Supermarine Spitfire HF Mk VII at Langley
The Supermarine Spitfire HF Mk VII was a high-altitude variant of the Mk VII, specifically optimized for operations at extreme altitudes. Below are the key specifications:
- Designation: HF Mk VII
- Type No.: 351
- Type: High-altitude, single-seat fighter
- Wingspan: 40 ft 2 in (12.24 m)
- Length: 31 ft 3½ in (9.54 m)
- Height: 11 ft 8½ in (3.57 m) (tip of prop, tail up)
- Engine:
- Merlin 61 (two-speed, two-stage supercharger, 1,566 hp / 1,167 kW)
- Merlin 71 (two-speed, two-stage supercharger, 1,710 hp / 1,234 kW)
- Maximum Speed: 434 mph (682 km/h) at 29,400 ft (8,960 m)
- Service Ceiling: 45,100 ft (13,745 m)
- Range: 660 miles (1,062 km)
- Armament:
- Two 20 mm Hispano cannon (120 rounds per gun)
- Four 0.303 in (7.7 mm) Browning machine guns (350 rounds per gun)
- Cockpit: Pressurized with a double-skin, sliding canopy for high-altitude performance
- Tailwheel: Retractable
- Propeller: Rotol four-blade, variable-pitch, constant-speed, made from Hydulignum (laminated wood)
- Production: 140 units (combined production for all Mk VII variants)
Notable Features:
- High-Altitude Performance: The HF (High-Flight) variant was designed to operate at very high altitudes, taking full advantage of the Merlin 61 and Merlin 71 engines, which provided extra power at extreme heights.
- Pressurized Cockpit: To aid in high-altitude flight, the pressurized cockpit allowed the pilot to operate comfortably at over 40,000 feet, crucial for long missions and combat at high elevations.
- Improved Propeller: The Rotol four-blade propeller helped improve the aircraft’s performance, particularly in high-altitude flight where thin air could affect aerodynamic efficiency.
- Extended Wingspan: The longer wingspan improved lift and overall performance at higher altitudes, though it made the aircraft slightly less maneuverable at lower levels compared to shorter-span Spitfires.
The HF Mk VII was a key aircraft for intercepting high-altitude enemy aircraft, particularly reconnaissance planes and bombers, during the latter part of World War II.