Trainer Aircraft

The basic jet trainer is a two-seater low-wing monoplane aircraft. The flight tests were carried out by AFTPS (Air force Test Pilots School, Aircraft Systems and Testing Establishment) at 4570 and 6700 m altitudes on this aircraft. The sampling interval for data acquisition was 31.25 ms. The flight-determined values are Cm =—0.5, Cm = —15, and CLa = 4.9 (WT value is 4.5). The latter derivative was fairly constant as the lift curve fairly and monotonically increased up to AOA of 12°. In the range of AOA = 8°-12°, the SP frequency was 1.5 rad/s and at low AOA it was 3 rad/s, whereas the SP damping ratio was fairly constant at the average value of 0.45 [20]. Another jet trainer version has the following characteristics determined from the specific flight tests conducted (at M = 0.5, 0.6, 0.7, and H = 5000 m; CG = 27.5%

MAC): NP = 32.5% of MAC; SP frequency = 2.5 rad/s; SP damping ratio = 0.4; the phugoid frequency = 0.08, and the damping ratio = 0.11.