| 摘要 |
PURPOSE:To enable to obtain an optimum specific thrust, by employing such an arrangement that the area ratio of a nozzle for a booster engine can be controlled to an optimum value according to the altitude. CONSTITUTION:A multiplicity of layers consisting of abrasive materials are applied over the inner wall surface of a nozzle 1 for a booster engine. A first layer 2 uses a material such as silicone rubber having an abrasion rate of 0.1- 0.5(mm./s)/Min and a second layer 3 uses a material such as glass, polyvinyl chloride having an abrasion rate of 0.6-1.3. Further, a third layer 4 uses a material consisting of mixture of silicon and polyurethane having an abrasion rate of 1.6-2.0. By employing such an arrangement, the first layer 2 is fused after passing of about 45 seconds from launching and the second layer 3 is fused after passing of about 60 seconds. Further, the third layer 4 is fused after passing of about 70 seconds. Therefore, the area ratio of the nozzle can be changed according to the altitude. |
