Don’t roll or loop your B-17 bomber. Important pilot restrictions for the B-17 Flying Fortress from the Pilot’s Manual for Boeing B-17 Flying Fortress:

DON’T lower flaps at speeds in excess of 147 mph!

DON’T dive in excess of 270 mph (with modified elevators).

WARNING: Some airplanes are restricted to 220-mph maximum diving speed, pending modification of the elevators. See warning placard in airplane.

DON’T exceed 46 inches Hg manifold pressure!

DON’T exceed 30 inches Hg below 2100 rpm!

DON’T stall the airplane! (except for training purposes.)

DON’T spin!

DON’T roll!

DON’T loop!

DON’T attempt inverted flight!

DON’T fly the airplane at maximum gross weight (64,500 pounds) UNLESS auxiliary wing tanks are full!

CAUTION: All power settings given in this section are for use with 100 octane fuel only. See appendix III for restrictions to be observed when using 91 octane fuel.