Sundstrand Power Systems is planning to mass-produce a 0.22kN (50lb)-thrust turbojet ,which it believes will have applications for target drones, decoys, unmanned air vehicles (UAVs) and even missiles.

"The engine is virtually creating its own market," says Sundstrand, which developed the low-cost TJ-50 through the US Advanced Research Project Agency's Small Engine Advanced Project. The engine has since become the focus for several UAV projects, including the Teledyne Ryan Aeronautical miniature air-launched decoy (MALD), which received a $24.4 million advanced-concept technology-demonstrator (ACTD) contract in late 1996 for development.

The first development TJ-50s for MALD are expected to be delivered by the San Diego-based Sundstrand division late this year to the nearby Teledyne site. Deliveries of initial production-standard engines will begin in February 1998, for installation in 32 MALDs for test and evaluation. Verification tests are to run from October to February 1998. The first MALDs will be launched mid-1998 from Lockheed Martin F-16s. A preliminary design review is scheduled for March 1997, and both companies hope that a critical-design review, set for June 1997, will pave the way for production of up to 3,000 MALDs at a peak rate of about 1,000 a year.

Production of the MALD, destined for use on a number of US fighters, could be extended with new derivatives now under study. The run could increase if contracts materialise from other nations.

The MALD will confuse enemy defences by imitating a fighter aircraft. Unit cost price has been targeted at $30,000, based on an order for 3,000 machines.

The first powered flight of the TJ-50 is expected to take place by the end of the month on the Lockheed Martin Vought low-cost autonomous "smart" submunition.

The programme is funded by the US Army, but, pending successful tests, would then fall under the US Air Force's ACTD funding.

It has also been selected for the Northrop Grumman Ferret, a small cruise missile being designed for launch from platforms which include submarines, aircraft and even an armoured vehicle. The Ferret will provide strike and reconnaissance up to 600km (320nm) behind enemy lines.

Key to the TJ-50's success is its simplicity, says Sundstrand. The entire engine weighs 4.9kg, with the gas generator itself weighing just 3.15kg.

The engine measures just under 290mm in length and is 102mm at its maximum diameter, with an inlet diameter of 750mm. It is made up of six major parts divided into two main sections: a rotor module and combustor module.

The rotor section consists of a cantilevered "monorotor" assembly, made up of a single-stage mixed-flow centri- fugal compressor and single-stage, combined axial/ radial turbine.

Also included are two hybrid ceramic bearings, a shaft-mounted integral fuel pump, a fuel-mist lubrication system and air-inlet housing.

Source: Flight International