Heavy, thick foamboard... ideas??

[Epitaph]

Last night whilst returning from the bus, I walked past a bin that had a piece of "foamboard" in it, but nothing like what you use over in the States. This piece was 70cm x 50cm and a full 1cm thick, the paper isn't actually paper but is more waxed, and the piece weighs in at 280g!! So this is heavy stuff, but it seems pretty tough to say the least. Considering the reduced amount to play with, are there any ideas for a small, "easy to fly in a reduced space" plane out of this? I was thinking some high wing profile invention... if I can make something out of this, then later on I can try and hunt down where it came from and make some designs without the limited amount issue (if the price is admissible, of course).

Ideas anyone?

 

[CrashRecovery]

Make a wing. Do a kf step

 

[Craftydan]

Obvious one is a nutball . . . but at that weight I'm not sure there's much fixed wing that will perform well at low speeds.

Does the paper peal? Think can the foam be shaped?

 

[RAM]

A boat!

 

[Epitaph]

The paper doesn't peel too well, the layers fo fiber the paper is made of rip apart... I'm not sure if it can be shaped with some heat. But even a small profile plane is going to be heavy with this.

 

[Craftydan]

Dang.

Heat shaping, is nice, but won't affect weight -- I was thinking more along a carving/sanding route . . . but if the paper won't leave quietly . . .

Have any cellophane or mylar? I know you've got covering material for your balsa constructions. You could use it to make a foamboard frame for a profile 3D airframe with lightening holes and voids, covered with the plastic . . . but at that point why not just use balsa?

 

[Epitaph]

Well, I don't have my balsa and other materials here as they are all in storage.

What about a profile FT scout or something along those lines but with ailerons?? Profile because of the limited amount of material. I think I'll rewatch that build episode to see about the size and stuff... as a profile plane, the wings would be heavier, but the fuselage would be lighter. I have a small 1804 2300kV motor here with no home to go to, as well as a few 5x3 props that are no longer any good for multirotors but fine for planes...

 

[jamboree1]

I don't think the size of that piece can do a meaningful build other than a mini, and being that heavy i don't see it working out that well, so i see 2 options, trash it and cut your losses, which is 0 or save the piece to use as reinforcement material for other builds

 

[TexasTeacher]

I have access to some that is 3' by 8' about 3/4" to 1" thick, will have to check the thickness. It is used for very large format trade show signs.

 

[Epitaph]

I calculated that I can make a plane with a total weight of 500g before I get to a wing load of 15oz/sq.in, which is a trainer wingload, with the size of wing I can make out of this... I might as well try something out, if it flies, good.. if not, well, hands on experience with materials is better than nothing.. if it doesn't fly, then I can make it holey and cover it in something...

Even a failure can be a success!!!

 

[Epitaph]

Well... I decided on trying out the FT scout, but with a 10% increase in size which raises its load bearing a lot, and also with a profile fuselage because I don't have enough material for anything more extravagant, not to mention the weight issue hehehe.

This build will take its time as I don't even have an ESC or servos for it, and they will take about a month to 6 weeks to come on the slow boat from China, so, what's the rush??

Also, I don't have a glue gun as it's not something I use in balsa builds, and this is a first step in foamboard. And rather than spending a small fortune on something I might not use much (because of how scarce FB is here), and instead of just getting a cheap one that won't do the job properly, I've opted for the 3rd option, being to use a slow curing epoxy that seems to work pretty well with this foamboard as I have tried it out before, and seeing as there is no rush, I can leave one piece all night curing.

So I've started by cutting out the wings, 670mm x 170mm, cutting them in half so I can do the dihedral easier (though it might be useful depending on how I do the fuselage), and cutting out the piece for the camber on the wing and gluing that into place... I've started on one side first. This foamboard doesn't work with just scoring it, it's just too hard, so I cut out a 2mm angle, leaving it connected by the backing on one side much like how the control beveling goes, and then just glue that into place with a couple of pieces under to keep the angle, and just put a few LiPos on top to hold it in place. Now comes leaving it for a few hours, and I might put a piece of tape on the cut and glued side in the end.



If that comes out any good, I'll file down the leading and trailing edges a bit to give it a rounded profile on the front and to thin out the back... one thing I was thinking of for the back was cutting through the foam on the trailing edge to separate the paper, then remove some of the foam inside, and restick it back together so it still has the paper on the top and bottom, but much thinner than the 1cm thickness this has... depends on how crazy I feel.

So I think I'll turn this into my build thread, and just go slowly, see how it all goes.

 

[Epitaph]

The epoxy dried enough to manipulate it, so I set the other wing up to dry whilst I played with the trailing edge of the dry one... first of all, cut a V out of the foamboard on the trailing edge, then pass through a nail file to clean it up.



Then I just mixed up a little epoxy, put it into the slot, and taped the top and bottom together. The tape is a little creased on the bottom where I had to stretch it but I think it's not too bad. I decided to just leave it as a straight edge rather than the batwing type trailing edge because that would just be a little too hard to do with the thinning out of the board.



I can't do the leading edge because I forgot to get a new sanding block, and I need some more white packing tape as I'm almost out... besides I'll probably do that once the 2 wing halfs are joined

 

[Epitaph]

Well, I have the basic wings done, just missing the leading edge really. I'll get some sanding blocks tomorrow for the leading edge and that'll be more or less done.

The fuselage, that's something I'm not sure how I'm going to do as this is going to be very different from the original. But just the wing alone is already 95.6g, although that said it does seem to catch the air well in flat freefall to slow its descent... we'll see how it goes.

 

[Epitaph]

Anyway, I rounded the leading edge off... just sit there in front of the TV with a fine sanding block...



The wing can now be left, and turn my attention to the fuselage, and I have NO IDEA what I'm going to o with that yet heheheh