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AR-1 N923DJ Texas 15-12-18

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  • #31
    thomasant, thank you for recounting the incident for us, especially during the Holidays.
    It's given me much to ponder.

    I wish you a Merry Christmas, and a soon return to the skies.

    Kolibri
    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."

    Comment


    • #32
      I always do a power off landings when wind exceeds 15 mph. Lets chance of turblance affecting the lift close to runway. Almost always have much smoother landings.
      http://gyroplanetraining.com/

      Helping Plan a grand 2017 PRA convention


      PRA BOD # 38604

      Comment


      • #33
        I land with some power in turbulence so I have more rudder authority and more options if I find myself sinking or ballooning in all of the gyroplanes I fly particularly anything with a turbocharger.

        It is not unusual to have a fifteen knot wind shear at five of the airports I regularly fly into; all are near the ocean and around 3,000 foot plus mountains. Santa Maria (SMX), San Luis Obispo (SBP), Santa Barbara (SBA), Santa Paula (SZP) and Camarillo (CMA). I have found this may result in an unanticipated sink during the roundout.

        Recently as I turned final at SBP I experienced over a twelve knot head wind that became a seven knot tail wind during my round out. Wind was reported calm on an ATIS that was less than five minutes old.

        During the round out I am consciously looking down the runway so I find it difficult to monitor airspeed.

        I find the lower I get the faster the ground speed appears making my perception of ground speed inaccurate.

        For me sight picture becomes the primary indicator of excess sink of ballooning up. I want to have a consistent
        rate of descent.

        So far I have been fortunate in the timing of wind shear.
        Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

        Comment


        • #34
          During turbulence, the more I think it over the more I prefer my lower round-out at about 2' near the numbers.
          From there I've plenty of runway to bleed off AS and rotor wash, and any wind shear I may experience will have little drama.
          I then touchdown at a walking speed or less.

          YMMV.

          Regards,
          Kolibri
          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."

          Comment


          • #35
            Originally posted by Kolibri View Post
            During turbulence, the more I think it over the more I prefer my lower round-out at about 2' near the numbers.
            From there I've plenty of runway to bleed off AS and rotor wash, and any wind shear I may experience will have little drama.
            I then touchdown at a walking speed or less.

            YMMV.

            Regards,
            Kolibri
            From 2' should not be a problem, it's getting to 2' safely I would think. Nothing that says the wind shear won't strike while you are getting down to 2' before the numbers. I guess the question is what is the safest speed, power setting and attitude to have in a gyro during that period when a sudden loss of lift may occur when one is higher than the aircraft can handle the impact. That's my question for all the CFI's.

            Comment


            • #36
              Think of it from a shooting perspective: a 180gr/2700fps .30-06 bullet drops less over 200 yds than a 350gr/2000fps .45-70 bullet.
              It's a matter of flatter slope.


              ______
              Another thing to clarify is the distinction between loss of AS (from a subsiding gust) and actual downdraft.
              While either will (unless sufficient power is added in time) result in a sudden loss of altitude, it's often more vigorous during a downdraft (thus one's AS must be higher, for a flatter slope as insurance).
              Also, one could simultaneously experience a loss of lift from lessened headwind, and a downdraft. Perhaps that's what happened to thomasant.

              Somebody in another thread (a gyro CFI, no less) opined that
              "Down drafts from rotors don't go all the way to the ground and will not smack a gyroplane right into the runway."

              When I disagreed, he snipped, "You are welcome to cling to your misconceptions that down drafts go all the way to the ground..."

              thomasant experienced some sort of downdraft from 4', and it smacked him right into the runway.
              At least that's the "
              misconception".

              Regards,
              Kolibri


              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."

              Comment


              • #37
                This thread went lively during Christmas. Tony, sorry if I came across incorrect on suggesting pilot error. Wind shear can happen at any time, anywhere. A micro-burst is quite different and much more dangerous. I doubt you had a micro-burst there.

                One should carry 1/2 the max gust speed to normal approach speed for safety in airplanes but I am not sure in rotary wing where there is no wing stall that quite applies the same way. There we need to worry more about getting on the back side of the power curve that will supposedly put us in a vertical descent at a given power setting.
                Gyro CFIs can discuss this 1/2 max gust speed idea and try and justify how that applies to a rotary disc that supposedly does not stall.

                Comment


                • #38
                  According to Britannica: "Updraft and downdraft, in meteorology, upward-moving and downward-moving air currents, respectively, that are due to several causes. Local daytime heating of the ground causes surface air to become much warmer than the air above, and, because warmer air is less dense, it rises and is replaced by descending cooler air."

                  I should add another cause is running into a ground obstruction like a mountain or a building. There will be lift on the windward side and sink on the lee side. This is important knowledge for anyone flying in the mountains or in turbulence.

                  The air has nowhere to go as it gets near the ground because the ground doesnít suck.

                  I personally find it comforting to know that down drafts donít go all the way to the ground when I am in a 1,500 foot per minute downdraft and losing altitude rapidly despite wide open throttle.

                  I spend a lot of time with clients helping them to understand the wind and how it affects a gyroplane.

                  I recommend some time in a glider to help them as pilots to better understand the moving air.
                  Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

                  Comment


                  • #39
                    I recommend some time in a glider to help them as pilots to better understand the moving air.
                    I agree. Having many times soloed in gliders, I think glider flying is a great prerequisite to any kind of piloting.

                    However, I remain amazed at Vance's assertion (first made elsewhere, and repeated in this thread):


                    Down drafts don't reach the ground because there is nowhere for the air to go.
                    I replied:

                    Vance, any downdraft with sufficient energy to reach the ground, will.
                    This is not restricted to merely microbursts.
                    He then wondered aloud:

                    If I am caught in a 600 foot per minute (6kts) down draft please tell me where the wind goes when it gets to the ground.

                    In a microburst it spreads in all directions as it collides with the ground because it is going much faster than 600 feet per minute.

                    This is pretty basic stuff and I cannot imagine why you refuse to grasp it.
                    Apparently, to him, unless a downdraft is at 600+fpm microburst velocity, it will neither reach the ground nor spread out.
                    ????

                    Imagining that some satire might get through to him, I posted:

                    Maybe you're right.
                    I just tried to blow away a piece of lint on the floor, from 2 vertical feet.
                    I couldn't do it because the downdraft of expelled breath didn't reach the ground because the air had nowhere to go.
                    It's amazing how the air knew that, and stopped on its own.
                    Such was unavailing, as he just posted in this thread:

                    The air has nowhere to go as it gets near the ground because the ground doesnít suck.
                    I personally find it comforting to know that down drafts donít go all the way to the ground when I am in a 1,500 foot per minute downdraft and losing altitude rapidly despite wide open throttle.
                    Perhaps somebody else will have better success in explaining to him that a downdraft with sufficient energy to reach the ground, will reach the ground and then spread out laterally.
                    Perhaps he will then be convinced to give up his baffling and dangerous false comfort during 1500fpm downdrafts.
                    Perhaps he will cease misinforming gyro students on the matter.

                    Regards,
                    Kolibri
                    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."

                    Comment


                    • #40
                      "Vance, any downdraft with sufficient energy to reach the ground, will.
                      This is not restricted to merely microbursts."

                      Of course it will reach the ground if it has sufficient energy. It just won't reach the ground as a down draft at the same velocity as it had high above the ground.

                      It appears to me that some people continue to confuse downdrafts with microbursts and imagine that a 600 foot per minute down draft with reach the ground going 600 feet per minute (6.8 miles per hour).

                      The National Weather Service has this to say about microbursts:
                      As it hits the ground it spreads out in all directions. The location in which the microburst first hits the ground experiences the highest winds and greatest damage. Wind speeds in microbursts can reach up to 100 mph, or even higher, which is equivalent to an EF-1 tornado!

                      As I calculate it a hundred miles per hour is 8,800 feet per minute.
                      Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

                      Comment


                      • #41
                        Of course it will reach the ground if it has sufficient energy.
                        Hallelujah, a consensus!

                        It just won't reach the ground as a down draft at the same velocity as it had high above the ground.
                        The same velocity? Whoever said that it would?

                        I only stated that a downdraft could be powerful enough to smack a gyro into the runway. (I.e., no microburst required.)
                        That just happened to thomasant.

                        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."

                        Comment


                        • #42
                          Originally posted by Kolibri View Post
                          Hallelujah, a consensus!


                          The same velocity? Whoever said that it would?

                          I only stated that a downdraft could be powerful enough to smack a gyro into the runway. (I.e., no microburst required.)
                          That just happened to thomasant.
                          A 600 foot per minute down draft is not a 600 foot per minute down draft if it is no longer going 600 feet per minute.

                          The usefulness of that information is; if I am in a down draft that I canít out climb it is not likely to push me all the way to the ground because the velocity will decrease well before it reaches the surface.

                          In my opinion a down draft did not smack N923DJ into the ground.

                          In my experience a wind shear of sufficient magnitude will make the rotor response slow making it difficult to manage the sudden loss of lift in a timely way.

                          Things are happening quickly during the round out and flare with the engine at idle.

                          I wasnít there and I donít know what did happen.

                          I have yet to encounter a down draft of sufficient magnitude that it pushed me into the ground.

                          I have often encountered wind shear strong enough to disrupt my round out and flare.
                          Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

                          Comment


                          • #43
                            So I still have the question is it helpful to have increased groundspeed and / or power input on approach to land with either gusty conditions, or in conditions where wind shear is a possibility? As application of power is considered the correction required when one actually encounters wind shear, so it would seem logical that having more power on approach would make one less susceptible to the loss of lift if wind shear is encountered. Is there something wrong with this logic?
                            I do understand that this may result in a faster landing speed which has it's own hazard, but that is another matter and may be preferable to risking being slammed into the ground from an excessive height. Earlier Brent mentioned power off landings when wind speed exceeds 15mph, and I can understand this when windspeed is constant, but I'd be concerned about trying this in gusty or possible wind shear conditions.
                            I am not a CFI, just trying to find out what the CFI's on this forum think, and why.

                            Comment


                            • #44
                              You are asking about ground speed Jeffery and I feel ground speed is not relevant during the landing till I touch down.

                              I will do my best to answer what I imagine you are asking.

                              In my experience more indicated air speed makes for a higher rate of descent.

                              When I land The Predator in more than fifteen knots of gusting winds I land with power to augment the rudder and slow the descent. More power does not need to result in more indicated air speed.

                              I begin my round out around fifteen feet above the ground at fifty knots indicated air speed and begin reducing speed immediately.

                              The slower I get the more a fifteen knot wind shear is going to affect me and the less distance I have to fall.

                              When I encounter a fifteen knot wind shear at or below fifteen knots indicated airspeed I am essentially in a vertical descent and even with full power The Predator will be coming down fast and the rotor response will be slow and vague.

                              My feeling is eight knots of extra indicated air speed wonít make much difference to my landing.

                              My concern about carrying more speed near touch down is that in my experience having more energy to manage during the landing may exacerbate challenges brought on by gusting conditions.
                              Regards, Vance Breese Gyroplane CFI http://www.breeseaircraft.com/

                              Comment


                              • #45
                                The usefulness of that information is; if I am in a down draft that I canít out climb it is not likely to push me all the way to the ground because the velocity will decrease well before it reaches the surface.
                                One hopes . . .

                                In my opinion a down draft did not smack N923DJ into the ground.

                                In my experience a wind shear of sufficient magnitude will make the rotor response slow making it difficult to manage the sudden loss of lift in a timely way.
                                A wind shear of vertical direction (downdraft) does not cause a "loss of lift " but actually moves the aircraft down while it is within the descending column of air.
                                N923DJ's lift within that column was probably constant (until power was added).
                                The lag time of increased engine thrust were a secondary matter.


                                During the third landing, my recollection is that things were fine till I was about four or five feet and yes, at idle RPM. Ground speed was normal, around 10 mph. In this situation, I felt like I was pulled down to the ground at a faster than normal rate. I opened full power. When powering out, normally it responds without problem and one can feel the climb sensation. Things happened very fast and instantaneously. I knew instinctively that I was going to touch down. When I felt the impact, which was significant . . .
                                Had it been an actual loss of lift (i.e., from decayed gust), he'd have probably also felt the nose dip.
                                He didn't mention that, but only being "
                                pulled down to the ground" followed by a significant impact.
                                To me, that sounds like a smackdown.
                                But, I wasn't there, either.

                                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."

                                Comment

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