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Printed wing concept

Posted by Oliver on February 12, 2010 at 3:41pm

Hi guys,

here is a rendering of the printed wing I have been designing. My idea is to create a rapid prototype/carbon fibre composite material which I can use in UAV applications. The concept is to be able to print the RP parts directly from CAD data and then cover in carbon fibre pre-preg. The use of RP allows quick design changes and iterations without tooling. The RP is used in the same way a structural foam would be used.This concept is for a UAV around the 20kg weight size, I'm not sure it would be possible to make it light enough for smaller UAV applications.........

I am hoping to produce the physical parts in the next few days. Part of the callenge is to create a lightweight structure that will build easily on the RP machines and something which will skin up ok in CF. I may need to do a couple of iterations before it is acceptable.

I'll post some pictures of the finished parts as soon as I have them....

Happy flying!

Oliver

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Replies

tosicoliver60@gmail,com March 23, 2016 at 2:15pm

I have similar idea, and fill it with styrofoam. But if You intend to use it in drones those cuboids (I thinlk) will be to strong
Andrew Rabbitt July 1, 2012 at 5:53am

It looks like a nice idea until you analyse it closely. The honeycomb adds a lot of weight and stiffness for construction loads, but little benefit, in my opinion, for flying loads.

I have spent some time analysing construction methods for the wings of my HDwing glider concepts and so far nothing can beat a fully balsa skinned, balsa structure wing for weight and stiffness, unless you're trying for some impossibly ultra thin aerofoil. Even a CF skin on its own made unmanufacturably thin is still heavier than a fully structured built-up balsa-skinned wing in my application.

Larger structures may close the gap, but I'll bet balsa will always take some beatng

Adding die-pultruded wet carbon filament spar caps can add a a lot of CF-style stiffness for very low weight (and cost)
Sam Steeb June 27, 2012 at 6:39pm

For the honeycomb areas, it would be possible to use laser cut parts to come to very near the same design. Then you could choose from sheet foams like depron, styrene sheet, woods, balsa, lite ply... Could keep costs down and allow enough weight savings to allow other design changes, like sheeting under the skin.

It was mentioned above as well, what material does your RP use? Can it handle the curing temps and pressures?

Have you done any FEA with the core 45° off current?

When using prepreg is a high vaccum needed during cure?(I'm not a composites guy)
Nick June 5, 2010 at 11:27am

Just a thought: it looks as though your design is enclosed in a skin. Depending on the printing process you use, that could be a problem. If you use SLS or SLA, you're going to have powder/resin stuck in the cells when the product is finished. If you use fused deposition modeling, you won't have that issue. As well, if you print these off at sea level and fly them at higher altitudes, it is possible that the pressure inside the cells coupled with the small honeycomb wall thickness could drastically reduce its structural strength and make it brittle, especially if the wing is exposed to heavy temperature changes. If the cells are able to vent into each other and the interior is printed without the skin, these problems can be eliminated, though you will run into the issue with sagging that was mentioned before.
Gerry Lichter May 28, 2010 at 5:14pm

I think it would be cool if you could print it between centers on a lathe. CNC convert you lathe, add an extrude to the tool post, and belt drive the lathe dog.

Maybe a spool gun for aluminum welding could be modified to lay individual carbon fibers?
Troy Reabe April 27, 2010 at 11:42pm

First; great idea and I like the idea of printing out a wing The few things that I see as a problem I know the the FEA in solid works is giving you data that says that this should work but what base plastic are you using and what happens when you cure your wing in the oven under vacuum? The next area that I have had problems with myself with foam wings it to do a good job of covering the wing and not having marks from bagging on the surface of the wing. If you are using a straight cross section, or just a tappered wing you can use a mylar sheet with holes punched in it and with it streached out right you will get the surface you want. You can try different thicknesses to see what works best for you.
Also did you look at a 4 axis hot wire? you would be able to cut most wing shapes untill you start to go eliptical or something like that. I know at Madison we were able to have a few test cores cut for us and the place that did it normaly cut foam for chairs.

Small minor note looking at your model you would like to bond you spar to your skin. this will add some weard forces to your spar but if you are buying your spar it will most likely be stronger than your skin and haveing a good way to directly transfer the force from the skin to the spar would help. Or you could glue your spar in but that costs weight.
Ryan March 8, 2010 at 7:13pm

3 x heavier is OK for my application, especially since I don't have to use spar. I will want to test it with 2 x layers of 200gsm twilt weave carbon at 45 degree.

How thick are those honeycomb wall? Can you make them 3mm thick?

How big of a panel can you make?
Dedadz March 8, 2010 at 6:56pm

Oliver, beautiful job! Please keep us posted as you make progress. Tom
James F. March 8, 2010 at 2:39pm

I've seen this done with a surfboard before (you can look it up on popular science or online, just search for cardboard surfboard), the biggest problem they had was sinking inbetween the cells.
Ryan March 8, 2010 at 12:18pm

How is your project going?

I just found this thread and it looks really awesome. By the way, I dont think you will need a spar as those honeycomb pockets will be more than enough, especially if the skin is carbon.