Super Cub 91246 Rebuild

Super Cub 91246 is a 1982 model PA18-150 with a little over 1500 hours of total time. It is interesting because it left Piper and went straight to EDO and was fitted with floats. Over the years it spent about 160 hours on floats in Minnesota before being sold and relocated to New Mexico. My daughter Tabitha and I became associated with the airplane after it was involved in a landing incident in New Mexico. She recovered it out of the mountains after 4 hours of two track roads west of Truth or Consequences. She and my father-in-law disassembled it and transported it back here where I helped the owner buy a flying Super Cub and I bought the wreck. Tabitha and I started disassembling and repairs but after a short time I realized with the shop and my work load I was not going to be able to devote the after hours time needed to get it back into the air in a timely manner. Our initial plan was to rebuild the airplane on speculation and then to sell it. Well I know myself well enough to know that I would not be able to let go of it once completed and the never ending questions of what modifications, panel layout, colors etc. kept popping up.

One Sunday morning I got an email from Nightflyer with a lot of pictures of a Super Cub he was looking to buy. After scanning the high resolution pictures I found a lot of discrepancies for what the owner wanted for the airplane. Having been involved in several annual inspections on freshly restored Super Cubs that had a lot of money thrown at them but the methods and techniques were some what lacking I have gotten very pessimistic in regards to some of these fresh rebuilds. I emailed Nightflyer back a lot of highlighted and marked up pictures of issues I saw. He replied back with a request to help him find a nice airplane. As I sat on the couch drinking coffee I thought to myself, I could sell him 91246 and we could build it like he wants it if he is willing to wait while it is built. After discussing these thoughts with Cathy I emailed him my proposal and we sat up a day for him to look the project over. Needless to say he liked the idea of building a Super Cub the way he wanted it and the deal was struck. My main goal with this thread is to document the rebuild of 91246 but another is to try and pass on some of the things I have learned over the last several years on how Piper did certain things and why. I have had the opportunity to disassemble and restore several late model, pretty original Super Cubs and in doing so I have found things that Piper did that have been left out in the subsequent rebuilds. Now not to say that I am a purist and want to rebuild them like they left the factory but that Piper did know what they were doing and there were reasons they did things the way they did. Also something that I believe strongly is that every time a modification is made it usually effects 2,3 or 4 other things. So, now I will try and document the restoration of Super Cub 91246.

These are the pictures I was sent showing the damage incurred during the landing incident. Both front and rear spars of the right wing are bent, right elevator counter balance bent and tail of the fuselage is twisted.

Tabitha and my father-in-law Bill had lots of help disassembling and loading.

Isn't there a time limit on these threads.? [emoji41]


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Attachment, (and previous poster) not valid

A lot of the late model Lockhaven built Super Cubs had full metal bellies. Makes it easy to inspect. You can see the bent bottom longeron and diagonal tubes here.

It should take about a month to get finished right? ;-)

Piper also went to metal flaps and ailerons on the later model Super Cubs. They are counter weighted thus heavier and some say the airfoil got changed because of the different construction. It is hard to find replacements sometimes.


We have a few slackers when there is a lot of work to do.

I'm looking forward to this new thread and expect to learn lots of things from it.

Bent both spars. For some reason I didn't get a picture of the rear one but this is the front one bent just inboard of the lift strut fittings. Note the stamped nose ribs, Piper started using these in the late 1970s and there Vero Beach Super Cubs had stamped full ribs as well. They were a little different than the Univair stamped ribs which are 5052-H34, Piper stamped them out of 2024-) and then heat treated them. You can also see the ground wire for the stall warning horn that was factory installed in the right wing of the later model Super Cubs.


The usual busted ash wing tip bow.



And you can't uncover an airplane without finding a mouse nest somewhere. Note the bent false spar as well.

Being that this Super Cub had the original, Piper installed Ceconite fabric on it there are little things that somehow get lost when the old fabric gets removed. I had never seen these plastic fairings over where the flap cables exit the fuselage. Note that someone added the foam weatherstripping to the fuselage under the wing root fairing. You can also see the single swedged cables that Piper made instead of the three individual swedges normally seen on other aircraft or after market cables. (In 1970 Piper started started using Ceconite fabric. That is also the same year they started TIG welding the fuselages which stretched 9/16" over the oxy/acetylene welded frames.)

The front aileron balance cables rub on these rub strips where the cables exit the fuselage and enter the wings. Piper used lots of friction tape and then varnished over it.

Your attention to details and showing/telling us is much appreciated.

Lots to learn about what is 'original'.

Steve Pierce said:

View attachment 21221

Click to expand...

Steve,
Do you suppose that someone added this rain gutter in the field because the water was getting in onto the headliner? Or is there evidence that Piper did it? It looks as though they tried a weather strip first and that perhaps the leaking was only on the right side. It does look like a good idea. I seem to recall making little hoods out of fabric for this purpose.

Steve,
Thanks for these photos and the information.

Overall, the damage doesn't look all that bad.

Is the tail section damage the kind that "boxing" the tail tubing is supposed to help, was was something else going on during the "event"?

I've been told that when wings get bent like this, the spars bend inboard of the strut attachment. Just like we see here.

Do you see any problems with the strut attach hardware, and are you going to install the Attlee Dodge strut attach reinforcements? How about the Hurricane Tie-Downs?

Interesting mouse nest. Those little beggars had to carry that insulation a long ways to get it in there. I notice there doesn't seem to be any chewing on the wing stitching. I would think mice in the wing would be a real problem on the stitching and lacing, but have been told they don't chew on waxed stitching. Are those pieces of rib lacing in the nest ?

Looking forward to updates.

Jim

skywagon8a said:

Steve,
Do you suppose that someone added this rain gutter in the field because the water was getting in onto the headliner? Or is there evidence that Piper did it? It looks as though they tried a weather strip first and that perhaps the leaking was only on the right side. It does look like a good idea. I seem to recall making little hoods out of fabric for this purpose.

Click to expand...

i believe these are factory installed only because the glue matches what the headliner was installed with.

55-PA18A said:

Steve,
Thanks for these photos and the information.

Overall, the damage doesn't look all that bad.

Is the tail section damage the kind that "boxing" the tail tubing is supposed to help, was was something else going on during the "event"?

I've been told that when wings get bent like this, the spars bend inboard of the strut attachment. Just like we see here.

Do you see any problems with the strut attach hardware, and are you going to install the Attlee Dodge strut attach reinforcements? How about the Hurricane Tie-Downs?

Interesting mouse nest. Those little beggars had to carry that insulation a long ways to get it in there. I notice there doesn't seem to be any chewing on the wing stitching. I would think mice in the wing would be a real problem on the stitching and lacing, but have been told they don't chew on waxed stitching. Are those pieces of rib lacing in the nest ?

Looking forward to updates.

Jim

Click to expand...

Boxing the tail helps strengthen the area in normal off airport use but I think in this event there would have been a failure regardless.

Most of the Cub wings I have seen have bent inboard like this. The Short wing airplanes bend outboard most of the time because there are doublets riveted above the strut attach fittings to the spar webs. I did not find any damage to the strut attach fittings. We are installing the 2K lb gross weight kit which installs a cap over the strut attach fittings on the rear spar along with a doubler on the rear strut attach fitting. I believe the doubler kit that Atlee Dodge sells is mainly to help with wind loads when tied down outside. Not sure on the spar attached wing tie downs.

i have not seen the mice eat the flat waxed rib stitching. Have seen them eat the I waxed round cord a lot. Saw one airplane with all the rib stitching eaten out of one wing.

Been following this.. Any updates?

Yeah, me too. Thanks for helping us learn, Steve. Much appreciated.

Bill

This is useful, hard-to-come-by information, thanks.

Steve is much better at doing this but I'll add some of the pictures that I have so far. The right wing that was damaged has been rebuilt and is waiting for covering. The horizontal stab and rudder have been covered and are waiting for painting. Tom Ford is still flying around with my left wing on his Cub, I hope he brings it back.

Here you can see the twist in the tail that was cut out and fixed.

A few random pictures.
New boot cowl with titanium firewall.
Extended baggage and 180 pound STC.
X-brace.
Cargo pod tabs being welded on.

We also cut the metal belly off except for the aft clean out. That was a lot of weight saved. Went to headerless fuel too.

The metal belly was 9.2 lbs. less all the steel tabs we cut off.

The tailpost was bent but rather than cut the top longerons loose and have to cut all the old post out we chose to splice the top part of the tailpost with a new Univair tailpost using an inner tube splice which was also used to splice the lower longerons that were bent. Almost forgot the inner sleeves in the lower longerons at the tailpost.

Installed 180 lb baggage STC less the 3rd seat belt attach fittings.

Dakota Cub's adjustable rear seat STC which allows you to move the seat back 3".

1/4"x28 nut welded to the oil hole on the rear stabilizer carry-thru for a grease zerk. Requires reaming aftervwelding.

Bushing welded to the tail spring fitting. Needs to be sanded smooth so the bolt and washer sit flat on the fitting.

I have an original 78 cub with the exact thing on both wings, so assume that is the way it came from the factory.