Why would it not work?  1.5mil polyester lamination film is just as strong and quite likely, stronger than any of the 'kotes, ie, monokote, ultracoat, econokote, tower kote, ect.  I struggle to see why lamination film alone wouldn't be effective for your needs.

If you want to enhance the strength of the covering, combine the lamination film with a sub-layer of silkspan/doctors office paper or polyspan/dress lining.  This will create a very tough composite covering structure.

Most builders don't use this method because it has no color and most guys want colored films.  Also, most builders stick with finishing methods that will produce the results that are a known quantity.  A 700" plane generally denotes a serious effort and expense, and at this size and complexity, most guys won't build big planes without an accompanying fancy finish.  If the quality of the finish is secondary to your needs, then the lamination film is a worthy option.  Lamination film can still look cool and slick and provide the necessary protection and strength, but it likely won't ever be a front row 20 point finish if that matters to you. 

At this stage in my flying career....I would be fine with a simple lamination film covered wing if the plane flew great and inspired me to fly more aggressively. 

Hi Brent,
You wrote:"...combine the lamination film with a sub-layer of silkspan/doctors office paper or polyspan/dress lining".
My main concern are air bubbles that can be trapped underneath the lamination film. Say, the Silkspan is brushed three times with the nitrate dope to attach and stretch it.

Will there be enough permeability to allow the hot air to escape "into the wing" through the wing balsa 1/16" sheeting? When balsa is saturated with nitrate it becomes less permeable.

At this moment, color and appearance are secondary for me but I do not want the trapped air bubbles to create the "chicken pox" on the wing.

EParrot's wing sheeting was spray painted twice with Tamiya paint and, after attaching the Doculam film on top, I spent some time puncturing the air bubbles. The largest one was roughly 1/2" but there were at least twenty of them. Tamiya handled the heat of the iron quite well but it sealed the balsa sheeting and made it much less permeable for hot air.

Dane,
My eParrot's wing loading is 11.73 lb./ft.^3.

Regards,
M


 

Hi John,
Which one of your posts shows the details of the process you have just described?

Perimeter of base covering is around open cells, right? So you do not cover the entire wing with, say, Silkspan as base covering- you cover only open cells.

What do you mean by " don't seal it there"? Silkspan must be attached around open cells with something. Dope, Elmers glue, whatever is used to attach the Silkspan perimeter will seal the balsa there. In other words: there will be, say, 1/2" of margin around the open cells that will be sealed/partially sealed by one of the glues used.

What do you mean by "Just don't slide the iron"? Over what? The perimeter around open cells when the lamination film is applied?

Assuming that Silkspan is used in this example, it must be saturated with the nitrate dope to tighten it over the open cells. Say, I brush this area with diluted nitrate only once and let it dry. Silkspan will stay not fully sealed after such minimal doping and will allow the hot air to permeate into the wing when the Doculam is ironed on top of it.

I will run tests to see how this works but, again, my main concern are air bubbles that can appear and be trapped between Doculam and the margin (perimeter) of Silkspan used to cover the open cells only.

Best Regards,
M



 

 

I know someone painted the film on the sticky side.
I don't think you will need anything else under the Doculam.
Here is how. Just put the smallest amount of paint possible.

https://www.rcgroups.com/forums/showpost.php?p=32194155&postcount=774