Lateral-directional stability and control characteristics of the quiet short-haul research aircraft (QSRA)

Original publisher: Moffett Field, Calif. : National Aeronautics and Space Administration, Ames Research Center ; [Springfield, Va. : For sale by the National Technical Information Service, 1990] OCLC Number: (OCoLC)25291172 Subject: Stability of airplanes, Lateral. Excerpt: ... APPENDIX DATA REDUCTION FORMULAS Corrections to aerodynamic data that were applied as part of the data reduction are from tests con-ducted prior to those that are the subject of this report. The vane-indicated angle of attack, oti, was corrected by adding the increment A a, given by the following formula, in degrees. As =-1.5 [ 1. + 0.0182 ( 6 =-55. ) ]-0.12 [ 1. + 1.5 ( 6,,-55. ) + 0.0108 ( N-60. ) ] c_ ( 7 )-0.0021 a 2 where iS,, is the USB flap deflection angle in degrees and N is the engine fan percent rpm, averaged among the engines. The sideslip angle / 3 for all test conditions was computed as 93.5 % of the angle indicated by the sideslip angle vane. This correction to the measurement was determined by the method described in reference 4. In this method the correction factor is determined by matching the rate of change of the side velocity computed from the vane measurement with this change computed from the side acceleration, roll and yaw rates, velocity, and attitude time histories. Pitot static data corrections had been determined from low level flights in calm air under conditions where the true speed could be measured and the air density was known. The following formula was used to compute a correction which was added to the indicated airspeed ( V_, knots ). AV = 0.3219 × 10-4Vi 3-0.01231V,. 2 + 1.4762 V_-53.405 The corrected dynamic pressure ( _ ) in pounds per square foot was calculated from the equation ( 8 ) = 0.003385 V_2 ( 1. + AV ( 2. + AV / V_2 ) / V_ ) The corrected static pressure ( P_ ) in pounds per square foot was computed from the indicated pressure ( P_ ) with the relation P, = P_-0.003385A V ( 2. + A V / V,. ) ( 9 ) The expression below was determined to be ...