| The systematic testing of tandem flapping membrane wings was conducted to determine the effect of phase angle, offset distance, and reduced frequency on thrust, lift and propulsive efficiency. Single flapping wings, asymmetric rocking tandem wings, the insertion of a stationary wing in the wake of a flapping membrane wring and the effect of increased dynamic pressure were also tested. Tandem flapping showed variation of thrust with phase angle and offset distance with a maximum located at the nearest wing offset distance and at 51° with the rear wing leading. Lift was increased moderately with flapping frequency but remained relatively unchanged with phase angle variation. Rocking wings and increased dynamic pressure exhibited slightly degraded performance from the symmetric tandem case. |
