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Wings for my 2+2 project

Hardtailjohn said:
Marty, what kind of strength do you think that adds? I know my sleigh runners gain a bunch from coating with West System....
John
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Not sure of the strength it adds, but the wing sure is solid. The thin ply leading edge was coated inside prior to laminating to the ribs. No drop at all when wash out block removed. I used West System to laminate parts and rather than letting the leftover cure in the can, I coated parts of the wing with the left over. When I was done and had to coat the remaining parts, only 1/3 of the wing needed coating. The wing is very strong and very light weight.

On a side note, when I talked over my decision of wood vs metal, my mentor asked why metal? He pointed out that there is no issues with dissimilar metal corrosion when working with wood. Take a look under the hinge on a Cub aileron or flap when recovering and you will find corrosion between the steel hinge and the aluminum spar. There are issues with wood for sure but with epoxy, water isn't one of the issues.
Marty
 
aktango58 said:
Need 17' spruce? That is easy... I have plenty of clear spruce down and decked, and about to take more down. Give me specifications on RPI and size and I bet I can get it cut here in town.

Sitka Blue Spruce.
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RVBottomly said:
That sounds pretty neat! I'll figure out the specs.

Shipping down here sounds like an adventure, though.

Thanks,
Vic
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That's simple, George flies a 185 on amphibs. Just strap the planks on the floats and fly them to Washington.

Alternatively, why not laminate the spars?
 
skywagon8a said:
That's simple, George flies a 185 on amphibs. Just strap the planks on the floats and fly them to Washington.

Alternatively, why not laminate the spars?
Click to expand...

Of course, what was I thinking? George could take the jaunt down to the Snake River by Swallows Nest Boat launch and I'll do the rest....

As for laminating, it's funny how I've come full circle in 10 months. I was looking at my wing notes from late January of this year, before I got fully occupied with the fuselage build. Last entry says, "check horizontal versus vertical lamination, spruce."

So that was where I was before I got myself diverted to looking at aluminum wings.
 
Laminating spars vertically, as a woodworker, is pretty easy but I would start with 7/8" and after gluing, plane down to the 3/4". It might be hard to get 7/8". If shorter lengths of 3/4" are available, than a scarf joint is perfectly ok. I've seen wood factory spars come out of wings with two or three scarf joints in the wood. There are specs as to where the scarf joints can be relative to lift struts and such bit it is acceptable. I do scarf joints with a hand plane and a scraper, no bit deal for a boat builder.

Marty
 
Regarding wood vs. aluminum wings, a compromise can be made using wood ribs on aluminum spars. This hybrid approach has been done in the past and offers some benefits to some builders.
 
stknrddr said:
Regarding wood vs. aluminum wings, a compromise can be made using wood ribs on aluminum spars. This hybrid approach has been done in the past and offers some benefits to some builders.
Click to expand...

That's exactly what the Wag Aero "Wooden Wing Kit" is made of. Aluminum spars with spacers for the wooden ribs.
 
Marty57 said:
Laminating spars vertically, as a woodworker, is pretty easy but I would start with 7/8" and after gluing, plane down to the 3/4". It might be hard to get 7/8". If shorter lengths of 3/4" are available, than a scarf joint is perfectly ok. I've seen wood factory spars come out of wings with two or three scarf joints in the wood. There are specs as to where the scarf joints can be relative to lift struts and such bit it is acceptable. I do scarf joints with a hand plane and a scraper, no bit deal for a boat builder.

Marty
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Thanks Marty. I get confused with how airplane builders use the terminology. When I say vertical lamination, I think of two or more full-width pieces glued together side by side. Example: you want 3/4 X 6 1/4 spar, then use two 3/8 thick by 6 1/4 pieces.

Horizontal in my way of thinking would be multiple pieces of 3/4 material stacked one on another until you reach the 6 1/4 dimension. (I've done this for sailing spars, and of course I usually make the whole thing a bit oversized to then plane down).

Most of the laminated spar pictures I've seen use the first method (wider pieces glued side by side). That seems odd to me because it seems the advantage of laminating with slightly different grain orientation is reduced.

In any event, I'm up on scarfing. I'm sort of lazy and built a jig for a power planer that worked well on things from marine plywood to 2x8 keelsons.

The only gnawing unknown for me right now is epoxy creep. Our summers often see 115 F in the shade. I'm pretty sure I don't want dark wings.
 
If you are concerned with epoxy creep, post cure your wings. Easy to do. Tent your wing in your garage with plastic sheeting or painters tarps and some moving blankets. Set up a few spot lights inside the tent area to get temp up to about 125-130 degrees, pretty easy to do. Let the wing bake at that temp for 12 hours and all will be cured to that temp. The idea is to post cure above max temp you will be exposed to to prevent creep. I stored my ribs in my attic while living in the desert, about 130 up there in summer. My shop was way over 120 many days so not worried. Another option is to secure wings to saw horses in your driveway and tent with black plastic in the hot sun. Check on temps inside but I bet you can get over 125 degrees inside that set up easy.
Marty
 
Thanks, Marty. That's something I didn't know.

I've seen 130 F in my wood shed often. Sounds like a plan.
 
I used to get really nice vertical grain Sitka Spruce from Flounder Bay Boats in Anacortes WA. I got a few sets of spars for Tcrafts from them and at a great price. If I remember right, there was a lady named Erica that ran the wood yard and she really knew her stuff!! Not sure if they're still in business, but one of the boat supplies around there should be handling cants and resawing. Another supplier that I've had great luck with was Big Sky Stearman in OR.
As far as scarf joints in a spar, my Tcraft had 14 individual pieces in one spar from the factory. They were pretty broke back in 46.
John
 
Hardtailjohn said:
I used to get really nice vertical grain Sitka Spruce from Flounder Bay Boats in Anacortes WA. I got a few sets of spars for Tcrafts from them and at a great price. If I remember right, there was a lady named Erica that ran the wood yard and she really knew her stuff!! Not sure if they're still in business, but one of the boat supplies around there should be handling cants and resawing. Another supplier that I've had great luck with was Big Sky Stearman in OR.
As far as scarf joints in a spar, my Tcraft had 14 individual pieces in one spar from the factory. They were pretty broke back in 46.
John
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Bob and Erica Pickett owned Flounder Bay, but sold out in the early 2000s.

I used to go up there from Tacoma and buy a few things. They had stuff in the storage area that I had only dreamed about.



Sent from my SM-J320V using SuperCub.Org mobile app
 
She was really knowledgeable on wood!! I really enjoyed dealing with her!! There was also a guy down towards Tacoma, Lyle Sindlinger if I remember??...he had a Guiberson powered Stinson SM8....he was also in the wood business. I only met him once......
John
 
Hardtailjohn said:
She was really knowledgeable on wood!! I really enjoyed dealing with her!! There was also a guy down towards Tacoma, Lyle Sindlinger if I remember??...he had a Guiberson powered Stinson SM8....he was also in the wood business. I only met him once......
John
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In the mid 90s we lived in Tacoma and I was always looking for wood, but I don't recall him.

The biggest missed opportunity I had back then was when I met an old contractor who wanted to sell off his inventory of wood. He had around 3000 board feet of clear old-growth douglas fir dimensioned lumber in all sizes, back when the Japanese were buying up all of ours. He wanted $2 a board foot, but I was just starting out a new career and didn't have any place to put it. A few months later I was a bit more flush, but it was gone. Everywhere else that kind of lumber was selling for $5 + a board foot. I was going to build a large ketch, but it ended up being a project not started.
 
I met Lyle Sidlingler in 1979 when I took a driving trip from Kansas City to Tenino,WA to pick up four sets of Hiperbipe wings from the Sorrels. We then made a trip to Hoquiam,WA to buy some extra spruce at Hobie Sorrel's suggestion. There were two business' operating in the same building. Sparcraft mfg and Posey mfg. I was just out of the military and had a pocket full of cash and bought a Pitts special wing kit while we were there. I think Lyle's dad was the designer of the 5/8 scale Hawker Hurricane replica and sold plans for that design for many years. It was a multi story brick building full of wood. It smelled great between all the wood stored and what they were cutting. Back in the day Sparcraft supplied a lot of Pitts and Skybolt wing kits to homebuilders. Anyway thats what name recognition will do for ya'. I'll quit trolling now.
 
We were on vacation in Washington state, visiting the national parks. Seeing lots of mills around, I spotted a small sign on a post advertising speciality woods. I called and explained what I needed. And yes, they started in the business in 1975 selling spruce to the big aircraft supply houses. So, I showed up, the owner rough cut some beautiful spruce for me, wrapped it in blue tarps, loaded it on the roof of my motor home with his fork lift and we continued on our vacation. The mill is still around, McClanahan Lumber in Forks, Washington. Worth a call from looking at their web site. http://www.mcclanahanlumber.com/

Marty
 
Cub junkie said:
I met Lyle Sidlingler in 1979 when I took a driving trip from Kansas City to Tenino,WA to pick up four sets of Hiperbipe wings from the Sorrels. We then made a trip to Hoquiam,WA to buy some extra spruce at Hobie Sorrel's suggestion. There were two business' operating in the same building. Sparcraft mfg and Posey mfg. I was just out of the military and had a pocket full of cash and bought a Pitts special wing kit while we were there. I think Lyle's dad was the designer of the 5/8 scale Hawker Hurricane replica and sold plans for that design for many years. It was a multi story brick building full of wood. It smelled great between all the wood stored and what they were cutting. Back in the day Sparcraft supplied a lot of Pitts and Skybolt wing kits to homebuilders. Anyway thats what name recognition will do for ya'. I'll quit trolling now.
Click to expand...

Sparcraft!!! That's the business!! I have his business card somewhere...I remember it was made of 5 plys of wood and not much thicker than a normal card stock!!!
John
 
Lyle now has more Guiberson diesel parts than he knows what to do with. He still flies the Hawker Hurricane replica that his dad, Fred Sindlinger built, has an Experimental Pacer with, go figure, all wood wings and a Champ. Lyle's a really good guy.
 
Another look at the wings

I ordered some PA 14 drawings from Club Cub and was surprised by the wing drawing.

I laid the PA 14 drawing out on the floor overlaid with the Wag Aero drawing and a printout of the Northland drawing of the wing. The PA 14 drawing is hard to make out, but readable in person.

20190107_195704493088411.jpg

I noticed that the Wag and Northland wings are very similar, but the PA 14 wing has an extra compression strut (aka drag strut on the Piper drawings). Also, the bay closest to the wing is different. The Wag and Northland have a solid diagonal to accommodate the fuel tank. The PA 14 has crossing drag wires. I don't know where the fuel tank was in the original.

Also, the PA 14 has what looks like 16 ribs and no additional nose ribs. The Wag drawing has 13 ribs plus nose ribs, and the Northland has 16 ribs plus nose ribs.

So the original PA14 wing is substantially different. Is it the same as a PA 12 wing in these regards?
 

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