Im thinking about just adding ribs on top of a flat dallor tree foam board to prevent the wristing ( rather than just adding KF)..Use newspaper. postcard paper or whatever to skin the top so I can paint it. I have big sheets of drawing paper...it's slightly thinner than regular writing paper. There's so much stuff you can use if you dont have to worry about NITRO...I been collecting clear plastic (#2 plastic) from cakes...A couple more cakes..I'll have enough plastic to skin a 40' wing..lmao I'll have to experiment with full symmetrical ( fat rigs)...basically a foam board for the center,( sort of like KF4) So it'll have to make ribs for top and bottom. If it works...Im going to cut lighting holes in the center board..starting from the outter bays. For a 30 " - 40" 3d park fliers..it should be okay. Not going to burn holes in the sky...Just make the model twist and turn in a tight space. I need to make it 550 grams or less for a 36" 3D type models. it's recommended in the plans..Sort of like that grass hopper.lmao. That particular model has a flat bottom air foil ...basically I want to make something like the something extra scale down.lmao...They just have different air foils...that's all...Air frame, wing span..ect are all pretty much the same...just cosmetic If it works...I'll just use packing tape to skin it...Just put strips of postcard paper on top of the ribs..so the tape will have a smoother surface to stick to. hmmmm....maybe use heffy trash bags to skin it.lmao

Great tip! Thanks 😎

Jeff McFadden I would think not. It expands and shrinks with the slightest temperature variation.

It really depends on the size. Smaller wings will more than likely weight the same. What you can expect is that you will have a more efficient airfoil over FT designs and use of this technique will lend itself in building balsa airplanes too. Paper on DTFB is heavy. This allows you to use foam without the paper and make a more scale airplane that will fly better than use of FT build techniques.

I know it's kinda off topic but does anyone know a good place to stream newly released tv shows online ?

@Fletcher Nicolas flixportal =)

@Lucian Kendrick Thanks, I signed up and it seems to work :) Appreciate it !

@Fletcher Nicolas Glad I could help :D

Sure! I've done this with numerous types of foils, semi and fully symmetrical. Undercambered would work well too though it may be more tricky to cover. For quick and dirty panels to try, you could simply how wire a foam core using templates and then spend the time on a built up wing like this. Lots of fun ways o approach it.

@@JoshuaOrchard Thank you - I'll be giving it a try!

Not really strengthen, but it will make the wing more rigid.

BennyCFD Yes, hand cut. Its far easier to cut foam over balsa. If you remove any film or paper than it is even easier. Yes, carbon would be good but depending on your application balsa or foam spars with shear webbing will be sufficient.

In this video, they were simply cut by hand. The new video I did cut them with a wire cutter but it's a bit different overall from this approach. The covering I used in this video did not shrink all that much because it is doculam... a document lamination film. Ultracoat or Monokote will indeed shrink more and tighten up more.

"I wonder if a thin strip of balsa, over the edges, to allow the use of other films. The weight penalty verses ease of other films ???" Balso is pretty light, and thin strips would be especially light. Other materials for covering (like tissue) would be much lighter than the office stuff (I think). It's a good idea (with the balsa edges) composite construction, but a lot of fucking around, that's all.

Justwantahover Yes, tissue would be lighter. But not as strong. The film does act like a stiffener (torsionally). You sure could do balsa cap strips to use other films that use a higher temp. I would reserve this for much larger wings though. The balsa would greatly contribute to increased weigh with wood AND glue. The added strength would be great. The idea is not to make a wing that is overly strong. Just strong enough to get the job done. Obviously I'm not a proponent of over building models.

Ailerons can be attached with any hinge material. You can insert a small piece of balsa on the inside of the wing if you have fears of it pulling free. I personally love to use old floppy disk material. Sand it a litte and any glue will hold it and it flexes nice too.

Sure is! My SE5a uses this construction method and it works well. See that video on my channel. You can add strength by adding sheeting (foam or balsa) to the leading edge or add carbon fiber within the foam spar. Even thin ply would go a long way here.

This was just a demonstration section. You can use any airfoil you chose. In this example, I traced an airfoil from a balsa kit that I had completed.

It absolutely can be glassed. You have to be strategic about what cloth you use and where you use what weight of cloth. I frequently use 0.75oz cloth and waterbased polyurethane (WBPU) as a surface finish that is more paintable and gives a very smooth finish. Epoxy will give strength at more of a weight penalty. Perhaps I should do a video on my glassing techniques.

@@JoshuaOrchard DEFINITELY!!! 😁

Yes I have painted it before and it did not peal or flake. I used Rustoleum Spray enamel.

You could use it to shrink it but it depends on the covering. In this case, doculam does not shrink all that much. Other coverings can be more forgiving but usually require a hotter iron... something that will melt the foam too.

It can be! The advantage is that its cheaper, faster, and sometimes lighter to build. If you mess up you really do not care because of the cost and time invested is not significant. You can cut out one rib in less than a minute whereas with balsa it takes several minutes to cut and sand to proper shape. You sheet of balsa will be about $5 for a 24x4" sheet where with this foam you can go to a dollar store and pick up a 20x30" sheet for a dollar. You can use that same foam for sheeting the wing as well. Its just a very versatile build medium. Thank you for having a look!

Joshua Orchard Eh I envy you the dollar store sheet ;) all I can get where I am from is depron and maybe some EPP etc...

I think weight is dependent on your design. Balsa is better if your worried about a nice plane. But for experimental planes this is the better route for cost reasons. Foam Board does a good job either way.

The foam wing would be lighter (a lot lighter) than the balsa wing even if you made the ribs thicker. I would NOT use foam spars, though, not even if this were for indoor rubber. While foam ribs would probably be OK for electric I would NOT do this for a glow powered model, it'd fall apart pretty quickly because foam has little compression strength. If you want to use foam for a glow powered plane you'd have to go with sheeted wire-cut foam cores rather than foam ribs (this is usually heavier than a similar sized balsa framework wing but is very strong and stiff).

@@chemistt DTF is actually a depron, but covered with paper.

Depends on the airfoil you want. You can readily use an online airfoil generator but if you are trying to design a whole panel you are looking at purchasing profili or compufoil.

just want to make simple wings for now,just like u did in ur video but a bit longer...

felipe j. Garzon flitetest.com/articles/how-to-make-inexpensive-hot-wire-templates See the links to the airfoil generators linked in that article. They will generate basic NACA 5 and 4 digit series airfoils.

My experience with covering films on foam at this point tells me that you really can use any of them but they are far more sensitive to temperature fluctuations. Do a test patch on some crap foam before you apply to the model and you'll be just fine.

Spars or Ribs? Rib spacing, I think, was 1.5-2 inches. The spar was a single piece and webbing inserted between ribs along the spar.

Kinda tho

Not very much!

You think around 30-40 grams? Lighter? Heavier?

Probably heavier if you consider reinforcements to keep the wings from folding. Any covering will add weight as well.

I was wondering because I build wings from very thin A grain balsa and tissue covering and can get 1 meter wings as light as 28 grams, and I thought that maybe by some miracle this method could be lighter than mine. Super lightweight techniques interest me because I am always trying to make the slowest flying aircraft that I can....and cause my flying field is small, so if I like keeping my planes around they'd better be slow...

I do not have the time right now to do a video of it but perhaps in the future. I'm currently building a plane with this design so maybe after that. Basically you want to enlarge the leading edge to create a lip for the skin foam to butt up against. Apply glue to the ribs and tape the sheet in place that will be the skin. You may have to remove a portion of the ribs to account for the skin thickness. It will add a lot of rigidity and strength.

FYI for you and others that have asked, see the following build log for sheeting with foam. forum.flitetest.com/showthread.php?11337-FFVS-J-22-Scratchbuild

It is but I recommend that you prep the surface by roughing the surface with some fine steel wool.

@@JoshuaOrchard thanks for your reply!

Absolutely! When cutting your airfoil out, you would need to factor in the thickness of the foam.

Joshua Orchard​ I was thinking of doing just what you have done, except for a 1/8 inch x 3/8 inch balsa spar directly above and below the foam spar, plus 1/8 inch balsa at the leading and trailing edges. Then use (4) slabs of 1/8 inch foam for sheeting between the balsa members so its all flush. The foam spar would really be part of the shear webbing in that case.

Joshua Orchard​ If your wing needed to be tapered you could hotwire a much shorter version of the wing in the conventional way, but then cut it into slabs to use for your ribs.

Yes, this is good thinking. Really all that we are looking at here is using foam as a different medium in balsa construction technique. It is easier to cut, less expensive, and has potential for very light aircraft without sacrificing too much strength.

LOL, not at all. This recording was done in my garage with the main door open on a rainy day. What you are hearing is cars driving by in the rain.

In this case I used Doculam. It is a film material designed for laminating documents at a low heat setting. It is also thinner than the higher heat laminating material.

very thanks, i gonna build an p38L with this type of wing

It's likely the humidity in my area. Try wetting a cloth and wiping the paper down before trying to remove it.

Joshua Orchard I found an approach that works quite well: massive overkill. The wet rag didn’t produce much change, so I put a sheet in the shower, turned the water to full hot, and let it run for few minutes. That made it easier to peel the paper away. Having achieved some success, I applied More’s law: “If a little’s good, More’s better, and too much is just right”. I put a sheet in the shower and flooded it, adding a second sheet trapping water between them. I let them soak, reapplying water. After about an hour the paper wrinkled, and peeled off in one piece. I was left with a bare sheet of clean foam, with no effort. The paper has a slick finish and it takes heat, time and water to dissolve the adhesive. I realize this is a long post, but I hope this will help others. Let’s be careful out there.

My SE5a used this exact method: kzfaq.info/get/bejne/mr18hKujkrnaYoU.html Build details here: kzfaq.info/get/bejne/nbl8dbaqt8CqqX0.html My built-up funder and lightning used it similarly but I sheeted the ribs with more foam: kzfaq.info/get/bejne/lbx-ar2cp9vcoXU.html

Yes but the strength gained is so small that it is worth losing in exchange for the exponentially decreased risk of terrible wing warpaing. Trust me, I've made the mistake of sticking tissue covering to the inner members of a balsa frame and shrinking it. That wing never flew...

@@AeroCraftAviation with covering film you just have to warp your wing in opposite direction and heat film again.

Yes, that’s true. But that has little do to with what I was saying. My point still stands.

Its the same thing just bigger

Agreed, however in this video I was using doculam, which has very minimal shrink. Low temp coverings would work better. You can get the idea from the video that you CAN cover it but yes, 1/16 balsa sheet would also work very well.