Hi folks,

Well, for the record, I have spent the past hour or so going through dozens of Four-Star threads, but couldn't find the specific problem that I have, which is:

I have just finished buiding the wing halves, but I made a mistake and glued in the bottom sheeting on one of the wings so I no longer have access inside the wing to glue in the dihedral brace properly (note to self: read the instructions more carefully next time...)

The two options that I can think about are:

1) Remove the bottom sheeting - the problem is that I would probably change the shape of the ribs in the process of cutting away the sheeting from the ribs, and I am not sure how to fix that.
2) Cut a whole in the first rib (rib #1, the one with the 2% dihedral) to get access inside the wing. I would obviously glue the piece back in, but I would think this would weaken the wing joint.

I have limited building experience as you can tell, so I would appreciate any advice you may have.

Thanks.

I can look at the blue prints tomorrow and help you out, you aren't the first one that has done that. I just need to see what is there inside the center section, been A few weeks sense I worked on that plane.
Gene

I did something similar wit hmy 4* 40. I fitted the sheeting before gluing in the wing locating dowel.

What I did was to cut a 'hatch" in the sheeting inside the ribs of the inner wing bay (between the leading edge and the first balsa spar) - this then did not affect the ribs. I fixed in the wing dowl as per instructions, then repaired the sheeting by making two riblets with the same profile as the W1 ribs but just long enough to reach the first 1/4" balsa spar. I attached these to the inside face of the full W1 ribs and used them as a footing to secure the sheeting "hatch" again. Not a lot of effort and you canhardly see the repair.

I would join the wings at the proper dihedral angle and then wrap the wing center section with a six inch wide piece of 6 oz. fiberglass cloth. Then I would use epoxy glue as a binder and smooth it out as best I could. This is a wrap around job that glasses both the top and bottom of the center section of the wing. With this process, you don't need no steenking dihedral brace and you'll have a much stronger wing in the end, but only slightly heavier than the stock wing design.

I don't trust dihedral braces anyway. I lost my first low wing model, an AAMCO Trainermaster (1971), on its 13th flight when the dihedral brace failed during a split S. The model's wing was designed to be covered in silk and dope, which acts as fiberglassing in providing strength. I used Super Monokote and paid the price. I no longer trust dihedral braces alone.


Ed Cregger

All,

Thanks for the replies - I think both solutions would work. Quite frankly, I am thinking about possibly combining the two: make the hatch and glue in the dihedral brace, then use a thicker piece of fiberglass cloth as Ed suggested. Yeah it will be a little heavy, but the Saito .91 that is going on it should take care of that .

Did you did add glue to the brace before you put the wing together? and just want to add additional glue? If you glued it, it may be just fine. If not cut the balsa sheeting between the ribs add the glue then glue in some 1/4" stringers to attach newwly cut balsa sheeting. You do want to add fiberglass to both sides of wing-1 1/2" to 2" tape. Don't worry about that little bit of weight-it's nothing on this plane.
PS-Never leave the dihedral brace out-Period.

Never Never Never leave it out. The glass is A big help, the brace and sheeting are the main strength.

I did the same thing with my first 4*60. Like you, I got carried away and got ahead of the instructions. What I did was mix up a big batch of 30 minute epoxy and used a long 1/8" dowel a painted the upper and lower spars with a very thich coat of epoxy, the painted the dhideral brace with a very thick coat and then just put them together. That joint didn't come apart, even when I destroyed the plane in a full throttle nose first landing into the hard pan.

The second 4*60 came to me as a partly assembled kit, the had "completed' the wings, and glued them together, but got the TE miss aligned by about 1/2". I had to cut the wing in half and then I made new root ribs and a new brace. I just laminated the old brace and the new one together. I destroyed that plane a couple months back, stalled on final and in it went. The patched wing is still in one piece, even though the front with the two dowels is now pushed back by about and inch and a quarter. The ply plate over the screw holes also busted out, but the spars and basic wing is still intact. It may be repariable, but I'm not going to try, I just ordered #3.

Don

I seem to remember doing the same thing when building mine. I think I cut some round access holes for gluing the dihedral brace and then filled them in later with some round pieces of scrap glued with CA.

I'm glad I saw this, I'm working on the wings now. I will read, read and read again. Sig makes great kits, sometimes they assume (In the Navy assume means...) you are on the same page as the author who wrote the manual. That is why I like to study this wonderful forum as I build. I'm good, but you all are good too.
I really want to put my Saito 125 in it. I feel it my be to big prop diameter wise. Any thoughts???

Walt

Campgems,

Thanks for the advice. It seems your building skills are much better than your flying skills?

To make you feel any better, this smart a** comment is coming from a novice who still cannot fly solo...

Sure wish I could disagree with you on the building vs flying. But alass, I can not.

Hope you are quicker than I was on getting your wings. I had taken about a 35 year absence from the hobby and just got booted up again two and a half years back. It took me close to 6 months, flying three to four times a week and crashes permiting, four to five flights a day. One thing that I've found is that you make your plane as visibale as possible. I've lost three planes due to getting disorentated and none of the three were that far away.

Enjoy the hobby. It keeps the mind sharp and ahh, I forget what else it does.

Don