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"Ask Bob" Beartracks series

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  • "Ask Bob" Beartracks series

    I almost always work on the Beartracks while I'm away from home, but I've been home more than usual lately. I was proofreading the next quarterly issue and my wife was reading an article about Bob's latest project over my shoulder. For something like this, I will call and talk with him on the phone for a while, take notes, and write the article. Then I send it back to make sure he likes it, and once we make any changes and get approval, it goes out in the newsletter. She wisely pointed out that we should run a series of "ask Bob" questions and answers. So instead of just covering recent events, we could use the same sequence of events to answer questions that builders may have. I'm thinking less about the type of technical questions you need an answer to right now (like what is the diameter of that hole that I can't find noted on the plans) and more of the philosophical type of questions. Like maybe why did you design that ___ that way, or what is something that you didn't like about the design and changed at some point, who knows. You all know! I've already asked him anything I can think of, let's answer your questions. Please send me your questions (web@bearhawkstore.com is a good email address), and I'll queue them up for future issues. The current issue is out for draft approval now and should be available on schedule before the end of the month. Thank you to the subscribers that make it possible to have a newsletter!

  • #2
    Lots of new folks on the forum lately. For those that haven't yet subscribed to Beartracks, you'll find your Return On Investment will be among highest you'll ever see in your lifetime!!!

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    • #3
      Agreed. Beartracks is a great tool and motivator....

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      • #4
        Why are the fuel caps outboard where it is impossible to reach them without a ladder?

        Cessna's often have steps on the side of the firewall and one on the strut With these you can check fuel levels/caps and add fuel from a can when backcountry. Cubs on Bushwheels can be reached when standing on the tire. If my bearhawk caps were inboard I could reach them when standing on the Bushwheels.

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        • #5
          I wonder if it is to put the caps as high as possible considering dihedral?

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          • robcaldwell
            robcaldwell commented
            Editing a comment
            That's what I always assumed... Caps are outboard to account for dihedral.

          • kestrel
            kestrel commented
            Editing a comment
            I expect that is the case, but for some uses, there is quite a bit of lost utility.

        • #6
          I have a question that I’ve already asked on here and not gotten an answer.

          When Bob had his accident what kind of seatbelt harness was he using...

          3 point or 4 or 5 point...

          i think that accident would would have been much worse in an RV all aluminium type plane...

          Bob is very honest and his opinions of the air frame post accident would be very interesting

          One of the best safety features of this plane is the nascar roll cage fuselage ...
          Last edited by way_up_north; 10-09-2020, 01:10 PM.

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          • jaredyates
            jaredyates commented
            Editing a comment
            Sorry about that, I'll add it to the Q4 question list.

          • way_up_north
            way_up_north commented
            Editing a comment
            Thanks Jared ... much appreciated

          • schu
            schu commented
            Editing a comment
            I used to think that then I saw how much energy is absorbed by the beer can crinkling. I watched a few cessna crashes and saw how tough the airframe is, I'm not sure you could say which is safer without specifying the context of the crash and a lot of research.

            To the seatbelt point, it's rare I'll get into a small airplane with anything less than a 4 point harness. The bearhawk should come from the factory with 4 point harness mounts.

        • #7
          Why are his designs called a Bearhawk? I’d love to know the story behind how he got that name for his birds.

          How long does it take Bob to go from idea to release of his first drawings for an aircraft? I know he’s working the Model 5 plans now but those are being Val/verified by the factory. I’m more interested in say the time it took to go from idea to design on say the 4-place A-model.

          just a couple thoughts.
          Bearhawk 4 Place Model B
          Plans #1552
          EAA Chapter 59

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          • Bcone1381
            Bcone1381 commented
            Editing a comment
            Bearhawk...strength of a bear, agility of a hawk.

        • #8
          The original 4 place Bearhawk has a flat slab horizontal stabilizer. All of Bob's wings are aluminum and flush riveted to achieve and more accurate and efficient airfoil. All current Bearhawk models now have airfoiled ribs for the horizontal stabilizer because it works better than a flat slab. What are Bob's thoughts on the weight, pluses and minuses of an aluminum horizontal stabilizer for all the same reasons that the wings are constructed that way? Has he ever evaluated the option? Perhaps with some strengthening (and added weight) to the vertical stab, the drag of the tail wires and braces could be eliminated. I would expect a faster, better handling Bearhawk with, perhaps, a slightly wider CG range. ...but at what weight penalty or other limitations?

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          • way_up_north
            way_up_north commented
            Editing a comment
            it’s funny...I was thinking the same thing..

            On top of the Bearhawk....I’m scratch building a CH-640 with my son and we’re making the aluminium rudder and elevator as I type this...

            I think it comes down to looks....the appearance of the plane would be different ...aluminium would give sharp angles to the tail....and we are used to curved edges like a spitfire on the tail...

            The plane won’t look like a Bearhawk anymore..

            But I agree it would simplify the tail and eliminate costly parts

          • zkelley2
            zkelley2 commented
            Editing a comment
            It's a whole lot more than cosmetics.

            The squared tails have more surface area and by all measures are better. It's why you don't see modern airplane with round tails. 140s have complete crap rudder authority at anything under flying speed. Makes them terrible in crosswinds. 170s aren't great either. You also want the non-rounded rudder under the horizontal for exiting spins. Re-making the rudder square is something I've considered instead of a ventral fin. Don't know if it'd be enough extra though.

            Cantilevered horizontals have less drag. A lot less drag than a strut bearing tail. Variable incidence horizontals also have a lot less drag. They also tend to have a larger CG range. CG through aerodynamics rather than, meh, just fly better.
            Aluminum doesn't deform at speed like fabric lifting surfaces do. Again causing less drag. There's a reason a 180 will walk away from a bearhawk and a Maule.

          • kestrel
            kestrel commented
            Editing a comment
            Svyolo, I am quite aware of Bob's expertise at compromises. ...and that is exactly why I'd love to hear his commentary on this.

        • #9
          I just want to know where Bob gets all his time, to plan, prototype, produce and perfect all these airframes? :-)

          James
          The Barrows Bearhawk: Who knew my wife could get jealous of a plane?

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          • JimParker256
            JimParker256 commented
            Editing a comment
            In my former business (now retired) they used to say "If you want something to get done, give the task to someone who is already busy." Being someone who was already working 65-70 hours a week, I didn't like that saying very much...

        • #10
          Quick note related to the use of harness’s as started above.
          There is a long thread on supercub.org called “a soapbox moment” in which I promote and highly encourage everyone to install the 5th/6th point. Not only does it keep you seated, it helps tie the upper and lower fuselage together.
          If your interested I’m sure google can find it.

          Flying today without shoulder harnesses is simply inconceivable, and if your mission includes low/slow off airport activities I encourage you to get a good race car 6 point harness and use it.

          pb

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