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  • Taken the first step-

    Got the 4 place B plans ordered today :-)
    General question----- IF.....that is IF.... I start the wings first and the steel tubing later.....
    Does the logical order in which wing parts are made start with ribs and then the spar or the other way round ?
    Seems like I remember someone saying that you fit the spar to the ribs---- implying that ribs should come first .....
    I am asking for the purposes of materials--- and if my 2-nd table needs to be finished now or down the road some.....
    Tim

  • #2
    Ribs first, then bend the spar to fit the ribs.

    It also gives you some practice on the basic processes/workmanship/skills on parts that are less expensive to toss a couple of on "learning".

    Have fun!

    Comment


    • #3
      Thanks BTAZ------
      I am planning on ordering the center bent cores for the spars from Avipro. Getting the Bend radius JUST RIGHT when you are trying to get a 3-rd party to do it---
      AND to NOT get any scratches or booboos--- sounds impossible. I have acess to an 8 foot brake-- but it appears to have been abused and im not sure its up to
      that critical of a job. I should think those might be some of the most critical bends on the whole structure. (quality-wise)

      If i am using the factory core pieces--- do I have to have them BEFORE I make ribs and adjust my rib jig several times until they mate well dimensionally with the spars ?
      I have never built before so the logistics and the logical sequence I dont know yet..... (have torn down several and put back together but never built...)

      Tim

      PS Cant wait to get the plans to start studying..... there are some good youtube videos too.....

      Comment


      • #4
        There's always going to be a bit of variation when scratch building (speaking as a scratch builder myself). If you're buying the spar blanks from Mark, I think I'd wait to get them before bending ribs. I'd say go ahead and start cutting ribs (it's going to take time -- make a few extras), but you might want to wait until the spars are in your hands so you can make sure your bending forms are sized appropriately for the spar blanks.

        ~Chris
        Christopher Owens
        Bearhawk 4-Place Scratch Built, Plans 991
        Bearhawk Patrol Scratch Built, Plans P313
        Germantown, Wisconsin, USA

        Comment


        • #5
          Chris is correct.

          If you are buying the bent up spar webs from Mark, you would need to make your ribs fit the spars and, as you described, you would need to futz with your rib form to make your ribs fit the spar webs. At that point, you would probably be better off buying the rib set from Mark as well.

          It is easier to make the spars fit your ribs as it is easier to iterate the spar dimension than your rib form.

          1. Run the setback calculations to get your overall spar blank height and starting points for your brake sight lines..
          2. Cut a few 3" long by your calculated height test blanks and bend them up on your brake with your foot cover. This allows you to dial in the actual blank height and brake lines so iterate dimensions as required. Note you will also want to dial in the actual bend angles as well during this process.
          3. Bend up your spar webs.

          I had my spar blanks sheared at a local HVAC shop and then used the 8' brake at the local CAF hangar to bend up my spar blanks.

          A key thought process for all of the build is understanding how to accommodate "dimensional tolerance" as you go
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          Comment


          • Bdflies
            Bdflies commented
            Editing a comment
            I like that! 'Accomodate "dimensional tolerance"'

            Bill
            Last edited by Bdflies; 09-23-2017, 09:34 PM.

          • Bcone1381
            Bcone1381 commented
            Editing a comment
            It took me a year to make all the wing, flap and aileron ribs. I learned a lot and developed skills doing that. If you are doing this for the educational value, then be assured that you can turn out beautiful parts. But for me, at that pace, building my wings was going to be a 5 year project, and the entire Patrol was going to be a 20 year project. But, thats me and my skill level....others are faster....BTAZ build his LSA in about three years....amazing!

            Had I considered the cost of my materials, consumables (include router bits), tooling (router, router table) and subtract that from the cost of Mark Goldberg's ribs, I would have bought them from Mark, and been one year ahead of schedule. Its not until I was done that I saw the appealing value in his products.
            Last edited by Bcone1381; 09-22-2017, 09:40 AM.

        • #6
          I think I have 95% of all the tools I will need. All ready have a press with rubber sheets for pressing sheet metal.
          I would like Avi's spar pieces because around here its seems very hard to get amything done correctly. Another factor is that many places refuse to do work that's for
          and airplane.

          I thought of a question about the spar blanks. From what I understand about building aircraft sheet metal parts--- and 4313 --- the conventional approach to making
          a structural sheet metal part is that you never lay out the part on the sheet so that the bend line is parallel to the grain direction. (which is the long way on the sheet)
          When I look at the spar blanks in AviPro's pictures--- they look like they are 8 feet long. How can they be 8 feet long and have the bend line cross wise the grain ?

          Hope the plans might be here some time next week--- cant wait---- !
          Tim

          Comment


          • #7
            The grain question has come up before with regards to laying out the ribs and I believe also the spars.

            The answer was that you will be using a generous enough bend radius to avoid cracking on the bend line.

            Comment


            • #8
              BTAZ-
              For the spars- YES now that you mention it- I do remember noticing that the spar bends seemed kind of big and sweeping (best I can remember) AND i THINK ITS ONLY .032.

              I wouldnt think the ribs would not be as critical as you might have an easier time orienting them on the sheet better.... of coarse- when its bent on all 4 sides maybe it isnt
              quite as obvious which way is best--- i would assume you would optomise strength in the direction of the maximum load on the part. (?)
              I will have LOTS of googleFoo and detail digging and studying of all the details on the plans when they arrive. (study 4 hours- work 30 min. kind of thing -- like when I was
              teaching myself how to build violins)

              I wonder if Bob shows the grain direction for ribs on the plan ? Finding out soon I hope !

              Tim

              Comment


              • #9
                Grain direction is pretty much unimportant for the ribs. Just orient them for best use of space and minimize waste. If you want to have a little wiggle room with your edge flanges so you can be sure to match your spars and still have good edge distance for rivets, you can make your flanges 5/8” instead of 1/2” when you trace them out before cutting. But note that it adds a bit of weight.
                Christopher Owens
                Bearhawk 4-Place Scratch Built, Plans 991
                Bearhawk Patrol Scratch Built, Plans P313
                Germantown, Wisconsin, USA

                Comment


                • #10
                  Fairchild

                  Highly recommend getting Eric Newton's four place build manual if you don't have a few builds already under your belt.

                  If you go to the LSA portion of this forum you will find links to my build logs in my "First Flight" post.

                  Remember, these are indicative of how it can be done, but certainly isn't the only way or the best way.

                  Get and study the Bingelis books from the EAA. Some of it is a bit dated but still very good.

                  Download and look through AC43-13 for acceptable methods for certified airplanes. Tread carefully if you start to stray from it.

                  That will give you plenty to do while waiting on your plans.
                  Last edited by BTAZ; 09-26-2017, 08:52 AM.

                  Comment


                  • #11
                    Can you give me a hint where I go to find Eric Newton's book ? That sounds like a "gotta-have" item. I have a hard copy of AC43-13. I have referenced it many time when doing
                    repairs and projects.
                    Tim

                    Comment


                    • #12
                      Originally posted by fairchild View Post
                      Can you give me a hint where I go to find Eric Newton's book ? That sounds like a "gotta-have" item. I have a hard copy of AC43-13. I have referenced it many time when doing
                      repairs and projects.
                      Tim

                      Comment


                      • #13
                        At the link above, there are three books: Wing, Fuselage, Finishing. He used to offer them in printed form, but now I believe are strictly PDF. Probably the best visual resource out there for building a Bearhawk!
                        Christopher Owens
                        Bearhawk 4-Place Scratch Built, Plans 991
                        Bearhawk Patrol Scratch Built, Plans P313
                        Germantown, Wisconsin, USA

                        Comment


                        • #14
                          Yes Chris- I remember seeing his wonderful site when I first got interested in the bearhawk. Will Have to order that. Looks like it gives a good overview.
                          The plans are near---- have to make a trip to the post office in the morning to pick them up. Hoping they would come via UPS-- but not. Cant wait to see them.!
                          Tim

                          Comment


                          • #15
                            In my opionion your next purchase should be an art portfolio to store the plans


                            ITOYA 18 inch x 24 inch Original Art Profolio Presentation Book/Portfolio- for Art, Photography, and Documents https://www.amazon.com/dp/B00009R8XD..._M9DZzbB20S1PG
                            Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.

                            Comment


                            • Bcone1381
                              Bcone1381 commented
                              Editing a comment
                              Listen to Whee. Thats the one I have and I love it!

                              I've seen builders with out and would not go that way. Prints scattered all over the basement with finger prints. Other builders without have seen mine and were very interested in the ITOYA product.
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