Most split/V tail designs I see are either perfectly vertical, or radiate OUTWARDS. Why did the SR-71’s split vertical stabilizer radiate INWARDS?

Question

Most split/V tail designs I see are either perfectly vertical, or radiate OUTWARDS. Why did the SR-71’s split vertical stabilizer radiate INWARDS?

In: Engineering

Answer 1

The SR-71 was a very unusual airplane. It had two giant engines, far from the centerline. Engines go out from time to time, particularly when you try to fly so high there isn’t much oxygen. This puts a huge torque on the plane, which of course you’d like to correct with the tail. Tail fins pointed out induce a roll, making a spin even harder to get out of, so that’s not going to be acceptable. Tail fins pointed in work better while you get the working engine turned off and then point at the ground to restart both engines. (Yes, that’s the procedure.)