scraping of propeller boss

例句：

1. 1.The plane's propeller was makinga scraping of propeller boss.
   飞机的螺旋桨正在发出刮擦声。
2. 2.The old car's engine was makinga scraping of propeller boss.
   旧车的发动机正在发出刮擦声。
3. 3. Thewind was making a scraping of propeller boss.
   风正在发出刮擦声。