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Thread: prerotator and full throttle

  1. #1

    prerotator and full throttle

    Question, On the other forum Desmond cites that he goes full throttle after prerotating regardless of the gyro. I was taught that you advance the throttle gradually in order to keep from flapping the blades.
    Two different opinions, why?
    Haven't there been a lot of blade flap problems this year. Could this be the reason?

    K. O

  2. #2
    PRA Secretary JOHN ROUNTREE 41449's Avatar
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    Actually he's explained it further and you can see from the video that he is slowing advancing the throttle only it is as soon he takes the runway.

    The thing that is different is while prerotating below 150 RRPM he holds the blades in neutral with no or little angle of attack. Else he states it can tip you over and flap the blades too IIRC.

    When you hit 150 RRPM you move the stick back when it's hits 200 RRPM he applies full power.

    However in the MTO that is about when it is balancing on it's mains with this procedure and you are ready for take-off at that point and you always apply full power once your blades are up to speed.

    At least that is my lay interpretation as I have never practiced that maneuver.
    Last edited by JOHN ROUNTREE 41449; 08-24-2015 at 07:06 PM.
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  3. #3
    Quote Originally Posted by JOHN ROUNTREE 41449 View Post
    Actually he's explained it further and you can see from the video that he is slowing advancing the throttle only it is as soon he takes the runway.

    The thing that is different is while prerotating below 150 RRPM he holds the blades in neutral with no or little angle of attack. Else he states it can tip you over and flap the blades too IIRC.

    When you hit 150 RRPM you move the stick back when it's hits 200 RRPM he applies full power.

    However in the MTO that is about when it is balancing on it's mains with this procedure and you are ready for take-off at that point and you always apply full power once your blades are up to speed.

    At least that is my lay interpretation as I have never practiced that maneuver.
    John let me try to clear this up where the Euro's are wrong.

    The gyro is not ready to fly at 200 RPM on any given day.

    When the front wheel picks up, the blades are up to speed for flying.

    What if the pilot has a strong head wind?
    What if the pilot has a light breeze and decides to take off downwind?
    What if the temperature is 40 deg F?
    What if the temperature is 95 deg F?
    What if there is one pilot?
    What if two people are in the gyro?

    In reality there is not set RPM for the blades. It varies with wind,temperature,humidity,weight, and even the cleanliness of blades from bugs and such.

    My blades have more pitch. They are tipping the front wheel at 180 RPM average. Some days its 250 RPM. Way to many variables.

    My blades cruise fully loaded at 320 RPM. So from tipping the front wheel to full flight speed is about 140 RPM difference.

    Most Euro's cruise closer to 400 RPM So from pre-rotate to flight cruise is 200 RPM difference. Doesn't it make sense that that is way to much difference in flight speed to assume that 200 is the perfect RPM to go full throttle?

    I'm think they need to change the way they pre-rotate and learn more about blade handling.

    I think going to 200 RPM in the Euro's, then increasing power over a 6 second move to full power would solve most of the flapping they have incurred in the last year or so.

    Just my opinion.

  4. #4
    So, training in a MTO (or Euro) and then transitioning to a Dominator ( or any light weight single place) would be a problem! Unless the instructor is on a radio with the student instructing when to move the trottle and the correct position of the stick. How many CFIs help the student in the students gyro (light weight)?

    K. O

  5. #5
    At the CFI meeting in Mentone this year Ron Menzie ask who would train a pilot in there own single place machine.

    With a show of hands. Ron Menzie, Gary Goldsberry, Steve McGowan, and I were the only ones.

    Not sure about other CFI's who were not at Mentone this year.

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