The R.1 had four working positions but only three crew members. Three Avro Bison prototypes, N153 to N155, were ordered to the same specification. Its upper-wing centre section bolted directly to the cabin roof, so the deep fuselage filled the entire gap between the wings. This full-depth form grew from design studies for the broad-fuselage Swift IV and Blackburn civil ten-seater. The main fuel supply occupied a saddle tank beneath the upper-wing centre section, over the centre of gravity and behind the pilot. Two streamlined tanks on top of the upper wing brought total capacity to 90 gallons.
Notable Point · 2:45-3:24
A full-depth fuselage for three crew and fuel
The R.1 remained a three-seater despite four crew positions, using a full-depth fuselage and up to 90 gallons of fuel for its reconnaissance role.