Avro 730 (R.156T / O.R.330)

History

At the end of World War II (1939-1945) in 1945, the Soviet Union became the main threat to the West, which prompted the then global air powers (US, UK, and France) to focus on developing a new generation of fighter jets centered on jet propulsion systems. Engineers got to work and came up with various solutions, many of which were doomed, while others immediately started classic or largely forgotten entries.

The Royal Air Force (RAF) has done well in one aspect of its defense construction - the nuclear-capable "V-Bomber" force centered on Avro Vulcan, Handley Page Victor and Vickers Valliant. Clearly, the service also needs a robust high-altitude hypersonic reconnaissance platform to gauge enemy strength.

This led to new requirements centered on radar-equipped, day and night, all-weather, high-speed, high-altitude reconnaissance platforms through the "R.156T" specification.

The new requirements were introduced in 1954, and the following year no less than five British Airways groups participated in providing various submissions. Basic requirements have been determined: an operational ceiling of up to 70,000 feet and a speed of Mach 2.5 is possible - the aircraft will evade enemy ground defenses and interceptors through high altitude operation and sheer speed.

The Air Ministry appears to have completed the new design as early as 1960.

Avro engineers created a futuristic design based on the prospect of super speed and minimal drag. The final finished design took on an overall arrow-like shape, with the front of the fuselage detailed only by the canard front wings and recessed cockpit, while the rear featured a vertical tail with the main aircraft seated. The main aircraft will experience recoil only at its leading edge, and in each member, the engines will be buried.

The engine will be drawn in through the cone-cap (two-stage shock absorber) intake (located in front of the leading edge) and exhausted to the rear through the regular port (behind the trailing edge). An early design form of 1955 had the engine mounted in a nacelle at the wingtip, but maintained more or less the same sleek design. However, this approach was abandoned.

The installation of wing engines has also been advocated from the outset as they support service access and direct unit replacement - the latter allowing the aircraft to use any new or different propulsion scheme with little change to the entire fuselage.

An unconventional four-legged landing gear would be envisaged to provide the required ground operation - a front leg paired with an inline main leg supported by outriggers located near each engine nacelle.

The embedded cockpit means that the pilot does not have a regular field of view from his position. Instead, he would operate the plane through a periscope-like device, which itself has problems and requires special training.

Several engine modifications were considered for the Type 730, involving only four units for a total of up to 16 turbojets. The operator will consist of two, three or four people, but at least one pilot and one or two navigators.

Throughout development, the target gross weight remained at 200,000 pounds, half of which had to be used for the necessary fuel storage to keep thirsty engines fueled.

Between the nose section and the main landing gear legs will accommodate the "Red Drover" side-looking X-band airborne radar unit - critical to the aircraft's mission success. The Mach 2.5 requirement ensures that the aircraft must incorporate steel (honeycomb sandwiches) into its design, which has proven complex compared to alloys but is necessary to increase heat generation at the speeds and operating altitudes required for aircraft to fight.

The final form of the Type 730 submitted to the Air Ministry authorities contains 4 x Armstrong Siddeley P. 159 afterburning turbojets rated at 20,750 lb thrust coupled to 2 x Armstrong Siddeley rocket motors, providing additional only during start-up maneuvers Thrust provided.

Avro engineers aimed for the first flight by the end of 1959, with three more airworthiness examples to be added to the program the following year. This work will result in a production quality form for field inspection, which will be officially adopted around 1964. However, the project was shelved in 1957 (by the infamous "Defense White Paper") while the first prototype was still being built. It is thought that by the time the Type 730 enters service, advances in Soviet air defenses will negate any performance advantages.

In addition, the British turned to the futuristic battlefield that belonged to missiles.

Aside from finished models, partial prototypes, and some early wind tunnel testing, there is little money, manpower and time to justify the complex Avro 730 implementation.

More successful around the same time, the Americans were developing their own supersonic high-altitude reconnaissance platform, which became the Lockheed SR-71 Blackbird reconnaissance aircraft described elsewhere on this page.

Specification

Basic

Production

Roles

Dimensions

Weight

Performance

Performance

Armor

Changes