PA-11 rebuild

[YJLopes]

I’m diving in to a 90 HP Cub rebuild and mapping out the plan. My end goal is a plain Jane, light airplane that my dad and I can beat around in and my kids can learn to fly in.

The only mods that interest me at this point are shoulder harnesses, Atlee front seat belt anchors, and 6” wheels (probably grove) with 8.00s. I’ll probably do the Atlee landing gear cables as well. The project has a RH fuel tank, but I’m not sure which one or if I want to keep it (why or why not).

Anything else I should consider while I’m going back together?

[Crash, Jr.]

I'd recommend even less. The Atlee floor seat belt tabs are great for crashing but not great for day to day livability. Passengers tend to step on them and they clutter the floor. Just use the normal seat belt attachments on the seat and make sure your seat attachments are solid and you're using new hardware. If you're in a PA-11 and plow into the ground hard enough for the seat to come free of the frame you've got bigger issues than where your seat belts are attached.

Don't bother with the safety cables if you're only running 800x6's. You shouldn't be doing anything on those tires that will cause the gear to fail. They're 4lbs of dead weight to just carry around. If you were on bigger tires and pushing the limits a bit I'd say get the safety cables. Check your landing gear regularly for damage/cracks and when you're rebuilding (and only if you're very concerned about gear failure) it put PA-18 style doubler plates on the front gear fitting. That will go a lot farther towards keeping the gear attached to the plane although it's probably not necessary. If you can get away with it legally, weld the "heavy duty" style gussets on your stock gear between the axle and gear leg tubes like you'll see on Atlee HD gear. The stock little straps are adequate but not by much and especially if you're on skis.

Other than that, just build a nice PA-11. The C90 is the sweetheart engine to go with so that's a great basis. Keep the instruments to the stock 4 gauges plus maybe an ipad or gps mount and leave it at that. Don't build a PA-18 out of a PA-11 and keep in mind that every doubler, gusset, bracket, and pulley adds weight. Don't put anything on that you don't need. Target weight should be in the 850lb range.

[mvivion]

Well, I guess I'd do a few things "extra". First thing I'd do is change to a PA-18 style elevator cable system. That would permit you to eventually install an actual baggage compartment pretty easily. I doubt the PA-18 elevator control system weighs much if any more than the stock 11's.

I'd definitely "box the tail" to stiffen up the tail a bit. I'd install a second lifting loop on the other side from the one that's there.

I'd probably go to an -18 style skylight. Standard -18 landing gear is legal on an 11 as direct replacement.

I'd definitely look at lifetime struts.

I'd install one of Atlee's long steps on the right side, and a short one on the left.....for boarding and fueling. Leave off the standard "boarding step".

I'd probably be looking at a wood prop, maybe.....do some research.

MTV

[Crash, Jr.]

Agreed on most of that. The PA-18 elevator system doesn't add any weight and the baggage is absolutely worth it. The PA-18 trim system is a worthwhile upgrade as well if you're in there. Use oil lite bushings on the trim crank shaft.

The long step is a no-go for me on a light cub. It's a decent amount of weight to add and if you're on stock length gear and little tires you can get in and out pretty easily. The fueling step is definitely a good idea though.

[55-PA18A]

If you add a second lifting loop on the tail, consider making them both oversize so you can lift with both hands, or while wearing heavy gloves or mittens.

An outside opener on the door doesn't add much weight. I hate reaching in through the left side to open the right side window/door.

Jim

[behindpropellers]

If you add a second lifting loop on the tail, consider making them both oversize so you can lift with both hands, or while wearing heavy gloves or mittens.


Jim

And move it to the top longeron.

[mvivion]

And move it to the top longeron.

So far, we're all on the same page here, methinks.....'cepting the long step, of course.....

As to the -18 elevator trim system and elevator routing, even if YOU don't care about a baggage compartment, the next owner might. And, it's not that tough to do on a bare fuselage.

MTV

[cubdriver2]

I like the handle on both sides of the lower longeron. A 11 is light enough to lift with one hand

Glenn

[BC12D-4-85]

Give some thought to changing the elevator and stabilizer....both for and against. Some prefer a light tail and the factory setup is lightest, although it offers the most resistance to elevator deflection in flight. Next for a lighter elevator feel would be the horizontal components from a PA-22, followed by the heaviest overall from a PA-18. I flew my PA-11 with the stock tail and liked it. Adding flaps (yet another + and - mod) required a PA-18 tail. I did not like the weight gain from either the flaps or tail. Just something to consider and maybe fly the options beforehand.

Gary

[YJLopes]

Thanks guys!

Any other thoughts on the Super Cub seat belts for the front seats? Anyone else done it and regretted the inconvenience?

I'll rethink the safety cables and study the gussets you mentioned.

A second lift handle seems easy to do and worthwhile.

Skylight...I'll think about that.

Super cub gear? why? Stronger?

I believe I got a set of lifetime struts with the project, if not, my shop is 20 minutes from Univair.

I've looked at the long step, and haven't made a decision yet. I suspect I need to crawl in a cub with one and see if I like it.

I was initially thinking wood prop, but had changed my mind based on the performance compromise I'd read about. Am I wrong?

I'm reading about boxing the tail, seems easy enough to do right now.

I only see STC SA590AL from FAD for extended baggage and it only lists the PA-18. Is there a baggage STC for the PA-11 that I'm missing?

I'm reading about the 18 elevator control system, is the only reason to do this the baggage?

I've read about 18 stab and elevators and came to the conclusion I wanted to keep it stock for now.

[wireweinie]

You can install a baggage compartment without STC as long as you don't cut or weld structure. Fabricate the compartment and install it with steel clamps and log entry only.

And, I bet I can come up with a lighter panel with electrical than the old school steam gauges.

Bottom line is to only install what you NEED (not want). Less is more in small aircraft.

Web

[dgapilot]

You can install a baggage compartment without STC as long as you don't cut or weld structure. Fabricate the compartment and install it with steel clamps and log entry only.

And, I bet I can come up with a lighter panel with electrical than the old school steam gauges.

Bottom line is to only install what you NEED (not want). Less is more in small aircraft.

Web

You can do that, but it still doesn’t change the 20 lb baggage limit. Don’t really see an advantage in making a bigger baggage compartment when still limited to 20 lbs.


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[dgapilot]

If you go with 6” wheels, the magnesium Grove will be the lightest. I just got a set of Airframes 6” wheels with double puck brakes, and they will add a little over 11 lbs compared to the 4” wheels. 8.00x6 tires and tubes weight the same as 8.00x4 tires and tubes, so no penalty there.


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[mvivion]

You can do that, but it still doesn’t change the 20 lb baggage limit. Don’t really see an advantage in making a bigger baggage compartment when still limited to 20 lbs.


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There are these things called “sleeping bags”: light, but bulky. And essential survival gear in most of the world…..

MTV

[wireweinie]

You can do that, but it still doesn’t change the 20 lb baggage limit. Don’t really see an advantage in making a bigger baggage compartment when still limited to 20 lbs.


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You always have to check your W&B. Just pointing out that you can make a baggage compartment without having to buy an STC.

Also, Mike beat me to the sleeping bag scenario. I've seen baggage compartments that were mostly unusable for storage, due to long length, but it provides a sleeping area when stuck on the ground.

Web

[Crash, Jr.]

It's too bad Atlee's STC SA459AL is only applicable to the J3 and not the PA-11. That would provide a full PA-18 stock size baggage area and be the way to go. I wonder if you could get their engineer to write a letter of no technical objection considering how similar the airframes are or maybe you could get a DAR to work with you on a field approval.

Regarding the weight limit, it's placarded because it has to be. What actually goes in the baggage is the pilot's business. My survival kit probably weighs more than 20lbs but I'm not about to leave it behind because of a sticker on the baggage lid on my J3.

[dgapilot]

I haven’t looked at that STC, but I’ve done a number of other STC deviations to allow them to be installed on similar aircraft with a DER approval.


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[Steve Pierce]

I installed the STC on a couple of PA11s several years ago. Kracke sent me a letter of deviation to the STC that approved them.

[nbills77]

A PA-11 flies perfect the way it is. Don’t mess with much of anything. If you start adding this mod and that mod go get an -18. Mods add weight and take away from the great flying qualities. I have a -18 serial #12. Completely stock and won’t ever change it it flies perfect the way it is. Small tail and single pulley trim. I wouldn’t even change that. All I ever do is two turns at the most either way.

[Crash, Jr.]

A PA-11 flies perfect the way it is. Don’t mess with much of anything. If you start adding this mod and that mod go get an -18. Mods add weight and take away from the great flying qualities. I have a -18 serial #12. Completely stock and won’t ever change it it flies perfect the way it is. Small tail and single pulley trim. I wouldn’t even change that. All I ever do is two turns at the most either way.

Couldn't agree more. I had problems with single pulley trim but a simple change of the trim pulleys took care of that. Less weight, less complexity. If you go too far off the rails adding a bunch of lift handles and extended baggage and whatnot it might be better to look for a PA-18. Seeing as this plane is going to be on 800x6 tires I have to wonder how much of this is useful at all for a simple mission of just flying around for sport. I think a lot of people are coming from the standpoint of bush flying where you may need a bunch of lift handles for ski use or need a big baggage for storing covers and survival gear for winter flying. I think the OP really needs to nail down exactly what they're expecting to do with this plane because every mod has a benefit but a cost in weight and those ounces add up to pounds.

[BC12D-4-85]

Here's my former PA-11's baggage area. Simple fabric top and aluminum below. Rattle can paint job. Worked.

Gary

[DJ]

Why go to 8.00x6 vs 8.00x4 with grove disc brakes. More weight, and more likely someone will put it on the nose. And you lose the "puffed yeast donut" (Richard Bach) look that some of us love.

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[nbills77]

For beating around the pattern and local fields and even teaching the kids to fly single puck groves on 800-4’s are perfect. Double pucks are way too much. Again keep it simple don’t ruin a trusted perfect design.

[YJLopes]

For beating around the pattern and local fields and even teaching the kids to fly single puck groves on 800-4’s are perfect. Double pucks are way too much. Again keep it simple don’t ruin a trusted perfect design.

Did we meet at Clyde's seminar at Univair last september?

I already was interested in less mods, so I think I'll be going that way.

I see value in the tail brace. It's fairly cheap and costs a little weight, so that'll probably happen.

I rode through a cub going on its back as a passenger. Shoulder harnesses will definitely happen.

Beyond that, I think it will stay fairly stock.

I'm on the fence concerning 6" wheels. I think I prefer the look of them. I like the greater variety of tire sizes if I ever decide I want to change. I also see the logic in keeping the 4" wheels. I don't have to make that call for a while so I'll chew on it for a bit.

I have a 185 with a pod for loading down with the family and going a long ways, so I don't see a reason for much baggage room on this bird. I think I'll skip that.

Thanks for the suggestions. Keep them coming. I'll try to post some build pics as I go. I think I'll be stripping the wings on friday for some triage. I hope to do a dry build in the next few weeks to see how things fit and inventory what I have.

[nbills77]

I did You and your Dad. I am glad to hear you are moving forward. The shoulder harnesses are a must I think, the tail brace might suit you more where you are vs me in KS. If you want a ride in a very stock -11 let me know a good friend at Front Range is a retired UA guy would be happy. A quick stop after you finish a trip. PM me if are interested I will connect you.

[YJLopes]

I did You and your Dad. I am glad to hear you are moving forward. The shoulder harnesses are a must I think, the tail brace might suit you more where you are vs me in KS. If you want a ride in a very stock -11 let me know a good friend at Front Range is a retired UA guy would be happy. A quick stop after you finish a trip. PM me if are interested I will connect you.

Walter?

I had lunch with him today.

[nbills77]

Walter?

I had lunch with him today.

Ha Ya Walt a great guy.

[cubdriver2]

My seatbelts, cable in vinyl tubing




Glenn

[DENNY]

If it is going to be a trainer then I would consider new gear or very close inspection of the old gear. I would also get safety cables you never know just how much excitement the training may bring. Seatbelts to the floor is a double edge sword, people do get step on them but if you make sure they are clear before you get in the front they work fine. Denny

[BC12D-4-85]

Wasn't there some talk about synthetic "rope-kevlar?" based safety cables earlier? Might work on a light plane w/o the weight penalty.

Gary

Edit: Hmmm= https://www.airframesalaska.com/Safety-Ropes-s/2062.htm

[YJLopes]

relocated the wings and fuselage yesterday for an evaluation.

The guy I bought this project from is a family friend. His dad was recovering it and got distracted by who knows what and never got back to it.

The fuselage looks pretty good so far. 2 tubes with a slight speed bend that should straighten without any headache. It has handles on both sides of the tail AND they are on the upper longeron so that suggestion has already been checked off. It will probably get blasted in the coming weeks for a closer look.

The wings are in great shape. I’ll put new trailing edges, false spars, and bows on them and go to town.

[cubdriver2]

You might want to add a lower handle so you can lift the tail?

Glenn

[skywagon8a]

Save the wing fabric for inspection opening and cable locations.

[BC12D-4-85]

Make sure you're happy with the low front seat position and front spar crossover right in front of your head.

Gary

[YJLopes]

Make sure you're happy with the low front seat position and front spar crossover right in front of your head.

Gary

Will do!

Is anyone familiar with Stoddard STC SA68AL? There is a tank installed in the RH wing with SA68AL stamped on it. Looking for paperwork, thinking I might keep it.

[BC12D-4-85]

https://www.supercub.org/forum/showthread.php?23413

There may be more...also check with Stoddards and Cub Crafters?

SA68AL Fabrication and installation of Stoddard Model 3 wing tank per Stoddard Aero Service Drawing List No. 68 dated February 7 1975 or later Federal Aviation Administration approved revision. Reissued 1/26/2012

Gary

[YJLopes]

https://www.supercub.org/forum/showthread.php?23413

There may be more...also check with Stoddards and Cub Crafters?

SA68AL Fabrication and installation of Stoddard Model 3 wing tank per Stoddard Aero Service Drawing List No. 68 dated February 7 1975 or later Federal Aviation Administration approved revision. Reissued 1/26/2012

Gary

PM'd the OP and already got a reply. Thanks!

[BC12D-4-85]

I bought and had an excellent local A&P restore my former PA-11. Owned it from 2001 to 2015 on wheels, skis, and floats. You will have many options to make it heavier but not necessarily better. I let it go because the stock front seating position and my knees didn't agree after an hour. If I had done the adjustable seat (PA-1 and PA-18 top deck STC's to replace the carry through spar I'd still own it. Have some fun with your project.

Gary

[supercrow]

Have done a couple of the top deck changes. Getting ready to do a third in the next month or so. That and the S. Cub seat makes a major difference in comfort.

[kase]

We put a 18 seat in our PA11 25 years ago. Worked great. One thing I wished we would of done was put in a PA18 torque tube with the short pedestal to relieve some of the back pressure when landing. Always running the trim.