5.2.4 Door Hinge Installation (Modification)

This entry is part 6 of 16 in the series 05 - Doors / Windows

One of the common complaints about the door design is that it can leak. This is due to the hinge cutouts.

Here’s the top of the pilot side door opening with the door removed. You can see where the two hinges mount.

And here’s a closeup. Notice how you can see though? That’s how rainwater ends up in your lap.

Malcolm suggested covering this opening. So I got a piece of scrap fiberglass and cut it to the correct shape. Then I bonded it up place with an epoxy/cabo mix.

Once it cured, I covered the inside with a layer of BID and then filled the outside and sanded it smooth.

It won’t look perfect, but I think it will not be at all noticeable and any rainwater that come in around the hinge will have no place to go but out around the door.

5.2.3 Door Opening

This entry is part 7 of 16 in the series 05 - Doors / Windows

One of the things that I’ve noticed is that getting in and out of the plane can be slightly… painful. The aircraft sits rather high. And the lower edge of the door opening is vertical lip about 1/8″ wide. If you rest your legs on it when entering or exiting the cabin, it feels like a knife on the back of your thighs.

Brooke Wolfe has a mod on his door openings that makes a huge difference. He widened the lower lip with a groove to tuck the carpeting in. Here’s how I did mine:

I took two layers of 1/4″ foam and cut them to fit. I also created an opening for the door latch micro switch.

Then I covered the foam with a layer of carbon fiber between two layers of BID.

 

5.3 Door Latch Micro Switches

This entry is part 8 of 16 in the series 05 - Doors / Windows

On each door there is a micro switch that detects when one of the door latch pins is fully engaged. When I made the lower door opening modification, I made a cutout for the micro switch.

To mount the micro switches, I made a hardpoint out of 1/8″ aluminum stock. I screwed the switch to the hardpoint and used structural adhesive to bond it in position.

Because it won’t be subjected to heat or stress, I’m not going to cover it with fiberglass.

The door pin doesn’t travel far enough to contact the micro switch. Some people have used wooden dowels to create an extension. But when water get in the wood swells and gets stuck holding the micro switch in the “engaged” position which means you won’t know if the door latch pins are engaged or not.

So I used part of a plastic coat hanger. I cut a small section off.

Chucked it in the drill and sanded the diameter down until it was the correct size. Then I created a depression in one end to match the door pin.

The length was determined by trial and error. I just kept trimming it shorter until with the door latched, the switch was triggered.

Switch with the door latched.

For a cover, I used some scrap fiberglass and cut to fit the opening. Then I created some small aluminum hardpoints and used structural adhesive to bond them in place.

 

5.3.6 Door Pin Sleeves

This entry is part 13 of 16 in the series 05 - Doors / Windows

The sleeves that the door pins go into have been something that I’ve been thinking about for a while. They are not only ugly, but they have a tendency to catch clothing when entering and exiting.

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Some builders have made aluminum plates to cover them. I tried that, but getting the hole drilled at the compound angle was proving difficult.

So I decided to try a somewhat artistic approach (even though that is definitely not my forte).

I mixed up some epoxy with cabosil and a little milled fiber and moulded around the sleeve. When it cured, I sanded it and then added another layer. Then sanded, filled, sanded and painted.

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Not sure how well it’ll hold up, but I haven’t got my shirt torn since.

5.1.4 Window Scratches

This entry is part 15 of 16 in the series 05 - Doors / Windows

Since taxi testing is hopefully going to be happening soon, I decided to remove the plastic covering the windows.

I’ve been pretty diligent about keeping the windows covered.  I make sure the window is spotless, then use a fresh sheet of plastic and tape it down tight with good duct tape.  The only time I remove the covering is when I needed to work on the window/fuselage interface.

But when I removed the plastic, I discovered some areas that I first thought was dust, but turned out to be scratches. My guess is that there was just enough loose plastic that during transport it was able to rub on the windows.

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I had purchased some Scratch Off a couple years ago (just in case) and was getting ready to try it out. Scott Swing dropped by one morning while I was still trying to get un-bummed about the whole window thing and I showed him the state of the windows. He was totally nonchalant about it.  He said that windows get scratched all the time. I told him that I had some Scratch Off that I was going to try and he told me how he does it (and I’m pretty sure he’s done a few). 2,000 grit sandpaper and Meguiar’s PlastX.

To say I was doubtful would be an understatement.

I already had some 2,000 grit sandpaper for knife sharpening so I went to Walmart and picked up some PlastX for about $7. But I didn’t want to test this on the actual windows.  So I went over to the factory and got a piece of scrap window material.

It didn’t have any scratches so I made my own… with 180 grit sandpaper.

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The marks on my window weren’t nearly that bad but I felt that if I could come close to fixing scratches that bad then my windows would be a piece of cake.

Because these were some serious scratches, I decided to start with 1,000 grit then 1,500 and finally finish with the 2,000 grit sandpaper. That definitely removed the deep scratches.  Then I used the PlastX with a paper towel (I left my good microfiber towels in the Cessna). After a minute or two polishing:

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I didn’t do as good a job as possible with the sandpaper and putting on the polish with a paper towel isn’t even close to the correct way, but the results indicate that this is going to work just fine.

Later I told Scott that I tested it on some self-inflicted scratches created with 180 grit sandpaper.  He said “ONE-EIGHTY!!!”  Hilarious. Hey, go big or go home.

5.6 Improving door fit

This entry is part 16 of 16 in the series 05 - Doors / Windows

During the last trip, I had a lot of time (10 hours) to determine that there were leaks around the doors. I didn’t think these leaks would make a huge difference but since painting the plane is around the corner, I makes sense to do it now.

I identified two places around each door where I could detect some air movement. It was the same locations on both doors.  The first was on the forward edge about six inches up from the bottom. The second location was at the very top of the rear edge.

When I looked at those locations, it was pretty obvious what was going on.

Here’s the forward opening on the pilot side door.

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The flange isn’t straight (this is where the two fuselage halves are joined).  Since the weatherstripping is following the flange, that is creating a gap between the weatherstripping and the door.

Top rear of the door opening.

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Same issue as the forward edge but over a larger area.

There are two possible fixes:

1) Increase the thickness of the door at these points.

2) Increase the thickness of the flange on the fuselage side.

Now method 1 is just plain wrong. In addition to that, it would make the door heavier.  Although not by much… But still heavier.

So I pulled the weatherstripping off in the affected areas and mixed up some epoxy with cab-o-sil and micro. Applied it, sanded it so I had the proper dimension and reapplied the weatherstripping.

Here’s the forward edge of the co-pilot door.

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There was one other thing that I had to address.

The outside of the upper, forward edge of the door was sitting proud of the fuselage. Not much. Maybe a strong 16th of an inch.  If the leading edge was below the fuselage, I would probably leave it be. But with it sticking out into the airflow, I thought that in addition to drag, it was probably generating some noise as well.

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Scott recommended using polyester resin for this type of fill. The advantage is that you can paint directly over it.

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I masked the area with tape, mixed up the resin, added some micro and cabo to thicken it, and then applied it. I did one more fill to get just right and then some glazing putty (polyester as well) to finish up.

Now the doors are perfectly fair with the fuselage. During this time, I was also making some changes to the nose oil cooler/heating and made a quick flight to test those changes.

The difference was surprising!  Before there was always a lot of wind noise and some whistling.  I assumed it was from the openings for the main landing gear.  Once I installed the vanity panel, that seemed to help a little. But on this flight, it was significantly quieter!  (And faster. Everything you do makes the plane faster. Soon I’ll be indicating 300knots… in the climb!)