I've built a dozen D-tube wings and never really liked the frantic CA pin/clamp/rubber band method. On my current project, a did the tape hinge off the L.E. routine and quickly applied medium CA to the spar, L.E., and ribs. I then quickly folded the sheeting back and piled magazines on the wing, and ceramic tiles on top of that (a lot of weight). All the joints appeared to bond very well and the wing is straight.

Is there a better way? Would yellow glue work just as well or better?

Yellow glue will work. I have used Titebond II in a syringe (purchased at a Farm & Home Supply) to apply sparing amounts to the ribs when doing this. You do have to be careful about the amount of glue (weight) you are adding. Of course, I've been told that all the weight of CA glues soaks into the wood and stays on the plane. Good luck! Dzl

I use elmers Pro Bond Polyurethane glue get a 12 min working time and it will slightly expand so it will get into the wood grain giving a super joint IE you will have to throw the wing away because you will never be able to strip the sheeting off once its set unless you sand it off hehehehe

Joe

I use CA, but I glue the sheeting to the LE first, then get under it to add CA to the ribs and then the spar. Then just fold the TE of the sheeting to the spar (a long, strong straight edge is helpful) for a few seconds till the CA is set.

Ilikeplanes,

There are probably as many different methods of doing this as there are modellers

I have used epoxy, ca, pva, and old fashioned balsa cement for this - preference for wings under 30" long is very slow ca, over that I use 30 minute epoxy.

FWIW the way I go is this -

Sand LE so that it is properly faired in with the ribs (IE NO STEP!!).
Mark rib positions etc on inside of sheeting.
Give sheet, spar and rib surfaces one coat of weak dope to seal. Dont sand off - you want the roughness on there.
Apply adhesive to both surfaces - the less the better.
An old rubber motor gives an excellent supply of instant compression - pins in the building board only and strap it on...but rubber bands is a second best. Go diagonal rather than chordwise to prevent gluing hills and valleys into the sheet.

The secret really is (IMHO) to use an adhesive that is strong enough to do the job and at the same time will have a "pot life" sufficient to get the sheeting properly in place.

One of the big tricks to making this easier is to take the sheet out over the top of the le, rather than trying to make a cabinet and rebate the front edge.

Does that help?

Has anyone tried contact adhesive or Heat activated type adhesive for this???

No, as far as I am concerned solely because you only get one shot, and I am working with wings that are 6-8mm thick.

Second reason would be that generally impact adhesives are intended for large surface bonds rather than edge (in my case 1.5mm) bonds. This being the case I would prefer to use my epoxies and ca which will not creep or let go under stress.

Well, I just used CA and worked as fast and accurate as I could. What made it work was the tape hinge and clamping/weighting process. I could apply all the CA and place my weight system in about 90 seconds. The skins were adhered very well and the wings are straight. I used almost exactly 2 oz of CA for the entire construction of both wings of my Ultimate.

I actually practiced (dry run) folding the skin back and placing the weights to make sure I was getting the pressure distribution I wanted, didn't bend or warp the wings, and could do it in an acceptable amount of time. This proved to be very worth while.

I now have two straight and strong wings for my CGM Ultimate.

I use med CA. I first preform the sheeting by wetting and trial fitting. Let the sheeting dry. I then mist the sheeting with kicker. Apply the CA top the LE ribs and spar. Set the sheeting in place on the LE and let it stick. I'll hit it with more kicker if needed. Then roll the sheeting on from LE to spar. I use a long flat bar sander to apply pressure. As soon as it's stuck good, I immediately sand the LE sheeting joint. Any fugitive CA will sand off better than waiting for full cure. Like someone said...more than one way to skin a wing.

one hint is when I use pro-bond [not polyurathane] I use disposable glue brushes[ acid brushes] to paint both pieces and then put them together this way you can paint on only what you need, and then I use sand bags to hold the sheet down.

I use the glue-to-the-LE-then-bend-down and-hold-in-place -with a long steel rule method, but, after the LE has set, liberally wet the sheeting with water before bending it down to the spar.

Water helps the wood to bend, so less force is needed, and the water tends to accelerate the CA so the long steel rule doesn't need to be held for so long. Make sure the bottom of the wing is supported on a very straight building board, and even a slight warp built into the wing up to this point will be straightened out after D sheeting.

David C.

RcTrax, what kind of glue are you talking about? ProBond is a line of Elmers glues including everything from aliphatic to polyu. As Joe mentioned the Polyurethane is the way to go. You've got plenty of working time, tremendous gapfilling (we're talking about "The Blob That Would Not Stop Growing") , and great strength. What more do you want?

I declare polyurethane (e.g. Elmer's ProBond PolyU or Gorilla Glue) the winner!