CALCOR AERO Systems, the developer of novel variable-exhaust-nozzle (VEN) and thrust-reverser (TR) designs, has signed an agreement with Pratt & Whitney Canada to demonstrate a combined TR/VEN on the PW306 which will power the Israel Aircraft Industries Galaxy.

The California-based company claims that the combination TR/VEN is a first for the industry and is useable on turbofans with up to 133kN (30,000lb) thrust.

Calcor reached a similar agreement with International Aero Engines (IAE) in June which involves testing the VEN on the International Aero Engines V2500 turbofan with "Airbus applications in mind", says company vice-president, Ron Binder.

The agreement with P&WC involves demonstrating a target-type TR with a variable-geometry nozzle. "It's never been done before," says Binder.

The PW306 nozzle will be able to vary the area of the exhaust by 11.4%, enabling increases in take-off thrust and climb performance while decreasing cruise specific fuel consumption (SFC).

The nozzle will be ground-tested in January and could be flown on a testbed in mid-1996 if the initial test results are encouraging. The VEN-equipped V2500, meanwhile, is due to undergo testing in October 1996.

Jean-Pierre Lair, inventor of the unit, says that cruise SFC for a 22-27kN engine could be reduced by between 1% and 1.8%, while thrust could be increased by between 5% and 10%. "There is usually a one-to-one improvement between thrust increase and [exhaust] throat area increase. The system also allows you to recoup a great deal of thrust loss in hot-and-high conditions."

When in the un-activated position, the combination nozzle-throat area, like conventional units, is optimised for cruise conditions. It will, however, be fully opened for take-off, similar to a military turbofan, and, under the control of a full-authority digital engine-control unit, will gradually close as the aircraft climbs to cruise level. On landing, the single unit splits to form a target-type TR.

Lair adds that the design of the TR makes it "mechanically impossible" for it to be accidentally deployed in flight. The shape of the TR also means that the nozzle is never in the path of core air, which means that the unit can be made of lower-temperature-resistant aluminum.

Source: Flight International