The growing presence of Unmanned Air Vehicles (UAV) at Le Bourget is an indication of the importance the aerospace industry is putting on this sector. For the engine manufacturers it is a whole new growth area.
Pratt & Whitney entered the market in February when the P&W-powered Northrop-Grumman X-47A Pegasus UAV took to the air for the first time, at the Naval Air Pacific Test Range in China Lake, California.
A few months after that historic flight using the Pratt & Whitney Canada (P&WC) JT15D-5C turbofan engine, the Naval Air Systems Command awarded the company a $12.7 million, 39-month contract which calls for P&W to demonstrate and validate a broad range of turbine engine technologies for potential US Navy and Air Force UAV and other applications. The effort will result in a technology demonstrator engine.
ArgumentsThe Navy contract augments Pratt & Whitney's own internal research into engine technologies that will best serve the special needs of UAVs, including low observability, light weight and high fuel efficiency.
By tapping into its own extensive resources and those of other United Technologies (UTC) companies, including Hamilton Sundstrand and Sikorsky Aircraft, P&W is confident of developing the technologies that will be essential to evolving UAV missions.
"Commanders keep finding new uses for UAVs," says Pratt & Whitney's Clay Small. "Payloads and missions will continue to change, but we can be sure that these aircraft will always have to be economical to operate. They will always have to be stealthy and able to fly long distances for surveillance or to deliver weapons and then return to base."
For the Pegasus demonstration, Pratt & Whitney and Northrop Grumman worked together to diminish an enemy's ability to detect the tail-less, kite-shaped 8.8m (27ft) aircraft.
The engine, which operates quietly and provides 3,200lb (14.2kN) of thrust, was buried inside the aircraft for low observability, but that meant the air it needed to burn fuel could not reach it in the usual unimpeded way. Instead, air entered the front of the fuselage via a series of slits, following a sinuous path and causing a high degree of air distortion.
Pratt & Whitney's extensive experience with inlets and low observability requirements on such aircraft as the F-22 Raptor and F-35 Joint Strike Fighter contributed to its ability to configure the engine to function normally under these conditions.
Pratt & Whitney also assisted in integrating the Pegasus engine controls with the vehicle management system, and with test operation support. The 12min flight of Pegasus met all test objectives, including low-speed handling, navigation, vehicle performance and simulated landing on a carrier.
The JT15D-5C engine and its predecessors have more than 30 years of experience and are commonly used to power the Cessna Citation. P&WC has delivered over 6,000 JT15D engines. They have accumulated nearly 30 million operating hours on over 2,700 different aircraft in 80 countries.
The recent contract with the Navy is part of the Joint Technology Demonstrator Engine (JTDE) programme, which in turn derives from the government-sponsored Integrated High Performance Turbine Engine Technology (IHPTET) initiative Phase III goals.
Pratt & Whitney's research under this contract will be conducted using an advanced PW800 engine core now being developed. P&W's efforts will focus on IHPTET Phase III component technologies such as high-temperature lightweight material systems to achieve the aggressive goal of doubling propulsion system capability.
This programme will not only advance component capabilities, but will also address a broad range of integrated subsystem concepts that are expected to have high potential payoff in advanced systems used for persistent intelligence, surveillance and reconnaissance (ISR) aboard UAVs and unmanned combat air vehicles (UCAVs).
Emerges"The tech demonstrator that emerges will be an engine with a common commercial core configured to meet UAV requirements," says Small, who is coordinating the effort. "This strategy means low cost and low risk for the customer."
The PW800 core is expected to be particularly relevant to the emerging classes of UAVs, due to its compact design, optimised specific thrust, and efficiency.
"This programme allows Pratt & Whitney to transition demonstrated technologies to several different product applications," adds Kevin Farrell, general manager of Small Military Engines, P&W.
Source: Flight Daily News
