The roots of innovation trace back to World War I. Rolls-Royce’s predecessor company in Indianapolis, the Allison Engine Company, adapted early automobile engines for the De Havilland DH-4, a single-engine, two-seat biplane bomber. Later, Allison designed and manufactured thousands of engines for such legendary American military aircraft as the P-51, P-38, P-39, P-40, and others, and provided engines for the British Spitfire. Throughout the history of its Indianapolis operations, Allison and later Rolls-Royce have remained a trusted Air Force partner through technological, economic, and military revolutions—including the acquisition and name change.
“When Rolls-Royce acquired Allison in 1995, it picked up that legacy and tradition of supporting first the Army Air Corps, and later the U.S. Air Force,” said Lt. Gen. Darryl Roberson (retired), senior vice president of business development at Rolls-Royce North America. “From the very start with this company, there was an innovative mindset—a determination to stay on the leading edge of technology and capabilities in support of warfighters.”
Engine making is and was always part science, part art. There is a reason just a few companies today can build high-tech jet engines. “There are fewer, in fact, than nations with nuclear arms,” he said. No wonder, he adds, that “Even today, the Russians and Chinese still try to steal our technology—they can’t match it on their own.”
That long-standing engineering culture helps ensure that Rolls-Royce delivers today—on its promises, with its technology, under any conditions, from extreme heat to destructive sands, to bone-chilling cold.
“There is a lot of technology that goes into this, as well as the ability to test and modify, to work out the wrinkles,” he said. “We use our long history, our experience, to optimize these engines in ways that others cannot.”
One reason, Roberson said: The deep, direct ties between Rolls-Royce employees and their Air Force customers. Roberson spent 34 years as a USAF fighter pilot and commander. “I was a part of the Air Force for half of the time that the Air Force had been in existence,” he mused. “I grew up with it.” Now he gets a thrill from continuing to contribute.
“As an industry partner for the Air Force, it is critically important for us to understand their needs and desires, where they’re trying to go and how best to help them get there. The years spent servicing those engines, upgrading those engines, helping to improve capabilities—that tight relationship and our daily side-by-side work—all that gives us a deep understanding of the culture of the United States Air Force.”
Rolls-Royce engines power the C-130, the workhorse transport and its derivatives, and the versatile CV-22 tiltrotor, as well as the unmanned Global Hawk long-endurance, high-altitude, remotely piloted surveillance aircraft.
C-130J airframes have flown more than 2 million flight hours performing airlift, search and rescue, special ops, electronic warfare, and other needs. “It is critically important and super versatile aircraft,” Roberson said. Whether older -H models or newer C-130Js, “I have no doubt we will be supporting C-130s for at least the next 20 or 30 years.”
Rolls-Royce was a pioneer in vertical lift, powering the Marine Corps’ AV-8B Harriers as well as the V-22 and the engineering enabling those engines to direct their thrust through the transition from horizontal to vertical flight and back again—among the most complex engine technologies. Rolls-Royce also provides the vertical lift capability for the F-35B Lightning II.
“We are the leader in understanding how to take off vertically and transition to horizontal flight,” Roberson said. “When you tilt it from one orientation to another, when you transition from vertical operation to horizontal operation, these are extremely complex conversions. Rolls-Royce’s experience is unparalleled.”
No less unique is the B-52, and Rolls-Royce continues to evolve engine capabilities. Engineers work to improve the propulsion, and to deliver more electrical power to support emerging systems.
“These advanced electronic systems that are important for survival in engagements with the enemy, the systems that are needed to put precision fires on a target—all of that requires additional power,” Roberson said. “We are constantly improving, constantly upgrading and advancing to provide what the Air Force needs to conduct the modern fight.”
Rolls-Royce is at the heart of an effort to keep the B-52 Stratofortress flying until it approaches the century mark. To do that, Rolls matched the proven engines from its business-jet business to the rigorous requirements demanded of a long-range bomber. Advanced engineering made that easy.
“The ability to digitally manipulate the data that we have on our engine made a big difference in the competition,” Roberson said. “Suppose a question came up: ‘What if we needed more power for this or that?’ Our ability to digitally analyze the B-52 allowed us to very accurately predict what we could or could not do, and what the impacts and potential cost implications would be. All of that allowed us to be very precise and responsive both to the Air Force and to Boeing.”
Rolls-Royce is likewise applying those technologies to manufacturing, using digital twins to model performance and predict maintenance, and applying digital engineering and advanced materials and manufacturing processes to reduce parts count, increase reliability, and boost performance.
“In some cases, we’ve leveraged modern manufacturing and materials technology to reduce the thousands of parts that make up an engine by a significant amount,” Roberson said.
“We’re delivering better fuel efficiency and longer flight times, but with less maintenance and greater reliability,” he said.
Military aircraft must fly under often difficult conditions, often under extreme heat, cold, and in dirty, sub-optimal environs. Combat conditions only make the demands more intense. “We work hard to give the Air Force engines that do what they need to do in combat,” Roberson said. “That requires a lot of engineering prowess.”
Modern technologies like additive manufacturing enables fewer parts, and new materials, such as coatings, can last longer and reduce downtime. Digital engineering is the key enabler, because it makes it possible to experiment using digital models rather than real life, so that in the long term, “We can manufacture parts in innovative, new ways, much more quickly, and much more reliably,” Roberson said.
“Technology now is allowing us to achieve greater levels of performance in higher-temperature engines than we ever could before,” Roberson said. Further down the road, Rolls-Royce is working on hybrid-electric flight, a solution Roberson said could give pilots greater stealth, as they switch to the quieter electric mode when approaching enemy positions. And the reduced heat profile of an electric engine would also reduce the likelihood of detection.
“This company is absolutely committed to hybrid electric and electric flight for the future,” Roberson said. “We always want to be on the leading edge.”
A Trusted Partnership
Throughout the history of its Indianapolis operations, Allison and later Rolls-Royce, which acquired the company in 1995, has remained a trusted Air Force partner.
1917 Early American military pilots begin flying DH.4 aircraft, initially powered by Rolls-Royce Eagle engines. Later versions featured Liberty powerplants, which were based on race car engines, from Allison Engine Co. in Indianapolis. 1942 Allison opens new factory in Indianapolis, Indiana, to produce V-1710 piston engines. These engines would power P-51, P-38, P-39, P-40 and other aircraft during and after World War II. Later versions of the P-51s would be powered by Rolls-Royce Merlin engines, iconic for their use in RAF Spitfires and Hurricanes. 1947 Allison begins producing J33 engines, which will go on to power the P-80 Shooting Star, the Air Force’s first operational jet fighter, as well as the F-94 Starfire and the T-33 jet trainer. Allison produced nearly 7,000 J33 engines. Its later J35 engines would become the primary powerplant for the F-84 Thunderjet and F-89 Scorpion. 1956 First production C-130A aircraft are delivered to the Air Force, the first among more than 2,600 aircraft to be produced in the C-130 line. The initial aircraft were powered by four T56 turboprop engines from the Allison factories in Indianapolis. The T56 becomes one of the longest production engines in aviation history, with over 18,000 engines produced. 1968 First flight of the USAF A-7D Corsair II, powered by a single Allison TF41 turbofan engine, a license-built version of the Rolls-Royce Spey. A-7D aircraft flew in the Air Force fleet for more than 20 years. 1985 An Allison engine, designated T406 and later renamed as the Rolls-Royce AE 1107C, is selected to power the V-22 tiltrotor aircraft. 1995 Rolls-Royce purchases Allison Engine Co. with U.S. Government approval, officially joining two companies with a long, intertwined history of aerospace collaboration. 1996 First flight of the C-130J, powered by four Rolls-Royce AE 2100D3 turboprop engines. 1998 First flight of the Global Hawk UAV aircraft, powered by a single Rolls-Royce AE 3007H turbofan engine. 2006 First operational CV-22 aircraft delivered to Air Force at Kirtland AFB, powered by Rolls-Royce AE 1107C turboshaft engines. 2019 Rolls-Royce AE 2100D3 engines surpass 8 million engine flight hours on the C-130J fleet. 2021 Air Force selects Rolls-Royce F130 engines, to be produced in Indianapolis, for B-52 engine replacement.