World War Photos

Supermarine Spitfire HF Mk IX, serial PT465 July 1944

The Supermarine Spitfire HF Mk IX series, including the HF Mk IXb, HF Mk IXc, and HF Mk IXe, were high-altitude variants of the Spitfire Mk IX designed for operations at greater altitudes. These aircraft were equipped with powerful Merlin 70 engines to optimize performance at higher altitudes. The HF variants also featured wings with increased span to enhance their lift and operational ceiling.

Specifications Across HF Mk IX Variants:

HF Mk IXb

• Designation: HF Mk IXb
• Type No.: 361
• Type: Single-seat High-altitude Fighter
• Span: 36 ft 10 in (11.23 m)
• Length:
  • Standard: 30 ft 6 in (9.3 m)
  • With broad chord rudder: 31 ft ½ in (9.46 m)
• Height: 11 ft 8 in (3.55 m) [Tip of Prop Tail Up]
• Engine: Two-speed, two-stage 1,710 hp (1,282 kW) Merlin 70
• Max Speed: 416 mph (670 km/h) at 27,500 ft (8,370 m)
• Service Ceiling: 45,000 ft (13,696 m)
• Range: 434 miles (698 km)
• Fuel Capacity:
  • Fuselage: Upper 48 Imp Gal (218 L), Lower 37 Imp Gal (168 L)
  • Auxiliary tanks: 30 (136 L), 45 (204 L), or 90 Imp Gal (409 L)
  • Long-range ferry tank: 170 Imp Gal (773 L)
  • Maximum long-range fuel capacity: 284 Imp Gal (1,291 L)
• Armament:
  • Two 20 mm cannon
  • Four 0.303 in (7.7 mm) Browning machine guns
• Cockpit: Unpressurized (with internal bulletproof glass)
• Tailwheel: Fixed
• Wing Type: High-altitude Increased Span (HF)
• Propeller: Rotol, Four-blade, Variable-pitch, Constant-speed, Type R12/4F5/4 (Jablo or Hydrulignum), 10 ft 9 in (3.28 m) Dia
• Production: 400 (Total HF Mk IX production)

HF Mk IXc

• Designation: HF Mk IXc
• Type No.: 361
• Type: Single-seat High-altitude Fighter
• Span: 36 ft 10 in (11.23 m)
• Length:
  • Standard: 30 ft 6 in (9.3 m)
  • With broad chord rudder: 31 ft ½ in (9.46 m)
• Height: 11 ft 8 in (3.55 m) [Tip of Prop Tail Up]
• Engine: Two-speed, two-stage 1,710 hp (1,282 kW) Merlin 70
• Max Speed: 416 mph (670 km/h) at 27,500 ft (8,370 m)
• Service Ceiling: 45,000 ft (13,696 m)
• Range: 434 miles (698 km)
• Fuel Capacity:
  • Fuselage: Upper 48 Imp Gal (218 L), Lower 37 Imp Gal (168 L)
  • Auxiliary tanks: 30 (136 L), 45 (204 L), or 90 Imp Gal (409 L)
  • Long-range ferry tank: 170 Imp Gal (773 L)
  • Maximum long-range fuel capacity: 284 Imp Gal (1,291 L)
• Armament: Four 20 mm cannon
• Cockpit: Unpressurized (with internal bulletproof glass)
• Tailwheel: Fixed
• Wing Type: High-altitude Increased Span (HF)
• Propeller: Rotol, Four-blade, Variable-pitch, Constant-speed, Type R12/4F5/4 (Jablo or Hydrulignum), 10 ft 9 in (3.28 m) Dia
• Production: 400 (Total HF Mk IX production)

HF Mk IXe

• Designation: HF Mk IXe
• Type No.: 361
• Type: Single-seat High-altitude Fighter
• Span: 36 ft 10 in (11.23 m)
• Length:
  • Standard: 30 ft 6 in (9.3 m)
  • With broad chord rudder: 31 ft ½ in (9.46 m)
• Height: 11 ft 8 in (3.55 m) [Tip of Prop Tail Up]
• Engine: Two-speed, two-stage 1,710 hp (1,282 kW) Merlin 70
• Max Speed: 416 mph (670 km/h) at 27,500 ft (8,370 m)
• Service Ceiling: 45,000 ft (13,696 m)
• Range: 434 miles (698 km)
• Fuel Capacity:
  • Fuselage: Upper 48 Imp Gal (218 L), Lower 37 Imp Gal (168 L)
  • Auxiliary tanks: 30 (136 L), 45 (204 L), or 90 Imp Gal (409 L)
  • Long-range ferry tank: 170 Imp Gal (773 L)
  • Maximum long-range fuel capacity: 284 Imp Gal (1,291 L)
• Armament:
  • Two 20 mm cannon
  • Two 0.5 in (12.7 mm) Browning machine guns
  • Up to 1,000 lb (454 kg) of bombs (500 lb on centerline and one 250 lb under each wing)
• Cockpit: Unpressurized (with internal bulletproof glass)
• Tailwheel: Fixed
• Wing Type: High-altitude Increased Span (HF)
• Propeller: Rotol, Four-blade, Variable-pitch, Constant-speed, Type R12/4F5/4 (Jablo or Hydrulignum), 10 ft 9 in (3.28 m) Dia
• Production: 400 (Total HF Mk IX production)

Key Notes:

• All variants shared the Merlin 70 engine, which was specifically tuned for high-altitude performance, allowing for a top speed of 416 mph and an operational ceiling of 45,000 ft.
• Armament differed slightly between variants, with the Mk IXe featuring a more powerful combination of two 0.5 in Browning machine guns alongside the standard 20 mm Hispano cannons.