ricknkim

Ok covering gurus,

I watched Minnflyer's covering video and have already covered two planes myself, but here is my question. What is the best way to cover a carved balsa wingtip? Should I cover it in 2 pieces, with the seam being in the center of the wingtip or should I try and cover it in one piece, tacking down the center and then heating and shrinking to get it to go around the curves? Which will look better and have less chance of wrinkles?

J_R

There are three ways, typically, to go at it. One is to do as you suggest: pull and heat. There is always the chance it will get so thin you can see through it, or it will tear. Another is to cut a piece as seam it, as you also suggest.

Another method was offered by Faye Stilly. After covering the wing, carefully heat and shrink the extra material that will go over the wing tip first, then pull it and heat it to cover. Most of us forget that we can shink covering before it is applied. The real problem with wing tips is that you have too much material. The only trick is to make certain that you do not allow the material to stick to itself while pre-shrinking it. You may want to try this on a mock up first.

MinnFlyer

My Feedback: (4)

Your best bet is to cover the bottom first - pulling as you heat (Remember, while it's heated, covering will stretch as well as shrink) Leave yourself lots of extra to grab on to - This is no time to be stingy and try to save money by cutting th covering "Just big enough". Leave yourself at least 2 inches more that you need.

Cover as much of the tip as you can, but you only need to go just pased half way.

Then, cover the top of the wing and repeat the process. This will leave a seam in the middle, but most times it totally unnoticable (When the top is covered last)

GoMike

This is kinda long - it comes from a Word document I typed up based on my experience. It works well for open (or sheet) wingtips or solid carved ones:

•I used Monokote. Low-temperature coverings such as Econokote or Towerkote will require less heat - either shorter periods of heating or holding the heat gun farther away.
•Use a glove on your pulling hand - you’re going to point the heat gun at close range almost directly at your thumb or fingers.
•You can work with the covering left hanging over when the wing was covered or use a separate piece of covering attached later. Make sure there is an excess of at least 2” hanging past the wingtip so that you can get a good grip on it while wearing a glove.
•When pulling and stretching the covering over the wingtip, you’ll have to brace your pulling hand or fingers against the other side of the wing or wingtip. A better way is to have the wing held or weighted down (phone books & catalogs work well) on a table with just the wingtip hanging over the edge. Then you can just pull straight down over the wingtip.

1. Attach the wingtip covering along the outboard wing rib (or the outer edge of a sheeted wing) from the leading edge to the trailing edge. Make sure it is attached well, especially to the front of the leading edge, so it doesn’t come loose when the covering is pulled hard.

2. Start by grabbing no more than an inch of the excess covering at the center of the wing tip between your thumb and index finger (wearing gloves). Hold it so that it can be pulled down with a good bit of force.

3. Fire up the heat gun and heat the covering, holding the gun about one or two inches away from the film where you’re pulling it (farther away for low-temp coverings). You will feel the film stretch and you’ll see the wrinkles come out of the area being pulled on. The hot film will stick to the wingtip - no ironing necessary at this point. Remove the heat after the film stretches and sticks to the wing tip.

4. Move down the wingtip toward the trailing edge about an inch or so (however much you can pull evenly) and use the same technique of pulling the covering hard over the edge of the wingtip and then heating that section until it stretches and the wrinkles disappear.

5. Repeat step 4 all the way to the trailing edge. By the time you get toward the rear of the wingtip, most excess covering and wrinkles have disappeared.

6. Repeat step 4 forward all the way to the leading edge. Near the leading edge, you may have to pull a bit toward the front of the wing to get the proper “lay” of the covering.

Note: After step 6, if there are small wrinkles, you can try going back and working from the wrinkled part to the back again heating, pulling, and re-sticking it, but you may not be successful. If it doesn’t work, remove the piece & try again.

7. After the covering is attached front to rear and the job looks good and wrinkle-free, go around the wingtip with a sealing iron to make sure the covering is sealed well against the wingtip’s edge. Then trim the excess covering as desired.


Give it a go on a practice wingtip and you'll see how easily the covering pulls over the wingtip and how the wrinkles take care of themselves.

==Mike==