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PA-18 wing rebuild

I'm squaring the wings and installing fiberglass wingtips so two full length ribs outside of the aileron rib (24 inches) I've spliced the spars and ordered full length Dakota ribs and want to be sure when I install the wingtips that I don't crack or break the rib or have the holes wallow out over time. I'm thinking 6-32 anchor nut riveted to the rib.
8306CC90-6B5E-4113-B61E-3752D3692689.jpeg
 

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If I understand correctly, you are going to cut off those tapered spar caps, install a full sized rib at the tip then screw on a squared fiberglass wing tip similar to the tips in my pictures? From a structural perspective 2 or three screws will hold it. However you will need more to just hold down the edges of the tip. Also 6-32 seems too small a diameter because of the bearing loads in the tip. It is easier for a small diameter screw to pull sideways in the fiberglass than a larger diameter like a 10-32. My tips use 10-32 machine screws in plate nuts spaced about every 6".

How much additional span are you adding?
 
Think we always used just #6 pk screws for installing tips. No need to get any bigger or nut plates. You will have many screws holding on the tips


Sent from my iPhone using SuperCub.Org
 
I'm just basically squaring the wing outside of where the farthest point of rounded tips would be then the fiberglass tips which are about a foot each side. going to place the last rib at 24 inches from the aileron rib which will be about two inches wider each side than the 11 I have now. I would like to go a little more but I am the slowest plane out there already. I checked the tips I have and 6-32 fit the holes already in the tips so instead of doing a bunch of fiberglass work I plan to just use the old holes also trying to keep the plane as light as possible so 6-32's weigh less than 10-32's (Thanks for messing with my mind Bill Rusk). Thanks Mike I just don't want to break a rib down the road is why I am asking. I guess I've seen some messed up ribs that you wouldn't know about until they were uncovered and flew just fine.
 
Are you extending your aileron's as well ???
If your not, you may want to consider that carefully.......... Long wing Cubs with short ailerons have caused lots of excited moments with some Very experience Cub pilots. Pretty undesirable combo in most cases. May wanta make a quick call to Reid or Dwight to consider this??? I am pretty sure both will advise you to extend your ailerons.[emoji16]
Good luck with your project should make a nice "Cub Special"
E

Sent from my moto e5 go using SuperCub.Org mobile app
 
Are you extending your aileron's as well ???
If your not, you may want to consider that carefully.......... Long wing Cubs with short ailerons have caused lots of excited moments with some Very experience Cub pilots. Pretty undesirable combo in most cases. May wanta make a quick call to Reid or Dwight to consider this??? I am pretty sure both will advise you to extend your ailerons.[emoji16]
Good luck with your project should make a nice "Cub Special"
E

Sent from my moto e5 go using SuperCub.Org mobile app

Never squared off wings without lengthening ailerons or moving them out. But have been hired to make wings back to round wings after severe crashes from lack of aileron control on squared off wings. (I’ll look for a picture)


Sent from my iPhone using SuperCub.Org mobile app
 
My 11 doesn't have extended ailerons and squared / extended wings been flying it for 20+ years so won't be doing this one.
 
Very important when you put the leading edge on. That tends to lock things in. If you don’t do it you will probably get some wrinkles when you force it in later.


Hope this helps


Bill
 
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