Gas Turbine Handbook : Principles and Practices

Applications 13
Figure 2-2. Courtesy of United Technologies Corporation, Pratt &
Whitney Aircraft. The PW4000 turbofan engine is a high “bypass
ratio” engine (BPR 5.1:1). This engine produces 68,000 pounds “takeoff”
thrust and currently powers the Airbus A330 wide body twinjet
aircraft.
Some turboprop engines have made the transition from flight
engines to land based applications (Pratt & Whitney Aircraft Canada
PT6/ST6). Indianapolis 500 Race fans may recall the introduction
of the Pratt & Whitney type ST6B-62 to that race in 1967. The car,
owned by Andy Granatelli and driven by Pernelli Jones, led the race
for 171 laps, only to fail a gearbox bearing in the 197th lap 1 . That car
had an air inlet area of 21.9 square inches. Later, the Indianapolis
500 Race Officials modified the rules by restricting the air inlet area
to 15.999 square inches or less. A year later race officials further
restricted the air inlet area to 12.99 square inches. This effectively
eliminated gas turbines from ever racing again. The aero-engines
that have been most successful in making the transition from flight
applications to land based applications have been the turbojets (Pratt
& Whitney Aircraft J75/FT4, General Electric J79/LM1500, and Rolls
Royce Avon) and the turbofans (General Electric CF6/LM2500, CF6/