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  • Third Quarter Beartracks is Out!

    I've just sent out the latest issue of the quarterly Beartracks newsletter!

    If you are a subscriber and don't see it in your inbox, please let me know. Paper copies will go out in a few days, and hopefully the content will be available on bearhawk.tips by the end of the week.

    Would you like to become a subscriber? It's only $8 per year, which goes towards paying article writers, and keeping the lights on at bearhawk.tips, and here. You can use this link:


    This issue has several articles that I'm really excited about and hope you enjoy, including Bob Triplett's take on engine choices, after flying a 540-powered airplane vs his 360-powered airplane. Kevin Deutscher kicks off a multi-part series about rigging and improving the way the airplanes fly. His advice is top-notch and should be required reading for all of us. There are a few pages of news, and a piece by Russ Erb about building a bead breaker for changing tires.

    Be sure to save the date for Bob's fly-in on Saturday, October 20th. More details are in the newsletter on page 7.

    Thanks to all of the folks who have supported the Beartracks venture over the years and continue to keep it going by subscribing, and by writing articles to share.

  • #2
    Great issue, Jared. Thanks for your hard work and dedication on our behalf.

    Comment


    • #3
      The article on rigging by Kevin Deutscher hit the bullseye! Looking forward to Q4 for part 2.
      Brooks Cone
      Southeast Michigan
      Patrol #303, Kit build

      Comment


      • jaredyates
        jaredyates commented
        Editing a comment
        I agree! It is very high quality stuff.

    • #4
      I read it through right away as well and enjoyed it a lot. The rigging article had many good points and I also look forward to part 2. One point I wonder about though: if I understood it correctly, he advocated the balance weights to be heavier than what is needed to make the control surfaces truly balanced. From what I understood in reading directions when building our Patrol, it seemed that balance was the goal but error toward too much weight is better than too little. Ours ended up being very close to perfect which is lucky in that the lead amount was added prior to covering with the covering weight an estimate. I would like to understand more of the rational for greater balance weight.

      Comment


      • rodsmith
        rodsmith commented
        Editing a comment
        I had the same question, balanced or slightly nose heavy?

      • robcaldwell
        robcaldwell commented
        Editing a comment
        That's what I read as well... I balanced mine (now covered) based on the manuals and what I've read here to be neutral. The article seems to suggest slightly forward heavy.

    • #5
      Originally posted by Ed.Meyer View Post
      I read it through right away as well and enjoyed it a lot. The rigging article had many good points and I also look forward to part 2. One point I wonder about though: if I understood it correctly, he advocated the balance weights to be heavier than what is needed to make the control surfaces truly balanced. From what I understood in reading directions when building our Patrol, it seemed that balance was the goal but error toward too much weight is better than too little. Ours ended up being very close to perfect which is lucky in that the lead amount was added prior to covering with the covering weight an estimate. I would like to understand more of the rational for greater balance weight.
      Let me reach out to Bob and see if he can give us a ruling. He did tell me that he was headed out to New Hampshire this week, but I'll report back as soon as I'm able to catch him.

      Comment


      • #6
        My understanding is that in a plane that has the max speed range of the Bearhawks - not having the counterweights exact is not an issue. I have been told that 90% balanced is good, and that over balanced is preferable to being under balanced.

        Bob answer would be helpful, but not sure there is the precision of a Swiss watch required here. Mark

        Comment


        • #7
          Mark is correct that 90% balance is adequate and this is this is not a Swiss Watch.
          The elevator is aerodynamic counterbalanced with a mass weight counterbalance placed at the forward most area of the aerodynamic counterbalance.

          If you pick up a completed, covered, painted, balanced
          elevator at the hinge line the desiresble is that the elevator counterbalance head toward earth. Just a little
          overbalance weight is all it takes, we are not trying to
          split hairs and have the elevator remain perfectly level.

          Slightly overbalanced aids in pitch stability in turbulence, hands off stability and return to trim speed and a consistent stick pressure as g loads are applied.

          Comment


          • #8


            "Slightly overbalanced aids in pitch stability in turbulence, hands off stability and return to trim speed and a consistent stick pressure as g loads are applied."

            I am still struggling to understand the why of this. I can understand why aerodynamic balance reduces control forces and I understsnd why mass balanced surfaces reduces or eliminates flutter risk. I also understand how an airplane that is properly rigged and has an appropriate CG is stable and returns to trim speed etc. Just not understanding the mechanism for mass balance in the surfaces affecting these things. I have read that the LSA is a delight to fly with completely unbalanced control surfaces. I love flying and working with airplanes and always like learning more about them...

            Comment


            • #9
              Here's an interesting thread on the subject with some very talented aero and mechanical engineers contributing to the discussion:

              http://www.homebuiltairplanes.com/fo...ead.php?t=2037

              I think the short story is at the speeds we operate at, get it as close as you can and go have fun. When your Bearhawk starts approaching mach, then that's probably a good time to worry about how close your counterweights are.

              Kevin probably has more experience than any of us rigging small aircraft. I certainly take his word for it.
              Last edited by Chris In Milwaukee; 10-05-2018, 10:39 AM.
              Christopher Owens
              Bearhawk 4-Place Scratch Built, Plans 991
              Bearhawk Patrol Scratch Built, Plans P313
              Germantown, Wisconsin, USA

              Comment


              • #10
                I enjoyed Bob Triplett's article on flying a 540 powered BH vs. his own 360 powered. However, I noticed his comment on fuel burn with the 540, and it is a comment misconception. He notes that he burned 14! gallons/hour with the 540 while only 10-10.5 with his 360. Well, I generally burn 10-11 gals/hr with my 540. While the 540's are capable of burning a lot more fuel, and due to their heavier weight might be expected to burn a tiny bit more than a 360, for the same hp and same airspeed, it is just about identical.

                I respect his comments about the effort to retrofit his flying BH vs. the value of building a new one. However, the fuel burn issue needs some objective data to be acknowledged.

                Before I got to know and trust my BH, I burned 13+ gal/hr. But now that I know it, trust it and have some sense of the numbers on the gauges, I have run long trips at 9 gal/hr with a 260 hp, carburetted O-540.

                Thoughts?

                Comment


                • JimParker256
                  JimParker256 commented
                  Editing a comment
                  What speed are you running when you're burning 9 GPH? I had an IO-540 powered Commander 114 that would fly at 9 GPH (LOP), but it was only making about 125 knots at that power setting (versus 150-155 at 12.5 GPH running LOP).

                • kestrel
                  kestrel commented
                  Editing a comment
                  Probably down near 100 kts. I haven't done it for a while, except when flying with Cubs. ...lacking a fuel flow indicator, not really trusting the accuracy of my gauges (IAS, MP, RPM) and not having good tables handy, I don't get good data unless I do a long x-country flight. 9 GPH was around 2100 rpm and 21 inches of MP then leaned as far as would run reasonably smooth (a bit lean of peak). I have an O-540, not IO.

              • #11
                Bearhawk272:

                Your last sentence cleared up my question as well. I read in a few places that overbalancing was better than under balancing. I never thought of G-loads or TB. Makes sense now.

                Comment


                • #12
                  I really enjoyed the performance that I saw in Mark’s airplane. I was honored that he untrusted me with that responsibility. I tried to fly it conservatively so that I could return it in the condition in which I found it. Max Conrad in his articles about this engine would indicate that the engine is capable of less fuel burn than I saw. My plane is a nice compromise but the 250 will out perform mine hands down. Other than speed I don’t think there is anything certified or uncertified that will perform any better than a Bearhawk ( horsepower to horsepower) in the four seat category. Build your plane light with either engine and you will have a great performing plane. I try to address maintenance issues on an ongoing basis since I have the repairmans certificate. My condition inspection will cost zero this year. In my estimation an experimental is the only way to go.

                  Comment


                  • #13
                    Hi Jared...I wanted to subscribe to the Beartracks newsletter as I'm in the process of getting ready to build a 4-Place but I do not have plans or a kit yet. When I tried to register the form is requiring Plans and Plans S/N..which I do not have. Does one need to be an actual builder to subscribe?

                    Thanks,

                    Kyle

                    Comment


                    • jaredyates
                      jaredyates commented
                      Editing a comment
                      I've sent you a PM, let me know if you don't get it!

                  • #14
                    Hey Jared, Ive tried to register for the access for the 1995-2001 beartracks as being a plans holder but the site will not let me register for access. Is there something else I need to do??

                    Comment


                    • jaredyates
                      jaredyates commented
                      Editing a comment
                      From my end you should be able to see the 1995-2001 already, since early August of this year. Send me an email if you are getting denials, we'll try and figure out why.
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