Moving Aileron 24" Outboard

[Lineman052]

Working on a Homebuilt Pacer floatplane, it currently has plane Booster wingtips with the stc's spar plate extension.
We are going to move the aileron out 24" and add 24" and another hanger to the flaps. Anyone have any old 337's or tips on how they did this. Will be adding full leading edge from root to tips.

[Stephen]

There is no approval for this mod. Eddie Trimmer has been working on an STC for years. If you are experimental a full length leading edge D section is good. I would also add reinforcements to the aft spar and compression struts to the alieron area. Also add aluminum panels over the false spar and aft spar. You are adding significant torsional load to the wing. I would also lower the flap extension speed.

[akflyer]

There is no approval for this mod. Eddie Trimmer has been working on an STC for years. If you are experimental a full length leading edge D section is good. I would also add reinforcements to the aft spar and compression struts to the alieron area. Also add aluminum panels over the false spar and aft spar. You are adding significant torsional load to the wing. I would also lower the flap extension speed.

There are multiple planes flying that have extended wings, moved the ailerons outboard and big flaps that were done on 337s. To my knowledge none of them have had a failure. If I was going home built I would be hanging D&E wings on it.

[Stephen]

There are multiple planes flying that have extended wings, moved the ailerons outboard and big flaps that were done on 337s. To my knowledge none of them have had a failure. If I was going home built I would be hanging D&E wings on it.

I spent 6 years on this exact mod, working on an STC. Both Eddie Trimmer and I have spent a lot of money with engineers. While in the past people may have gotten a field approval, it is not likely anymore. There are significant load increases that should be accounted for. I would not fly in a plane with this mod without significant reinforcements. Frankly, the reinforcements I listed are no big deal. Extra compression struts are easy to add, extra ribs are no big deal. I think this mod is a nice improvement for our planes.

[dgapilot]

The inboard rear spar is one of the weak areas on the short wing. Bending moment with flap deployment is pretty significant. I read all back in the 60s, the big thing was to rig the flaps with some negative or reflex to get more speed, kind of like the Maule MX-7. After a couple rear spar failures, everyone gave up on that idea.

In today’s world, any change to a moveable control surface can only be approved by STC. Most outer mold line changes, especially to wing plan form, can only be approved by STC. So in the current FAA system, the changes you are considering could only be approved on a certified airplane by STC.


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[akflyer]

I am guessing your guys skipped right over the part where he said it was homebuilt. While what your saying is correct if he were dealing with certified, it does not apply if he is building an EAB. If it were certified, the easiest path forward is to go experimental exhibition.

[Stephen]

I am guessing your guys skipped right over the part where he said it was homebuilt. While what your saying is correct if he were dealing with certified, it does not apply if he is building an EAB. If it were certified, the easiest path forward is to go experimental exhibition.

He also asked for 337's.

I did not skip anything....at least this time. While my information was aquired for certified aircraft, the load issues are the same. Certainly, he has the freedom to do mods without approval but, he can't avoid the laws of physics.

[akflyer]

Do you have any hard numbers on known failures on short wings that were extended and have big flaps? I know the struggles to get the STC etc, but I also know there are a lot of planes out there flying with 337s, big flaps and ailerons moved outboard. Yes, as a homebuilt there are some pretty easy ways to beef up the weak areas. I would venture to say he is asking for 337s so he knows what areas were beefed up and how the person did the mod so as to not reinvent the wheel again. It is really easy to "over build" and beef up areas not needed when one is attempting to build a bomb proof wing.

I truly wish the powers that be would let you folks move forward with the STC. I would be buying it from you in a heart beat.

I know of more than a few who extended the wings per the bushmaster STC but did not extend the fuse. I would really be interested in doing something of that nature.

[dgapilot]

I am guessing your guys skipped right over the part where he said it was homebuilt. While what your saying is correct if he were dealing with certified, it does not apply if he is building an EAB. If it were certified, the easiest path forward is to go experimental exhibition.

Don't forget that even with Experimental Exhibition, if it is a "previously certified" aircraft, all the Part 43 requirements are still there (Read 43.1) - approved data, 337 forms filed . . .

[Stephen]

Do you have any hard numbers on known failures on short wings that were extended and have big flaps? I know the struggles to get the STC etc, but I also know there are a lot of planes out there flying with 337s, big flaps and ailerons moved outboard. Yes, as a homebuilt there are some pretty easy ways to beef up the weak areas. I would venture to say he is asking for 337s so he knows what areas were beefed up and how the person did the mod so as to not reinvent the wheel again. It is really easy to "over build" and beef up areas not needed when one is attempting to build a bomb proof wing.

I truly wish the powers that be would let you folks move forward with the STC. I would be buying it from you in a heart beat.

I know of more than a few who extended the wings per the bushmaster STC but did not extend the fuse. I would really be interested in doing something of that nature.

Let me know specifics about stretched Pacer projects who did not lengthen the fuselage. That would be like cutting two feet out of a Cub fuselage. The plane should lose stability in two directions and lose elevator and rudder authority.

[Stephen]

I talked with Eddie Trimmer a few days ago. He said he was meeting soon with his engineer on this STC. Maybe it will happen.

[Ononeleg]

Just out of curiosity, what is the difference between the PA18 and the PA22 wing that the rear spar on the 18 can handle longer flaps than the 22 can? Are the mods to make the flaps longer and to move the ailerons out basically just making it like an 18 wing, or are they something new and different? Also, I've noticed that Eddie's STC allows for extra tanks. Is that possible because of the mods, or just something that folks wanted anyway, so he attached it to his aileron STC?

[Steve Pierce]

The construction and parts are pretty much identical between a PA18 and a Pacer wing except the PA18 has an extra bay, jury struts and a 1750 lb gross weight. The later Tri-Pacer wing has a 2000 lb gross weight but also has a bulbed stiffener above the lift strut fittings. There is an STC to up the PA18 gross weight to 2000 lbs by adding a doubler over the top of the rear spar and a doubler inside the aft rear strut attach fitting. Aviat did a similar doubler over the rear spar at the strut attach fitting on the Husky.

[Steve Pierce]

I know the struggles to get the STC etc, but I also know there are a lot of planes out there flying with 337s, big flaps and ailerons moved outboard.

With those N numbers the original poster could obtain those 337s from the FAA.