Airfield Models - How To

Make a Wing Cradle

May 05, 2015



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Airfield Models (http://www.airfieldmodels.com/)How to Make a Wing Cradle

This is a tool that I really wish I had thought to make many years ago.  This is another of those ideas that just popped into my head.  I wish I could have ideas like this on command.

I was getting ready to silk a wing and needed something to support the wing that was smaller all the way around than the wing so that the excess covering could hang freely.

The cradles are effective, easy to use, extremely easy to make and very inexpensive.

When not in use the liner stays attached to the pipes.  The whole thing is rolled up and stored someplace convenient.  It takes up very little space which is good because I don't have any more..

 
 

Making the Wing Cradle

This cradle was made for a wing having no dihedral.  I haven't used the cradle with a wing having dihedral but I would probably need to make two shorter cradle assemblies and hinge the system somehow.

I doubt all that would be necessary because I will normally use the cradle for things like installing wing servos or making aileron adjustments.  I can have one end of the wing hang off the cradle and weight the other half in place on the cradle.

Wing Cradle Drawing Make the Cradle Pipes from inexpensive PVC pipe.

Make Cradle Pipe Supports from appropriate hardwood.  Cradle Pipe Supports should be securely mounted to a base.

Space each pair of supports such that each pipe is suspended slightly from the base.  The PVC I had on hand is 1-1/2" which was slightly too small but didn't cause any problems.  The wrapped liner increases the diameter enough that the pipes don't roll between the pipe supports.

You may want to mount the Cradle Pipe Supports to a sub-base that is then bolted to a larger base.  This will allow you to space the cradle assembly appropriately for any given project.

What I'm doing is better than that.  Read on...

Make the Cradle from “sticky” rubber-coated mesh shelf liner (blue).  The shelf liner is available in various widths in the kitchen junk section of Walmart.

Use a single piece of liner to wrap both pipes.

Apply the first full-length piece of double-sided tape to each pipe (red).

Tape each end of the shelf liner to a pipe.

Apply a second piece of tape to the pipe adjacent to the first piece of tape.

Roll the pipe on shelf liner until the liner creates a loop around the pipe and is attached in two places.

The cradle is very easy to make. I cut the PVC for the project at hand.  I made each pipe about 2" shorter than the wing.  The pipe toward the wing leading edge is shorter than the pipe toward the wing trailing edge due to the tapered wing tips.

It probably wouldn't be difficult to adapt this idea so the pipes telescope which would allow the cradle to be used with a wider range of wings.

If the cradle isn't used to hold the wing when covering then it really doesn't matter how long it is.  I needed the cradles to be shorter than the wing so they wouldn't interfere with over-hanging covering.

From idea to finished product in about 15 minutes. A single piece of shelf lining is wrapped around both pipes.  I wrapped them so the pipes couldn't roll away.

I put the cradles on my painting boards which have runners glued to them.  This allows me to adjust the cradle width from 2" to about 11" center to center.

Lead shot bags weight the pipes to help prevent them from moving. I used the cradle for several days and decided I wanted it to be a little more secure.

I have several quart freezer bags filled with lead shot.  I rolled up four bags and stuffed one in each end of each pipe.

Because I'm using my painting boards which have exactly 2.8 gazillion holes drilled in them, I could put short rods in a couple holes to prevent the pipes from moving if I ever felt that much security was necessary.

The wing is gently supported.  The sticky shelf liner grips the wing well enough that it doesn't slide around easily. The cradle is very gentle to wings.  The sticky shelf liner helps prevent the wing from sliding around.

I doubt the cradle will be very useful when using iron-on coverings because it won't keep the wing from moving when tugging the covering while ironing it in place.

With the cradle closely spaced, the wing can be held on edge. This is why I decided to weight the pipes.  I didn't want to risk a pipe moving and the wing falling over.  It hadn't happened but it seemed like it could.
With both hands free, working on the leading edge and trailing edge is much easier. By spreading the pipes slightly the wing can be tilted to allow hands-free work on the leading or trailing edge.

With the weighted pipes the wing is secure enough that I have full confidence in their ability to hold the wing.

 
 

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Copyright © 2009 Paul K. Johnson