Lockheed Martin will adapt SR-71's powerplant to provide expendable strike vehicle with top speed of Mach 3
Lockheed Martin plans to adapt the Rolls-Royce Allison Advanced Development YJ102R engine, first tested on the SR-71, to provide a Mach 4-plus propulsion system for an expendable, air-launched vehicle.
The new propulsion system has been selected by the US Office of Naval Research (ONR) for a Phase 2 contract under the $50 million Revolutionary Approach To Time-critical Long Range Strike (RATTLRS) flight-demonstration programme.
Lockheed Martin's RATTLRS vehicle is being designed to provide speed equivalent to the SR-71's listed maximum of M3, but will rely on unspecified turbine cooling technology advances to avoid the high fuel consumption of afterburning engines.
The ONR-led propulsion programme falls under the US National Aerospace Initiative, which is seeking to fund hypersonic advances. RATTLRS and the navy's HyFly hypersonic demonstration programme are intended to produce missile propulsion systems capable of Mach 4 and Mach 6, respectively.
First-phase RATTLRS contracts have also been awarded to Boeing, Orbital Sciences and Raytheon, but Lockheed Martin is the first to announce a Phase 2 contract. The RATTLRS system is required to be capable of integrating with an existing tactical aircraft, and specifically the Boeing F/A-18E/F Super Hornet, Lockheed Martin/Boeing F/A-22 Raptor and Lockheed Martin F-35 Joint Strike Fighter.
The air-launched version is required to weigh no more than 800kg (1,800lb) with a 225kg payload and a sea-launched version should be no heavier than 1,540kg with a 340kg payload, including a vertical launch booster.
Lockheed Martin is aiming for an M4 propulsion capability, but the ONR contract requires the vehicle to cruise at M3 for at least 5min in level flight. ONR has budgeted $50 million for the five-year flight demonstration programme, with potential options increasing the funding to a maximum of $175 million.
STEPHEN TRIMBLE / WASHINGTON DC
Source: Flight International
