Frustrated builder
 

So I've been building a carl goldberg piper cub and it's gone together very nice so far, I've built all major parts except for adding the ailerons. While trying to set the wing into place I noticed something not exactly right, one wing is a quarter of an inch longer then the other give or take a hair. Also the wing fits perfectly in the saddle of the cabin area as it should. And I'm suppose to mount the wing equal distance from the tail, so will this affect my plane and the flight characteristics? Or should I just not worry about it?

Unfortunately sometimes the plans stretch or shrink and this happens. I don't think 1/4 will cause you any real problems. You do still want the wing square to the tail but obviously if you are measuring from the stab to the wing tip the distance can't be equal if one wing is a hair longer.

Well I'm hoping it will be fine, I measured from the first rib to the last on the table and one wing half is a quarter of an inch longer then the other exactly a quarter on both the leading and trailing edge, so maybe I should probably just go ahead and finish joining the two halfs

Will not have any effect on flying. I had an old trainer back in my early days. Crashed & rebuilt so many times it was a joke. So crooked & uneven my buddies called it the flying banana.

Only use a tape measure with 1/2" markings for now on. It will fly fine, nobody will be able to tell if you don't.

I think that little error has been on the plans from day one. It has no effect on the plane at all but when you are using the string to align the wing keep that 1/4 inch in mind or the wing won't line up correctly. The plans were all hand drawn back in the good old days so something on a kit being off isn't anything unusual. As an old printer I will say that shrink and spread does happen with offset printing. Water is used across the printing plate and transferred onto the paper. Most shops were not climate controlled so it does effect the paper but not usually that much. It plays hell with the pressman when doing color work and trying to align the colors. Halftones/photos most of all. They are made up of dots and the dots have to align or there is a blur. A 1/4 inch was not a shrink or spread problem, just a problem when the plans were inked. For a fun time try building from plans drawn/inked by Joe Demarco. I don't think he knew what a ruler was for!!

I had the same problem with a biplane that I built a few years ago. The bottom wing was off to one side so it really messed up all the alignment for both wings. I finally rebuilt the bottom wing and allowed for the mistake on the plans and all came out fine in the end. I have since learned that I need to measure the plans to make sure they are good because I have found this issue on more than one set of plans. It shouldn't be an issue for your Cub as stated above however as they fly really well.

You know, I didn't realize the wing halves were not joined yet. IF you wanted you could carefully band saw of the extra,and re-install a new root rib.. but I wouldnt waste the effort..it could be done if a person wanted to. you just don
t want to mess up something else involving the dihedral brace or landing gear spacing...

Keep in mind there have been a number of times a DC-3 with a damaged wing was fitted with a surplus DC-2 (a good 5 feet shorter) with great results. My father in-law was a 37 year A&P for AA and started his career working on DC-3s and has completed such an installation. I don't think you need to worry about or make any changes.

Ah, the DC-2 1/2

Its fun, my father in-law called it that too!

If it were mine, I would have to fix it. :rolleyes:
Just because I could. But Hey, that is me:confused:

Good Luck whichever way you go...

If the wing isn't joined it's just a mater of adding a 1/4 inch shim shaped like the rib. Not a big deal. Only thing it will change is making the alignment measurement easier. The Cub doesn't care about minor imperfections.

Soon as that thing floats into the air, you'll forget all about it. Like every one else said, long as your wing is square to the fuse it won't affect anything, but, you could just as easily fix it with a 1/4 shim on the short wing. Good luck.

I like for things to be just right but I mean it's just not worth my trouble to mess with the 1/4 of an inch! Not even with an eye for detail as I have can you notice it in anyway.
So ill just square it up with the one side just a quarter longer and not worry
about it. Thanks for the help!

The thing with errors like that is after a while you simply forget about it. if you can add a quarter inch rib at the root that's what I would do. Otherwise I wouldn't worry about it. It won't make any difference. I wouldn't shift over the wing if you would be able to tell. For example if the wing has dihedral then the break would be noticeably off-center.

Man o man ! why was I doing subtraction when adding was the obvious answer ! hahahahhahahha

As for squaring it up...just put a piece of painters tape out toward each of the the wingtips and measure & mark it equally on both sides. The mark is then your reference for squaring and you don"t have to do any mental gymnastics trying to account for the minimal difference in lengths.

That is a great idea Frets! I was thinking along the line of just measuring parallel to the fuse from the trailing edge of the stab to the trailing edge of the wing, but I like your idea better.

John

That 1/4" adds up to 2.5 sq. in. of wing surface if the wing measures 10" from leading edge to trailing edge (3 sq.in. if the wing measures 12"). That will give the longer wing extra drag and extra lift. Under normal circumstances the short wing will always stall first. That will lead to a crash, and lots of damage that could be avoided if you just cut the longer wing to match the shorter wing now.

Cubs tend to ground loop. Leaving your cub with a longer wing will exacerbate the problem.

Fix it now, and avoid extra problems. It's easy to fix now. It will be harder to fix later.

And many an old fighter jock has flown with 2 to 3 feet of one wing missing.

+1. since we're talking a cub and not a precision aerobatics machine, you'll never notice it.
in the event you MUST however, add 1/4 inch to the short wing.

And we wonder why ARFs are so popular:rolleyes:

This is how nuts I get..:eek:

I built a 64" ARF Extra,
I added a 1/16" rib to one wing to make them the same. Uncovering the end of the root rib gluing and reattaching the covering was a PITA
I cut the wing tube out of the fuselage and relocated it because the wing was out of alignment.
I also changed the incidence of the horizontal stabilizer based on the history of this particular plane.
I actually have that in a thread somewhere in the ARF section.

You know the crazy part about it............ I destroyed it on the third flight:mad:. The pilot (me) had his head squarely placed somewhere it did not belong.

It flew great the first too flights.......:cool:
OH WELL.... I love this HOBBY!