by Marina Malenic
The first replacement engine for the Air Force’s E-8C Joint Surveillance Target Attack Radar System, or Joint STARS, has been delivered by Pratt & Whitney, a division of United Technologies [UTX].
The 17-aircraft JSTARS fleet provides long-range wide area surveillance for the military. It is flown by the 116th Air Control Wing based at Warner Robins AFB, Ga.
“The newly manufactured JT8D-219 engine contains several internal and external upgrades from its commercial counterpart,” John Dobbins, Electronic Systems Center Joint STARS re-engining program manager, said in an Air Force press statement.
The new engine shipset is predicted to increase the thrust and fuel efficiency of the Joint STARS, according to Dobbins, resulting in significantly increased mission duration and altitude, and enabling operations from shorter runways.
Four JT8D-219 engines form the core of a Joint STARS re-engining shipset, which also includes pylons, thrust reversers, cowlings, pneumatic bleed air systems, updated wiring hydraulics and cockpit gauges.
A test configuration of the shipset is presently on the Joint STARS T-3 test aircraft and undergoing flight testing to validate performance characteristics and to collect data for E-8C flight simulator training systems.
Key upgrades to the engine include a nickel high-pressure compressor rotor system for increased corrosion resistance, an enhanced bleed air override system, improved tower shaft and gearbox elements to accommodate E-8C electrical loads and modifications to the pylons for attachment to the aircraft wing.
Pratt & Whitney’s updated version of the JT8D-219 and Seven Q Seven’s shipset design both recently received Federal Aviation Administration Supplemental Type Certificates for commercial use on Boeing 707 series aircraft, according to the Air Force. The E-8C is a modified Boeing 707-300 series commercial airframe extensively remanufactured and modified with the radar, communications and other subsystems.
The Developmental Flight Test Program is scheduled to culminate this fall following retrofit of the first production shipset and updated pneumatic bleed air system to the T-3 aircraft to verify system performance.
Following testing, the program will proceed to a full-rate production decision based on the needs and priorities of the Air Force, along with the results of the developmental and operational testing.
An ongoing analysis of alternatives for ground-moving-target-indicator solutions will help determine if more than four JSTARs will be re-engined, or if different aircraft could address all or part of the need, Air Force officials have said. The service is debating where future investments should be made for such target-tracking aircraft (Defense Daily, March 9, 2010).
The Air Force has already spent $22 billion to develop and sustain the E-8 fleet, according to budget documents. A new engine is the most pressing JSTARS upgrade, should the Air Force choose to keep the current fleet flying. The 40-year-old engines are causing massive maintenance bills and preventing optimum mission performance.
To date, Congress has supported only incremental funding for new engines. Two ship sets of JT8D replacement engines are currently on order, and an additional two are in the pending defense budget. Four sets are programmed for 2013 and five each in 2014 and 2015.
Boeing [BA] is pitching the Air Force a new version of the Navy’s P-8 Poseidon surveillance plane to take the place of the aging E-8 fleet. Company officials said earlier this year that a new fleet of 17 weaponized, 737-based aerial ground surveillance (AGS) planes with a next-generation radar would cost the Pentagon $5.5 billion (Defense Daily, Feb. 7).