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Old Aug 22, 2009, 03:20 PM
Registered User
Ballwin, Missouri, USA
Joined Aug 2009
3 Posts
Question
Tissue, synthetic iron-on or silk ? Or ?

I built a number of control-line planes a number of years ago and a few RC, almost all covered in silk (or something smlilar) and dope but never the iron-on covering material. Also built some ARF foamies covered with a plastic coating. So I'm rally an old rookie today.

Anyway, really enthused and getting into building RC airplanes now, mostly scale and so far, mostly Gullows. However, I really like balsa airframes and plan to branch out into other kits, really made for RC.

My question has to do with the covering. I like the look of scale with vary thin balsa covering but know that adds weight and may turn out to be the death of the Guillows kits with the added wing loading when they are already a bit high. I really enjoyed covering and like the strong skin with the silk-like materials in the past and am thinking about using that again.

My current project is an old Carl Goldberg Falcon 56 that I plan to power with an Eflite 25 Outrunner motor. It was purchase many years ago and the airframe built but repaired recently and still not covered. I know silk is expensive now but can it be bought cheaper at a fabric store or somewhere on the web ? Should I just give in and learn to use the iron-on materials ? Is tissue strong enough ?

For the next projects, I have 3 Guillows already bought but not started:
Skyhawk 172 #802, B-25 Mitchell #805 and B-17 Flying Fortress.

The Skyhawk I am fine with fabric covering since it will be a scale-like appearance but the 2 warbirds I would love to cover with very thin balsa sheeting and sand even thinner, then cover with dope.

Any suggestions on covering the Falcon 56?

Will I ever get the others to fly well with the higher wing loading. Any suggestions (including making shelf models of them) on building the Guillows kits ? Will I ever get them to fly well ?
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Old Aug 22, 2009, 04:33 PM
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Cromer,Norfolk, UK
Joined Nov 2006
2,505 Posts
Tissue and dope is fine for almost any size of model, providing the tissue weight is chosen to match. In fact, it adds a great deal more strength to a model than heat shrink films do. Especially for electric applications, tissue and dope is an ideal covering.

The guillows models never really fly well out of the box, for two main reasons;

Wood as supplied is usually too heavy, and of poor quality

Designs work well for static models, but contain "too much structure" for good flight performance.

I would imagine you might struggle with getting the B25 and B17 down to a decent flying weight, especially if you fully sheet them. If you want a smooth "non sagging" surface to replicate the full size, then I would suggest tissue/dope over thin mylar.

Thin mylar can be glued on with heat activated adhesive, and can also be heat shrunk. The tissue/dope goes over that. It can actually be lighter than normal tissue/dope due to the fact that less coats of dope are needed to seal the tissue.

On the B17 and B25, I would think that your best bet is to build as light as you can with good wood, and if doing them free flight, convert them to electric.
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Old Aug 22, 2009, 09:31 PM
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Ballwin, Missouri, USA
Joined Aug 2009
3 Posts
Thank you for the reply. I had never heard of tissue and dope over mylar. Sounds like a good idea for looks and lightness.

I will try to replace at least some of the wood and make the airframe lighter as I build them by sanding or cutting down some of the balsa while trying to keep the strength and depending on some of the covering to help. Another excellent idea, thanks again.

I am planning on building all 4 as RC fliers and I will use the very lightest servos and other items to keep them as light as possible. I also intend to use a lighter style of brushless motor but still have enough power. The exception will be the Falcon 56, in which I intend to use a eFlite 25.

Does it seem to make sense to enlarge or otherwise modify the wings to get more lift in order to offset the weight ? I know it is possible but I don't know how to get more lift other than to add some sort of flaps but that would add more drag. Any suggestions ?
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Old Aug 23, 2009, 03:17 AM
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Staffs, UK
Joined Nov 2003
9,896 Posts
There are many detailed threads about a number of Guillows conversions in the Scale Electric Planes forum. Here's a list of most them http://www.rcgroups.com/forums/showthread.php?t=827861

Steve
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Old Aug 23, 2009, 11:55 AM
if I only had the time
adammoren's Avatar
United States, WI, Green Bay
Joined Jul 2009
30 Posts
I've noticed alot in all of these threads about guillows conversions that they all have different view points. Some prefer mylar and some prefer tissue or silk. But the thing im always getting confused about is weight. No one ever has a clear answer as to which is actually lighter. Why is this? Is dope that heavy that it can affect the wieght?
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Old Aug 23, 2009, 01:04 PM
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Staffs, UK
Joined Nov 2003
9,896 Posts
Yes dope makes up a fair percentage of the overall weight of the covering. And different types of tissue/material need different amounts of dope to seal them properly. And some people thin it a lot and spray it lightly in many coats and others seem almost to pour it on full strength then swish it round with a brush .

Hence why you'll have real trouble getting accurate answers about which covering method is lighter. You can only get accurate weights for that new-fangled heatshrink covering and even that varies a lot by type and even by colour .

Steve
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