Results for “LiP7” | Engineering Papers

DOE OSTI2020

Materials Data on LiP7 by Materials Project

LiP7 crystallizes in the tetragonal I4_1/acd space group. The structure is three-dimensional. Li1+ is bonded to six P+0.14- atoms to form distorted LiP6 octahedra that share corners with two equivalent LiP6 octahedra and corners with eight PLiP3 tetrahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of Li–P bond distances ranging from 2.68–2.96 Å. There are four inequivalent P+0.14- sites. In the first P+0.14- site, P+0.14- is bonded in a trigonal non-coplanar geometry to three P+0.14- atoms. There are two shorter (2.21 Å) and one longer (2.22 Å) P–P bond lengths. In the second P+0.14- site, P+0.14- is bonded in a 4-coordinate geometry to two equivalent Li1+ and two equivalent P+0.14- atoms. In the third P+0.14- site, P+0.14- is bonded to one Li1+ and three P+0.14- atoms to form distorted PLiP3 tetrahedra that share corners with two equivalent LiP6 octahedra and corners with six PLiP3 tetrahedra. The corner-sharing octahedra tilt angles range from 36–64°. There are one shorter (2.22 Å) and one longer (2.23 Å) P–P bond lengths. In the fourth P+0.14- site, P+0.14- is bonded to one Li1+ and three P+0.14- atoms to form distorted PLiP3 tetrahedra that share corners with two equivalent LiP6 octahedra and corners with six PLiP3 tetrahedra. The corner-sharing octahedra tilt angles range from 67–73°. The P–P bond length is 2.29 Å.

36 MATERIALS SCIENCE↗

NASA NTRS1961

Flight Tests of a 1/6-Scale Model of the Hawker P 1127 Jet VTOL Airplane

An experimental investigation has been made to determine the dynamic stability and control characteristics of a 1/6-scale flying model of the Hawker P lIP7 jet vertical-take-off-and-landing (VTOL) airplane in hovering and transition flight. The model was powered by a counter-rotating ducted fan driven by compressed-air jets at the tips of the fan blades. In hovering flight the model was controlled by jet-reaction controls which consisted of yaw and pitch jets at the extremities of the fuselage and a roll jet on each wing tip. In forward flight the model was controlled by conventional ailerons and rudder and an all-movable horizontal tail. In hovering flight the model could be flown smoothly and easily, but the roll control was considered too weak for rapid maneuvering or hovering in gusty air. Transitions from hovering to normal forward flight and back to hovering could be made smoothly and consistently and with only moderate changes in longitudinal trim. The model had a static longitudinal instability or pitch-up tendency throughout the transition range, but the rate of divergence in the pitch-up was moderate and the model could be controlled easily provided the angle of attack was not allowed to become too high. In both the transition and normal forward flight conditions the lateral motions of the model were difficult to control at high angles of attack, apparently because of low directional stability at small angles of sideslip. The longitudinal stability of the model in normal forward flight was generally satisfactory, but there was a decided pitch-up tendency for the flap-down condition at high angles of attack. In the VTOL landing approach condition, with the jets directed straight down or slightly forward, the nose-down pitch trim required was greater than in the transitions from hovering to forward flight, but the longitudinal instability was about the same. Take-offs and landings in still air could be made smoothly although there was a slight unfavorable ground effect on lift and a nose-down change in pitch trim near the ground. Short take-offs and landings could be made smoothly and consistently although the model experienced a decided nose-up change in pitching moment as it climbed out of ground effect.

Smith, Charles C., Jr.↗