Static characteristics of an ACV (Air Cushion Vehicle) over irregular ground are investigated theoretically and experimentally. The exponential theory is developed for this purpose. Calculations are made for the case of two and three dimensional models, and the results are compared with experimental ones. Theoretical results show good agreement with those of experiments except the particular cases such as the hover height is very low, or the higher portions of ground roughness is close to the peripheral nozzle. The effects of the partition on lift and moment characteristics are also studied. Calculations show that partition equipped on the base affects the lift augmentation ratio especially at large d/D, but there exist little effects on experimental results. On the other hand, moment characteristics calculated agree with the measured values qualitatively.
This report is concerned with the developement of a simple low-thrust plasma thruster, composed of a Duoplasmatron-type plasma source and a magnetic nozzle. The results of the experiment with various kind of propellants showed moderate thrust efficiencies (up to 31%) in wide range of specific impulse (400-8, 000sec), and high ionization efficiency. Such experimental results demonstrate its capability as a low-thrust plasma thruster. On the present device, in which a diverging magnetic field (magnetic nozzle) is applied to the discharge and exhaust region, there are several possible plasma acceleration mechanisms. The results of diagnostics of plasma beams in this device suggested that the prevailing acceleration mechanisms are (1) acceleration by magnetic expansion process and (2) acceleration by converting rotational kinetic energy to directed kinetic energy.