Engineering:Xian H-7

H-7
Role	Strategic bomber
National origin	People's Republic of China
Manufacturer	Xi'an Aircraft Industrial Corporation
First flight	January 1978 (H-6I demonstrator) Unflown (H-7)
Status	Cancelled
Primary user	People's Liberation Army Air Force
Developed from	Xian H-6

The Xian H-7 bomber (Chinese: 轰-8; pinyin: Hōng-7) was a Chinese military aircraft and a possible successor to the aging twin-engined H-6 jet bomber. The prototype was reported to be an enlarged H-6 with underwing engines, but the project was canceled in 1980 before the bomber went into production.

Development

Originally proposed by Xi'an Aircraft Factory in June 1970 as a 4-engined version of Xian H-6 (aka H-6I), design begun in February 1971 after the proposal was granted by the state. In 1973, People's Liberation Army Air Force (PLAAF) issued additional requirement of incorporating capability against sea targets, and formally joint the project. By the end of 1977, the first sample was completed and the maiden flight was followed in January 1978.

The aircraft was able to climb 40% faster than H-6, and the range is also increased by a third to 8,000 km. More weapons could be carried, including bombs of various sizes, sizing from 100 kg to the massive 9-ton ones. The bomb bay was sized at 8.6 meter x 1.8 meter x 2.72 meter, capable of holding a maximum of 18 tons of ordnance, i.e. 2 of the 9-ton bombs, though to achieve maximum range, the payload had to be greatly reduced to 7 tons. Nuclear bombs could also be carried, as well as anti-ship and land attack missiles, and in the latter configuration, a total 3 missiles are carried, one under each wing, and a third semi-buried in the bomb bay. The permanent weapon of the aircraft is a tail gun mount incorporating a twin 23 mm gun.

The crew totaled 6, seated in two separate pressurized compartments. Pilot/mission commander, co-pilot/flight engineer, navigator/observer, and bombardier/flight mechanic were seated in the forward pressurized compartment, while the electronics warfare/communication officer and tail gunner/assistant communication officer seated in the pressurized compartment in the rear. The avionics of the aircraft borrowed heavily from the reverse engineering similar American systems obtained from captured or shot-down United States of America aircraft provided by North Vietnam during/after the Vietnam War.

Variants

• Xian H-6I - Prototype of Xian H-7. Powered by 4 Rolls-Royce Spey Mk 512 engines, originally purchased as spare engines for Hawker Siddeley Trident bought previously by China. Program first begun in 1970 and maiden flight was made in 1978. In comparison to the original H-6, the fuselage was lengthened and the engines were rearranged to be carried in individual pods under the wings. Ferry range is increased to 8,100 km (with standard payload), and combat radius is increased to over 5,000 km (with nuclear payload).
• Xian H-7I - Follow-on of Xian H-6I, which replaced the Rolls-Royce Spey Mk 512 engines with four WS-6J (Type 910) turbofans to reduce operational cost and to simplify logistics. A back-up design used six Pratt and Whitney JT3D turbofans. None were built.
• Xian H-7II — A H-6 with increased wing span, powered by six WS-6J turbofans in evenly spaced nacelles, and possibly a re-designed flight-deck with an extended solid nose. No aircraft were built.
• Xian H-8 - A small bomber known as "Xiaohong".

Specifications

General characteristics

• Crew: 6
• Length: 48.50 meters (159 feet)
• Wingspan: 46.47 meters (152 feet)
• Height: 13.85 meters (45.44 feet)
• Wing area: 293 m² (3,153 ft²)
• Empty weight: 63,000 kg (139,000 lb)
• Loaded weight: 145,000 kg (319,670 lb)
• Max. takeoff weight: 163,000 kg (359,353 lb)
• Powerplant: 4 × Shenyang WS-6J turbofans, 107.9 kN (24,280 lb) each

Performance

• Maximum speed: 100-1,050 km/h (621-652 mph)
• Cruise speed: 800 km at low to medium altitude, 850-875 km at high altitude (497 miles at low to medium altitude, 528-543 miles at high altitude)
• Range: 8,100 km with 7 ton payload (5,033 miles)
• Combat radius: 5,000 km (3,107 miles)
• Ferry range: 11,000 km (6,835 miles)
• Service ceiling: 14,000 m (45,932 ft)

Armament

• Guns:
  
  • 2× NR-23 cannons in manned tail turret
• Bombs: 18,000 kg (40,000 lb) of free-fall weapons