The Boulton Paul P.80 Superstrand was a design for an improved version of the P.75 Overstrand, but it was already obsolete by the time it was suggested, and didn't enter production.
The Overstrand was itself a modified version of the earlier P.29 Sidestrand, a biplane twin engined medium bomber, that was itself loosely descended from the Boulton Paul P.7 Bouges of 1918. The Sidestrand was followed by the P.75 Overstrand, the first RAF aircraft to feature a powered turret. The Overstrand was produced in small numbers in the mid 1930s and was used by No.101 Squadron.
The P.80 Superstrand was a design for an improved version of the Overstrand. It was still a biplane, but it gained a retractable main undercarriage, more powerful Pegasus IV engines, and a new nose turret similar to a design produced for the Boulton Paul P.70 bomber project. The Overstrand had a tall cylindrical glazed turret, with a domed roof and floor. The P.80 turret would have had a glazed upper half, and the lower half would have been enclosed within the fuselage cover. The P.80 also introduced a folding transparent hood for the rear gunner, part of a long cockpit canopy that stretched from the pilot's position in front of the wings back to the dorsal gun.
One Overstrand was given the 720hp Pegasus IV engines as part of the design process for the Superstrand.
By the time the Superstrand was proposed by Boulton Paul, the age of the biplane was rapidly passing, and all future RAF bombers would be monoplanes. The P.80 was developed at about the same time as Boulton Paul's own P.79 monoplane bomber design, and was clearly obsolete. No prototypes were ordered.
Performance figures estimates
Engine: Two Pegasus IV engines
Power: 720hp each
Top speed: 191mph at 15,000ft
Service Ceiling: 27,500ft
Range: 1,050 miles at 150mph at 15,00ft