ESTIMATION METHOD OF AVERAGED INDUCED ROTOR SPEED FIELD IN LOW-SPEED HELICOPTER FLIGHT Russian patent published in 2009 - IPC G01M9/00 G01P5/00 

FIELD: physics, testing.

SUBSTANCE: invention refers to aerodynamic testing, specifically to helicopter rotor aerodynamics, namely to induced rotor (R) speed measurement in low-speed flights and can be used for higher calculation accuracy of helicopter airspeed components. In the course of method implementation, level-flight airspeed is measured; rotor disk area, average induced disk area speed are calculated on the basis of pulse theory. Then average induced disk area speed redistribution is estimated depending on helicopter flight speed and rotor ram effect. Tip eddies are visualised with smoke released by smoke generator from flying helicopter blade ends. Rotor ram effect is recorded by motion picture camera away from rotor rotation axis to cross point of tip eddies and blade taper on azimuth 180°. Preset helicopter speed is estimated for relative area of rotor ram effect. Then average induced disk area speed redistribution is estimated considering relative averaged induced disk area speed.

EFFECT: enhanced aerodynamic rotor calculation in low-speed helicopter flight.

5 dwg