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Old Jul 17, 2014, 08:34 PM
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Delaware
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532 Posts
3D Hobby Shop 92" Edge "Turtledeckectomy"

Team,

I try to find and post repairs that are interesting and unusual and this one certainly fills the bill. We are going to try to replace the entire foam and balsa turtle deck on a plane that was damaged in shipping with one from a donor 92" Edge that crashed over the past weekend. The crashed plane was mostly damaged in the front of the leaving the turtle deck completely intact and I hope usable.

The plane's turtle deck is mostly cosmetic and the majority of the structural integrity for the tail of the plane is provided by the plywood sides of the fuse. The turtle deck is constructed with a thick foam core covered by balsa sheathing. This structure is glued directly to the top plate of that connects one side of the fuse to the other. In a sense the turtle deck and the shape of the bottom of the fuse define the brand of the plane, Extra, Slick, Edge, etc. In addition, the turtle deck is connected to the vertical stabilizer structure but does not provide much if any support to the stab. The vertical stab gets almost all of its support form the fuse. This area is one of the strongest on the entire plane.

The Edge to be repaired was crushed in shipping. The box was smashed directly above the turtle deck and the damage extended to the fuse side and a small portion of the bottom of the fuse near the tail. I was hoping to repair the bottom of the fuse without cutting the bottom covering.

RCMC
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Old Jul 18, 2014, 08:01 PM
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Delaware
Joined Jan 2006
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3D Hobby Shop 92" Edge "Turtledeckectomy"

Team,

Actually, I was able to get a lot done this afternoon. I removed the damaged turtle deck from the new plane, cleaned the foam off the top rail and completed 95% of the woodwork on the damaged fuse.

I "harvested" the good turtle deck from the donor plane and used some of the plywood to patch in the broken sections on the new plane.

The next step is to place some rigid boards along the new fuse's sides at the top rail to insure that they are perfectly straight before I attempt to install the new turtle deck. If the fuse side aren't straight it will make installing the turtle deck a huge chore. Any waviness that I find can be corrected with cross pieces of plywood strips glued under the top rail.

RCMC
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Last edited by RCMC; Jul 18, 2014 at 08:13 PM.
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Old Jul 19, 2014, 07:02 PM
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Delaware
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3D hobby Shop 92" Edge "Turtledeckectomy"

Team,

The attached pictures will require some explanation because my repair is not like the original construction from the factory. It is important to mention that the repairs to the 92" Edge have not added any additional structural support to the airframe. It is, also, important for the team pilots to have the same equipment that is sold to the company's customers.

The original turtle deck is attached to the top plate with epoxy between the foam liner and the sheathing edge. Because removing the new turtle deck from the donor plane was not as clean as the original construction from the factory I needed to find an alternate attach method.

Some foam material was lost in removing the new turtle deck from the donor plane which means the sheathing will be a little short from reaching the top rail when installed on the new plane. The important connection will be the turtle deck sheathing to the plywood headrest and the area near the vertical stabilizer. Once there is a good glue joints there I can fill any gaps on the fuse sides where the sheathing meets the top rail.

As you can see from the pictures I have added 3/8" x 3/8" strips of balsa just above the top rail. I then cut out a 3/8" piece of foam along the bottom of the new turtle deck to receive the balsa strips. The foam will be attached with epoxy to the 3/8" balsa and the sheathing will be glued to the side of the strip with CA at a later time.

One other wood addition was plywood and balsa strips that were added to straighten the fuse side as they were bent slightly from the crushing of the turtle deck during the shipping accident. I used metal shelving standards on each side of the fuse and held in place with clamps to straighten the fuse sides. These clamps were left in place while the stiffeners were installed. These stiffeners were installed between each bulkhead under the new turtle deck.

If you aren't confused by now I shouldn't wonder why.

RCMC
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Old Jul 20, 2014, 06:07 PM
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3D Hobby Shop 92" Edge " Turtledeckectomy"

Team,

There is an old saying in the carpentry trade that you should, "Measure twice and cut once." And that phrase is true in model airplane repair as well. But there is another action that is required that is just as important and that is: "Check the fit." Check it again and again and again and keep checking it. I'm not sure how many times I placed the new turtle deck on the new fuse to check the fit but it was in excess of a dozen. Then, just before I glued it I checked it again and along ever inch that would come in contact with the fuse.

There were some small areas of the turtle deck that needed patching. I cut balsa sheathing patches and filled those areas.

RCMC
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Old Jul 20, 2014, 07:53 PM
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Awesome work Ralph, thanks once again for sharing
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Old Jul 22, 2014, 10:00 AM
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Awesome work Ralph!!
John
P.S. I repaired anothet time my EFlite Extra 260....I will post pics asap
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Old Jul 22, 2014, 10:30 AM
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Quote:
Originally Posted by hot wings View Post
Awesome work Ralph!!
John
P.S. I repaired anothet time my EFlite Extra 260....I will post pics asap
John,

Add anything you like and be sure to post your methods if possible. Looking forward to any repair projects.

RCMC
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Last edited by RCMC; Jul 22, 2014 at 11:51 AM.
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Old Jul 23, 2014, 10:26 AM
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Delaware
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3D Hobby Shop 92" Edge "Turtledeckectomy"

Team,

This is the final post on the turtle deck replacement on the 92" Edge that was damaged in shipping. I removed a good turtle deck from a crashed Edge and used to replace one on a new fuse.

At this point all the wood work is complete and the covering and graphics will be applied.

I hope you enjoyed this repair. I was fun and came out pretty well.

RCMC
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