With today's wood being heavier I am looking to be able to use MonoKote/Ultacoat on a simple non-flapped wing. In the past most of the wings that I have used the M/U on were ok but not as twist resistant as if it were done in silkspan/dope.  I remember the old TopFlite Tutor wing was design for a film covering and basically had the last rib bay planked. On OTS ships adding the planking could be a problem. adding it below the rib line might work. Any other ideas to add stiffness?

Best,  DennisT

   Unless you are building it from the most soft and punkish wood you can find, I wouldn't worry. Add a gusset here or there at the corners, maybe. I have built wings of all sizes and covered them with Monokote with no warping or twisting. Sailplane wings from the 70's and 80's are a prime example. With out iron on covering, they are veritable "Flexible Flyers!" and have no torsional resistance at all. But cover them with Monokote and they then become a stressed skin designs. As far as I'm concerned, Monokote was always the best for this id applied correctly and shrunk properly. I remember one flying buddy that stripped the Monokote off the wing  of an SD-100 standard class model and replaced it with some sort of woven cloth, a Coverite product I think, that advertised its strengths , thinking he could get a turbulation effect from the weave across the airfoil. On the first launch, he about fluttered the wing tip panels off! He took a pocket knife to it right there and next time I saw him the airplane was back in it's familiar colors! And no more issues with flutter. You can add a gusset here or some diagonals there if it will help you sleep at night, but if it's a known C/L design or anything similar, it shouldn't be a problem as long as you can get a good anchor all the way around a wing panel , and shrink the covering first before attaching it to any ribs or spars.
  Type at you later,
    Dan McEntee

Similar to Douglas.  This wing was monokoted.

Ken