Boulton Paul’s submission to Specification F11/37 never progressed beyond this piloted half-scale model, the P.92/2 V3142. Note the hump where the turret would have been on the full-size P.92.

«Веллингтон» (per. L4250) с 40-мм пушкой и новым двухкилевым оперением
The only company to flight test its 40mm cannon turret and predictor was Vickers, which modified Wellington II L4250 for the purpose, as seen here at Boscombe Down in January 1942. It originally flew with a single fin and rudder.

An impression by artist Frank Munger of the Parnall Type 381 Gunnery Research Aircraft as it might have appeared in the markings of the period. This shows the upper turret installation for two heavy-calibre guns.

Frank Munger’s impression of the alternative under-turret installation on the Parnall Type 381. The aircraft was to have provision for both upper and under turrets, though only one would be fitted at any one time.

General arrangement, Parnall Type 381, with a second side-view showing the under-turret version.

An open side elevation of the Type 381’s forward fuselage, showing the dispositions of the crew and turret.