Recover

BudG · Post by **BudG** » Fri Mar 14, 2008 1:12 pm

This one is to TomD. Hey Tom, I was talking with a Lake driver, Ken, I think. At Harvey the other day. He said he knows you. Anyway he mentioned that you were having to get your bird recovered. Did you have to get it recovered again. I remember your bird being a nice yellow and green. Ken mentioned that your bird was at Tim Broughner's. Question, if you are having to recover it for a second time, who recovered it the first time. I'm looking at recovering mine at Yakima Sports in Yakima, Wa. right across the airport from Cubcrafters. 15-20K for everything was the quote, even aluminum stringers. Hope to see you out at the airport. take care. Bud N6VD.

TomD · Post by **TomD** » Fri Mar 14, 2008 5:37 pm

Long or short story.

The company ( I will leave their name out of it until negotiations are completed) subcontracted the fabric job. To put it mildly they screwed it up.

Plane was in an unairworthy condition after the center seam on the top separated. In all actuality technically it could have been out of compliance since 2000 due to the dipstick who covered it not adhering to the STC's overlap requirements.

The plane is right now down at Evergreen Aviation Services in Scappoose and is looking pretty good. Their work is light years better than what I got in 2000.

Full disclosure to follow.

TD

a64pilot · Post by **a64pilot** » Sat Mar 15, 2008 9:09 am

I want to think Maule's drawings call for stainless steel or wood stringers, not aluminum.

aero101 · Post by **aero101** » Sat Mar 15, 2008 10:11 am

The Maule supplied stringers on fuselage side are 3/8" chromolly with stainless steel for the bottom stringer. After having ordered from Maule, paying their price plus shipping I think the next one will be done with aluminum cub type stringers. Stringers are non-structural and it's debatable whether a form 337 would even be required although I think I would do field approval just to cover bases?

a64pilot · Post by **a64pilot** » Sat Mar 15, 2008 11:15 am

I think I would go the field approval route just to CYA. Of course you may get a letter saying no 337 required, which would CYA also.

UP-M5 · Post by **UP-M5** » Sat Mar 15, 2008 1:34 pm

i know of a certain maule that was just rebuilt with aluminum cub stringers. they work perfectly. this particular aircraft also had 2 extra stringers added to the belly for a total of 3, similar to a piper. it keeps the fabric much more taunt down there, and adds a little more shape to the belly------ so i heard

BudG · Post by **BudG** » Sun Mar 16, 2008 11:39 pm

Thanks Tom,
I will look into Evergreen. I have awhile before it needs to be done. See you soon.
Bud

TomD · Post by **TomD** » Mon Mar 17, 2008 10:05 am

Two questions come to mind about aluminum stringers.

1. Do the belly stringers contribute to the linear integrity of the airframe? Will substituting aluminum reduce the linear crush resistance?

2. How prone to electrolytic corrosion will the aluminum stringers be in comparison to steel?

I like the double stringer concept.

I don't know if the weight savings of aluminum over stainless is that great. Is it a six pack or only a couple of cans?

TD

TomD · Post by **TomD** » Mon Mar 17, 2008 10:08 am

Two questions come to mind about aluminum stringers.

1. Do the belly stringers contribute to the linear integrity of the airframe? Will substituting aluminum reduce the linear crush resistance?

2. How prone to electrolytic corrosion will the aluminum stringers be in comparison to steel?

I like the double stringer concept.

I don't know if the weight savings of aluminum over stainless is that great. Is it a six pack or only a couple of cans?

TD

aero101 · Post by **aero101** » Mon Mar 17, 2008 10:21 am

The sole purpose of the stringers is to support the outer fabric and otherwise are non-structural. The aluminum extruded stringers such as used in cubs are certainly much stronger then the original wood, but probably not a strong as the chromoly / stainless as maule uses. If stringers are primered prior to installation the galvonic reaction should be kept to a minimum... They certainly work ok in cubs. I think the weight savings is very negligable and actually the chromoly / stainless tube as maule now using, could be fabricated locally for about same cost. So it's probably more a matter of what works for you and whether or not you have access to welding equip?

TomD · Post by **TomD** » Mon Mar 17, 2008 10:22 am

Two questions come to mind about aluminum stringers.

1. Do the belly stringers contribute to the linear integrity of the airframe? Will substituting aluminum reduce the linear crush resistance?

2. How prone to electrolytic corrosion will the aluminum stringers be in comparison to steel?

I like the double stringer concept.

I don't know if the weight savings of aluminum over stainless is that great. Is it a six pack or only a couple of cans?

TD

aussieaviator · Post by **aussieaviator** » Mon Mar 17, 2008 1:43 pm

For what it is worth... I used 1/4" marine ply for the stringers on my M5. The result is strong, light and looks nice with a coat of varnish. I'm sure they will out last me.
Brian

a64pilot · Post by **a64pilot** » Mon Mar 17, 2008 2:21 pm

Aluminum, stainless, marine grade plywood, I don't think it matters in the real world. I try to stay as close as possible to the factory drawings because one day, I hope my Maule sells. If I'm looking at an airplane and start bumping into non-standard stuff I lose interest even if it was airworthy stuff. FWIW, the biggest thing that tripped my recover was the wood bottom stringer collapsing and allowing the control cables to come into contact with the fabric.
I could see how an FAA guy could argue the multiple bottom stringers change the shape of the aircraft and could affect flying qualities. Do I think it would? No, but what I think doesn't matter. It depends on how stupid they are, and I have seen some real winners lately.

aero101 · Post by **aero101** » Mon Mar 17, 2008 5:53 pm

Yes, I agee with you in that if an Inspector sharp enough to even notice the multiple bottom stringers identified them, it could be a real pain getting them approved in some areas!!! They could go as far as require a full test flight program and a one time STC which could end up being very costly!! (Don't laugh, I've seen this happen with less serious stuff) I think the single stringer with Stainless will probably far outlast me!!! The outlaw stuff which I see a good deal of up in this country can present a real challenge when you have to switch shops, or your shop switches IA's, or you get a friendly and knowedgable FAA type who happens to discover? At that point, he'll probably want to look at logs, a thorough look at airplane, etc, etc, etc, and could open a real bag of worms both for aircraft owner and your friendly IA that signed off the last annual inspection. If you can't get it documented and approved, it's not worth doing anymore!!! Risks aren't worth it for owner, the IA, and it can cause a real pain in the rear when trying to sell the airplane...

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