- This topic has 15 replies, 6 voices, and was last updated 14 years, 7 months ago by
Tim Thomas.
Tim Thomas.-
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djsroc
Does anyone know the weight per sq. ft? Im looking at around 1/2″ thickness and the fiberglassed stuff.
This will be for my upscale contest rocket. I need to keep the weight down as much as I can so I dont end up having to fly on a M or bigger.
This is a very complicated 7.5x upscale that I plan on flying on the largest L while still being L2.Of course cost may make me change my entry if I have to fly on an M
or the nomex gets out of hand.Thanks
Warren B. Musselman
I’ve worked with the stuff and plan on an M-powered bird that will fly with 1/8″ Nomex honeycomb fin cores. Unfortunately I don’t have a weight for you. I plan on putting beveled G10 strips for leading and trailing edges and adding a full layer of 5.6oz standard weave carbon on each side to the basic cores before mounting them on the airframe and then 1/3, 2/3, and full size tip to tip layers across the airframe.
I haven’t seen 1/2″ honeycomb material – I’ve just used the 1/8″, 1/4″ and 3/8″ material Giant Leap sells. My L2 bird has fins made from the 1/8″ material.
djsroc
Unfortunately to make the upscale I will have to go around 1/2″ to keep everything in scale. I may just use the thinner stuff and possibly loose points to keep this as light as possible.
Nothing is set in stone yet, I do have 3 other upscale ideas if this one gets out of hand.
edward
How large of pieces do you need. I have some different assorted thickness of carbon fiber aluminum honeycomb.
Edward
Ed Dawson
I have some of the 1/2″ and some 3/8″ in the shop. These are the ones that Giant Leap sells.
I can go out and weigh them to be exact, but don’t worry too much about the weights. The 1/2″ is almost the same weight as the other dimensions. It’s all pretty light stuff.
djsroc
Im thinkin of a sheet around 4’x6′ should do.
Right now im just throwin around ideas so at this point I dont need any just yet but thanks for lookin. When I get the actual plans scaled up Ill know more of total size.edward
A 4′ x 6′ sheet of what I have would probably be on the extreme high end of the price range 🙂
Edward
Doug Gerrard
I found a 1/4″ piece 24″ X 48″ online for $160. A little more for balsa core. I didn’t see 1/2″ thick but that is where I bought mine from.
Doug
Warren B. Musselman
Balsa end-grain is almost as light and considerably stronger from my understanding.
Another option to consider is foam-core fins. I built a fin can for someone a couple years ago made up of a skeleton-frame of foam-core board (cheap) with 2-part foam filling the spaces in the skeleton. The root edge and leading and trailing edges were done with basswood. The whole fin was skinned with carbon and glass and survived an L boost without a problem.
Very light and very stiff once the carbon was applied and far, far cheaper for materials cost than Nomex honeycomb. They definitely took more labor, but I’ve been thinking about doing this sort of thing again for a scale Nike-Smoke project I have in mind if I ever get around to moving on from my current fixation with MD altitude birds.
One final thought – in general, the thicker you make a stressed-skin construct like a foam or Nomex-core fin, the stronger and stiffer it is. Making a fin blank from a couple layers of foam-core may very well be stronger than plywood.
Ed Dawson
I finally went out to the shop and weighed the honeycomb I have in the fin material stash. I have a 1′ x 3′ piece of both 3/8″ and 1/2″.
3/8″ weighs 703g.
1/2″ weighs 475g.Yes, that is correct – the 1/2″ is lighter.
djsroc
Warren B. Musselman
edward
Ed Dawson
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