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Interest in AST.364 was shown by BAC and Hawker Siddeley, but it was Shorts who reacted most vigorously. Having lost out on OR.351. The company immediately offered the Belfast fuselage/C.141 wing S.5/45 and pointed out to the Ministry that an almost identical civil variant SC.5/41 had home and export sales potential. SC.5/43 had beaver tail rear loading in addition to a swing nose and all-up-weight of 420,000lb.The powerplant was to be the high by-pass ration 25,000-lb thrust RB.178 engine originally known as the Super Conway. The wing was aerodynamically similar to that of the C-141. All-up weight was to be 420,00lb and 123,000lb of freight could be carried across the North Atlantic at an optimum cruising speed of 440kts. Two loading decks were incorporated in a 17ft 7" diameter fuselage and in a mixed cargo/passenger role the SC.5 could carry 140 passengers on the upper deck and 70,000lb of cargo on the lower deck. Span was 163ft 3in, length 136fy 5in, and win area 483 sq feet. Sweepback on the 25 percent chord line was 5 degrees. Maximum zero fuel weight was 297,000lb and empty weight 146,010lb. In civil form, with full reserves, 100,000lb payload could be carried over 3,750 statute miles.

From Flight International 01/07/08

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Rolls-Royce promotes turboprop solution for new civil airliners

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Rolls-Royce is talking up the possibility of a new generation of turboprop-powered aircraft replacing a substantial proportion of today's narrowbody jets.

The manufacturer believes high oil prices are likely to drive airframers to sacrifice cruise speed for economics.

"The TP400 engine [for the Airbus A400M military transport] is a very efficient propulsion system," R-R director engineering and technology, Colin Smith, says. "There is a very sound argument to be made for the majority of the 150-seat market, which flies mostly for less than 1.5h [being turboprop-powered]...if somebody does want a high-efficiency turboprop then have we got one for you."

R-R civil aerospace president Mark King adds: "More and more manufacturers are looking at whether the bottom half of this market would be better addressed with turboprops."

The jet aircraft consigned large, 100-seat-plus turboprops such as the Lockheed Electra and Vickers Vanguard to the history books four decades ago. The largest turboprop airliners today seat no more than 80 passengers, although Bombardier is evaluating a stretched Q400 variant that could seat up to 100.

King stresses that the engine-makers have yet to be asked by the airframers to satisfy a specific requirement: "All we know is that a lot of people who currently fly around in 150-seat aircraft will need transporting in the future. Is that going to be in a single-aisle or twin-aisle? There are plenty of persuasive arguments about what that will be.

"What is the range of this thing? A thousand miles [1,600km] or 3,000 miles leads to fundamentally different machines."

King stresses, however, that there remains great uncertainty about the timescale of when airframers will launch new programmes in the 150-seat class, and says the timing will in turn affect the technological solutions offered by engine-providers.

He says: "There are so many different things that affect the timescale. Open rotor is 2018 turboprop we are in the middle of advanced turbofan is just the typical engine development timescale."

Rolls-Royce will start running a new open-rotor engine test rig in the next couple of weeks, which it says will allow testing of units that "are not core size but are pretty big".

King adds: "The kind of open rotors that we are looking at are still quieter than today's aircraft. They are just not as quiet as they would be if you were to design solely for noise."

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