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HoneyBee G2 Design Flaws

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  • HoneyBee G2 Design Flaws

    I apologize in advance for bringing up an old topic that is probably sensitive as some builders never received the kits they paid for.
    I am curious about what may have been the flaws with this design? I read they had issues with the ultralight version and ultimately had a fatal accident in one. I was not necessarily concerned about the design of the Ultralight but the Light Sport single place versions. Were there also design issues with the non-103 single place HoneyBee G2ís? Does anyone have any first hand experience with the HoneyBee G2. What issues were experienced and was it attributed to a bad design? I am also curious if there is anything that could have been improved upon in the non-103 Gyros. One major and valid point I read about is the HTL of the HoneyBeeG2. Could this easily be corrected without a complete redesign such as lowering the motor mount to more of a CLT position? Could this be addressed by raising the horizontal stab into the thrust line? (IE Aviomania Genesis) The reason I am interested the HoneyBee G2 design is that it is the closest I have found to the design I am working on. I work with CNC Mandrel Tube bending equipment at my day job and could easily manufacture something similar. That being said I do not want to start with a flawed design...

    I am not to sure about the engines they were using either or if they had anything to do with the problems at all. I am mainly wondering about the chassis design, layout, and proper horizontal stab etc...
    I greatly appreciate everyone input and wisdom about this topic! I hope I did not rub salt in old wounds or bring up a topic that upsets folks here on the forum. This is purely for research purposes to see if I am even thinking along the right path...

    Thank you all in advance and I look forward to hearing from you on this Subject!

    Best Regards,

    Nicholas Dawson
    Click image for larger version  Name:	E653E405-E186-46B5-935A-6AE23BAB195A.jpeg Views:	2 Size:	508.0 KB ID:	1128902

    Last edited by Flynic3; 01-12-2018, 10:06 PM.

  • #2
    Some feel the high thrust line in relation to the center of gravity is a problem.

    The person who designed it felt that near centerline thrust was a "red herring" and not important.

    I have not flown one so I don't know how well they fly.

    The fit and finish was nice.

    Some of the load paths and the suspension looked a little iffy to me.
    Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

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    • #3
      Vance,

      I greatly appreciate yoir input and thoughts on the subject! It looks like it may not even be worth the hassle but I think they had something going here. I am curious if the designer is still around so I could pick his mind a little. Interesting though from what I read they were based out of Hastings, MI which is where I was looking at training from. I think they may have had a right idea but just could not execute it into a proper design with CLT. I am really interested in what could be done to improve this basic design. Even if I only ending up making one for myself, I think it would he worth it...

      Thanks Again Vance!

      Cheers!

      Nicholas Dawson
      Last edited by Flynic3; 01-13-2018, 10:41 AM.

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      • #4
        Jim Fields designed it.

        The high thrustline creates a powerful nose-down moment. You'd have to test an actual example of the craft to determine the exact location of its CG. The vertical distance between the prop thrustline and the CG determines the lever arm, and hence the magnitude of the nose-down moment. Gyros with a lever arm (thrustline height) of only an inch or two can be stabilized in pitch by their horizontal stabilizers. Once the spread gets up into the half-a-foot-or-more territory, it becomes increasingly unlikely that the H-stab can supply a complete solution. The numbers just don't work.

        None of us should give a bit of credence to what someone "feels" about this sort of design issue. The numbers are black-and-white and cannot be argued with. Four hundred pounds of thrust applied half a foot above the CG equals a 200-foot-pound nose-down torque, period. This is the simple arithmetic of a torque wrench -- not exactly sub-atomic physics. The arithmetic doesn't care what somebody "feels."

        An additional issue with all gyros is torque reaction. Ideally, the tail surfaces should be designed and set up to create a roll torque that counteracts the torque applied to the frame by the engine-prop unit. A tall vertical fin and/or differential incidences on the two halves of an H-stab that's deeply immersed in the propwash, can accomplish this task.

        If these two stability issues aren't addressed in the design, the rotor will stabilize the gyro in most BUT NOT ALL circumstances. The "not all" part is low-G, high-throttle flight. Low G is the same thing as low rotor thrust. With little rotor thrust, either the torque roll or the nose-down pitching torque can flip the gyro in the air. More often than not, the gyro in these conditions executes a combined snap roll and forward somersault, leading to a non-recoverable tumble and fatal crash.

        Other design issues: Flexible fiberglass landing gear is certainly soft, but it's a pure spring, with no energy absorption. This tends to make an aircraft jiggle and bounce on the ground, like an old car with bad shocks. Ideally, landing gear includes a friction device of some sort that turns that "jiggle-bounce" energy into heat, so it's carried away by the air.

        The curved down tube from the mid-mast to the nose may stiffen the mast in a way that we don't want. Two-blade rotors need to be mounted so that the rotor head can "hunt" back and forth a bit. An overly stiff mast forces the blades themselves to try to distort within their plane of rotation, which can lead to cracks in the blades themselves or in the rotor hub. The "gold standard' of mast flexibility is the Bell helicopter system of soft mounting, also visible in the Robinson helicopter.

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        • #5
          Originally posted by Doug Riley View Post
          The arithmetic doesn't care what somebody "feels."

          My coffee mug.
          Click image for larger version

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ID:	1129063

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          • #6
            Good Evening Doug,

            Thank you kindly for the well written and informative post! What you have stated makes a lot of sense and solidifies my current feeling that I should abondon this design concept completely. I thought it may have been a good starting point considering the machines I work with on a daily basis. It was also the closest thing I had seen to the design I have been thinking about. I can bend any type of tubing in any direction at any degree bend angle with no creases. I can bend a tube up to nine times in a single sequence and can even incorporate multiple bend die radius in a single sequence. I have a lot of freedom with these machines to create complex tubular frames of any metal type. I have the machine side down quite well and can make the machine work for me. That being said, I am still learning the Design side and am currently working on getting Solidworks certified through the EAA. I have a lot of learn but am anxious to use the tools at my disposal to create something! I greatly appreciate your input and the wisdom you have shared. It means a lot to me and I appreciate you taking the time to explain this to me!

            Brian,

            I Love the Mug! Very True!

            Cheers!

            Nicholas Dawson

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            • #7
              Nicholas,

              The Airbet Girabet gyros may be more in line with the method of construction you are considering.



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