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Fuselage difference, PA-18 & PA-18-150

t30mg

Registered User
Building a pa18 and want to go from stock 90hp to 160hp. I was told that there are some 3/8 tubed that go in somewhere to make it legal.

Can anyone show me a picture of these specifically?

I have my 18 & 18-150 fuselages right next to each other and they look the same.

Thanks
 
They may be the same. After about 1956 (?) they used the same fuselage for 90 and 150 cubs. My 1958 cub was a 90, but had all the welded fittings for flaps and the four extra tubes near the battery box that made it easy when I upgraded to flaps and and 150 hp. Not as easy to upgrade the wings with flaps. Do a search on this site and you'll find more discussions on the upgrades.
Webfoot
 
I have a 1953 90 horse. Still the original fuselage. It has the flap handle mounts on the seat, the tube for the battery, the mounts on top for the flap pulleys and the mounts for the bottom bungee spring on the elevator. My cub was the 9th from the last one made as a 1953 model.
 
I am wondering more specifically about some 3/8 diagonal tubes that would go in some bays somewhere aft of the rear window??
 
Early PA-18 Super Cubs had a gross weight of 1500 lb. Later ones including the PA-150 had a gross weight increase to 1750 lbs. Bill Ellis and Roger Borer developed SA292AL to allow installation of an O-320 on an early airframe. I bought that STC for N18SY, PA18-387, an early 1950 Super Cub.
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I have the STC , instructions and information in the hangar and can copy it if you need it. The upshot as I remember was to weld in a number of 3/8 diameter, .035 wall 4130 tubing in the empennage and installation of the PA18-150 cabane which has larger bolts than early PA18s. If you want the whole instructions, let me know and I will scan them. If you are certified and need the STC, I think Roger Borer's family is still marketing his STCs.
 

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It involves 3 tubes under the battery box, one on each side between the bottom and top longerons and one between the top two longerons. The STC for the tubes Darrel mentioned calls for 1/2" tubes. Your 1960 fuselage should already have the tubes.

Sent from my SM-N900V using SuperCub.Org mobile app
 
My L-21B has the 150 hp frame and the O-320 upgrade with the Wag Aero STC. I'll be using the STC supplement to upgrade it to 1750 lb.

1750 GW increase.JPG
 

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The Ellis & Borer STC specifies adding Four 3/8 OD, .028 wall 4130 tubing and reaming out the holes in gear fittings for the later Cabane.
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Our 59' PA-18 started life w/90 Cont, came w/the specified tubing, brackets for flaps etc., even has a few tabs for the spray hopper. and 3/8" gear bolts. In talking w/the late Frank Swinehart, Sr. (the senior welder on the Super Cub line) he said from the late 50's on . . . all frames came down the line the same. In 59' only 90 hp & 150 hp were offered as options. He said our frame most likely was heading down the line to be built up as a sprayer when an order came in for the C-90. Common practice was they would pull it out of the line and mount the eng., non-balanced elevators and flapless wings. So, I would presume all later model 90's would have the correct frame tubing. Part of the Borer STC also calls for hydra sorb units, and -2- 18 gal. wing tanks. The Piper brochure calls for the "Deluxe" 90 model to have the wing tanks as well as hydra sorbs, and an elec. system. Larry C.
 
Darrel, thank you for posting that STC. I would like to purchase SA292AL as well as the O320 engine STC SA136AL. Could anyone tell me how to get in touch with Roger Borer's family?

Thanks you, Dennis
 
Roger's daughter, Karen Byerly, was handling the STC's for the estate. As of Feb.2011 her address was: 1088 Walnut Circle, Anchorage, Alaska 99516. Ph.907-522-1028. (Husband-Glen). On the phone she sounds like a neat lady. Got lots of family history. At the time she was battling some serious health problems. Hope all worked out. STC SA292AL (gross wt. increase) was $225.00. Turn-around time was very fast. Larry C.
 
Roger's daughter, Karen Byerly, was handling the STC's for the estate. As of Feb.2011 her address was: 1088 Walnut Circle, Anchorage, Alaska 99516. Ph.907-522-1028. (Husband-Glen). On the phone she sounds like a neat lady. Got lots of family history. At the time she was battling some serious health problems. Hope all worked out. STC SA292AL (gross wt. increase) was $225.00. Turn-around time was very fast. Larry C.

Larry, I talked with Karen the other day, she is a very nice lady, still has health issues, and is committed to keeping her dad’s memory alive by supporting his STC’s. She is very appreciative of the people who purchased his STC’s and expressed gratitude to those who post her contact information as she is not very computer savvy. The information you posted is current. I purchased two STC’s; SA136AL and SA292AL, (prices have gone up little). She does not have Piper dwg 14468 for SA136AL and asked if someone could make a copy for her. It is a large drawing but if someone would make a copy and send it to me, (as I need it also), I will make a copy for Karen. I’d be happy to pay the expenses for it please send me a PM if anyone can help. Thanks, Dennis
 
If you look at the list of approved aircraft, it applies to PA18A and just about everything else except the straight PA18. The drawings reference PA18-105 and up. So just how does one go about demonstrating that it is applicable to a PA18? Requirements in Canada are more exact. Aerodon
 
I'm not sure if these will help. These are what I have. Some of these are more recent revs of what many have. There is a Canadian document in there too outlining some differences.

EDIT - It looks like these did not come through as full resolution. Let me know if you want them emailed.
 

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