Supermarine Spitfire Mk III
Spitfire Mk III Specification:
Dimensions:
- Span:
- Clipped: 30 ft 6 in (9.30 m)
- Standard: 36 ft 10 in (11.23 m)
- Length: 30 ft 4 in (9.25 m)
- Height: 11 ft 5.5 in (3.48 m) [Tip of Prop, Tail Down]
Engine:
- Primary Engine:
- Initial: Two-speed, Single-stage Merlin XX with 1,280 hp (954 kW) [+12 lb/sq.in boost]
- Later Tested: Two-speed, Two-stage Merlin 61 with 1,565 hp (1,167 kW)
Weights:
- Tare (Empty): 5,127 lb (2,326 kg)
- All-Up Weight: 6,572 lb (2,980 kg) at Eastleigh, 14/03/1940
Performance:
- Maximum Speed: 400 mph (644 km/h) at 21,000 ft (6,400 m)
- Time to 15,000 ft: 4 minutes 30 seconds
- Service Ceiling: 41,800 ft (12,740 m)
Fuel:
- Fuel Type: 100 Octane
- Fuel Capacity:
- Upper Fuselage Tank: 53 Imp Gal (241 liters)
- Lower Fuselage Tank: 46.5 Imp Gal (211 liters)
Armament [Proposed Configurations]:
- Option A: Eight 0.303 in (7.7 mm) Browning machine guns
- Option B: Two 20 mm Hispano cannon and four 0.303 in (7.7 mm) Browning machine guns
- Option C: Four 20 mm Hispano cannon
Cockpit:
- Unpressurized, with internal bulletproof glass
Tailwheel:
- Retractable
Propeller Options:
- Rotol: Three-blade, Variable-pitch, Constant-speed, Dural, 10 ft 9 in (3.28 m) diameter
- Rotol: Four-blade, Variable-pitch, Constant-speed, Dural, 10 ft 9 in (3.28 m) diameter
- de Havilland: Three-blade, Variable-pitch, Constant-speed, Dural, 10 ft 9 in (3.28 m) diameter
- Rotol: Three-blade, Variable-pitch, Constant-speed, Jablo, 10 ft 9 in (3.28 m) diameter
The Mk III was an experimental aircraft designed to improve the performance of the Spitfire, particularly at high altitudes, with its more powerful engines, refined aerodynamics, and retractable tailwheel.