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Old Nov 17, 2009, 10:07 AM
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Rubber band wing to bolt on

Is there a good 'how to' on converting a plane from a rubber band wing to a bolt on? The Solo Sport I was flying the other day's vertical stabilizer fell off, so while I'm repairing the other damage, I figured I'd make the switch. I guess I know how to do it, but i'm not sure how to ensure proper alignment

Thanks!
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Old Nov 17, 2009, 11:18 AM
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Its not very difficult at all. I will assume that your wing is sheeted in the area where you will be converting to bolts. If you do not have a solid TE then you will need to reinforce the wing where the bolt heads go.

Basically you need to decide if you just want to use 3 or 4 bolts to hole the wing on or 1 or two bolts and 1 or two pins. Study the design of the Sig 4 Star 40 or Great Planes Extra 300s for the second option, the construction manuals should be online and you should be able to adapt one of those methods to your plane.

Basically for each bolt location you will want to epoxy a hardwood block (for smaller planes balsa can work but drip thin CA into the hole after its tapped) to a sturdy part of the fuselage so that it will butt right up to the wing when the wing is installed. Pretty much any area on the wing saddle will be strong enough. You can glue in some shims if you get it wrong.

Then drill and tap that hole, if you use a balsa block you can use a nylon bolt to tap it, otherwise you will need a real tap.

Next sharpen the bolts to a point and put them backwards through the hole so that the point will poke the wing when you install the wing. Put the wing on the fuselage with all points sticking out and press the wing onto the points to mark your drill locations.

Drill holes in your marked locations and you are ready to go. Be sure the holes you drill in the blocks are in line with the holes you drill in the wing...

I'll draw up what I would do for your plane later tonight. Can you post a picture of the opening when the wing is off?
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Old Nov 17, 2009, 12:25 PM
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I could get a picture, but it wouldn't be until much later tonight. I think I might be able to figure it out with the info you gave me, but any extra advice is always welcome

It seems like doing 4 bolts would be easier, but then you'd have to do 4 every time you got to the field. I think i'll go for the dowel pin option
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Old Nov 17, 2009, 12:30 PM
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It looks like if you go the dowel pin option that you will need to mount the dowels on blocks below the wing because there is nothing to hold them in on the fuselage where it meets the LE.
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Old Nov 17, 2009, 01:26 PM
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You can also drill the wing first, or if you're brave just drill the wing and block at the same time. Just remember to use a smaller pilot drill because if you use the final wing-hole size you just screwed yourself and the block-mount hole is now too big.
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Old Nov 17, 2009, 04:57 PM
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Quote:
Originally Posted by spots25 View Post
I could get a picture, but it wouldn't be until much later tonight. I think I might be able to figure it out with the info you gave me, but any extra advice is always welcome

It seems like doing 4 bolts would be easier, but then you'd have to do 4 every time you got to the field. I think i'll go for the dowel pin option

I'm in the process of putting a bolt on option to a CG Eagle II Kit i was given... This plane I believe is similar to your solo sport in that the leading edge sits atop the fuse such that the leading edge is not in a place to have dowel coming straight out to meet into the fuse (aka 4 star). The 4 star (low wing) is the ideal setup.

While it's a bit more trouble to do, it can be done if you want to go the dowel in front, two nylon screws in back. I would reccommend one screw front and two in back all three running basically vertical. The angles needed only to allow the bolt heads to sit flush with the wing. This would be faster than what I'm doing.. and now that I read that in this thread.. I should have done that !!

Here is a thread on RCUniverse I'm writing and it just so happens I'm on the part where I'm installing the dowel. I have a bit to do on it but you'll get the idea. The third page begins to show the hardwood blocks and dowel installation. I'm going off the plans but changed what they suggested as I didn't see a good reason for the way wanted to do it. You will have some of the structure extending down into the cabin but I;m not really concerned about that. I hope to start glueing and bracing tonight. Good luck !!
http://www.rcuniverse.com/forum/m_91..._3/key_/tm.htm
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Old Nov 17, 2009, 05:24 PM
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What I did on my Solo was cut the top of the fuse off in front of the wing and made it into a hatch. Then I made a doubler out of 1/8 ply, two pieces of ply to make 1/4. Epoxy to front of the former that the leading edge of the wing butts against. now you can drill through the former into the wing for your dowel. the hole was low on the wing so that the bottom of the dowel was showing, I put two layers of 2.5 oz. cloth over it with epoxy and have been flying it for 3 years now and have not lost a wing. On the back I put oak blocks in the back corners to drill and tap 1/4 by 20. triangle blocks work well and give clearance for the aileron control rods. On the top of the wing I epoxyed a piece of 1/8 ply as wide as the fuse and twice as wide as the trailing edge, don't forget to remove covering and glue wood to wood. The new hatch is held on by magnets on the back and a lip on the front. The whole job can be done in one night, hope this helps.

Have Fun
Rick
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Old Nov 17, 2009, 11:00 PM
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I worked on it for a bit tonight, but I only got some repair ribs made. The trailing edge is made out of ply, so that'll work well for taking bolts. Where the leading edge of the wing contacts the body will need to be partially redone anyway, as that's the part that hit the bush the hardest. Say mayhew, I'd double check the attachment of your vertical stabilizer...
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Old Nov 18, 2009, 05:08 PM
I'm a pilot... 100 yrs to late
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USA, FL, Palm Harbor
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Quote:
Originally Posted by spots25 View Post
I worked on it for a bit tonight, but I only got some repair ribs made. The trailing edge is made out of ply, so that'll work well for taking bolts. Where the leading edge of the wing contacts the body will need to be partially redone anyway, as that's the part that hit the bush the hardest. Say mayhew, I'd double check the attachment of your vertical stabilizer...
Be sure you double check the idea about putting the bolts in the trailing edge.. even though it's ply?. Are you sure.. that is unusual.

Usually the bolts are going through some block just ahead of the triling edge spar. Allows for a stronger joint since there is more glue area. If your just going through the trailing edge, I would lay a thin piece of ply on top to tie together the trailing edge stock, the trailing edge spar and ribs. Just my opinion.
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Old Nov 18, 2009, 10:34 PM
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Thermalin is right you can't just bolt through the trailing edge, with the torqur rods there isn't much holding them on. The plywood I glued on the top of the wing covered the trailing edge and 1 1/5" over the top of the wing, then I drilled through.

Only had one crash in 5 years of flying this plane and that was a result of dumb thumbs not lost parts. Oh well I rebuilt it and it flys better than ever. Almost forgot, she's a tail dragger now love it!

I quess I should go put the skis on now, the damn snow came yesterday and looks like it might stay.

Rick
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