In the aerospace world, it's called a "systems engineer."
The lead:
1: Understands the whole system, but not necessarily every detail.
2: Plans the whole project.
Edit:
Sometimes in the software world, the title is "architect."
This is rarely the "manager," except in organizations that have a hard-on for hierarchy and artificial promotion for "career advancement." Managers are usually concerned with people, schedules, and resources; but don't go very deep into technical issues.
That being said, the lead/manager may fill in for each other when one is on vacation, sick, quits, ect.
The lead:
1: Understands the whole system, but not necessarily every detail.
2: Plans the whole project.
Edit:
Sometimes in the software world, the title is "architect."
This is rarely the "manager," except in organizations that have a hard-on for hierarchy and artificial promotion for "career advancement." Managers are usually concerned with people, schedules, and resources; but don't go very deep into technical issues.
That being said, the lead/manager may fill in for each other when one is on vacation, sick, quits, ect.