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C. Beaty
Gold Supporter
Last Activity: Yesterday, 07:36 AM
Joined: 04-16-2004
Location: Florida
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  • It is refreshing to see that originality is alive and well in France....
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  • C. Beaty
    replied to Mike Goodrich Visit to FD92
    in News
    JC, I donít have a rational explanation for my empirical experience with 2/rev vibration. I selected round tube for my airframe because it was available and I chose tube size to approximately match the stiffness of the Bensen square tube airframe.

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  • C. Beaty
    replied to Mike Goodrich Visit to FD92
    in News
    My knowledge of round vs square masts is primarily empirical, JC.

    My first gyro, built to Bensen B-8 dimensions except for use of a round 2024 mast did not have 2/rev vibration problems whatever the rotor; Bensen wood blades, Bensen metal blades or Hughes helicopter rotor blades. The first...
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    Last edited by C. Beaty; 05-21-2018, 11:07 AM.

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  • C. Beaty
    replied to Jet Gyro project gyroplane
    Well, why not? Gyros are toys for grown ups in the same category as coaster wagons and tricycles for kids.

    With that in mind, it is not at all out of place to propel the most inefficient flight vehicle with the most inefficient means possible.

    Iím sure that had I found a jet...
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  • C. Beaty
    replied to Jet Gyro project gyroplane
    Letís see:
    1 hp = 550 ft-lb/second.
    At 50 mph, 250 lb of thrust = 33 hp
    At 500 mph, 250 lb of thrust = 330 hp.
    Thatís the reason we donít have jet propelled tug boats and railway locomotives Gas turbines driving electrical generators is a different story....
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  • C. Beaty
    replied to Mike Goodrich Visit to FD92
    in News
    JC, I wonder if anyone truly understands the functioning of the Young rotor. I have most of the available textbooks on rotorcraft and all analyze Cierva rotors in excruciating detail but lightly skip over the underslung, teetering rotor.
    Anyhow, a soft inplane Young rotor offsets the rotor CG...
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    Last edited by C. Beaty; 05-15-2018, 06:12 PM.

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  • C. Beaty
    replied to Mike Goodrich Visit to FD92
    in News
    JC, this youtube film, ďBirth of the Bell Helicopter,Ē part 3, shows some of the early problems of Arthur Youngís seesaw rotor. At 3:10 on the film, severe 2/rev vibration is first encountered during the first free flight at speeds above 20 mph. At 4:43 on the film, the first solution is shown; a device...
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  • C. Beaty
    replied to Mike Goodrich Visit to FD92
    in News
    JC, when I first built this gyro with rigid rotor pylon, 2/rev vibration was so violent that it was dangerous to fly. In searching for a solution, I tried a drag hinged rotor with a coning hinge at the center of rotation and no undersling.
    The coning hinge looked like a door hinge with the hinge...
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  • C. Beaty
    replied to Mike Goodrich Visit to FD92
    in News
    I think youíve underestimated the periodic aerodynamic drag variation of the rotor, JC.
    In any case, my 2050 N gyro shows a polished area on the roll axle of 3-4 mm....
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    Last edited by C. Beaty; 05-14-2018, 05:57 PM.

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  • C. Beaty
    replied to Mike Goodrich Visit to FD92
    in News
    When the Sparrowhawk gyro first came out, they were precluded from using the magic rubber bushing because RAF Canada had a patent on it and with a 2x4 mast, 2/rev vibration was intolerable.

    Jim Mayfield asked if I had any objection to AAIís use of a slider and of course, I didnít.
    ...
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  • C. Beaty
    replied to Mike Goodrich Visit to FD92
    in News
    A slider is redundant when used with a sufficiently flexible mast but is essential when the rotor is mounted on a rigid pylon.
    My tail boom on top gyro, built in 1989, had so much 2/rev vibration that it was dangerous until I came up with the slider.
    The bearing surfaces of the rotorhead...
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  • C. Beaty
    replied to Mike Goodrich Visit to FD92
    in News
    An isolated rotor moving through tha air must have a 2/rev vibration as a result of drag variation broadside to endwise.

    Bolted to a bulldozer, there would be no 2/rev vibration but something would eventually break. Thatís the reason isolation is required....
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  • JC, Prof. Bennettís calculations were based on normal weight and standard rotor diameter for a C-30 but Shapiro does not provide details.

    He provides this reference: Bennett, J.A.J. The Vertical descent of an Autogiro. Aircraft Engineering Feb, 1940, p. 40 .

    I think Aircraft...
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    Last edited by C. Beaty; 05-13-2018, 04:14 PM.

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  • During vertical descent, the rotor behaves like a parachute and it makes little difference on rate of descent whether the parachute is made from silk or nylon.

    The attached chart by Prof. JAJ Bennett, chief engineer of Cierva Autogiros at the time, shows calculated rates of descent for...
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  • C. Beaty
    replied to Hughes 269 Blades
    Lift is an often misused term. If a gyro weighs 630 lbs and flies, the rotor is developing 630 lbs of lift. If it doesnít fall out of a turn, itís developing the necessary amount of lift.

    When someone says; ďmy rotor has good liftĒ he means his rotor holds up his gyro with minimum drag,...
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  • C. Beaty
    replied to Hughes 269 Blades
    Heavier than air flying machines fly by accelerating air mass downward; makes no difference whether itís a FW, helicopter or ducted fans. The drag incurred in doing so is called induced drag....
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  • C. Beaty
    replied to Hughes 269 Blades
    There was a pressure sensor mounted on the rotorhead that measured force along the roll pivot axis and an inclinometer mounted on the keel. From this, the angle of the roll pivot could be determined and total rotor drag could be calculated.

    Profile drag, the aerodynamic force resisting...
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  • C. Beaty
    replied to Hughes 269 Blades
    Here are some measurements I made a number of years ago.
    I was using an airspeed indicator that measured true airspeed, which produces readings a bit higher than would be indicated with a standard aircraft airspeed indicator. Corrected for summer heat and humidity in Florida, the equivalent pitot...
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    Last edited by C. Beaty; 05-10-2018, 09:53 AM.

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  • C. Beaty
    replied to Fuel pumps on macs
    Mechanical fuel pumps didnít last long on a Mac because they ran at crankshaft speed, -4,000 rpm rather than at camshaft speed when used on an automobile.

    I used OMC outboard pulse pumps with good results before Mikuni pumps were generally available....
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