The Boulton Paul P.105 was a design for a multi-use naval attack aircraft.
Although Boulton Paul never designed a successful naval aircraft of their own, they did produce a number of other company's naval designs, and their chief designer John North put a great deal of effort into designing his own naval aircraft.
The P.105 would have been a multi-role aircraft, designed to serve as a fighter, torpedo bomber, reconnaissance aircraft or dive bomber. In the reconnaissance version there was ventral glazing to allow the observer a good view down. The fighter version would have been armed with four 0.5in fixed forward firing machine guns or four 20mm fixed forward firing cannon. Other versions would have carried two 0.5in fixed forward firing machine guns. All two man versions would have had the option of two rear firing 0.5in machine guns. At a normal weight of 12,500lb it could carry one 1,650lb torpedo, two 1,000lb bombs or two 70 gallon fuel tanks.
The P.105 would have been powered by a Bristol Centaurus CE12SM engine. It would have had an inverted gull wing, similar to the Chance Vought Corsair, and for the same reason - to allow for a combination of a large propeller and shorter main landing gear legs.
It was designed to be either a one man or two man aircraft, with the second position removable on the carriers.
As would be expected a wide range of performance figures were produced, depending on the use. Range varied from 3,320 miles to 1,300lb.
The P.105 never progressed beyond the design stage. However a 'Special Features' Defiant was ordered to test out some of the features of the P.105. This aircraft was to have contra-rotating 'dive brake' propellers, landing gear that extended when lowered to allow for a larger propeller and automatic undercarriage doors that could be opened to test the impact of bomb bay doors. Like the P.105, the Special Features Defiant was never built.