New tail material...

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crash_out
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New tail material...

Post by crash_out »

I've never been happy with coroplast for anything, and my two latest planes both have warped tails that simply will not stay straight, so I've been looking at other options. I played with fanfold foam, but was not happy with it's stiffness, and though depron would be stiffer, it's more expensive and pretty hard to find where I live.

I've used "sturdy board" from WM before-it's about a 6mm thick foam sandwiched between 2 peices of what is basically posterboard. The foam itself is pretty flimsy, but the paper sheathing makes it alot stronger.

At the local Hobby Lobby, I found similar stuff, but the foam center is only about 3-4mm thick. It seems a but stiffer than the thick stuff at WM, and many times stiffer than fan fold. I don't think it would require any additional stiffening for use as tail or aileron stock.

The peice I got was $1.99, and was about 2'x3'. They have a peice that seems to be about 4'x3' for twice the price.

I'm going to build a model with it to see how it performs. If it works out, it'll keep me from having to order coro online and scrounge road signs and repaint them. It should also be lighter than coro. I'll weigh tails made from each material and give the lowdown on that. Hopefully so, since all my planes have come up hopelessly tail heavy...

This should be ideal for 3696 birds, and might work on 2548 E-planes as well. Obviously, being made of foam and paper, it's not going to work well with fuelie planes...
crash_out
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Post by crash_out »

I weighed the sturdt board, and a 20x30 peice of it weighs 9.3 ounces. In comparison, a peice of 4mm coro the same size weighs around 10.2. That's not the weight savings I'd hoped for, but at least it's not heavier. I guess every little bit helps. I suppose in a tail group one could subtract the weight of a bamboo skewer that you probably wouldn't need, but add the weight of whatever system you used to hinge the elevator(tape). One could cut some lightening holes in it to further reduce the weight, then cover them with tape or iron on covering.

So while this is a viable replacement, it seems it's more of a convenience than anything, since it's readily available at most department stores whereas coroplast is typically an order item.
crash_out
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Post by crash_out »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by crash_out</i>
<br />I weighed the sturdy board, and a 20x30 peice of it weighs 9.3 ounces. In comparison, a peice of 4mm coro the same size weighs around 10.2. That's not the weight savings I'd hoped for, but at least it's not heavier. I guess every little bit helps. I suppose in a tail group one could subtract the weight of a bamboo skewer that you probably wouldn't need, but add the weight of whatever system you used to hinge the elevator(tape). One could cut some lightening holes in it to further reduce the weight, then cover them with tape or iron on covering.

So while this is a viable replacement, it seems it's more of a convenience than anything, since it's readily available at most department stores whereas coroplast is typically an order item.
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
THend
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Post by THend »

The weight delta may seem small measured on a scale. However, you should keep in mind the impact the moment arm has on the effect of that weight. If you have .5 oz located 15 inches behind the cg that effective weight is 7.5 oz on the moment. Basically, the small weight is compounded due to the distance from the cg.

I know you know this, we all do, but we tend to sell short the impact of a little weight located far off the cg. We just think that it is not much weight and keep on building.

The big advantage with coro is that it is so dang tough! One other option is to cut your tail feathers out of balsa, and then vacuum bag them. They'd be real light, strong, and straight.

I know guys that use 2 mil coro on the electric stuff, but it too will warp at times. I imagine it is lighter.
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