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AR-1 N923DJ Texas 15-12-18

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  • Originally posted by GyrOZprey View Post

    The VIRGA-effect was experienced by Greg Gemminger ...when a group of Magni fliers did a tour out to Southern Utah several years ago! Great trip as narrated ..but above ALL ...I remember the experience that one pilot ( ???maybe Greg??) had when flying under a cloud shedding virga ...the scary experience as narrated IMPRESSED upon me ...NEVER fly under VIRGA! ...On my flights in FL two years ago & in Australia April 2017 I was very careful to give the innocent-looking little grey clouds with the pretty virga-veils of evaporating moisture ...a WIDE berth!
    Here is what Greg wrote about virga in another post:
    "In the high and hot New Mexico desert several years ago, I ventured leisurely flew into a "dry microburst" under a virga cloud. I entered the microburst at 600 ft and 60 mph circling over a friend on the ground. 5 - 10 seconds later I flew out the bottom of a severe downdraft at about 100 ft. (Microbursts can have downdrafts up to 200 ft./sec). It was not fun! It was very scary! It was turbulent, and the stick initially was beating up my legs for a second or so - a lot of rotor flapping! I was lucky to get out of it before hitting the ground! When I was hit by the microburst, I remember an initial sudden but short upward strain on my seat belt - negative Gs! But the gyro also suddenly nosed up with sudden high airspeed indication. I went to quick full turbo power and pushed the nose down to try to keep airspeed down to about 90 mph to try to arrest the sudden rapid descent and get out of the downdraft. All the while I was yelling on the radio to my flying compatriots about my situation. This was obviously the sudden and strong downdraft you and many others have always said would be the initiator of a buntover (or PPO in a HTL gyro.) Sorry, I am not dead! The gyro never even tried to tuck it's nose or buntover. I maintained level roll and straight ahead direction control throughout. I certainly cannot say a CLT saved me! In truth, I am very grateful to the Magni factory to have provided a design that can handle all those nightmare scenarios suggested by the pure CLT preachers. I thank God and Magni for the BTWB, the high inertia rotor, and the super strong structure and rotor - the things I credit for my survival! (I also now know to avoid virga!)"

    Comment


    • "Pure CLT" isn't necessary to make a gyro angle-of-attack stable. An effective horizontal stabilizer will do just as well.

      BUT the key word here is "effective." The design and placement of the H-stab must be such that, among other things, the nose rises to meet downdrafts, even at wide-open throttle, at any airspeed. Greg doesn't say if he was at WOT, but he implies not, as he says he "leisurely" flew into the virga at altitude at 60 mph.

      Creating an H-stab arrangement that does the job on a HTL gyro at all throttle settings and airspeeds is not easy. Most simple amateur attempts are NOT adequate to stabilize a gyro with significant HTL. The more powerful the engine, and the higher the HTL, the more difficult it becomes to make the H-stab adequate. A foot of HTL, a low-placed body pod, and 600 pounds of thrust, as we see on some gyros, make the task just about impossible. CLT makes the design task much, much easier.

      Another war story: I once carelessly zero-G'd my Gyrobee while frisking around right after takeoff. I wanted to execute a brisk climbing turn. I intentionally dropped the nose to grab some airspeed while at full throttle. When I felt the seatbelt go tight, I thought "WTF? That was stupid." I was probably doing 65-70 at the time. Stupid or not, nothing scary happened. The nose did not continue to drop beyond the amount I had commanded with the stick. This Gyrobee had the Watson H-stab (6 sq. ft., airfoil section, tip plates, 3 deg. negative incidence and a location in the propwash, 5 feet aft of the CG). To me. it flew just like a Dominator, despite a couple inches of HTL.

      Comment


      • Originally posted by Tyger View Post
        I am very grateful to the Magni factory to have provided a design that can handle all those nightmare scenarios suggested by the pure CLT preachers.
        I think he can especially thank the particular direction of the burst that has increased its forward speed on its horizontal tail.
        The same burst coming from behind rather than forward, might have made him regret not having bought a CLT.
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        Comment


        • Interesting point, Jean Claude, but the Magni tail does seem to be pretty effective even at low airspeeds.

          Comment


          • Below is AutoGyro's Height-Velocity Diagram for the MTOsport, with a recommended blue dashed line describing precisely
            the flat and low roundout/flare that I portrayed in my green line.

            One takes risks at 20 feet/30mph IAS and 4 feet/10 mph IAS.

            Safe flying,
            Kolibri


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            PP - ASEL complex (C172RG, Piper 180, C206, RV-7A), SP - Gyro (Calidus, RAF, SC2), 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."

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