Bubble doors

[tommg13780]

I'm looking for advice on the installation of acrylic bubble skins on the aluminum bowed door frames. The fit around the outside edge appears to be fine. It seems that the radius of the molded acrylic is somewhat different that the door frames in the center area leaving as much as 1" separation between the acrylic and the aluminum frame. Perhaps this is correct? The airplane is model 4.

[HighWing]

I have no personal experience witht the bubble doors, but my understanding from reading that it is normal. I don't know what is recommended now, but in the past, some felt that the acrylic added enough strenth to the door that they cut out the two cross tubes apparently without issues.
Lowell

[hansedj]

http://www.teamkitfox.com/Forums/showthread.php?t=2860&highlight=bubble+door


that is correct here is a link.

[tommg13780]

Thanks Daryl and Lowell. The situation is perfectly clear now. I appreciate the help.

[jiott]

If the 4 is anything like the 7 the center crossbar is deliberately spaced away from the acrylic to allow you to use it as a handle for opening/closing the door.

Jim

[HansLab]

Agree with that (horizontals to be used as handgrip).
Mr McBean answered on my question that it is possible to remove the horizontal bars. But when I installed the doors and sat in the plane, I found out how handy they are. And they're bent so, that they hardly take any space (or provide any, for that matter), so I left them where they were.

[tommg13780]

I'm planning on keeping the horizontal bars in position and using stainless sheet metal screws to attach the acrylic to the frames. The 3M tape is available locally at the NAPA store at $48. All that's left is door latches from kitfox aircraft.
Tom

[tommg13780]

here's the results. No door handles yet.

[HighWing]

Seeing Tom's picture brought up a thought. My understanding is that the Bubble doors initial purpose was to add a bit of width to the cockpit. If the horizontal tubes are retained, it seems it would reduce that advantage a bit. If it is the look you are looking for, I did a Polycarbonate installation that gives the look pretty much, but eliminates the cost and the weight of the heavier Acrylic. I used a very thin commercially available H channel that I bend to fit and the poly was slotted into the top and bottom if the channel. What might look like funny striping on the bottom panel is actually the pre-upholstered seat pan as seen through the panel.

[ackselle]

Lowell,

Could you please post a close up showing the detail of your channel/poly install. Very interesting!

Lowell,

Were you able to install a single piece of polycarbonate on each door?... or did you have to split it in the middel to allow for the compound curves?

Cheers,
Ackselle

[HighWing]

The channel is 1" wide and the slots are about 1/8". I bent it by hand over a piece of padded fairly large diameter pipe. In the first picture you can see the marks I put on the channel to estimate the bend location. The haze around the bend was due to the anodized surface crazing. To keep the bend smooth, I inserted strips of thin aluminum into the slots to fill the gaps snugly. This prevented the outside aluminum from simply collapsing into the slot. It was bent to an eyeball acceptable shape. Once bent and cut to a rough slightly oversized length, I fitted it over the door and marked and cut off the internal flange and web at the ends so the outside flange would fit snugly over the Poly and door. I didn't trim to length until after the whole thing was clecoed onto the door frame.

As far as the Polycarbonate is concerned, I fitted it to the H channel first. The internal contours are more than I could have estimated. Then the poly was fitted to the door frame using clamps. After everything was good drilling and clecos replaced the clamps. The Polycarbonate was trimmed to it's final shape and the H Channel was then marked and trimmed to length, painted, reclecoed into position and finally riveted. I found some black aluminum rivets on line as black is my interior color and I wanted everything to match.

[tommg13780]

Lowell,
I like the way that turned out, particularly the black rivets which almost disappear into the black door frames. Also as you mentioned there's got to be a substantial weight penalty to the acrylic. Did you use the rubber tape in between the polycarbonate and aluminum door frame? Nice.
Tom

[ackselle]

Nicely done!

Looks great.... and like you say, you get the look/view without the additional weight.

Cheers,
Ackselle

[HighWing]

Twp pieces of Polycarbonate were used to accommodate the compound curve. No I didn't us the tape. I will have to give that future consideration. One issue that will inevitably will crop up is dust, etc. lodging betweent he round tube and the plastic which will be noticable from the outside. I wonder if the black tape will help eliminate that. As it is now, replacing the polycarbonate skins would be similar to replacing the windshield - drilling out the rivets, using the existing plastic for patterns, trim and drill, cleco and rivet. Probaby half a day.
I did the whole thing to eliminate the warping that was so common on the fiberglass shapes that conntected upper and lower panels.

[ackselle]

Re-covered my doors over the past few days... and while doing so, I also built new door latches as I was never satisfied with the originals. I'm very satisfied with the door seal, which was another reason I wanted to change the old latches.
6128

In an attempt to "hide" the door frame, I painted the lexan from the inside 1/2" in from the rivets and outwards. I've had good luck with this method in the past, and I'm quite happy with the results.
6129

Also... I made myself a new "lock" so I can secure the doors at fly-in etc. And my key is an allen wrench.
6130

Now my IV is ready to face the winter again.... when the blizzard stops!
6131

Next project.... switching from heat muff cabin heat to inside heater core (Earls oil cooler) and computer fans.... just in time for next winter!

[tommg13780]

Very nice results. The paint around the edge makes it look particularly good.