Page 1 of 2 12 LastLast
Results 1 to 40 of 47

Thread: Wings for my 2+2 project

  1. #1
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like

    Wings for my 2+2 project

    I'm starting to source materials for the wings on my 2+2 build. That, of course, got me thinking too much and caused me to realize how little I understand.

    The quick summary: The mission for the airplane is moderate cross-country ability with option to access reasonable rough strips in our area (Idaho and Washington). I'm not going to be gonzo, I don't think, because my wife will be flying with me most of the time. We like to go to fishing holes and plan to go to the Seattle area a few times a year (Paine field or thereabouts--280 miles from us). Floats are in the semi-distant future.

    The source of doubt: My Wag Aero plans are for a wooden wing, but you can buy a "wing kit" in aluminum from them. I want to keep the option open for Keller flaps--I contacted Performance STOL and they discouraged use on a wooden wing. Fair enough. I'll go with aluminum.

    I have no drawings for a metal wing for my project (other than Northland's), but the 2+2 plans indicate 2200 GW. My issue is I can't see for myself what is required for a for that GW. I've read fairly exhaustively here about GW increases with spar doublers, etc. I'm nervous about what seems to be a cavalier design.

    I'd like to scratch-build my ribs, and it seems like I could fit a 4.5" rear spar in instead of a 4" one. Is that even done? Can someone point me in the right direction for research?

    Otherwise, after looking at Stewart's Wildcat Cub build, I'm starting to think I want something like that. http://www.supercub.org/forum/showth...l=1#post704442

    I guess the basic question is: how should I scratch build a 2200 pound gross weight wing? What should I look out for, etc.

    Thanks,
    Vic
    Last edited by RVBottomly; 11-28-2018 at 05:21 PM.

  2. #2
    Cub junkie's Avatar
    Join Date
    Mar 2002
    Location
    My Moms basement
    Posts
    1,989
    Post Thanks / Like
    I would emulate the PA18 wing approved for higher gross wt. If you want the keller flaps they fit. I think Javron is the best deal for any exp parts. If you use the PA18 wing planform I would start on them early. You will need to change the wonky designed control cable runs from the 2+2. All personal opinion. Your rate of climb may vary.
    Thanks RVBottomly thanked for this post

  3. #3

    Join Date
    Jan 2007
    Posts
    1,382
    Post Thanks / Like
    A 2 x 2 empty weight should come in around 1300 pounds. Two people +50 gallons of fuel (cross country) is a little more than 700 lbs, that leaves you with minimal weight for baggage, camping gear, camp chairs, stove, cooler, etc. A taller spar is not the answer to the problem. It fails from a twisting motion. Look at Bill’s thread on his cub build and you can see how Jay did it. I would go for a gross weight of no less than 2200 pounds. Also recommend the larger squared wing.
    DENNY
    Thanks RVBottomly thanked for this post
    Likes Beaverpilot liked this post

  4. #4
    Marty57's Avatar
    Join Date
    Jan 2005
    Location
    Nipomo, Ca
    Posts
    1,338
    Post Thanks / Like
    The 2+2 will take any PA18, 12, or 14 wing. You will need to run the cables according to the wing so you will need wings built before finishing the fuselage. Flap handle and pulleys will need to be added for the flaps. On my 2+2, I built the wood wing with stock Super Cub flap bellcrank set-up and I ran my cables inside the wings. The 2200lb gross weight is for the wood spar; had an engineer run the numbers for me and the wood wing is way over built. Weight of my wing without the tank, tank cover or cables came to 64 lbs with all other hardware installed. AOA of the 2+2 is different than the PA18 so you won't get the same short field capabilities but that different AOA gives the 2+2 a faster cruse. I have stock length flaps and ailerons, also all wood. I haven't flown yet, currently working on firewall forward and covering. Scratch building is a big job. Is your fuselage welded up yet? Everything I've done so far is on my web site.
    Marty
    N367PS
    Psalm 36:7 "High and low among men find refuge in the shadow of His wing"
    www.marty2plus2.com
    Thanks RVBottomly, Beaverpilot thanked for this post

  5. #5
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    8,257
    Post Thanks / Like
    Quote Originally Posted by RVBottomly View Post
    I want to keep the option open for Keller flaps--I contacted Performance STOL and they discouraged use on a wooden wing. Fair enough. I'll go with aluminum.
    A properly braced wood spar wing should support the flap loads. It is the bracing which supports the loads, not the spars. I'm curious as to why they discouraged a wood wing. I helped a friend get an STC to install stock -18 flaps on a wood spar J-3.
    N1PA
    Thanks Beaverpilot thanked for this post

  6. #6
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Cub junkie, thanks for keeping me grounded (in a good way). After I read your post I remembered not to try to reinvent the wheel.


    Denny: Thanks for the good points. BTW, one small correction: My wife's small and the two of us weigh around 270. But that 30 pounds doesn't take anything away from what you say. I'll look over Bill's thread more carefully. 900 pounds useful load sounds like a lot, but I know better.

    Marty: Thanks for chiming in! I've studied your website obsessively. I really appreciate the amount of work you've done documenting things. I wish I could do the same, but I'm so short of time. I'm aware of the AOA differences and am fine with that. I suspect magical flaps might help some, but I'm not looking to enter contests, etc. Cruise is at least 50% important to me.

    Yes, I've welded up the fuselage and am working on the landing gear right now. I've been having a pretty good time of it--it helps me decompress from the rest of the demands on my time.

  7. #7
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by skywagon8a View Post
    A properly braced wood spar wing should support the flap loads. It is the bracing which supports the loads, not the spars. I'm curious as to why they discouraged a wood wing. I helped a friend get an STC to install stock -18 flaps on a wood spar J-3.
    I think it was because it was an unknown. I like wood and am comfortable with it, after having built lots of wooden boats.
    Thanks skywagon8a thanked for this post

  8. #8
    Marty57's Avatar
    Join Date
    Jan 2005
    Location
    Nipomo, Ca
    Posts
    1,338
    Post Thanks / Like
    Quote Originally Posted by RVBottomly View Post
    I think it was because it was an unknown. I like wood and am comfortable with it, after having built lots of wooden boats.
    That's exactly why I went with a wood wing; many years building wood boats, guitars, teaching woodworking, etc. Nothing wrong with wood. I have everything on my web site to add wood flaps to the wood wing, all the drawings are there for all the parts.
    Marty
    N367PS
    Psalm 36:7 "High and low among men find refuge in the shadow of His wing"
    www.marty2plus2.com
    Thanks RVBottomly thanked for this post

  9. #9
    aktango58's Avatar
    Join Date
    Aug 2004
    Location
    18AA
    Posts
    8,783
    Post Thanks / Like
    floats, water, you might like aluminum better.
    I don't know where you've been me lad, but I see you won first Prize!

  10. #10
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by aktango58 View Post
    floats, water, you might like aluminum better.
    Hah! I have a 22 year old scrap-wood dory that sits outside year 'round. Still runs the rapids, but I did epoxy-encapsulate it with fiberglass reinforcement. Needs paint from time to time.

    But I'm still leaning toward aluminum because, for one thing, it would be a new fabrication skill to acquire.

  11. #11
    jimboflying's Avatar
    Join Date
    May 2005
    Posts
    463
    Post Thanks / Like
    For my 2+2 I went with Dakota Cub PA12 wing parts and added their flaps according to their drawings. The parts and drawings are first rate in my opinion. They may be able to supply spar doublers. Plenty of work to assemble them and modify them for flaps and their 24 gallon tanks which you may want for cross country and backcountry flying. PA12 wings have the cables inside as opposed to PA18 being external.
    Thanks RVBottomly thanked for this post
    Likes pfm, Nolan liked this post

  12. #12

    Join Date
    Apr 2014
    Location
    Manitoba Canada
    Posts
    131
    Post Thanks / Like
    Areonef out of Quebec has aluminum spar blanks they are beefier than the standard piper spars and I think they are load tested to over 2400lbs. My project came with their ribs and I think I’m going to go with their spars as well. They have a website and you can have a look.


    Sent from my iPhone using SuperCub.Org
    Thanks RVBottomly thanked for this post

  13. #13
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by Beaverpilot View Post
    Areonef out of Quebec has aluminum spar blanks they are beefier than the standard piper spars and I think they are load tested to over 2400lbs. My project came with their ribs and I think I’m going to go with their spars as well. They have a website and you can have a look.


    Sent from my iPhone using SuperCub.Org
    Thanks. I saw that referenced somewhere in an older thread, but I now I can't find anything. Maybe Olibuilt has heard of them?

    I've looked over Bill's thread on the Javron, and see the reinforcing on the spar. I've also noted reinforcements offered by most of the other wing folks. But I'm sensing (from lack of interest in my inquiries) that I'm expected to buy a wing kit before getting to see details.

    Which is fair--someone goes to all the testing trouble, they ought to get reimbursed. But, I'm not really interested in a kit. It's tempting, but right now I'm still in scratch-built mode.

    I'm willing to buy drawings, but so far I'm running into silence. That does not mean I've exhausted my options in trying to communicate--just that I'm too swamped to get very far right now.

    And, to reveal how double-minded I am, I started looking closely again at the wood wings in the drawings I have. I'm getting drawn back in--I love working with wood.

  14. #14

    Join Date
    Apr 2014
    Location
    Manitoba Canada
    Posts
    131
    Post Thanks / Like
    Ollibuilt used his ribs for sure. That’s how I found him.( I have the same ribs and couldn’t identify them at first) marcelblanchette@videotron.ca is aeronef.
    As far as drawings go wouldn’t you be able to use the drawings on Buggs’ site or the Northland drawings-or is there that much of a difference on the 2+2?


    Sent from my iPhone using SuperCub.Org
    Thanks RVBottomly thanked for this post

  15. #15
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by Beaverpilot View Post
    Ollibuilt used his ribs for sure. That’s how I found him.( I have the same ribs and couldn’t identify them at first) marcelblanchette@videotron.ca is aeronef.
    As far as drawings go wouldn’t you be able to use the drawings on Buggs’ site or the Northland drawings-or is there that much of a difference on the 2+2?


    Sent from my iPhone using SuperCub.Org
    The Northland drawings are good for a standard wing, up to 1750 gross wt, I think. But the 2200+ gross weight wings seem to have additional reinforcement.

    The wood wings on the Wag plans go with the 2200 GW, and Wag sells a kit for aluminum wings--no flaps. When I asked for a drawing, I was told they only sell kits....no drawings or custom changes.
    Vic

    Sent from my SM-J320V using SuperCub.Org mobile app

  16. #16
    Marty57's Avatar
    Join Date
    Jan 2005
    Location
    Nipomo, Ca
    Posts
    1,338
    Post Thanks / Like
    Quote Originally Posted by RVBottomly View Post
    And, to reveal how double-minded I am, I started looking closely again at the wood wings in the drawings I have. I'm getting drawn back in--I love working with wood.
    I had an engineer friend run the numbers on the wood spars in the 2+2 wing; they are way over built. Flaps are included in the 2+2 plans as an option but most of the detail is missing. I drew the wood wing layout with the flaps and all the measurements in CAD, here's the link: http://www.marty2plus2.com/wing-layout.pdf

    Next, you will need to modify the aileron hanger for the wood wing slightly for the flap hangar, another link to those drawings: http://www.marty2plus2.com/flap-hanger-outboard.pdf

    The wing attachments on the wood spar change the hinge locations on the flap, another drawing you will need: http://www.marty2plus2.com/full-flap-drawing.pdf

    and the flap hangar at the bellcrank .....http://www.marty2plus2.com/full-flap-drawing.pdf

    I also had the wing analyzed to remove the cross brace that goes inside the tank bay and through the fuel tank. My wing has a sheer plate (1/8") plywood under the tank and the tank now just sets in place on the straps. Removing the tank doesn't require de-rigging the wing. All my cables run in front of the tank, inside the wing for a very clean set up. One other note, with the leading edge skin glued 1/16" ply there are no screw heads under the fabric for a very clean design. When I glued the leading edge on with the washout block set under the outer rib, no drop occured when the block was removed.

    I also have drawings for wood flaps and ailerons, they came from another source and I drew them up in CAD. If you decide to build in wood, I have all the necessary drawings and you are welcome to use them. Considering the number of wood wings on the aerobatic side of things still, wood is a good choice. You will spend more time building but the wood wings are very satisfying to build.

    Wood is a viable option. I've got all the drawings so something to think about; especially if you are a woodworker. You will still get plenty of sheet metal skill development in the firewall forward so lots to learn.

    Marty
    N367PS
    Psalm 36:7 "High and low among men find refuge in the shadow of His wing"
    www.marty2plus2.com
    Thanks RVBottomly thanked for this post

  17. #17
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by Marty57 View Post
    Wood is a viable option. I've got all the drawings so something to think about; especially if you are a woodworker. You will still get plenty of sheet metal skill development in the firewall forward so lots to learn.

    Marty
    You are pushing me over the edge, Marty! I love looking at your photos. I still have plenty of epoxy from my last boat project.

  18. #18
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    8,257
    Post Thanks / Like
    Vic,
    I'm enjoying following your project as I have Marty's. There is something to be said about the beauty of finished wood. Sort of like a piece of fine furniture or jewelry. Wood has been used in airplane construction since day one. The biggest issue as I see it is to protect it from moisture. With the use of modern adhesives and protection coatings, a set of wood wings should outlast you. I've owned old airplanes with wood wings. Pay close attention to where a drop of water could find a home and prevent that location from happening.
    Pssst, I'm sure that Marty would be very proud should you use his plans to produce a set of wings.
    N1PA
    Thanks RVBottomly thanked for this post

  19. #19
    Marty57's Avatar
    Join Date
    Jan 2005
    Location
    Nipomo, Ca
    Posts
    1,338
    Post Thanks / Like
    Quote Originally Posted by RVBottomly View Post
    You are pushing me over the edge, Marty! I love looking at your photos. I still have plenty of epoxy from my last boat project.
    Working on it! My entire wing is coated in West System Epoxy, way better than my first boat. When you put a bolt into the wood, coat the bolt with bees wax to seal the inside of the hole ..... that's after the hole was sealed with epoxy. Best source for Bees wax is the hardware store ..... toilet floor gasket. I've learned a lot from the guys who have built wood wings for years ........

    Marty
    N367PS
    Psalm 36:7 "High and low among men find refuge in the shadow of His wing"
    www.marty2plus2.com
    Likes Beaverpilot, Hardtailjohn liked this post

  20. #20
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by skywagon8a View Post
    Pssst, I'm sure that Marty would be very proud should you use his plans to produce a set of wings.
    Thanks for that, skywagon. His plans have been in my "2+2" folder for over a year. I'll confess to wanting to make a few subtle changes though.... More on that in due course, having to do with flaps.

    I've also been giving a lot of thought to moisture accumulation. That's one place have some practical experience from boatbuilding.

  21. #21
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by Marty57 View Post
    I've learned a lot from the guys who have built wood wings for years ........

    Marty
    I hope you keep passing some of that along.

  22. #22
    Marty57's Avatar
    Join Date
    Jan 2005
    Location
    Nipomo, Ca
    Posts
    1,338
    Post Thanks / Like
    Quote Originally Posted by RVBottomly View Post
    I hope you keep passing some of that along.
    That's the reason for the web site. I have gotten such great help I just want to make it available for others. Still lots to learn.
    Marty
    N367PS
    Psalm 36:7 "High and low among men find refuge in the shadow of His wing"
    www.marty2plus2.com

  23. #23
    Olibuilt's Avatar
    Join Date
    Nov 2009
    Location
    Montreal, Canada
    Posts
    740
    Post Thanks / Like
    I know exactly where those spars are.


    They are a HD version of stock Super Cub spars. I've use them in my Red Cub
















    The numbers bellow are in metric, and French, sorry...




  24. #24
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Oli, thanks!

    BTW, I read French pretty well.

    (ou, je lis le français assez bien...)

    Unfortunately, aeronefmontreal.com is no longer active.
    Likes Olibuilt liked this post

  25. #25
    Cub junkie's Avatar
    Join Date
    Mar 2002
    Location
    My Moms basement
    Posts
    1,989
    Post Thanks / Like
    I like wood but the down side to wood spars anymore is getting them. Wicks has quit selling spars and aircraft spruce sometimes has a hard time coming up with 17 ft blanks. The alternative to spruce is douglas fir but that comes with a higher weight(about 15% stronger) I feel lucky that I got nice blanks from Wicks in 2016 for my champ, $525 ea. I waited 7 months for them to call me and tell me it was my turn. Bottom line is if you like wood you aren't going to be happy with metal wings. Metal allows a much easier path to the Keller flaps if you want those. If you go with metal and you get burned out building parts you can buy piece's as you wish. The wood 2+2 wings as depicted in the plans use mostly J3 wood wing drag wires, compression struts and fittings. The flap option as you know is a drawing of a flap, otherwise you are doing what Marty had to do and free style the flaps into the structure. The original prototype 2+2 had PA12 wings so all the wood wing stuff was done by field builders.

  26. #26
    Hardtailjohn's Avatar
    Join Date
    Jan 2007
    Location
    Marion, MT
    Posts
    621
    Post Thanks / Like
    Quote Originally Posted by Marty57 View Post
    My entire wing is coated in West System Epoxy, way better than my first boat.

    Marty
    Marty, what kind of strength do you think that adds? I know my sleigh runners gain a bunch from coating with West System....
    John

  27. #27
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by Cub junkie View Post
    I like wood but the down side to wood spars anymore is getting them. Wicks has quit selling spars and aircraft spruce sometimes has a hard time coming up with 17 ft blanks. The alternative to spruce is douglas fir but that comes with a higher weight(about 15% stronger) I feel lucky that I got nice blanks from Wicks in 2016 for my champ, $525 ea. I waited 7 months for them to call me and tell me it was my turn. Bottom line is if you like wood you aren't going to be happy with metal wings. Metal allows a much easier path to the Keller flaps if you want those. If you go with metal and you get burned out building parts you can buy piece's as you wish. The wood 2+2 wings as depicted in the plans use mostly J3 wood wing drag wires, compression struts and fittings. The flap option as you know is a drawing of a flap, otherwise you are doing what Marty had to do and free style the flaps into the structure. The original prototype 2+2 had PA12 wings so all the wood wing stuff was done by field builders.
    Cub junkie, thanks for all that info. I think first thing would be to check availability of spar material. A year ago I started looking and was even considering Doug Fir--I have a friend who owns a tree farm and small saw mill in the Blue Mountains. He has some very nice vertical grain stuff in long lengths, but his wood is even heavier than the standard quoted weights in the tables. I decided against it for that reason. I didn't trust myself to try to fiddle with changing dimensions to account for the increased strength.

    I haven't totally foreclosed aluminum, it's just that the equation in my mind works out like this:

    Aluminum wings: "Interesting project--I think I could do it in not too terribly long."
    Wooden wings: "Really? This sounds so cool I can almost taste it."

    As for the Keller flaps, I'm not convinced that there is a real problem. I would probably modify the compression struts anyway, maybe with a truss type system at the flap hinges. But I also am thinking of going with more simplified slotted flaps.

    So it goes. I want to check on spruce availability first before I jump in with both feet. I'm not going to wait 7 months.

    Vic

  28. #28
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by Hardtailjohn View Post
    Marty, what kind of strength do you think that adds? I know my sleigh runners gain a bunch from coating with West System....
    John
    Not speaking for Marty, but from boat building I know that coating with epoxy and fiberglass you get a lot of increased stiffness (and added weight). Coating with just epoxy doesn't add as much to stiffness, but you get a benefit of keeping moisture out.

    But on external curved surfaces subject to flexing forces, it is liable to crack without the fiberglass, and that defeats the water-sealing purpose. That's why wooden plywood boats covered on the exterior with fiberglass and epoxy seem to be a very successful combination. The interior portion is often just epoxied without fiberglass.

    Same goes for strip-planking. But traditional carvel planking (broad thick planks) does not do well with epoxy because those planks are designed to swell when wet.
    Likes Hardtailjohn liked this post

  29. #29
    aktango58's Avatar
    Join Date
    Aug 2004
    Location
    18AA
    Posts
    8,783
    Post Thanks / Like
    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.
    I don't know where you've been me lad, but I see you won first Prize!
    Likes Hardtailjohn liked this post

  30. #30
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by aktango58 View Post
    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.
    That sounds pretty neat! I'll figure out the specs.

    Shipping down here sounds like an adventure, though.

    Thanks,
    Vic

  31. #31
    Marty57's Avatar
    Join Date
    Jan 2005
    Location
    Nipomo, Ca
    Posts
    1,338
    Post Thanks / Like
    Quote Originally Posted by Hardtailjohn View Post
    Marty, what kind of strength do you think that adds? I know my sleigh runners gain a bunch from coating with West System....
    John
    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
    N367PS
    Psalm 36:7 "High and low among men find refuge in the shadow of His wing"
    www.marty2plus2.com
    Likes Hardtailjohn liked this post

  32. #32
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    8,257
    Post Thanks / Like
    Quote Originally Posted by aktango58 View Post
    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.
    Quote Originally Posted by RVBottomly View Post
    That sounds pretty neat! I'll figure out the specs.

    Shipping down here sounds like an adventure, though.

    Thanks,
    Vic
    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?
    N1PA
    Likes Hardtailjohn liked this post

  33. #33
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by skywagon8a View Post
    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?
    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.

  34. #34
    Marty57's Avatar
    Join Date
    Jan 2005
    Location
    Nipomo, Ca
    Posts
    1,338
    Post Thanks / Like
    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
    N367PS
    Psalm 36:7 "High and low among men find refuge in the shadow of His wing"
    www.marty2plus2.com

  35. #35
    stknrddr's Avatar
    Join Date
    Mar 2011
    Location
    Greenville (north east), Wi. U.S.A.
    Posts
    51
    Post Thanks / Like
    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.

  36. #36
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by stknrddr View Post
    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.
    That's exactly what the Wag Aero "Wooden Wing Kit" is made of. Aluminum spars with spacers for the wooden ribs.

  37. #37
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Quote Originally Posted by Marty57 View Post
    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
    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.
    Likes Hardtailjohn liked this post

  38. #38
    Marty57's Avatar
    Join Date
    Jan 2005
    Location
    Nipomo, Ca
    Posts
    1,338
    Post Thanks / Like
    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
    N367PS
    Psalm 36:7 "High and low among men find refuge in the shadow of His wing"
    www.marty2plus2.com
    Thanks RVBottomly thanked for this post

  39. #39
    RVBottomly's Avatar
    Join Date
    Sep 2017
    Location
    Asotin County Washington (KLWS)
    Posts
    307
    Post Thanks / Like
    Thanks, Marty. That's something I didn't know.

    I've seen 130 F in my wood shed often. Sounds like a plan.

  40. #40
    Hardtailjohn's Avatar
    Join Date
    Jan 2007
    Location
    Marion, MT
    Posts
    621
    Post Thanks / Like
    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

Similar Threads

  1. Project help??
    By WWeldon in forum Member Projects in Progress
    Replies: 7
    Last Post: 03-20-2015, 02:08 PM
  2. Wings next project
    By MNSC360 in forum Experimental Cubs
    Replies: 21
    Last Post: 09-22-2009, 06:33 PM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •