Clearing bent arm when installing/removing Cabin Top

[lr172]

I am getting ready to start fitting the cabin top. The tops of the forward braces are already bent back a bit. I should be able to bend them back to straight, but suspect I will be limited in how many times I can do that before work hardening.

The instructions tell you to spread the canopy top sides while intstalling/removing the top to clear this bend. I did a bit of experimenting with this and I am not sure that the movement of the sides while spreading will be adequate to clear the arm. I have the older green top.

Am curious if others have had issues with this or will I find it to be a non-issue once I try for the first time.

Thanks for your assistance.

Larry

[rocketman1988]

Pretty sure those braces are supposed to stay bent. I was able to clear everything by spreading the cabin top sides (pink top).

If you have the QB fuselage, make sure that all of the rivets in the door area of the fuselage sides are FLUSH rivets. My QB kit had 14 AN470 rivets that were incorrect, making the cabin top exceedingly difficult to fit...until I found those incorrect rivets...

I suggest you put a "Cuss Jar" in your shop prior to starting the cabin top fitting. Put a dollar in the jar each time you cuss. By the time you are done with the cabin top and doors, there will be enough cash in the cuss jar to pay for a bunch of your avionics...

[Paddy]

Larry, I must have had the cabin top on and off a dozen times or more. No need to bend anything out of the way, the cabin top should be flexible enough to persuade it onto place once it's trimmed. It can be difficult before trimming when the extra material is still there, making everything more rigid.

[Kyle Boatright]

Originally Posted by lr172

Am curious if others have had issues with this or will I find it to be a non-issue once I try for the first time.

Thanks for your assistance.

Larry

The first few fits are the worst. I ended up thinning the perimeter of the door openings much farther than I expected. I eventually relieved mine so it was a snug fit, not a press fit. At that point, the cabin top door surrounds got pretty thin.

I had the same concerns as you with the vertical aluminum members, but it turned out to be a non-issue (since I was sensitive to the issue).

[rocketman1988]

Yes, those sides get pretty thin, in fact, you end up sanding them into the radius to get them to fit.

Too late now, but if the cabin top door width would have been just 1/4" less, the fitting would have been a much better experience...

[Tassie]

I left those front tabs straight while the cabin top went on and off a dozen times. They only need to be bent over at the end. I also didn't drill the bolt holes until I was ready to fit the cabin top permanently, just used #30 clecos on the vertical parts of the door frame, and #40 clecos along the horizontal part. Clecos maintain alignment just fine, and are a lot easier than installing and uninstalling bolts all the time. Have to be inserted from the inside when the doors are being fitted of course.

A.

[lr172]

Thanks for the input guys. Much appreciated

[jeffwhip]

Here are the incorrect round-head rivets Bob is referring to. They were on my QB fuselage as well.

https://photos.app.goo.gl/uSaD5ewUSQhY4xYh1

https://photos.app.goo.gl/Ze53Y5xe4GrGNKZE2

If your QB fuselage has these, you'll have to drill them out and replace them. Also, my cabin cover was very poorly made. Van's talks about making you initial cut up to the scribe line. If you zoom in on this photo, you'll see the most uneven scribe line you've ever seen. A kindergarten student could draw a straighter line.

https://photos.app.goo.gl/BMUiRLj5qEIYCKbx1

Because my scribe line was so crooked, I had to really think about how to draw a true straight line. So I took a small carpenter's ruler and took all of my measurements from the inside bevel. I drew my cut line based on this and then clamped a straight edge firmly in place. Then I took a disk sander and sanded right up to the straight edge. My lines were perfectly straight.

[Kyle Boatright]

My $0.02 - wherever possible use the measurements given in the plans, not the scribe lines. I used the scribe lines and had to go back and extend certain flanges where the scribe lines left things short.