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Looking for Bensen information/advice

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  • Looking for Bensen information/advice

    Hello I'm new to this forum and in the process of purchasing a Bensen gyrocopter and was wondering if there is a company that still sells Bensen parts. I will be looking for a pre rotator, a joystick conversion(from overhead type) also rotor blade balancing weights I believe I was told. I have a commercial and flight instructor rating rototorcraft helicopter and have gone through the entire Robinson r22 program including factory training so I'm not afraid of heights. I have always been fascinated by gyrocopters and am now pulling the trigger on one. Thanks in advance for any help

  • #2
    Welcome to the Rotary Wing Forum Dan!

    Please get flight instruction with a qualified gyroplane CFI.

    A gyroplane does not fly anything like a helicopter.

    A Bensen does not fly like other gyroplanes.
    Regards, Vance Breese Gyroplane CFI


    • #3
      Vance is so right. I took 7 lessons in a 2 place Magni gyro with a CFI and for the past 3 months I have been making the transition into my Bensen. I have all of the books from Bensen with flight instruction and I have followed them to the T. THE BENSEN IS A DIFFERENT MACHINE AND TAKES SOME GETTING USED TO.. As far as Bensen parts I have found Mac 90 motor parts from R&D. Nuts bolts and washers along with other hardware from Spruce. My Bensen is complete so I have not had to hunt for any other parts.


      • #4
        Thanks for 're reply. I fully intend on taking some lessons. Do you know of any good places on the west coast?


        • #5
          Give me a call Dan and we can talk about the challenges you may or may not be facing. (805)680-9523 9:00 am to 9:00 pm pacific daylight savings time.

          I train out of Santa Maria, California and that is not close to you. Its about 200 miles south of San Francisco on the coast.

          There is an instructor much closer to you in Cave Junction, Oregon but I need to know more about his Bensen or single place experience. If you want I will explore it with him as he is a friend.
          Regards, Vance Breese Gyroplane CFI


          • #6
            Thanks Vance


            • #7
              Hello Cormax I fly a Bensen and it is a lot of fun, I am wondering about the rotor balancing weights you are talking about. Do you have wood blades?
              David Bacon


              • #8
                Do you have any pics?
                David Bacon


                • #9
                  Dan: What Dave Bacon said. There are lots of present and former Bensen pilots in our community. We can help with the nutsy-boltsy aspects of your project.

                  The old 1 hp engine-driven Bensen prerotator will be hard to duplicate. A Wunderlich flexible-shaft unit will be more powerful, however, and they are readily available from Calumet Air.

                  I believe the plans for the all-steel, homebuilt welded Bensen joystick system are available online. Hundreds of them were built and used over the decades. I haven't heard of anyone offering them as finished goods, but perhaps someone does.

                  Bensen metal rotor blades do not require balancing weights, either chordwise or spanwise. The older wood blades do employ noseweights to achieve chordwise balance. In the Bensen kits, these noseweights were to be made by the builder, using an airfoil-shaped steel strap and poured lead. I'm not aware of any gyro blades that use spanwise weights, though occasionally you'll encounter some that could use some very minor spanwise balancing.

                  The stock Bensen gyro is rather twitchy and unstable by today's standards. The simplistic tail surfaces design presents the possibility of uncommanded torque roll, PIO and nose-down pitching during low-G events. These characteristics have killed literally scores of untrained gyro pilots over the years, many of whom had time in other types of aircraft.

                  The Bensen is also extremely closer-coupled in yaw, so that torque management with the pedals is almost helicopter-like at takeoff.

                  All of these quirks, charms, flaws (or whatever you choose to call them) can be eliminated by various modifications that have evolved over the decades. OTOH, many pilots have learned to compensate for them and fly more or less stock Bensen units. But you must deal one way or another with these oddities or you will be in deadly peril.

                  Good luck -- from just another old Bensen driver.


                  • #10
                    Ya some like Dave learn to fly the stock Bensen extremely well. I , being a relentless tinkerer turned a perfectly good 1966 Bensen into something else. Now it flies more like a Sport Copter and takes a lot less control input. The Ken Brock training video and taking it out to the desert away from all the distractions of an airport helped me get it in the air after 12 hrs. of dual training. Hope you enjoy the experience as much as I have.


                    • #11
                      Ron Herron offers plans for a T-tail he designed for the Bensen that will increase pitch stability.

                      Mike Gaspard
                      Forum Administrator
                      Kaplan, Louisiana
                      Bensen B8MG, NX36MG


                      • #12
                        Gilbert, from your post #10 it looks as if only the "soul" of your Bensen is still stock! All sorts of updating there.


                        • #13
                          IIRC, Gilbert told me he runs his MAC on regular gas, and hasn't had the MAC-attack problems countless others have suffered through. I believe he modified his engine.

                          I remember him telling me he had one engine out w/ his MAC, out on Alvord desert dry lakebed, resulting in a long walk back to his camp to trailer the gyro back. He may have modified the engine after that occasion.
                          Last edited by Kevin_Richey; 08-24-2018, 09:07 AM.


                          • #14
                            Ya Doug Its taller, longer, the seat and peddles are raised for higher CG, has a castering suspension nose wheel with detent centering and adjustable friction dampening, very light weight cable differential brake steering, main gear independent suspension, a decent tail that is a foot further back and weighs less than the old bullet proof stop sign tail, dropped extended tail boom, engine mount has a triangulated light tube mast stiffener going up to the cheek plates. The prerotator is gear drive.None of my mods are for looks and don't add much weight after replacing the original forklift grade wheels. The 90 mac has been ported, balanced statically and dynamically angle knife edge crankshaft port windows and front bearing snap ring, the magnets in the mag are rare earth ones doubling the primary voltage, mikuni carb, streamlined 2 1/2 " exhaust, 52 X 32 prop with home made spinner which slows the engine down and I think is the reason for the head temp being 100 deg. lower than with the recommended pitch prop. There was nothing done to the engine to make it run on non ethanol 92 gas it just does..... without the carbon buildup from 100LL. It only has 200 hrs. on it so a quiet surprise could be coming up.. I only fly it out at the Alvord dry lake where the runway is 11 mi. X 7 mi. smooth and flat.

                            The engine out that Kevin referred to was a mag rotor that came unglued.

                            The tube under the engine is to pull air through the overheated mag.


                            • #15
                              Gilbert, tell us about the tail feathers. That's on my mind at the moment. I'm good with composites but would prefer aluminium. I'm thinking of using some Luscombe stuff I have as a bases for the construction.