.  I’ll sand this with some finer grit sandpaper before reshooting the primer and finish coat.

Between coats of raw epoxy on the plenum, I got started fitting the wheel pants.

After figuring out where the two halves fit the best, I added some witness marks to make sure I put it back together the same way each time.

I trimmed the forward end to the scribe line and then sanded the edge until it sat flat on the table.  You have to spread the wheel pant slightly when checking because it naturally springs inward a bit.  It you sanded it flat in it’s rest state, the line wouldn’t be straight when installed on the aft half of the pant.

Started Fitting Wheel Pants

Leave a comment

Before fitting the wheel pants, I needed to get the weight off of the wheels and get the fuselage perfectly level in both dimensions.  Since the wings aren’t on, I can’t jack on the tie down points, and I wasn’t comfortable jacking under the firewall flange.  The engine mount is plenty strong, but I didn’t just want to start jacking against one of the horizontal tubes since these are not designed to have loads placed on them perpendicular to the tubing.  Right under the top of the gear leg mount tubing is an exceptionally strong portion of the mount since it handles all of the bear impact loads, but it’s not flat enough to put the jack directly on.  After a little head scratching, I came up with a great way to jack against this point.

I slipped a 1/2″ socket extension through the hole in the top of the jack and wrapped a piece of MIL6000 hose around the end to pad it.

Here’s a shot looking up from underneath showing how the hose pads the jack point.

After jacking up the front, I raised the tail until the fuselage was level at the longerons.  I also confirmed it’s level laterally.

I’m holding the tail up using a strap around the tailwheel spring.

The other end is wrapped around one of the rafters in the ceiling.  The giant green thing is my cyclone dust collector from when the garage was a wood shop.

Next, I adjusted the outer wheel pant attach bracket to be perpendicular to the floor using a carpenter’s square.

The wheel pant needs to be 1″ above the top of the wheel.  I hunted around the shop for a bit and found these old wooden knobs.  I taped a washer to the end to bring them up to exactly 1″ thick.

These will sit on the top of the tire to keep the wheel pant the appropriate distance away.  After this, I used a long piece of duct tape to temporarily attach the knob to the tire.

After opening up the hole on the bottom for the tire and trimming a relief on the inside for the gear leg, I fit the wheel pant for the first time.  This is going to require quite a bit of adjustment, but it’s approximately the right position here.

Worked on Canopy Fit

Leave a comment

I had previously set the gap between the forward skin and canopy skin at about 1/32″, but this was causing the canopy skin to catch on the forward skin as the canopy was opening.  I opened this up to about 1/16″ and that works much better.

I also fit the weatherstripping along the sides of the cowl.  The canopy fits much more tightly with this in place and requires it to be pulled down firmly in order to be latched.  I shouldn’t have any problems with air leaking around the sides with this in place.