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Thread: Wake turbulence, vortices and light aircraft

  1. #1
    WindOnHisNose's Avatar
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    Wake turbulence, vortices and light aircraft

    Watch this closely...35 seconds delay was not enough time from Blackhawk helicopter liftoff to significant trouble for a Cirrus aircraft.

    https://www.youtube.com/watch?x-yt-t...=85114404#t=43

    It is easy to become lackadaisical about avoiding wake turbulence.

    Randy

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    Ouch!, lots of pent up energy when you beat the air into submission!
    Remember, These are the Good old Days!

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    I am wary of helicopter rotor wash. Ours have a base at the light plane fueling dock. I set the brakes when a helicopter is airborne near me.

    In the pattern, they are allowed to cross the fixed-wing flight path. Directly across the airport at 200' below pattern altitude - right where heavy J-3s and 220 Stearmans are - and on approach they fly right through our base leg. I write NASA reports each time a black helicopter crosses my path. They do not get a "clearance" - it is "at your own risk".

    I have had a couple of close calls - black helicopters are almost invisible when below the horizon.

    It will not change until someone dies.

    On the other hand, I have seen Cirrusi do that without benefit of rotor wash.

  4. #4
    TurboBeaver's Avatar
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    Was landing a beaver one time , right behind another beaver as he came into ground effect he spooled back up and I got caught in his prop turbulence and could NOT get out of it! Had to add full power to go out over him and still dam near hit him........... few years later Ketchums on lake hood had a bunch of beavers all departing for McKinley and one of them was right behind his buddy, thd first one lifted off and second one got caught just like me only he was NOT able to get out of it.............. killed everyone in the plane from memory,

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    WindOnHisNose's Avatar
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    Bob and TurboBeaver, excellent points. Thank you.

    Every year I enjoy "flying the river", just north of New Holstein, in the evening. Lou has posted a couple of videos which show the beauty of the flight, and Sarah and Jim Dickerson always get some great photos of the river flying sessions. I remember the first year I did this, and I was really new and green to flying behind other aircraft, and I was unfamiliar with the "wash" that came in the air behind the aircraft just in front of me. I will never forget the first time I did this because I hit some air that sent me into an unusual attitude like right now! Scared the dickens out of me and I discussed this with Steve Lewis and Steve Eaton and they pointed out some of the finer points of this type of flying. I was amazed at the amount of turbulence that was created by our super cubs. I learned real quickly that one needs to position to be above or below, to the left or the right, of the aircraft in front of me.

    Someone told me this also happened at Johnson Creek on departure, leading to some scary moments.

    Randy

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    cubdriver2's Avatar
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    Quote Originally Posted by WindOnHisNose View Post
    Bob and TurboBeaver, excellent points. Thank you.

    Every year I enjoy "flying the river", just north of New Holstein, in the evening. Lou has posted a couple of videos which show the beauty of the flight, and Sarah and Jim Dickerson always get some great photos of the river flying sessions. I remember the first year I did this, and I was really new and green to flying behind other aircraft, and I was unfamiliar with the "wash" that came in the air behind the aircraft just in front of me. I will never forget the first time I did this because I hit some air that sent me into an unusual attitude like right now! Scared the dickens out of me and I discussed this with Steve Lewis and Steve Eaton and they pointed out some of the finer points of this type of flying. I was amazed at the amount of turbulence that was created by our super cubs. I learned real quickly that one needs to position to be above or below, to the left or the right, of the aircraft in front of me.

    Someone told me this also happened at Johnson Creek on departure, leading to some scary moments.

    Randy
    This is why I always try to take off first in front of Joe because his CC climbs so fast that I'm always eating his wake.

    Glenn

  7. #7
    Eddie Foy's Avatar
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    When learning to fly in formation in the Air Force, you quickly learned to avoid the jet wash! It killed a squadron mate that hit it at low altitude during a rejoin.

    Eddie
    "Put out my hand and touched the face of God!"

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    RaisedByWolves's Avatar
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    Quote Originally Posted by cubdriver2 View Post
    This is why I always try to take off first in front of Joe because his CC climbs so fast that I'm always eating his wake.

    Glenn
    Or smoke

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    coxcub's Avatar
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    Watchout downwind of wind Turbines

    Our CAA issued an advisory publication for wind farm developers which, amongst many other things, mentions that the turbulence downwind of a turbine can extend 16 times the rotor diameter.

    I have a particular interest in this as my neighbouring farmer has applied for planning permission to erect one of these monsters on the base leg of my one way strip. The turbulence with the prevailing wind in these parts will cover the whole of the approach/departure path and half the length of the strip! - never mind creating an obstacle.

    The local council refused permission but he has appealed ...........The fight continues!!

    Frank

  10. #10
    skywagon8a's Avatar
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    Quote Originally Posted by WindOnHisNose View Post
    ... I learned real quickly that one needs to position to be above or below, to the left or the right, of the aircraft in front of me.
    Randy
    Randy,
    An aircraft's wake turbulence settles behind the plane. This is particularly obvious while following a large airplane on final approach over the water. You can watch the turbulence hit and disturb the water surface. Also it is possible to learn the wind direction by noticing which side of the approach path the disturbance appears.

    If you are chasing another plane low along a river, you will want to be slightly above the leading plane. Also the larger the plane the greater the wake turbulence. Have you ever been practicing 720* turns in smooth air and run into your own turbulence? I'm sure that you have.
    N1PA

  11. #11

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    Quote Originally Posted by coxcub View Post
    Watchout downwind of wind Turbines

    Frank
    And Above them!
    Remember, These are the Good old Days!

  12. #12
    SteveE's Avatar
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    Quote Originally Posted by WindOnHisNose View Post

    Someone told me this also happened at Johnson Creek on departure, leading to some scary moments.

    Randy
    Yep it did,,, and nowhere to run when it happens, from bystanders and planes. Its easily done as long as the trailing plane takes off first, but in this case the opposite happened and it was a wild ride... That happened maybe 4 years ago now, I cant really remember, and occasionally I still pull seat cushion out of my rear....

  13. #13
    Cubus Maximus's Avatar
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    Took off behind a 90hp Champ once years ago, climbing out behind and below... zero control authority, pointing way nose down and skidding along sideways at 200 ft, survived...never again...

  14. #14
    Cubonaut875 SchulerJL's Avatar
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    Quote Originally Posted by coxcub View Post
    Watchout downwind of wind Turbines

    Our CAA issued an advisory publication for wind farm developers which, amongst many other things, mentions that the turbulence downwind of a turbine can extend 16 times the rotor diameter.

    I have a particular interest in this as my neighbouring farmer has applied for planning permission to erect one of these monsters on the base leg of my one way strip. The turbulence with the prevailing wind in these parts will cover the whole of the approach/departure path and half the length of the strip! - never mind creating an obstacle.

    The local council refused permission but he has appealed ...........The fight continues!!

    Frank
    I regularly fly over wind turbine farms, usually about 400 feet above them - there is a definite chop and bumps even at that height. I could hardly imagine flying behind one of those things. They are a menace and a blight on the countryside.

  15. #15
    cubdriver2's Avatar
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    I fly around or between them once in a while. Like any ground generated turbulence it's different on different days. I got wacked pretty bad in NW Maine just North of Doutens a while back but they are on a steep ridge.
    I'm right in the middle of the farm here



    Glenn
    Last edited by cubdriver2; 02-04-2015 at 12:23 PM.

  16. #16
    kase's Avatar
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    Guy in the Cirrus should of pulled the chute. This pic was on BCP showing turb from turbines.
    Click image for larger version. 

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  17. #17
    little wing's Avatar
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    My closest river run has them from .25-1.5 miles upwind (generally) from, and parallel to, the river. The ridge they set on is 1-300 feet above the river. Even on relatively calm days, winds 7-10, you can still feel some pretty good bumps from time to time. When the winds hit 15+ this can be dangerous, especially if descending below the tree line. Stay above the trees, keep the speed up, and stay vigilant. These damn things are a menace! Trouble is, all the dang city dwellers want them, then they come stick them in my back yard, and anywhere remotely interesting to fly. I wonder how their enthusiasm would be sustained if they were surrounding their precious urban dwellings? BTW, did you notice your bills go down when they installed them near you? Doubt it. Also love how the greenies see then as the greatest thing since sliced bread, many of the same people that hug trees would like to hug the cougars, hogs and bears, sad that they are the leading cause of killing birds that find themselves on the endangered list. IRONY!?!

    Sorry, this is a sore spot with me.

  18. #18
    SuperCub MD's Avatar
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    I was working a wind farm in very hilly terrain and it was starting to blow hard enough that the turbines were all spinning fast. Flew up a ridge under the blades, crested the ridge and pushed over to stay under the blades when a wake/gust or something hit the plane and kicked it about 100 feet left directly at one of the turbine towers. I flew out of it but it was ugly. I don't fly under the blades anymore if it is blowning hard enough to spin them.

  19. #19
    cubdriver2's Avatar
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    Quote Originally Posted by SuperCub MD View Post
    I was working a wind farm in very hilly terrain and it was starting to blow hard enough that the turbines were all spinning fast. Flew up a ridge under the blades, crested the ridge and pushed over to stay under the blades when a wake/gust or something hit the plane and kicked it about 100 feet left directly at one of the turbine towers. I flew out of it but it was ugly. I don't fly under the blades anymore if it is blowning hard enough to spin them.
    They do make a good slalom course but remember the snow condition change daily.

    Glenn

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