FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1984
1984 - 0760.PDF
PROPULSION PW4000 aimed at $45 billion market EAST HARTFORD Pratt & Whitney has ordered components for an initial batch of 150 PW4000 turbofans, which will compete against General Electric CF6-80C2s for no less than 5,600 big-engine sales worth nearly $45,000 million by 1994, according to P&W market analysis. The same P&W forecast, presented to Flight the day after the PW4000 first ran on April 10, postulates sales of about 1,600 twin-aisle air liners up to 1994. Only one- third of such airliners will be long-range types, but they will account for almost half the 5,600 big engines (new units plus spares equivalents), and more than half the value. This projection assumes, a 5-4 per cent annual average airline growth-rate world wide, to 2,000 billion available seat miles by 1994. Pratt & Whitney anticipates gaining at least 50 per cent of the continuing big-fan market. The PW4000 is one of the major planks in United Tech nologies' policy of becoming the low-cost producer in all its markets, with a real reduction of 4 per cent per annum as its corporate target. Current PW4000 price is said to be about $250,000 below that of the competition, but P&W executives place little reliance on this being immutable in today's competitive environ ment. Neither is P&W quite so vociferous now about the PW4000's low parts count. The new engine is 54 per cent better than the JT9D-7R4 (with 30,000 fewer parts), but GE is now motivated in the same direction. Design targets for the PW4000 include extremely low inflight shutdown rates for overwater-twin opera tions; low cost of ownership; and the ability to fit existing -7R4 powered airframes with out airframe modifications. The 56,0001b thrust version of the PW4000 will fly for the Pratt & Whitney ran the first of nine development PW4000s for the first time on April 10 first time in June 1985 aboard an A300, and is due to be certificated in July 1986 ready for delivery in August. This version will be followed by a 60,0001b thrust engine which went into development three months ago, prompted by the almost insatiable thrust requirements of the 747-300 and A300-600. Certification at 60,0001b is scheduled for April 1987. The 50,0001b PW4000 has been deferred in favour of the 60,0001b engine. The high-pressure spool of the PW4000, derived from that of the PW2037, is good for 68,0001b of thrust, but a new fan and low-pressure turbine (with an extra stage) would be needed for this thrust level to be achieved. Pratt & Whitney does not anticipate a requirement for more than 60,0001b until the 1990s. Once the decision had been taken to go for a new design rather than simply developing the JT9D, the company moved PW4000 engineering and manufacturing depart ments together. Production tooling was committed from the outset. The impact of computer-aided design has been enormous, particularly in plumbing. Extensive full-scale rig test ing preceded the first run of the PW4000, and included 366hr and 80 surges on the thermatic rotor compressor, which turns 27 per cent faster than that of the -7R4 and has 4,000 fewer parts. Efficiency was higher than predicted, and surge margin was 5 per cent better than expectations. No blade-tip wear occurred on the compressor, whose unique one-piece drum is fed by 15th stage bleed-air during cruise to expand it and reduce tip-clearance for maximum efficiency. Cooler 9th stage bleed-air is used for take-off to allow greater clear ances. The "black art" of devel oping the low-emission rolled- ring double-pass annular combustor also benefitted from full-scale rig tests, as did the new accessory gearbox. Nacelle development at Rohr is aimed at gaining 1 per cent better installed fuel burn than achievable with the -7R4 nacelle. Overall, Pratt & Whitney is guaranteeing 7 per cent better fuel consumption than the -7R4, which equates to a $1 million saving per 747 each year, while maintenance material costs should be 25 per cent better (back to -7A levels). Pratt & Whitney believes that its new engine is lighter and more fuel efficient than the General Electric offering, and will run 70°-80° cooler for equal thrust. Target fuel burn for the 56,0001b PW4000 is 11 per cent better than that of P&W's own -7R4. Nine development engines will provide the acid test. Fadec eliminates PW2037surge Compressor-instability prob lems encountered on Pratt & Whitney 2037s during Boeing 757 flight-tests were elimi nated overnight by Pratt & Whitney executive vice- president Tadry A. Domagala, who flew to Seattle in a company-owned Mitsubishi Diamond, carrying re- programmed electronics for the engines' full-authority digital electronic control (Fadec) system. Higher than expected airborne acceleration and deceleration rates on the 2037s led to surge problems when throttle-opening was followed by rapid closure. Twin bleed valves were remaining open longer than required, but re-programming cured the problem simply by isolating one of the valves. Pratt & Whitney is totally "sold" on the Hamilton Standard/P&W Fadec, which also eliminates the necessity to "trim" the engine after strip-down or modification. Ten PW2037s have been delivered to Seattle, six of them flight-rated. Boeing has already flown two sets of engines on the first 2037- powered aircraft to establish a firm data base. Ten more engines are engaged in a continual development/reli ability test programme at P&W's East Hartford plant. 1158 FLIGHT International, 28 April 1984
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
