During development it was decided to further improve the basic design by adding another feature then becoming common, a "two spool" compressor arrangement.

It nevertheless required higher power to support a 230,000 pounds (100,000 kg) gross weight, so Rolls responded with the larger RCo.5.

Construction of the prototype V-1000 was well underway at Vickers Armstrong's Wisley works in the summer of 1955 when the entire project was cancelled.

The Conway was saved once again when it was selected to power the Handley Page Victor B.2 variant, replacing the Armstrong Siddeley Sapphire used by earlier models.

However the RCo.8 was skipped over after receiving a request from Trans-Canada Airlines (TCA) to explore a Conway-powered Boeing 707 or Douglas DC-8, having interested both companies in the idea.

Rolls-Royce responded by designing an even larger model of the Conway, the 16,500 pounds-force (73,000 N) RCo.10 and offering the similar military-rated RCo.11 for the Victor.

Boeing calculated that the Conway with a bypass of only 30% would increase the proposed 707-420's range by 8% above the otherwise identical 707-320 powered by Pratt & Whitney JT4A (J75) turbojets.

Boeing's 707-420 featured a distinctive, scalloped exhaust nozzle (pictured above) incorporating noise suppression and mechanical and aerodynamic thrust reversal up to 50%, which was developed and supplied by Rolls-Royce.

[5] Douglas developed the DC-8's reverser-suppressor nozzle to work in conjunction with a variable ejector, which provided necessary, additional noise suppression.

Nevertheless, the Conway was successful on those aircraft, and was the first commercial aero engine to be awarded an operational period of up to 10,000 hours between major overhauls.

[13] In November, 1966, the inlet to the Conway engine, together with those for commercial Avon and Spey installations, was the subject of a patent infringement claim against Rolls-Royce by Rateau, a French manufacturer of steam turbines and automobile superchargers.

Société pour l’exploitation des appareils Rateau of La Courneuve, who alleged the inlets infringed two of their expired 1939 patents.

[14][15][16] The patent stated that the intake, by its diffusing internal shape, determines the speed of the air entering the engine compressor.

Witnesses for Rolls-Royce, including Frank Whittle, convinced the judge that an intake did not produce the effect claimed[17][18] and that the claim was "speculative" because, by 1939, no axial-flow aircraft jet engine had been built [19] and that earlier patents from Frank Whittle and others had already considered the design of the intakes.