This isn't the first harebrained scheme he's had.

这已经不是他制定的第一个愚蠢计划了。

《柯林斯英汉双解大词典》

Looking back, I laugh at the harebrained folly of my scheme.

回头想起来，我对自己欠考虑的计划荒唐事感到可笑。

youdao

"It seemed like such a harebrained scheme, " Richard Buckley, the lead archaeologist on the project, tells CNN.

CNN: Richard III: The mystery of the king and the car parking lot