It’s hard to tell from the picture, but there’s about 1/2″ clearance between the top of the intake and the inside of the cowling. It’s tight, but it should be enough.

The top needed a bit of work though. It was a bit bumpy with a couple low spots. So after consulting with Malcom, I filled the low spots with micro and covered the whole thing with  one layer of fine BID.

A little bit (hopefully, very little) of filler and it should be ready to move on to the next step.

Now that I know how the system works, I’m going do the pilot door a little differently. As in stronger. The first thing to do is create a large backing plate/hardpoint out of 1/8″ aluminum.

Then I cut an opening in the top of the D-tube that will accept the plate. I drilled and tapped holes in the plate that will align with the mounting bracket and also drilled holes for rivets. Then I formed the plate so that it matched the contour on the D-tube.

Finally, I spread structural adhesive on the inside of the D-tube and the back of the plate and slid the plate into the D-tube and riveted the plate into position. Once the adhesive set, I inserted a piece of soft foam into the space and left a cavity about 1/2″ deep that a little longer than the opening I made to get the plate in. Then I mixed a flox/cabo paste and filled the area behind the plate. This will strengthen the D-tube where the bracket is.

Once cured, the area gets sanded down and I’ll cover it with a layer of carbon Uni and BID.

Here’s a picture looking forward from the back of the plane with the door closed.

Notice how the direction the strut is pushing is inboard of the hinge. Before the direction of force was outboard of the hinge.

Outside view.

Now I’ve just got to make the hardpoint permanent (it’s only temporary now), patch the holes in the B-pillar and repeat the whole install process on the pilot side door.

For the B-pillar hardpoint, I decided that since the mount would be in shear, I would use steel instead of aluminum. It only added about 5oz of weight and seemed the best approach. I had some steel from a trailer hitch mount that I cut a piece off of. Drilled and tapped for the stud.

Then I cut a slot into the B-pillar and inserted the hardpoint with some structural adhesive and let it cure overnight.

The next morning, I mounted the gas strut and…

From the inside with the door closed:

So far so good at this point. But after a few operations, I made a discovery.

Where I cut the slot to insert the hardpoint weakened the d-tube so that the stress of the 90lb gas strut cracked the fiberglass. When Malcolm builds the doors, he inserts a large piece of aluminum and secures it with structural adhesive and fiberglass. Since my doors are already together, I had to use a plan-B.

I drilled a hole near the hardpoint and injected an epoxy/cabo/flox mixture into the cavity behind the hardpoint. This creates a solid mass that distributes the load over a larger area.

The next morning I put everything back together and it worked.

But then I noticed a new problem. One that almost every builder has fought.

This is a view of top rear of the closed door.

The right, which is higher is the door. The left, which is lower is the fuselage. Now this is before latching the door. Once the latching pins are engaged it’s not as noticeable.  But here’s the problem.

The blue arrows are the hinges for the door. The single red arrow is the gas strut and the direction of the 90lbs of force that reduces the amount of effort required to open the door and hold it open. Since that force is pushing up at the rear, the front hinge becomes the pivot for the whole door. And what is about 3/4″ to the rear of the top hinge becomes about 1.5″ of deflection at the bottom of the door (black arrow).  The end result is that the door can’t be closed easily. I have to push the door forward to get it to close all the way before I can latch the door closed. And throwing the latch isn’t very easy either.

The current factory approach is to reverse the gas strut so it point down when the door is closed. But that just reverses the deflection pushing the door forward.

So I’m currently working on a solution. I’ve got it narrowed down to two candidates.

A) Reinforce the hell out of the top of the door. I determined that the area of the door where the hinges attach is flexing. If I can eliminate the flex, then I will have reduced the amount of deflection.

B) Use two opposing gas struts. When closed, one strut will be applying force upward and the other downward. They should cancel each other out resulting in zero deflection. I think two struts is going to look downright weird, So I’m going with Plan A first.

I’ve ground off the rear hinge pad. Then built up the area with 4 layers of Carbon Fiber BID. Since carbon doesn’t have the flexibility that glass has, I’m hoping this will reduce the flexing. If it does, problem solved. If it doesn’t… Plan B.

Now it’s time to, sadly, modify the cowling so the air intake will fit.

Here’s a side, top and inside view:

I drew a shape to provide a symmetrical guide and rounded it out.  Then I made the cut and sanded the surrounding area.

To prevent an “bubble” where the hole was, I made relief cuts around the opening. Then I cut a piece of foam that was a little smaller than the relief cuts to go under the cowling. I large piece of aluminum sheet went under that. Then I made a “plug” out of triax that I covered with duct tape.

Then the area was covered with two progressively larger layers of BID.

First task is to create hardpoints in the D-tubes that make up the door frame. For hardpoints, I’m going to use a 2″ x 1-1/2″ x 1/2″ block of aluminum. First I drilled and tapped the holes in the hardpoint. Then I located the position of the bracket.

Next I marked where I would open up the D-tube to slide the hardpoint in.

I then sanded the inside of the door frame and the aluminum hardpoint. Masking tape is applied to the outside of the door frame and bracket to keep adhesive from sticking to it.

Then I mixed up some structural adhesive with some cabo to thicken it. The adhesive is applied to the door frame and the hardpoint.The hardpoint is then inserted and the bracket is attached until the adhesive sets.

Once it set, I patched the d-tube and moved on to the hardpoint on the b-pillar.

Then I had to decide on how to hold the battery in place. My initial plan was to use “J” hooks. Buy I wasn’t sure how that would work in terms of wearing through the battery tray where the hooks went through. So instead, I used some 1/2″ aluminum and created a bracket that screws to the outside of the tray supports that has a drilled and tapped hole for the rod which holds the battery down.

I then located the battery tray between the master/starter solenoids and the brake reservoir making sure that it cleared the nose gear when it was retracted. Once the location was set, I drilled a few holes, mixed up some structural adhesive and pop-riveted the tray in place.

Once the adhesive had cured, I had to grind a divot in the inner skin. The battery I’m using is just a bit too big so I had to make some space. So I removed the inner shin and some of the foam. Then covered it with 2 layers of BID.

Battery tray with battery mounted.

A view of the corner where I removed the inner skin and foam.

And a view looking down from the top.

Malcolm uses a thin strip of soft foam to apply the necessary outward pressure. But the geometry of my gear legs wont’ allow that. They keep ripping the foam off.

So I came up with a “Plan B” (I love a plan B). I cut a small piece of titanium and mounted it to the fixed side of the hinge. It’s damned near impossible to bend titanium so this tiny piece will hold the small door out with just the right amount of pressure.

Here’s the titanium tab sandwiched under the middle nut-plate.

Mounted with the gear up

And with the gear down (You can just see the tab between the gear leg and the door). It clears the gear leg by about 1/8″.

Albert gave me a Ground Power Receptacle a while back so now all I have to do is figure out where to put it. I was going to put it under the battery tray but once I looked at the size of the plug I realized that wasn’t going to work.

So I put it in the nose. This way, it’s easy to get to on the ground when the nose gear doors are open. People that use the factory nose landing light can’t do this because the landing light is in the way. Yet another advantage of landing lights in the canard.