PARTICIPANTS IN THE US defence department's Integrated High Performance Turbine Engine Technology (IHPTET) initiative have begun studies of advanced-propulsion technology goals for "beyond IHPTET".

The studies will help decide the direction which US fighter-engine technology will take beyond 2003, when the current three-phase IHPTET programme is due to be completed.

Initial evaluations show that the next phase, whether it is a fourth IHPTET phase, or a new initiative will still concentrate on improvements of the basic rotating-turbine technology of existing jet engines. Studies of more advanced, non-conventional, fighter engines are still expected to be included, however.

The IHPTET is aimed at increasing fighter-engine thrust-to-weight ratio by 100% while cutting fuel consumption by 38%, compared to a baseline advanced engine such as the prototype Pratt & Whitney YF119.

Apart from achieving better and more rugged performance, the IHPTET is also aimed at cutting production and maintenance costs. Contracts for Phase II have been awarded and planning for the final phase is now under way.

US Air Force IHPTET programme manager William Koop says: "There is a lot more potential beyond Phase III. We've concluded that there is a lot left in the turbine engine as we know it."

In particular, "beyond IHPTET" is expected to concentrate on three main tasks: eliminating some current parts altogether, simplifying others and continuing the pattern established during the current IHPTET programme of developing new components.

Koop identifies the diffuser and augmentor as examples of common engine-parts, which could be eliminated in the future. Variable-exhaust nozzles could be simplified and new core components such as "a cooler - or chiller of some sort", could also be developed.

"We could also look at making the cycle more flexible," says Koop, referring to further enhancements of variable-cycle engine technology similar to that developed by General Electric for the YF120.

Meetings to further define "beyond IHPTET" will continue this year.

Source: Flight International