After the last post, I cut the edges (rain gutter) of the door openings on the cabin top to Ivan Kristensen’s measurements. Approx 1 5/16″ along the top, 1 1/4″ in the top corners, going down to approx 1″ along the sides and bottom. I then drilled a 1/16″ hole in a skinny piece of aluminum to mark a 1/4″ line from the inside edge of the door. This gap will allow room for the McMaster door seal bulb to sit in and allow the door to close and squish the seal bulb properly.

I then test fit the McMaster seal. Initially just a section along the bottom of the door, then all the way around. I will still need to sand down a couple of high spots in the corners as the thickness of the fiberglass is > 1/4″. I might also need to build up some areas using the seal as a template for an epoxy/flox mix, although I’ve seen some builders say that they didn’t need to do this.. so guess I’ll see what makes the most sense a little further along.

Then it was on to preparing the hinges. You use an AN3 bolt with the threads cut off as a hinge pin. Then proceed to get the hinges up in their pockets and match drilling the 4 holes. The main thing here is identifying that the hinges are different and getting them in their proper location. You can actually see in the hinge pin picture below that the hinge “legs” where the pins pass through actually have an offset to them to match the curve of the cabin top. It’s important for the high side on the forward hinge to point forward and the high side of the aft hinge to point aft. The lower points should be inboard.

The door was put into place, taped up top to hold it in place and the 4 holes on the door side match drilled.

The end result is a functional door!!

I was a little nervous walking into this part of the build. In the end, I’d say it wasn’t as bad as I had expected. My door halves are now bonded together! Before starting, I used packing tape to cover the cabin top all around the door opening so that any epoxy that squeezed out wouldn’t bond the door to the cabin top. I worked on one door at a time and only mixed enough epoxy and Cabosil for one doors worth. The plans have you first spread some straight epoxy on the three areas that actually bond the door together, the elbow cavity (shown below with fiberglass parabeam on it), the cranial cavity at the top of the door, as well as the latch cavity. You then wet out the Parabond material previously cut with straight epoxy and put it in place on the inner door shell. Then add some Cabosil to the mix until it thickens enough to not pour out of the cup. That mixture was then spread over the remaining mating surfaces (the window flange and the outer door flanges).

Once done, the outer door shell is placed on top of the inner shell and cleo’ed along the lower edge and 2 places in the upper window flange prior to placing it onto the fuselage.

Attached to the cabin top and cleko’ing the window flange. A reasonable amount of epoxy squeeze out along the edges.

The entire door was cleko’ed to the cabin top so that it cures into the outer shape of the cabin top. The plans have you use clamps, tape, and weights. This, to me, is a much better method that I’ve seen other builders suggest.

I then left the garage heat on 60 degrees and let the doors cure over 2 days. I took the doors off and removed all the Clekos.

I then cut the window flange down to the 3/4″ line previously marked. Additionally, I made up a couple of angles and match drilled them to the forward and aft index holes and then drilled a couple of holes into the door to hold the doors in place so they could be trimmed. This will also allow me to keep the doors in the same position for all other door work without them moving.

One of the next things is to trim the outer door edges to within 1/8″ of the scribe line, which I did. I then did something that I saw on Dr. Mark’s blog in terms of making a tool to mark the inside edge of the cabin top on the outside of the door. I riveted 2 pieces of metal together and bent one piece at a 90 degree angle to follow the inside cabin top door edge. I then drilled a 1/16″ hole aligned with the 90 degree bend to trace on the outside of the door where the inner edge was. That was the line I used to trim to for the entire perimeter of the door.

I then had my buddy come out and check out the progress.

This is the result after trimming to the line made by the tool. I’m at the point of needing to trim the cabin top rain gutter back some more in anticipation of using the McMaster door seals. The door won’t fully sit flush with the cabin top just yet until I do that. So that and door hinges are up next.

Slow progress lately…

This part of the build is somewhat challenging in that I am reading from 3 different sets of instructions from 3 vendors and trying to understand what to do next. Next up was to grind down the stock pin blocks in order to drill #12 holes into the doors to hold the blocks in place.

Then you take the new oversized blocks from PlaneAround and sand them to fit well into the recessed pockets of the door. Then match drill them to the holes you drilled with the stock blocks.

Then it was time to take the striker plate from the Aerosport Low Profile handle kit and center it in the handle pocket by rounding off the forward corners and drilling the holes needed for the inner ring and lock.

Once that was done, the inner handle assembly was completed per plans with some modifications based on the Aerosport instructions. One modification that I did was to cut a longer slot in one side of the handle assembly so that the handle would only lock in the closed position and not the open position too. I didn’t take any pictures of that.

I then took some scrap metal and made it the width of a rack without teeth and just long enough to stay in the handle gear mechanism while marking the sidewalls of the handle cavity where the racks will come out and need a hole for clearance.

I then assembled the push rods with the Planearound 3rd latch system and got everything the way I wanted it. This allowed me to mark the push rods for 1.5″ protrusion from the sides of the door and about 1/2″ retraction into the Derlin pin blocks.

I’m also using the angled machined pins from Planearound. The push rods were cut down 2 more inches to accommodate the length of the pins themselves, and tapped with a 5/16″ x 24 tap to attach the pins with a screw.

Below is a quick video that I made to explain the operation of the door handle and pin/latch operation.

Knowing that there will likely be several posts about doors… I will do posts in “parts” Otherwise I will quickly run out of ideas for post titles. Unless, of course, there’s something more clever that comes to mind at the time.

I’ve decided to postpone bonding the doors together just yet to get the Planearound latch , door handle mechanism, and Aerosport exterior handles all installed. Nevertheless, I did sand down the spots on each shell depicted on the plans that will touch and bond together.

Trying out a sanding pad on a pneumatic die grinder

Next you put the door shells together using the dimpled index holes in the fiberglass that were drilled in each half. Like so many others, mine didn’t line up very well. The aft index hole lined up okay, as did the forward index hole (although it wasn’t aligned with the fuselage hole in the plans). It was aligned with the last hole of the upper forward fuselage about 4 holes up from what the plans say. The index holes in the corners of the window were pretty much useless. There was 1 on 1 door that did line up and another on the other door that was close, but the others weren’t even close. Doing some reading this seems to be fine, you basically make sure the door is centered the best you can. Mine seemed to be fine using the aft and forward index holes, so I went with that.

Right door attached to forward and aft index holes

Then you use a hole finder (seeing I had one) to perfectly match drill the open rivet holes in the fuselage with the door shells. This allows a cleko to be put in and the doors held tight to the fuselage.

Hole finder to drill the door shells perfectly.

Once the bottom holes were done along the fuselage, you’re supposed to tape the upper part of the door to the cabin top. Then match drill and cleko the window opening. I had read of others drilling holes along the door pillars and cabin top to hold the door shells very tight to the fuse and not have to rely on tape. To me, this is a much better method that allows the door shells to hold the shape of the door opening much more precisely. It may not be obvious from the picture, but the door shells are still oversized for bonding so they make contact with the outer surface of the door opening in the cabin top. This is what allows the door to be shaped to the cabin top when bonding.

Right door attached to cabin top/fuse.

Left door done too showing clamps that were used while drilling the pillars.

A view from the front after both doors done.

Inside of pilot’s door

An example of extra holes drilled in the cabin top/door pillars

Next up was to drill and attach the door strut stiffener. This is a simple match drill holes.

I then hopped over to start working on installing the Planearound center latch system. First is locating the proper position, cutting out a slot on the bottom of the raised door edge, and also drilling and slotting a hole for the shaft.

center cam gearbox and markings for the cut.

After drilling a 1/2″ hole, and making a slot for the shaft in the gearbox. 

I then drilled the 4 holes that will hold the gearbox in place and countersunk them in each door and prepped for attaching the supports for the cut area of the door. I mixed up some Epoxy and cabosil first as I will attach both the door strut and these door cut supports all at once. Once I did the door strut supports with Expoy and Cabosil, I didn’t have too much left, so I added more epoxy and thicken it up with flox. So I ended up with a mostly Epoxy and flox mix with a tad bit of cabosil too.. No big deal. I wrapped the gearbox in packing tape so it doesn’t accidentally get adhered to the structure and added a generous blob in each corner with the support pieces in place.

Gearbox taped and supports added with Epoxy/Flox. 

Door Strut support plate cabosil’ed in place. 

Now I’ll wait for these pieces to fully cure before continuing.