covering an undercambered wing section?

[capncrunch]

what's the standard practice for covering an undercambered wing? it seems to me that an airfoil with any significant undercamber would rule out heat-shrink film covering? is the best route a sheeted foam wing with a painted finish?

-barrett

[vintage1]

Certainly you need a method of shrinking that is at a lower temp than whatever holds the covering in place.

In my 'yoof' we certainly used tissue, held on by water based tissue paste, and doped to shrink.

I have a sneaking suspicion that solite will shrink slightly below the temp at which the glue softens.

I would knock up a test piece and tack with the iron, and heat gun very carefully.

[jlk]

You can and I have many times used heat shrink. Like vintage said you have to adhere the covering to the ribs first with an iron and then carefully shrink the bays also with the iron. No heat gun! The heat gun will give too broad a heated area. The trick is to heat the bay without reheating the adhesive on the rib so that it stays stuck.

Jordan

[capncrunch]

so I shouldn't be too concerned about covering an open-bay built up balsa wing with solite, even if it has a sharp-ish camber?

I am trusting you dudes!

I understand that most of the SAE aerodesign craft are designed with an undercambered foil. although they are a few times as heavy (and larger) than I am designing (an AP platform), how are they generally constructed? composite? sheeted foam?

-barrett

[Andy W]

I have covered a sheeted, undercambered wing before. The information above is useful - you obviously can't start at the corners and work in as you would with a "normal" wing.. Just take your time..
..a

[Highflight]

The Stits polyfiber manual at http://www.polyfiber.com/stits/ covers all aspects of covering with (in this case) fabric, and it also shows the technique for how to cover under-camber wings.

It's a good reference manual to have, and you just may find yourself converted to using the Stits system instead of film in many cases.

Highflight

[Sparky Paul]

I place small spars along the chord at points which will have a relatively straight line between them on the rib line when using heat shrink over open structure.
It will pooch out to try to make a flat panel for each segment.
The only way to cover undercamber and keep the profile is to fully sheet it, and stick the covering to the sheet.

[BEC]

Have done undercambered wings several times with iron-on coverings. Start by tacking the covering to each rib at the high point of the camber (if there's a spar there to attach to, so much the better). Then go to the corners at the LE and TE but don't pull it too tight, and do the LE and TE.

Seal the covering to each rib with the iron starting from the tack-on point. It can help to have a bit of moistened paper towel handy that you can follow the iron with as you attach the covering to the ribs to cool and set the adhesive quickly.

Concur on the "no heat gun" advice.

That said, I've never tried SoLite on an undercambered wing yet.