on a wing and a prayer idiom
准备不充分但又希望成功;只有一线成功的可能
If you do something on a wing and a prayer, you do it hoping that you will succeed, although you are not prepared enough for it.
With hardly any funding and a staff of six, they were operating on a wing and a prayer. 几乎没有什么资金而且只有6名员工，他们的经营如履薄冰。