LOONY BOY

Hi all,
I am making wings out of 6mm (1/4)balsa sheat for small span=750mm(30inch) wings. I want to make them as rigid as possible, currently I think they flex and twist too much at high speeds which is causing some concern. I think It changes the angle of attack under certain conditions.

What is the best way to get around this I have thought about using carbon tape but this will probably only work lengthways and not for twist which may be my problem.

Do you think that fiber glassing the wing with epoxy and a carbon spar would fix the problem or should I just scrap the balsa wing idea and learn to make bagged wings.

Thanks a bunch in advance.
LOONY BOY

MinnFlyer

My Feedback: (4)

1/4" is too thin for a 30 in wing. You'll need to build it thicker using ribs or foam inside.

CafeenMan

I agree with MinnFlyer. You're basically building a heavy, yet not rigid wing for sake of simplicity.

You might try making an X over (or under) the wing using carbon tape, but really the way to go is to build the wing. It will be lighter and stronger.

DMyer

My Feedback: (2)

I assume you used contest grade balsa and airfoiled the wing. I would glass the wing with .5 - .75 which will make it rigid enough for loads that a 30" wing could expect. What type of plane is this? I assume there was a reason for wanting a simple balsa sheet wing versus a built up or foam cored wing. best of luck.

probligo

Sounds like the wing off of one of my ffhlgs

I agree - what is it you are building? If you are going Phantom TR don't be shy, I can understand

Rahlberg13-delete

Try two layers of a light .5oz - 1.5oz figerglass cloth. Two thin layers over the whole thing will add an incredible amount of rigidity without much weight. You need the two layers to work with each other. One layer will work, but not near as well.

Russ

LOONY BOY

Thanks for the tips people.
As for the aircraft its a scratch build that i have designed to suit a modified HORNET AP .09 turning 6x6 at 22000rpm and the reasion I opted for a 1/4" wing is
1. for simplicity, this way if I stack it won't s#%t me as much. We all know whats its like to spend weeks on building and then throwing your hard work down the runway (don't get me wrong I love building but with this model it's just to bash around)
2. cost$$
3 . To keep drag down to a minimum.
4. weight, don't want to exceed 500 gramms (17.6oz), but CafeenMan said that its heavy so it's good to know that it can be made much lighter

The wing is profiled as a symmetrical wing and the body is just wide enough to hold a one ounce tank, elevator servo JR371, reciever JETY 5 ch, battery NiMh 300ma thats about it I think.There is no throttle so dead stick is the only way to land and man it don't like to glide.
I might be getting a digital cam this weekend so I will put up some pic's.
Thanks
LOONY BOY

LOONY BOY

Here is a pic of my motor and the tuned pipe that I made for it.
Its not that clear but I hope this changes soon and if you need some advice on spinning and silver soldering tuned pipes just ask.
LOONY BOY

yakman

How did you make the pipe? looks great.

yakman

I have found a way to make thin, strong wings quickly with a laminar type section . Very good for racer type planes.

First trace the shape of your wing on 1.5mm balsa.

For a 750mm span 8 ribs are needed and they are very basic, no spars, L.E. or T.E. needed. Use 3mm for ribs.

Make ribs about 3-4mm high(depends on chord) in the centre and taper both ends to nothing so they are symmetrical top to bottom and back to front. These should have a nice curve and be about 12-14mm shorter than the chord, so the sheeting can be glued together at the T.E. and L.E.

Then glue ribs onto the bottom sheet about 100mm apart and 6-7mm from L.E. and T.E. In the centre glue 3mm webbing in, just put the grain spanwise for simplicity.

Now glue the top sheet on being careful that you are not building a warp in the wing.

When it is dry, sand the T.E. round and taper the T.E. a little (not to much or you'll weaken it).

Ailerons can be cut out, facing the hinge lines with 3mm. The resulting wing is very strong and slippery.

good luck.

probligo

The Phantom T/R wing is now built with 1/16 birch ply core lightened with holes as appropriate (largish holes). with 3/32 balsa epoxied each side. It was originally designed with 1/4 hard balsa.

Then sand to symetrical section. (fine TE).

Takes a lot of abuse (talk to the C/L boys about team racing... )

LOONY BOY

Cool guys
probligo do you have any pic's of your wing, sounds good. Yakman that is a good idea I will have to try that method, as for the pipe it is spun on a lathe with the use of a mandrel of the desired internal shape then the metal (brass or aluminium) is forced down onto the mandrel using long hand held tools, every once and a while it is anealed so it will not crack or warp. The final result is a perfect shaped tube or cone and when all the parts of the pipe are made they are butted together and silver soldered.
Thanks again for the tips.
LOONY BOY

CafeenMan

So what you're saying is I can't make one with an X-Acto knife and CA?

LOONY BOY

Well not exactly but your post did give my an idea!, just say you were to make the internal shape of your pipe out of thin cardboard ( use your X-Acto knife and CA, just cut to size then roll and glue instead of using wax to make your internal mold) then coat with a release agent now wrap carbon fiber and resin around your model pipe, allow to set.
Now for removing cardboard maybe place in water to soften cardboard then pick it out with tweezers.
Just a quick idea, might not work but what the hell give it a go.

If you never ever go, you will never ever know.


LOONY BOY