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Unsatisfied with the weight of my first model (a FT Tiny Trainer), I decided to build something lighter. Since overweight foamboard was the downfall of my first model, I decided to try reducing amount of foam by building a rib-and-stringer balsa design at with foamboard. I scaled down these plans to half scale and have assembled the fuselage and tailplane. When complete, the plane will have about 85cm wingspan and will be 65cm long.

Initially, I was planning to cover the plane with thick, semi-waterproof paper of about 300gsm thickness, and created a test section of the fuselage using the paper. Unfortunately, after putting together the ribs I found that the thick paper was too heavy and would bring no significant weight loss. I've been thinking for some weeks, but I haven't been able to come up with anything good to cover my plane in.

These are some of the things I've considered using:

  • Conventional covering film (specifically this brand. This would be light enough, but I'm not sure if it would adhere to foamboard. I also don't wish to buy a heat gun (apparently a hairdryer isn't enough), considering that I probably won't make more covered models in the near future.
  • Office paper (about 90gsm). It would be very light, but the paper would rip easily and fail on contact with any moisture. In addition, it would add almost no strength to the body.
  • Plastic tablecloth material (similar to this). It's light and waterproof. However, it would probably be a bit baggy and wouldn't add any strength to the body.

I'd also like the material to come in opaque white color, as the plane I'm modelling is normally white.

So, the question is: What material would work best to cover my plane?

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    $\begingroup$ BTW, you can save about half the weight of foam board by removing the paper. The paper on the inside of the fuselage and wing is adding very little to the strength, and it will still fly if you remove all the paper, it will just pick up scratches more easily. Also, hot glue is heavy. UHU POR or Gorilla glue is lighter, but not as fast or easy to use. $\endgroup$
    – Robin Bennett
    Jul 15, 2021 at 7:28
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    $\begingroup$ AFAIK covering film can be ironed on. In fact I've never seen it being applied differently (perhaps because it was used on foam models, which would melt and deform if hit with a heat gun) $\endgroup$
    – FlashCactus
    Aug 26, 2021 at 11:58

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How about the thin white polythene/polyethylene from carrier bags or bin liners? I think you could stick it on with a foam-safe contact adhesive such as UHU POR.

Alternately, you can save weight from your Tiny Trainer by peeling the paper off the foam.

It sounds like what you really want to build is an old fashioned balsa model, covered in tissue and dope. They're really no harder than the model you have just built, and the balsa for that size of model is only $5-10. The tissue shrinks when you wet it, and then the dope makes it rigid, adding significant strength to the airframe.

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  • $\begingroup$ Thanks for the ideas. I searched up 'white polyethylene bin liner' but I was only shown results for 'white polythene bin liners'. Are these the same? Regarding my Tiny Trainer: It's almost impossible to peel the paper off my foamboard, and in any case I'd like to have more than one model. $\endgroup$
    – ThatCoolCoder
    May 4, 2021 at 7:54
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    $\begingroup$ That's the ones I meant - I think polythene is the trade name and polyethylene is the chemical name. $\endgroup$
    – Robin Bennett
    May 4, 2021 at 8:07
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I wonder if you might have luck with plastic wrap? (Also known as 'cling film' or 'saran wrap'.)

You could wrap multiple layers for extra strength and can apply with a little tension to keep it taut; getting a wrinkle-free aerodynamic surface might be fiddly but it would probably fly well enough.

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  • $\begingroup$ Interesting idea! Do you know if it's possible to find opaque white plastic wrap? I'd rather not have to paint my plane. $\endgroup$
    – ThatCoolCoder
    May 1, 2021 at 21:52
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    $\begingroup$ @ThatCoolCoder I've never seen it in white; I also don't imagine it would paint very well. You could perhaps combine it with the paper covering option - but either way I don't see this solution being particularly aesthetic (other than in so far as 'homemade' could be considered a style?) $\endgroup$
    – Kralc
    May 2, 2021 at 13:53
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    $\begingroup$ I finally got around to trying your idea. Unfortunately the gaps between my ribs were too far and the cling film refused to properly conform to the shape of the body. I also could not eliminate the many creases present, and the cling film didn't adhere at all to the body. While this idea won't work for covering my body, I think it might work well for making models of a much smaller scale. $\endgroup$
    – ThatCoolCoder
    Jul 15, 2021 at 2:52
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Have you considered using lamination sheets (semi-rigid, slightly bendier than paper, plastic sheets)? You can attach them with a staple gun and also spray-pint the interior to make them white.

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For what it is worth, I used outdoor grade of polyurethane brushed it onto my Tiny Trainer. It added almost zero weight and while I would not fly it in the rain, it seems to shed water nicely.

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