A&AEE trial (Merlin II, fixed-pitch prop, 6040 lb)
flaps and undercarriage up: 73 mph
flaps and undercarriage down: 62 mph
A&AEE trial (Merlin III, two-pitch prop, 6584 lb)
flaps and undercarriage up: 76-78 mph
flaps and undercarriage down: 62 mph
A&AEE trial (Merlin III, constant-speed prop, 6750 lb)
flaps and undercarriage up: 78 mph
flaps and undercarriage down: 62-63 mph
Note these are ASI readings, not necessarily actual speeds.