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C. Beaty
Gold Supporter
Last Activity: 12-12-2017, 07:16 PM
Joined: 04-16-2004
Location: Florida
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  • C. Beaty
    replied to New gyro planned with jump takeoff?
    I understand that hydraulic props operate from the engine’s oil pump and I think that requires passageways through the prop shaft. But yes, I think a hydraulic prop would do it.

    OTH, I’m only guessing; I’ve never had occasion ot look into variable pitch props.

    Cartercopter...
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  • C. Beaty
    replied to New gyro planned with jump takeoff?
    I think the A&S 18A managed jumps with fixed pitch props; the shape of the power curve of engines designed for direct drive of a prop ordinarily has a large excess of power at RPMs well below normal operating speed. Not so in the case of engines tuned for peak power at 5,000 rpm or so.
    ...
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  • Pope Frances and California’s Gov. Moonbeam at a Vatican press conference declared the California brush fires and the heavy snowfall in Northern Europe are Trump’s fault for his skepticism about man made global warming.
    I could use a bit of global warming right now- It was 37ºF (3ºC) at 8AM this...
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  • My, how times have changed. OCR from the book: AUTOGIRO The Story of the Windmill Airplane by George Townson.

    “The KD-1 A was a slightly modified KD-1. An engine driven generator and an electric engine starter were added. The fuel tankage was re-duced from 44 to 30 gallons. Seven of these...
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  • C. Beaty
    replied to New gyro planned with jump takeoff?
    Dick Degraw’s jumpers have a collective pitch lever just like a helicopter.

    Lever on bottom, zero lift pitch for over-speeding the rotor; upper stop for jump pitch and a mid range detent for autorotation.

    The A&S 18A automates that sequence by the use of pitch-cone coupling...
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  • C. Beaty
    replied to RAF Rotor Blades
    I expect you’re correct, JC. I know that Bensen wood rotor blades had considerable positive moment coefficient that caused the stick to reach the forward stop at ~60 MPH.

    But I still have difficulties understanding how Bensen’s metal blades could have had a strong nose up moment; being...
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  • C. Beaty
    replied to RAF Rotor Blades
    JC, the Bensen rotor blades had 0.032” upper skins and 0.050” lower skins; the other metal blades of that era, Stanzee and Rotordyne. had 0.032” aluminum skins wrapped around an aluminum spar.

    The stick was against the forward stop because the Bensens of that time were mostly CLT and had...
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  • C. Beaty
    replied to RAF Rotor Blades
    JC, during my early days of gyrocoptering, my partner and I wanted to find the limit of pitch setting for rotor blades.

    We set our Bensen type metal blades at the upper limit of their pitch adjustment and with the two of us hand spinning the blades, managed to get them started.
    ...
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    Last edited by C. Beaty; 12-07-2017, 03:12 AM.

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  • C. Beaty
    replied to Johnny Hallyday's death
    Speaking of French music, when I was in France sometime in the 1950s, I gave a ride to a French acquaintance and the AM radio in my VW Beetle happened to be tuned to the US Armed Forces radio network when Tennessee Ernie Ford came on, singing 16 tons. My friend turned to me and said; “You Americans...
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  • C. Beaty
    replied to Johnny Hallyday's death
    JM, the first genuine Frenchman I ever saw was a gentleman by the name of Joe Chavan (I'm not sure of the spelling of his family name, in English phonetics it would be: sha-van’)

    Joe entered the US ~1900 by crossing the Mexico-Texas border where he worked in sulfur mines for a time before...
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    Last edited by C. Beaty; 12-06-2017, 07:48 PM.

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  • C. Beaty
    replied to RAF Rotor Blades
    The designers of the RAF-2000 gyro, like most retail gyro designers, used the ”by guess and by gosh” method and wouldn’t have the foggiest notion of how rotor RPM related to air density. They knew from experience that rotor RPM increased with altitude.

    My guess is that they increased pitch...
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  • C. Beaty
    replied to RAF Rotor Blades
    Quite some time ago, I extracted the ordinates of an RAF blade section and ran an airfoil analysis on a program called “Javafoil” and surprisingly, it was very near to a zero moment coefficient airfoil, meaning it had no residual pitching moment. The downside was that its nose shape was pretty bad,...
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  • C. Beaty
    replied to RAF Rotor Blades
    Here’s the NACA measurement of stalled area of Kellett KD-1A rotor at various forward speeds. The measurements are given as tip speed ratio, mu, the ratio of forward speed to rotor tip speed. Since the KD-1 rotor ran at a tip speed of ~400 fps (272 mph), mu of 0.15 ~41 mph and mu of 0.35 ~95 mph....
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    Last edited by C. Beaty; 12-04-2017, 03:13 PM.

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  • C. Beaty
    replied to New gyro planned with jump takeoff?
    Here’s the GE report on the evaluation of the Doblhoff Wnf-342 tip jet helicopter, written by Igor Bensen, the project engineer.

    For cold tests of the rotor, streamlined plugs were installed in the jet exits and it was mounted on a Kellett Autogiro which had a 60 HP prerotator. The Jacobs...
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  • C. Beaty
    replied to New gyro planned with jump takeoff?
    The problem, Chris, is finding that 26 HP. Most highly tuned engines with redrive don’t have a surplus of 26 HP when driving a fixed pitch propeller.

    Dick DeG has some tricks in his partially powered rotor mechanism that frees up extra engine power when overspeeding the rotor....
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  • C. Beaty
    replied to Stainless
    The yield strength of SS 304 is low because it’s intended for deep drawn shapes where it can be easily formed into complex shapes without tearing or breaking. That’s known as ductility.
    It would never be used as a structural material for serious aircraft designs but it’s fine for hobbycopters...
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  • C. Beaty
    replied to Ignition damping box
    This riddle could be solved instantly with an oscilloscope and a running 503/damper box....
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  • C. Beaty
    replied to Ignition damping box
    In which case, the damper box totally suppresses oscillations of the ignition primary circuit; resonant oscillations can only be initiated by the opening of the breaker points. No other action has frequency components in the range of primary circuit resonance....
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  • C. Beaty
    replied to Ignition damping box
    JC, do you think the resonant frequency of the combination of condenser across the points and the inductance of ignition coil primary in parallel with the exciter coil is so low that a half cycle requires more time than the open time of the points?

    If the condenser is 0.25 mfd and the inductance...
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    Last edited by C. Beaty; 11-30-2017, 05:34 AM.

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  • C. Beaty
    replied to Stainless
    It’s all starting to come together for me; the Gyrobee was Ralph Taggart’s adaptation of Martin Hollomann’s Bumblebee, an adaptation of a Bensen B-8. Bensen used 1/8” inch aluminum cluster plates; no point in making the cluster plates stronger than the 1/8” wall aluminum airframe tubing. Anyhow, as...
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