Retreating blade AoA.

Aviator168

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In general cruise, what is the AoA of the retreat blade? At what RRPM or fly speed will I see the retreating blade stall?
 

Doug Riley

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The AOA of the retreating blade varies across the span of the blade. The inmost foot or two is stalled most of the time. This stalled region spreads outward from the root toward the tip as the aircraft's airspeed increases. A sudden, full stall of the entire blade in steady flight is unknown.

A full-blade stall can occur if (1) sufficient RRPM is lost during a low-G maneuver, followed by a sharp increase in disk AOA; or (2) if a violent nose-down rotation of the airframe, with spindle fixed, occurs, suddenly increasing the retreating blade's AOA.

What gyro pilots call "ground flapping" is a special case of Scenario #1 above, except that the low RRPM is not a result of a low-G maneuver, but instead results from insufficient pre-rotation during the takeoff sequence.
 

Jean Claude

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I piloted gliders C800, Bijave, C 310, airplanes Piper J3 , PA 28, Jodel D117, DR 220, Cessna 150, C
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For example, the A.o.A calculated for an ELA 07 gyroplane at 75 mph, 950 lbs. The red area is stalled (more 12 degrees)
Sans titre.png
 

Jean Claude

Junior Member
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Jan 2, 2009
Messages
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Location
Centre FRANCE
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I piloted gliders C800, Bijave, C 310, airplanes Piper J3 , PA 28, Jodel D117, DR 220, Cessna 150, C
Total Flight Time
About 500 h (FW + ultra light)
Of course ! These results obtains the autorotation steady rpm, with the disk A.o.A required. Here 375 rpm, with disk A.o.A: 8.8 degrees and a1: 2.2 degrees
 
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