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pod and wing repair

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pod and wing repair

Old 09-29-2013, 05:30 PM
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Popriv
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Default pod and wing repair

Put it off all summer Now trying to get this ready to fly this coming Saturday..lol
Pods almost doneI sandwiched ply on each side of the original post.
see the photo where I added material to how the original post went straight up.. should add strength.
dry fit only, still have to epoxy into final position.
Ended up using " not for aircraft " 1/8" 3ply from AC Moore for the pod repair. middle ply seemed pretty tough.. best stuff I could find locally.
I think the " added material " will make it stronger than the original.
what do you think?

Overpowered with the OS.60 so I'm not worried about extra weight.

now on to the wing...
I just cut some sheeting off on the bottom to see what I've got.
looks like I've gone in to the length of the original spar. Gonna cut the ribs so I can double up with ply on front and back of the original spar.
Then repair the rib damage and resheet.???? What are my options for spar material? no good wood at LHS and no time to order anything.
definatly do not want to chance the wing folding on me...


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Old 09-29-2013, 05:36 PM
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Should add that the wing spar snapped when I crashed. should be a one piece wing! pretty clean break.... not much other damage..

Steve
Old 09-29-2013, 09:21 PM
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Steve my recommendation for the the spar doublers as on your other thread wll be to use two 1/8th inch birch ply one on the front side of the top and bottom spars and them one inlaid to the back side this of course involves cutting the ribs back a bit before refilling in the ribs and then the sheeting. Thirty minute epoxy is perfectly fine for the spar doublers.

I have done a number of cutting wings in half to provide anhedral and currently three cuts on an existing wing to provide a gull wing for a stick. This type of reattachment of the wings works very well.


I understand your desire to use a substitute for this repair but if it were me and I was out of my supply of Birch Ply (If I remember correctly 1/8th is four ply) I would be on the phone with my club rooster and I would find from my mates for sure.

On your other thread about this one of the fellows listed a supplier. Do yourself a favor and order yourself up some for the future. Most all the normal hobby wood suppliers carry Birch Ply in the very handy 6 x 12 inch size.

John
Old 09-30-2013, 02:07 AM
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Originally Posted by JohnBuckner
Steve my recommendation for the the spar doublers as on your other thread wll be to use two 1/8th inch birch ply one on the front side of the top and bottom spars and them one inlaid to the back side this of course involves cutting the ribs back a bit before refilling in the ribs and then the sheeting. Thirty minute epoxy is perfectly fine for the spar doublers.

I have done a number of cutting wings in half to provide anhedral and currently three cuts on an existing wing to provide a gull wing for a stick. This type of reattachment of the wings works very well.


I understand your desire to use a substitute for this repair but if it were me and I was out of my supply of Birch Ply (If I remember correctly 1/8th is four ply) I would be on the phone with my club rooster and I would find from my mates for sure.

On your other thread about this one of the fellows listed a supplier. Do yourself a favor and order yourself up some for the future. Most all the normal hobby wood suppliers carry Birch Ply in the very handy 6 x 12 inch size.

John

Looks like it all comes down to the material I can get for the wing joiner?
Also, I guess it's not the spars I'm repairing but the "wing joiner" that snapped.
the 1/8" ply from AC Moore is 3 not 4 plys.

Is it worth the trouble to wrap the wing joint with fibreglass after I join the two wings together?

steve
Old 09-30-2013, 05:23 AM
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It's hard to tell how that's made, but since it's so messed up anyway I'd try to get in there and remove the broken piece and rebuild it. That will be lighter and stronger than making doublers to repair it. Glassing the middle of the wing definitely adds strength without adding much weight, so it's up to you if you think the wing needs it.
Old 09-30-2013, 05:37 AM
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I can only tell you Steve what has worked for me over the years with that type of repair of a joiner or reattachment of two wing panels. Yes the original wing joiner that snapped may only be 1/8 inch but what I am suggesting above is to laminate two more joiners one in front of the spars and one to the rear of the spars that are also 1/8th inch and also Birch Ply (which will give you a total of eight plys).

And if I was short in material I would get it from my club mates for sure. Its a very common model builders material.

Yes fiberglas on a wing joint does help with strength but the number one joint on a wings integrity has to be that joiner at least in my book.

Take a look at this photo. It is taken on the flight test day of a wing that I modified for a cross country Cadet float plane that will carry a gallon of fuel. This day it is mounted on just a regular Cadet trainer with a .65 OS ax engine. This wing is from old airplane and the center section has be hack sawed in two and latter reattached in exactly the same way I described above with the same doubled Birch joiners in the front and rear of the original spars. There is fiber glas over lay but lite two ounce I think.

This wing also has been increased in wingspan by ten inchs at the tips. There are exactly eight pounds of sandbags taped to the center section of this test rig and the airplane weights seven pounds. It flew very successfully that day and what I would say is a pretty good test of the centersection joint. This wing has flown since on the final airplane now quite successfully and at the all up eight weight of seventeen pounds.

John



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Old 09-30-2013, 06:50 PM
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Went with ACMoore ply. 1/4" in front, 1/8" in back. I'll wrap the joint in glass after..
dry fit for now..

steve

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Old 09-30-2013, 08:24 PM
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Steve your workmanship looks excellent and your repairs no doubt will be quite durable.

Please don,t forget to come back and let us know how thing go next Saturday.


John
Old 10-01-2013, 06:42 PM
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Default strength of glue joint?

Lots of progress. Wing is done.
Next issue is gluing the pod onto the support.
Original plan was to run the new ply all the way down into the fuse. the full length of the post.
this would require modifying the way the wing fits around the post. I didn't want to do that..

Now that I put the wing in position there is not as much of the post to glue to as I thought.
About 2.25" of post.

Is that enough area to glue for this purpose? Wrap in Fiberglass? Drill and pin a couple of dowels through the posts?



thanks Steve

Old 10-03-2013, 05:53 AM
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Hi Steve,

Looking good, I think as long as you can sand the old glue/epoxy off of the remains of the old post and you use a slow set epoxy you should be good. If it does bother you, could you open up the slot in the wing? That way you could have more gluing surface. Anyway, just my 2 cents, nice repair job.

Calvi

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