bullseye000

Hey all

I have some plans for some smaller size (.049-.10) models I'd like to build to experiment with electric gear. All of them are calling for 1/64" ply doublers for the fuse. I need quite a bit of it and it is ungodly expensive to be experimenting with. Any ideas for a reasonable substitute? One suggestion was using poster board, anyone tried this? Another was jumping to 1/32" ply. Is this a big weight difference? It's strategically placed in front for strength but would it add too much weight?

Dsegal

Just use some thicker balsa sheet as a doubler instead.

fritzke

My Feedback: (1)

I might try kraft paper or tyvek, both are dirt cheap. Adhere with
77 spray or epoxy, which might add stiffness. Either would add a
great deal of strength to sheet balsa, but not much more rigidity. Poster board is
pretty heavy. I might also try harder 1/32 balsa, glued on at
an angle or perpendicular to the other sheet. It would be pretty strong.
I'd use that on up to a .15 power gas plane on 3/32" fuselage sides.
1/32 ply on an electric 1/2a plane seems like a bunch of overkill.
Dave

kdc

1/64 ply is great stuff and sure to be useful in future too. However you could try veneer ( obeche or hardwood as used in furniture ) for a fus doubler as used in some models. Alternatively use 1/32 lite ply just in the crucial places....landing gear area & wing seat etc.
The main reason for ply doublers is if you have a crash the ply holds the model fairly intact instead of splintering to nothing. Makes repair easier.

bullseye000

Thanks guys

I think the thicker balsa will work fine with some ply in strategic areas. I think the ply covering almost the whole side of the fuse is overkill in a model this size.

jvigani

Ditto on Dsegal's recommendation. I have generally stopped using ply doublers on the fuse of my electrics and now use balsa. Electrics run with minimal vibration and the balsa doublers have worked just fine even on my larger 40 size electrics. If your still concerned, put some thin (0.5 oz) glass cloth between the balsa laminations.

BMatthews

Likey you don't even need doublers with electric as long as you don't plan on planting it. ESPECIALLY full length ones.

JeffH

My Feedback: (43)

Balsa doublers run with the grain 90 degrees to the fuse grain would be the best. The only thing the doubler is really doing is keeping the balsa from splitting down the grain in the event of a wingtip landing. The bolt block will try to twist out and the grain will split. If rigidity is needed, add a few square balsa stringers from former to former, or even from rear wing former to the firewall will had great bending resistance and minimal weight. I have found that over time, the 1/64 ply will eventually delaminate from the oils in the ply I guess. I have used everything from titebond to ca to epoxy and even cleaned the wood with acetone and still it is easy to peel the ply off the balsa after a few years.

bullseye000

That's what I wanted to know guys. I've been getting into smaller planes this year and am enjoying the convenience that comes with them. I have a couple that I'd like to try and am collecting stuff so I can build them when the weather changes. Thanks for all the replies.