Hello,

I have a wing which I would like to remove the dihedral and make into a flat wing, it is from a GP trainer 60,
it is constructed by joining the 2 halves with a wedge block
which provides the angle and glassing the centre.

Any suggestions as to the best way to do this ?

Thanks,

L

Well, I wouldn't take ALL of the dihedrahl out of the wing. You probably won't like the way it flies if you do. A little dihedrahl is good for a high wing trainer.

But if you want to do it, you will need some hard plywood. I don't know if this is a KIT or an ARF. If it's a kit, just build it per plans and then cut a new dihedrahl brace from the hard plywood with the angle that you want.

Or you could get another hardwood block- maple or oak- and cut it to the angle that you need.

Sounds to me like this is one of those wings that has a pocket which the dihedrahl block slides into. If it is, then just buy the hardwood block and cut it to the angle you want. Make sure you use SLOW CURE epoxy (30min) on the joint and put a LOT of epoxy in it when you glue it together. The epoxy should be running out of the joint when you push the block into the pocket. Coat the block with epoxy before you slide it in, and fill the pocket with PLENTY of epoxy. Spread epoxy on the two ribs also.

It's handy to have a bottle of rubbing alchohol around and a few of those red shop towels when your doing this. Get one of those shop towels soaking wet with alchohol and use it to wipe off the excess epoxy when it squirts out.

I can't stress it enough---you MUST have the pocket and block completely covered with epoxy and it should be squirting out when you slide the two wing halves together.

So what if you waste $3.00 worth of epoxy and spend $5.00 on alchohol and shop towels.

How sad are you gonna be if you crash your plane because the wing joint failed due to not having enough epoxy on the joint?

I have seen MANY MANY planes crash because of wing joint faliure at the center joint. Most of the time it is because the modeler didn't use enough epoxy.

If your changing the dihedrahl to get the plane to perform better, you might want to take this into consideration-----If your tired of trainers, and want a high performance plane----then buy a higher performance plane and leave the trainer in the shop.

But, have fun and do what makes you and your wallet happy.

Lenn,

If this is the old design with the symmetrical wing, I have been through it. I took all the dihedral out and took out a rib bay from each side (reducing the span by about 6"). The results were fantastic! It was a great and willing flier and landings were much easier. The higher wing loading kept it from ballooning on approach.

I do think that a small amount of dihedral would be recommended. Not for flight characteristics so much as for appearance. With zero dihedral, my wing looked like it was sagging. A 1/4 to 1/2" on one wing tip should be fine. I also added a dihedral brace to mine. It was a lot of work, but the added strength was a great comfort. Like RC said, these designs can separate wing halves and the resulting flight capability of the aircraft is dismal. Oh it will fly ... like a lawn dart! You will have to remove the center sheeting behind the spars and cut a slot through the center rib sections so that you can insert the dihedral brace (3/32" A/C ply would be fine).

This was one of the most fun aircraft I have had. Good luck!

Bedford

yes, its the old fully symmetrical wing.

Its is an excellent plane but is really limited by the dihedral somewhat.

Sand it off, add some 1/8th ply each side, and trim the covering off, Now glas about the width of the fuz and a little extra, usde firbreglass or carbon fibre sheet.

My suggestion but it mya a bit dodgy. Alternativly, add thicker ply first then sand down later. I think adding the sanding later then joining is better.

You could chop saw it in half then chop saw a half inch from each side at 90 degrees. Then build new wing ribs for the ends. Make some type of joiner and recover. This is untested but sounds like it might work. I'd use a finish blade also.