The research of the lift, drag and pitching moment of a transport aircraft with slipstream effect of four turbo-propeller engines
RMIT University Melbourne Australia
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The slipstream effect of a transport aircraft with four turbo-propeller engines is studied by wind tunnel force test and seven-hole probe technique. The lift curve slope with slipstream increases by about 7 at typical climb condition. The zero lift drag coefficient increases by 19 and 76 drag counts at typical cruise and climb conditions respectively compared with non-slipstream condition, while the induced drag factor has a slightly decreasing trend. With slipstream effect, the pitching moment curve shows a sinusoidal type shape at different angle of attack AOA, and the elevator efficiency is enhanced and reaches the peak between 10 to 12 degrees of AOA. The non-linear longitudinal stability and elevator efficiency is caused by the phenomenon that the wake of the slipstream sweeps from beneath the horizontal tail to above it with increasing AOA, which is proved by the wake flow field measured with seven-hole probe rake.
- Military Aircraft Operations