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  • #16
    Originally posted by Steve_UK View Post
    Not so long ago Air Gyro were the US representatives for AAT, having imported Tercel N557AT and three seater Taurus N553AT, plenty of marketing about this on both companies websites.

    http://www.airgyro.com/page6/performance.html

    http://www.trendak.eu/en/aat-visiting-america/
    So they started with AAT then switched to CA or are they still representing AAT? The confusion never ends with these companies. Sounds like Air Gyro wanted their own aircraft, so to speak. I wonder if flight qualities had anything to do with the switch to CA or if it was all business?

    Comment


    • #17
      Originally posted by Vance View Post

      This is a good example of the challenge a flight instructor faces when they solo someone.

      It appears he invented his own take off technique.
      Reading the full pilot's narrative, I can see why a CFI (who has a student wreck the aircraft on their solo) might feel frustrated.

      This particular fellow lists several possible reasons why his accident happened, including:

      1.The missing oil reservoir cap that mysteriously re-appeared at the accident scene which may have hindered his ability to have full back stick position.

      2. The teetering hinge used in gyroplane rotor systems that initially is easy to move the stick, and then requiring subsequently increasing force to move to full forward or rearward stop limits.

      3. His repeating back to his instructor the steps to solo takeoff, which include to apply full power. No mention of slowly adding that full throttle while observing increasing rotor rpms, as I believe a CFI would teach. I suspect full throttle was slammed in ALA airplane mode, and rotate when airspeed is sufficient. No waiting for the levitation, which is preceded by a nose that starts rising, and countering stick/rudder inputs needed at that time.

      4. He states that the three gyro instructors only told him to move his stick back further, instead of explaining why it needed to be back more. Huh? If true, he had no knowledge of autorotating wings and how they require being nursed up to speed. I particularly find that hard to believe, from three different gyroplane CFIs.

      5. His suggestion that CFI training be changed to help students not do what he did.

      6. His suggestion that simulator training might be helpful to future students, to see the video of what happened to him.

      7. His prior fixed-wing experience being a possible reason why he initiated lifting the nose of the gyroplane, because of muscle memory from doing so in airplanes. His doubts that most gyroplane students have any airplane experience.

      He doesn't write anything about his CFIs teaching him to monitor the rotorblades rpms as he slowly accelerates his take-off roll. Nor any mention of matching his airspeed (from increasing the throttle) to the rotors gaining rpms.

      I find it hard to believe that any of his CFIs not teach him about how doing 45 mph and not having to use right rudder and right stick in a take off might indicate a problem. Then, he says the gyro was at 61 mph and no nose movement and no rudder movement that was usually required, so he initiated the rotation.

      Several cell phone video stills are included. Hard to tell, but the first shot looks like the rotors might not be perfectly straight out from centrifugal force, like they might be flapping already.
      The big horizontal tail of the Zenon/AT/Tercel makes it easy to see the attitude of the gyro when it was so far away in the 2nd, 3rd, and 4th photos.

      https://dms.ntsb.gov/pubdms/search/d...763&mkey=98052
      https://dms.ntsb.gov/public/61500-61...763/619773.pdf

      Comment


      • #18
        Thank you for posting the pictures Kevin.

        I used them as a teaching aid just this morning.

        I try to keep it simple.

        If the cyclic was full back to begin the takeoff roll there was no way to lift the nose by pulling the cyclic back.

        It appears to me the retreating blade stalled because it was not up to flight speed when he tried to rotate.

        I have a client who is a high time helicopter pilot with considerable gyroplane experience and instruction and he said the pictures and my explanation helped him to understand something that he had heard about and wondered about.

        Successful communication is the goal of flight instruction and this is a nice tool.
        Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

        Comment


        • #19
          I am wondering how the upper mast, rotorhead, and rotorblades became unattached from the lower mast structure (as seen in photo #1) in the accident without any apparent damage to that lower mast section.

          One would think there would be torn sheet metal from the skin (or fiberglass) and the visible lower mast would have some deformed attachment.

          Comment


          • #20
            That Tercel N557AT rotorhead/mast breakage is not unique. On the right is another machine. Not much material there.

            Click image for larger version  Name:	Tercel - Xenon rotorhead-mast breakage.png Views:	1 Size:	779.8 KB ID:	1142806

            Click image for larger version  Name:	Xenon rotorhead-mast breakage.png Views:	1 Size:	436.5 KB ID:	1142807

            PP - ASEL complex (C172RG, Piper 180, C206, RV-7A), SP - Gyro (Calidus, RAF, Sport Copter II, M912), soloed in gliders

            "
            When an honest but mistaken man learns of his error, he either ceases to be mistaken -- or he ceases to be honest."

            Comment


            • #21
              There have been no mast separations in flight for the Tercel reported to the NTSB to date.
              Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

              Comment


              • #22
                Personally, I would be uncomfortable flying any gyro which broke like that from merely a take-off tip-over.
                I hope that owners will often and carefully inspect that area.

                Also, the Xenon-type gyros seem to have a weaker mast than others, breaking off from below.
                These separate examples aren't the only ones:


                Click image for larger version  Name:	Xenon N912XV 20170417.png Views:	1 Size:	999.0 KB ID:	1142817

                Click image for larger version

Name:	Xenon flung rotor and upper mast.jpg
Views:	1
Size:	496.7 KB
ID:	1142818

                PP - ASEL complex (C172RG, Piper 180, C206, RV-7A), SP - Gyro (Calidus, RAF, Sport Copter II, M912), soloed in gliders

                "
                When an honest but mistaken man learns of his error, he either ceases to be mistaken -- or he ceases to be honest."

                Comment


                • #23
                  Originally posted by Kevin_Richey View Post
                  I am wondering how the upper mast, rotorhead, and rotorblades became unattached from the lower mast structure (as seen in photo #1) in the accident without any apparent damage to that lower mast section.

                  One would think there would be torn sheet metal from the skin (or fiberglass) and the visible lower mast would have some deformed attachment.
                  There is a large amount of stored kinetic energy in a rotor system at flight rpm Kevin.

                  Contact with the ground at near flight rotor rpm releases that energy suddenly and the weak link either bends or breaks.

                  Looking at the absence of injuries and the minimal damage to the rest of the aircraft after a rotor strike; having the mast break away clean like that may be a safety feature Kevin.
                  Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

                  Comment


                  • #24
                    The mast construction is very different on the Xenons compared to the 2 place tub designs. Mast shearing off might just suggest that the mast has a rigid attachment to the fuselage, whereas most tubs are welded stainless steel with the mast welded in such a way it is more likely to bend before it breaks.

                    As Vance points out, if this was a problem it would have shown itself by now. These models have been flying for a decade or more now.

                    It seems no gyro design can handle blade flap very well.



                    Jordan

                    Comment


                    • #25
                      Contact with the ground at near flight rotor rpm releases that energy suddenly and the weak link either bends or breaks.

                      Looking at the absence of injuries and the minimal damage to the rest of the aircraft after a rotor strike; having the mast break away clean like that may be a safety feature
                      While I'm relieved that nobody was struck by the detached mast/rotor, let's be honest: such non-injury cannot be assured, and is mostly a fluke.

                      The SCII that had the rotor strike during a rushed take-off at Van Nuys stayed completely intact, but twisted the mast/firewall mounts.
                      I'd prefer that result vs. a buckled over or broken mast.


                      _________
                      if this was a problem it would have shown itself by now. These models have been flying for a decade or more now.
                      JAL, while that seems compelling on its face, I suspect that many gyro owners are flying on much less margin of strength than they know.
                      This was certainly true for me when I was flying on the OEM RAF rotor system.

                      Remember, a gyro isn't stressed only in the air, but also from ground handling. The softest grass has corrugations and can be rather jarring.
                      I've become a big believer in actual suspension on gyros, vs. merely a spring leaf main gear and rigid nosewheel.
                      The contrast between the Sport Copters I've been flying, and my RAF, is stark -- and the Eurotubs aren't much better.

                      Folks: please often and carefully check your mast and blades for crack initiation/propagation, especially after a few hundred hours.
                      Some companies have specific SBs about this (e.g., AutoGyro).

                      Regards,
                      Kolibri
                      PP - ASEL complex (C172RG, Piper 180, C206, RV-7A), SP - Gyro (Calidus, RAF, Sport Copter II, M912), soloed in gliders

                      "
                      When an honest but mistaken man learns of his error, he either ceases to be mistaken -- or he ceases to be honest."

                      Comment


                      • #26
                        Originally posted by Kolibri View Post
                        While I'm relieved that nobody was struck by the detached mast/rotor, let's be honest: such non-injury cannot be assured, and is mostly a fluke.

                        Regards,
                        Kolibri
                        "Mostly a fluke" it typical of your hyperbole and fear mongering.

                        It would be nice if you would be honest.

                        I don't know why you feel you need to make things up about how dangerous a gyroplane is Kolibri.

                        I feel your unfounded fantasies misdirect pilot's efforts to mitigate the risk that is inherent in flying.



                        Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

                        Comment


                        • #27
                          I'm sorry you feel that way, Vance.
                          When a broken blade or broken mast departs, the pilot cannot control where it goes or what it impacts.
                          It is thus a matter of luck -- not pilot skill -- that nobody is hurt.
                          This is not what I would describe as a "
                          safety feature".

                          I don't know why you need to apologize for gyros of questionable structural strength, especially as they acquire 300+ hours on them.

                          Regards,
                          Kolibri

                          PP - ASEL complex (C172RG, Piper 180, C206, RV-7A), SP - Gyro (Calidus, RAF, Sport Copter II, M912), soloed in gliders

                          "
                          When an honest but mistaken man learns of his error, he either ceases to be mistaken -- or he ceases to be honest."

                          Comment


                          • #28
                            Originally posted by Kolibri View Post
                            I'm sorry you feel that way, Vance.
                            When a broken blade or broken mast departs, the pilot cannot control where it goes or what it impacts.
                            It is thus a matter of luck -- not pilot skill -- that nobody is hurt.
                            This is not what I would describe as a "
                            safety feature".

                            I don't know why you need to apologize for gyros of questionable structural strength, especially as they acquire 300+ hours on them.

                            Regards,
                            Kolibri
                            If the rotor separates after impact it has already used up a lot of the stored kinetic energy.

                            The pilot and the passenger are the ones most likely to be in the vicinity of the energy that is left.

                            I feel it may be safer to have the rotor depart the aircraft after impact.

                            Several pilots and one passenger that I recall have been killed by being struck by a rotor that stayed attached to the mast after impact with the ground. As far back as I read the NTSB reports no bystanders have been killed by a detached gyroplane rotor assembly.

                            You have continued to promote fear and ignorance about problems that only exist in your imagination Kolibri.

                            You continue to demonstrate your ignorance about even the simplest engineering concepts and an unwilling less to back off of your untenable claims when confronted with facts.

                            This accident, the pilot's narrative and the pictures are a wonderful example of how to crash a gyroplane on takeoff.

                            I have already used it successfully as a training aid and will continue to do so.

                            I try to promote reality because I feel your rants direct people away from the demonstrable hazards of flying a gyroplane Kolibri.
                            Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

                            Comment


                            • #29
                              If the rotor separates after impact it has already used up a lot of the stored kinetic energy.
                              Not as much as you imagine:


                              AutoGyro Calidus 83-AMW 20141024 gusty, fell from 25m, half of blade thrown 600+ feet

                              Click image for larger version  Name:	AutoGyro 83-AMW 20141024 le-dl-1414157554.jpg Views:	1 Size:	223.9 KB ID:	1142894




                              ELA 07 N534EA 20180508 taxi turn tip-over, 5’ rotor end piece thrown 350’

                              Click image for larger version  Name:	ELA 07 N534EA 20180508 with missing blade piece.JPG Views:	3 Size:	130.2 KB ID:	1142893



                              The pilot and the passenger are the ones most likely to be in the vicinity of the energy that is left.

                              I feel it may be safer to have the rotor depart the aircraft after impact.

                              As far back as I read the NTSB reports no bystanders have been killed by a detached gyroplane rotor assembly.
                              Again, this relies upon luck, something bystanders may not have:


                              Click image for larger version  Name:	Rotor debris is safe-5.png Views:	1 Size:	728.3 KB ID:	1142890




                              Several pilots and one passenger that I recall have been killed by being struck by a rotor that stayed attached to the mast after impact with the ground.
                              An easily buckling mast and spaghetti-like blades could indeed jeopardize cabin occupants.
                              Regarding the
                              "one passenger" you seem to be referring to the Ortmayer trainer with the old-style RAF hub bar and blades.
                              Regarding "several pilots" you'll have to cite specifics, but meanwhile I suspect that any such incidents will be classic examples of masts and blades lacking rigidity.

                              From a companion thread, I appreciate the below from Doug Riley:

                              But, though it may hurt me instead of somebody else, I think the blades ought to stay attached in a strike.


                              I have consistently advocated robust 4130 chrome-moly masts with blades strong enough to not pretzel or fly apart from impact.
                              Currently, only two gyro manufacturers provide such to their customers.

                              I am sorry that you seem to believe that this does not matter, or has no bearing on pilot safety.

                              Meanwhile, I'll stick with my "
                              rant" previously expressed:

                              Personally, I would be uncomfortable flying any gyro which broke like that from merely a take-off tip-over.
                              I hope that owners will often and carefully inspect that area.
                              PP - ASEL complex (C172RG, Piper 180, C206, RV-7A), SP - Gyro (Calidus, RAF, Sport Copter II, M912), soloed in gliders

                              "
                              When an honest but mistaken man learns of his error, he either ceases to be mistaken -- or he ceases to be honest."

                              Comment


                              • #30
                                It is all about priorities.

                                When I fly and air show I am required to be 500 feet from the crowd. I don’t recall ever landing close to people.

                                The gyroplane Kolibri claims to fly doesn’t have a robust 4130 mast and he will sell it to someone as is when he gets his Sport Copter.

                                In my opinion there is nothing wrong the mast on an RAF despite it not being 4130 or particularly robust.

                                In my opinion there is nothing wrong with the mast on a Tercel.
                                Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

                                Comment

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