Project Mayhem is U.S. Air Force’s latest hypersonic development program looks to be aimed at acquiring expendable testbeds for new advanced jet engines, including turbine-based combined cycle designs for developing viable hypersonic aircraft, such as Lockheed Martin’s in-development SR-72.
The Expendable Hypersonic Multi-Mission Air-Breathing Demonstrator programme, referred to also as Mayhem, would be a competition to design, fabricate and integrate a large cruise missile, says the AFRL in a request for information posted online on 12 August.
“The Mayhem System Demonstrator will need to be capable of carrying larger payloads over distances further than current hypersonic capabilities allow,” says the research laboratory. “The payload bay will be modular and capable of carrying or delivering at least three distinct payloads in order to execute multiple government-defined mission sets.”
The AFRL is looking for companies to partner into two teams, each which would develop a new propulsion system and vehicle design, as well as a plan to integrate the entire system. It wants the demonstrator to first take flight within a five-year timeframe, it says.
It wants the missile body to have a standardised payload interface, to make it easier to integrate multiple types of future payloads.
Lockheed-Martin LMT +0.4% and Raytheon are separately working on a Hypersonic Airbreathing Weapon Concept (HAWC) for the Air Force, and Aviation Week reported in June that a Lockheed HAWC missile accidentally fell of a flying Air Force B-52 during testing. Lockheed also revealed it was working on a successor projected called Hypersonic Weapon Air-Breathing (HSWab).
In April, the Air Force also requested information from companies to study U.S. industrial capability to create an air-launched, air-breathing hypersonic cruise missile in “Future Hypersonics Program.” This weapon would have open systems architecture, use a solid-fuel rocket booster and be launched from an existing U.S. fighter or bomber—such as the B-1B Lancer or F-15EX.
According to journalist Steve Trimble of Aviation Week, the Mayhem missile has been confirmed to be the same as a R&D budget item for “Multi-Mission Cruiser” described as using “multi-cycle” engine for hypersonic cruising at speeds up to Mach 7. Nearly $21 million is assigned to the Multi-Mission Cruiser for 2021, with a total of $145.7 million projected through 2025.
Multi-cycle, or combined cycle, engines are able to switch between different propulsion modes. The budget document implies the missile could accelerate using turbine and rocket-mode propulsion, then shift to scramjet-propulsion mode while cruising at hypersonic speeds. The document highlights managing the intense heat generated by such a propulsion system as a major challenge.
The ten-page proposals are due by 2 PM on September 25. The RFI makes clear that submissions don’t count as formal offers that can be accepted in a legally-binding manner. Instead, proposals received will serve as market research that will inform more detailed requirements the Air Force will issue down the line.
Still, the document makes clear the Air Force eventually wants to award two indefinite-delivery/indefinite-quantity (ID/IQ) contracts each for “Larger-scale propulsion development and flight-weight ground test” and “Air-vehicle design and scramjet integration.” Thus, the scramjet engine and vehicle body will apparently be developed separately.