Partners say work aimed at long-range missile could be switched to other applications

Boeing and Pratt & Whitney are pushing to extend a US Office of Naval Research (ONR) pulse detonation engine (PDE) risk- reduction programme that could lead to a demonstration PDE for a supersonic missile or a range of other applications.

The team, combining Boeing Phantom Works, P&W and United Technologies Research Center, is in the third year of the programme and is now "trying for a budget for a fourth year", says Gary Lidstone, programme manager from P&W's Seattle Aerosciences Center.

"Our goal is to demonstrate the performance of a full-up engine and we have a missile application with the ONR," he says. "However, it is possible we might shift to other applications."

Originally aimed at a Mach 2.5 long-range missile, Lidstone says the work could be applied to augmented turbofans and PDE-cored turbofans, duct-burning engines and combined cycle concepts. "PDE is also being considered for VAATE [Versatile Advanced Affordable Turbine Engines programme] as well as hybrid engines, and PDE technology could be used to help meet VAATE goals," says Lidstone.

PDEs, which are air-breathing jet engines with no moving parts, promise great efficiency but have yet to be proven or flight tested. Other PDE work is under way involving General Electric, NASA and other interested parties in Japan, the USA and several European nations.

Recent tests have included a large-scale PDE rig representing a notional inlet on a supersonic unmanned combat air vehicle (UCAV). Tests at P&W's Florida site evaluated the 0.2 x 0.8m (8 x 32in) ogive-shaped inlet at high and low power. The team says the rig is the "largest PDE ever successfully operated. It represents a viable design option for future high-speed vehicles." The unusual shape of the rig was designed to demonstrate integration of PDE propulsion with "aggressively shaped vehicles" and, in the case of the UCAV shape, resulted in equivalent reductions in supersonic drag of more than 12% and a cut in transonic drag of more than 14%.

Other work includes demonstrations of an integrated test rig at flight pulse-detonation frequency at the Naval Air Weapons Center in China Lake, California, and development by P&W of a Pulse Detonation Rocket Engine with the US Air Force Research Labs and NASA Marshall Space Flight Center.

Source: Flight International