UHP Composite Wing

I finished the first UHP composite wing.

It is a Geo Bolt root and tip. However it is equal panel so it isn’t really a full blown GEO Bolt.

First I PVA the mold then spray in a VERY VERY thin coat of primer.

This takes about 30 minutes to an hour.

The lay up is 2oz glass pulled at 24hrs with proset epoxy.

That takes about an hour to cut the glass and get the peel ply and the vacuum bag setup.

Then the next day I remove the peel ply, it removes all the excess epoxy.

Then I mix up an oz of an epoxy and spread it into the now hardened glass. Then I lay in 1/8" thick Rohacell and another piece of 2 oz glass that I soaked with Epoxy on a piece of wax paper. Another piece of peel ply and back into the bag far another night of pressure.

That takes about hour.

The next evening the part is done. Pop it out of the mold and trim the edges off. Then back in the mold and sand flat with the mold. Set that aside and repeat.

Then lay the part in the foam cradle that the Male mold was made from and install the bell crank and the LO guide and the TW box.

Then test fit the two parts together. Test this several times and sand the edges to get a good fit. I used balsa 3/32 all the way around to create a wooden edge inside the wing to have a good surface to glue together. Once you like the fit go around the seem with Thin CA. Once it is glued it is done. Lightly sand the primer and pow you are ready for paint. This one was my first complete one. It took about two weeks to complete but the actual time was around ten total hours from start to primered completed wing. I had to stop in there for a few days and pass a kidney stone and have a back spasm at the same time. OUCH!

Now I am not going to lie to you. What you are looking at is not the lightest part. The first half I made weighed 9 oz. The second weighed 6oz and the total for the wing as you see it is 16 oz. I think I can still get about 4 more oz out of it. I am learning more and more about how to properly spread and use the proper amounts of epoxy.

I will keep you posted on how it goes.

Could you elaborate more? What is UHP?

Ultra Hobby Products helped by putting up some of the cost for this project. Even though it isnt that much. Getting stared can be a bit pricey but you can build 100 wings with the amount of Epoxy we have and about 50 with the glass they bought.

?#1 What does the term "GEO Bolt" wing mean. I am familiar with the GEO XL by B.Werwage; is it a derative of that wing design. Where does the "BOLT" part come from..
?#2 Do you intend to market the wings at some point..

LAST EDITED ON Jul-25-04 AT 08:57 AM (CDT)
 
I think it means the same wing that's in Bill's P47 (GEO Max-Thunder BOLT)

Hi Spark,
You're right, but it is just the P-47 wing used in the plane he just won the World's with and is a very different airfoil. The "Geo" was simply referring to the rib lay out. The Geo Max/Geo XL wing was a slightly modified USA-1 wing.
Great job on the geo wing plane (SV-22?) you are builing!
Bill <><

Nice work, Doug, thanks for the report.

I'm thinking that eventually some sort of molded CF spar, inside two (lightweight) fiberglass half shells may yield the lighter epoxy composite wing (at a reasonable cost) being sought. A molded CF spar could be made with the control and gear "ports" cast into it. Similar ideas for a molded TE spar, again you could have hinge slots already built in. Fairly thin fiberglass shells work well as wing tips.

I have no doubt that your effort yields a magnificent wing - straight, incredibly strong, and smoothly finished. It may be stronger than it needs to be, implying that you could reduce its structure a bit.

Good luck, keep us informed.

Please get this technology perfected and then hand it to us, OK? Heheheh.

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"That which seems the height of absurdity in one generation often becomes the height of wisdom in the next." -John Stuart Mill

Larrys idea of the carbon spar and moulded shells is exactly how alot of the R/C heli rotor blades are made.Very strong and light even thought they end up with the leading edge of the tip full of lead.

Larry,

I have been told by a few guys that the spar idea is the way to go. However the wing you are looking at needs no spar beleive me. This thing is super strong.

I know the spar will help with the loads under flight conditions for sure and it is something I am going to try.

However I dont know how to glue it in. I know that sounds dumb but this is a top half bottom half type of deal. You cant get to the spar on one of the sides in order to get any glue on it. So you just drop on a bunch and hope it grabs???? I dont think so.

In order for composite to be strong it has to have a binder between the layers right? You know like carbon over honeycomb backed by carbon is stronger than just two layers of Carbon. So I am using Rohacel. It is a foam like substance that will form to the mold pretty easy without breaking like Styrofoam would. IT is pretty cool stuff and makes more of a shell instead of a skin. I use alot of the very same techniques Windy used on MAII. I looked around some at other ways of doing it but the weights just seemed to high. Or their structures have many glue joints. The more joints the weaker the structure.(please dont take that like I know what I am talking about, or like I am saying they dont know what they are doing, just making observations about what I think would and wouldnt work for CLPA use) RC guy told me not to long ago alwasy try for the least amount of seams as possible. He is a professional model builder. He builds proto type models for Bell Heli. He has a mill that will cut wood into 3d objects. He can cut a fuse buck in a couple hours. You could load in your whole fuse rudder and all and it would spit it out in wood. Too Cool! He says the less seams the better.

I really wish I knew how the Russians and Kaz did their stuff. I have seen the finished products, but I would like to see the photos and an write up on how they do it.

I have made a couple of skins but they are all way to flimsy. By the time you reinforce them you could have just backed them with a Rohacell or another type of layer material and just built it hollow.

Those of you with Spar ideas bring them on. I want to know how I would install them and make sure they glue up to both halves. Remember this is a top and bottom type of structure.

Alos tell me more about how to make skins more usable ones. 2.9 oz carbon at 99$ yard is not that usable for most modelers including me.

I am all ears.

Another note, in the wing tips I use a layer of 5oz carbon where the Rohacell would be. Rohacel doesnt go around curves like a wingtip to well so I use carbon in its place. So the tip is 2oz glass, 5oz carbon, and 2oz glass. Man that is a tough tip.

Doug,

I have seen somewhere - was it on this forum? - a photo of a wing constructed with a molded spar assembly and a tip rib (?? I think). The wing shell was glued together and simply slid over that framework. I think the tip rib (attached to the spar assembly) got glued to the shell. There was no need to have glue inside the wing shell, since it fit the spar framework snugly.

(Post cure gluing for epoxy composites is difficult enough - Windy has some expensive special glue to do it..)

However, I suspect that one could drill a few small holes (say on the bottom) on the spar line where glue could be injected, and these could be finished over.

I started to make a joke here about just threading the spar and putting in some small flathead flush mounted screws to secure the wing shell to the spar. Then I realized that might not be too bad an idea either!

Good luck on this enterprise!

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"No one will ever win the battle of the sexes; there's too much fraternizing with the enemy." -Henry Kissinger

>I have seen somewhere - was it on this forum? - a photo of a
>wing constructed with a molded spar assembly and a tip rib
>(?? I think). The wing shell was glued together and simply
>slid over that framework. I think the tip rib (attached to
>the spar assembly) got glued to the shell. There was no need
>to have glue inside the wing shell, since it fit the spar
>framework snugly.

Yeah, that was F4FGuy's wing. It's on this forum somewhere.

I think Kaz Minato uses honeycomb between the layers of the shell. You can see the hexagonal pattern if you look closely at the wing.

>>I have seen somewhere - was it on this forum? - a photo of a
>>wing constructed with a molded spar assembly and a tip rib
>>(?? I think). The wing shell was glued together and simply
>>slid over that framework. I think the tip rib (attached to
>>the spar assembly) got glued to the shell. There was no need
>>to have glue inside the wing shell, since it fit the spar
>>framework snugly.
>
>Yeah, that was F4FGuy's wing. It's on this forum somewhere.
>
>I think Kaz Minato uses honeycomb between the layers of the
>shell. You can see the hexagonal pattern if you look closely
>at the wing.

Ron B.
F4Fguy

Yeah,that was mine.It is .5 carbon/1/20"6# balsa/.5 carbon,bonded with WEST Systems Epoxy.Its molded in one piece from the bottom trailing edge,around the leading edge,and back to the trailing edge.The spar assembly is molded of carbon/balsa/carbon it also carries four ribs for torsional stiffness,the gear mounts and the trailing edge and flap leading edge spars.The spar assembly is installed by springing the molded skin open at the trailing edge and inserting the pre glued assembly in place,then rebagging it in the original cradles.The whole assembly,with flaps,landing gear with 3- 1/4" wheels,controls ,leadouts and slider,tip weight box and tipweight,tips,finished painted and ready to install(it's a takeapart),weighs 19 oz.The area is 735 sq.in.,root chord(inc.flaps)13",tip chord 8"

I destructively tested a thinner version(1/32" core)to 50#concentrated load at the AC with supports at the root and tip ribs.No catastrophic failure occurred,only minor skin crippling on the compression side near the load point.

I used mat instead of cloth for several reasons:
(1)I couldn't find any carbon woven material anywhere near the desired weight,and even the lightest stuff I could find was prohibitively expensive.
(2)Woven cloth of any kind requires more weight than random laid mat to get stiffness in all directions.
(3)working with lighter mat gave the opportunity to "tailor" the thickness to the load requirement.Although I found this was not necessary I've since done wings of this size with .3oz.mat using a much different technique.
The down side is that mat is more "brittle" than cloth.I've addressed that by using a layer of .2oz.Kevlar in strategic places vulnerable to "dings".

LAST EDITED ON Jul-26-04 AT 06:50 AM (CDT)
 
Hi Doug:

You might look at Kevlar fabric. It is nearly as strong as carbon but less expensive and less brittle--so a thin skin is less likely to be punctured. (and lighter than glass) It works well with epoxy--just dont try to sand it--like at the edges. it needs to be cut.

Kevlar will destroy a cutting edge almost immediately. I used to do aircraft composite work for a while.

"SAVE ALL THE PIECES"-Phil Brown

>Now I am not going to lie to you. What you are looking at
>is not the lightest part. The first half I made weighed 9
>oz. The second weighed 6oz and the total for the wing as you
>see it is 16 oz. I think I can still get about 4 more oz
>out of it. I am learning more and more about how to
>properly spread and use the proper amounts of epoxy.

Awesome Doug.

You did it!!!

Where's mine?

Yeh, Doug, where's ALL OURS?!

And FLAPS. We need FLAPS!

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"If wrinkles must be written upon our brows, let them not be written upon the heart. The spirit should not grow old." -James A. Garfield

Doug,
Autocad 2000 sketch sent by e-mail.

>Doug,
>Autocad 2000 sketch sent by e-mail.

Where did you send this?

I didnt get anything.

Sent to [email protected]
is this correct?

>>Doug,
>>Autocad 2000 sketch sent by e-mail.
>
>Where did you send this?
>
>I didnt get anything.

Yeah that is right but Inever got anything.

Try,

[email protected]

Thanks

Yep Brad we got it built.

Now Tom Farmer better watch out. Because Steve and I are going to build one Heck of a Big a-s-s Profile of the Super Furias and see how it flys.

Larry

About the flaps. I am thinking about flaps with TE edge reinforced with carbon rods. I have also found that leaving the flaps flat and not tappering the down yeilds a much better flap. I want to reinforce the TE because that is where the flap washes out during flight. I have seen people reinforcing the LE but why? I mean that is where it is hinged to the plane and there is plenty of support to keep it from flexing. Why would people reinforce the LE?

Hi Doug good work,You would have loved speaking to the yesenko brothers, they have a composite plane with the body of molded balsa with 1/64 ply doublers. wings made of a synthetic balsa(could not get more info on product) Molded balsa stab and elevator. I have 6 composite airplanes flying in the NY area. My latest method involves the use of 1/32 balsa skins vacumed in female molds. the weight are 12oz.with out controls. ( procedure .75 glass cloth 1/32 balsa 1/16 foam and .75 glas.) I have over 400 photos cant figure out how to reduce in order to post. PS thanks windy for the development work and leading the way.

Jose,

Sounds Awesome!

YES BIG THANK TO WINDY FOR SHOWING THE FEMALE MOLD IDEA ON TAPE!

I followed his female mold making steps I just used cheaper gel coat stuff.

You have some at 12 without controls. That is very good!

Are they primerd out of the mold?

Are they top and bottom halves meaning just two pieces? Or are they more than that? Please describe.

My last layup gave me a 6 oz complete side with primer on it! That is the number. I get there consistantly and it is ON! I flew a composite plane MA II and I dont know about you but it seemed to be MUCH MUCH MUCH more consistant everywhere. I got the same repsonse at every turn.

Yu have to get your PICs on here.

Open up Microsoft Photo editor. The put your size at 100% It will probably be off the screen at that point. Then go to "resize" the photo. Scale it down to about 40% and then save the file. That will get it down to under 50kb for sure. Usually gets it about 20. That is how I do my pics. It is easy and fast. If it still doesnt work email one of your photos exactly as it is when you load it from your camera to the PC to the following address and I will see what is up.

[email protected]

PS I missed hanging out this year!

Try this free program.

http://www.irfanview.com

"SAVE ALL THE PIECES"-Phil Bown