Tag: Randy Furnas

High-Power Systems’ Needs Drive Design Challenges

Panelists: Moderator Graham Warwick, technology managing editor, Aviation Week and Space Technology; Randy Furnas, chief of the power division, Research and Engineering Directorate, NASA’s Glenn Research Center; Rick Hooker, design engineer, Lockheed Martin Aeronautics; John Nairus, chief engineer, Propulsion and Control Division, Air Force Research Laboratory; John Scott, chief technologist, Propulsion and Power Division, NASA’s Johnson Space Center

by Hannah Godofsky, AIAA Communications

Today, the F-35 or 787 are both state-of-the-art — each has a few hundred kilowatts of secondary power installed on the aircraft. But future demands for electricity in air and space systems will be even  greater, and design will need to adapt, a panel of experts said July 26 at 2016 AIAA Propulsion and Energy Forum in Salt Lake City.

“When I now look at electric propulsion, I feel like being in on the ground floor of a technology that’s going to change aerospace.  It’s going to enable space missions that we can’t do at the moment, and it’s going to change the way aircraft operate. Electric propulsion is actually here,” Graham Warwick, the technology managing editor for Aviation Week and Space Technology, said while introducing the “High Power Systems for Aerospace Applications” panel.

Warwick mentioned several small aircraft that have contributed to advancements in electric propulsion, such as Solar Impulse-2 or the E-Fan demonstrator plane, but he said, “Really, what interests all of us in this room is the high-power stuff. It’s the powering the airliners. That’s where the potential is. The potential for changing the environmental impact of aviation is on these high-power systems. What I’m really interested in is to be here as we’re beginning to explore these high-power systems.”

John Nairus, a chief engineer with the Propulsion and Control Division at the Air Force Research Lab, provided some clarity as to what makes something a high-power system.

“In the Air Force, when we talk about high-power systems, what we’re really talking about is a megawatt,” he said, adding that electric power has become flight-critical for most military aircraft.

“If you have a blip in your electrical power system, in the blink of an eye, you can lose your aircraft, because these aircraft are inherently unstable.”

Rick Hooker, a design engineer with Lockheed Martin Aeronautics, said high-power systems are driving new aircraft design.

“They’re designing the aircraft we’re coming up with, and they’re driving how we are integrating propulsion-airframe integration,” he said. “Really, I see efficient propulsion-airframe integration as an enabler for high-power systems.”

Hooker said some new aircraft engines are now the same size as the aircraft fuselage, which has a huge impact on the design of new airplanes. He described some of the cutting-edge research that has been done in making the integration of high-power systems into aircraft more efficient.

“Over-wing nacelle installations can be actually 5 percent more efficient than underwing nacelles,” he said.

John Scott brought up a different definition of high-power systems that applies to use in space: “Anything beyond 150 kilowatts that is provided today by the international space station.”

He explored, “A value proposition for what might happen if we were to drive well beyond those power levels, thereby accelerating the exploration of Mars and possibly even spinning off to the traditional energy industry a disruptive solution.”

Scott said high-power systems in space involve a lot of complicated tradeoffs in expense and technology and can drastically change mission timelines or the amount of mass that needs to be sent into space.

Panelists overall agreed that high-power systems are necessary to take big, disruptive leaps in technology and capability.

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Stretch Goals Eyed in Additive Manufacturing of Rocket Engines

Speakers: Moderator Randy Furnas, chief of the power division, Research and Engineering Directorate, NASA’s Glenn Research Center; Elizabeth Robertson, team lead, Liquid Engine Systems Branch, NASA’s Marshall Space Flight Center; Jay Littles, director of advanced launch vehicle propulsion, Aerojet Rocketdyne

By Ben Iannotta, Aerospace America Editor-in-Chief

Makers of rocket engines have plenty of evidence that costs and production time can be significantly reduced by making some components almost entirely through additive manufacturing, in which metal powder is laid down and fused by laser or electrons.

Engine makers have now defined the next steps, which will include defining standards and inspection processes to win customer confidence in additively manufactured components.

Elizabeth Robertson, leader of the Liquid Engine Systems Branch of NASA’s Marshall Space Flight Center in Alabama, said additive manufacturing has great promise, but she cautioned that there may be limits on “human rating” of components until inspection issues are figured out.

Jay Littles, director of advanced launch vehicle propulsion at Aerojet Rocketdyne, said one of additive manufacturing’s great advantages — a reduction in the parts count — also creates a disadvantage. Conventionally manufactured parts can be inspected individually, but an additive component subsumes many parts into just a few pieces that are joined together.

These “complex geometries” complicate inspection, Littles said. “You can’t go in and look at these.” A big challenge is “basically how you do the quality assurance.”

Robertson and Littles led the July 27 session “The Impact of Additive Manufacturing on the Design Process” at the 2016 AIAA Propulsion and Energy Forum in Salt Lake City.

Littles said other goals include making larger components and understanding the performance of specific additive manufacturing machines.

“We’re in the Betamax-tape part of this additive thing,” he said, referring to the 1970s-era Sony videotape standard that was beat out by VHS. “It’s going to be interesting to see where we go over the next decade.”

As powerful as additive manufacturing is proving to be, Aerojet Rocketdyne also has learned some of its limits.

“Additive really does open up the design window, but there’s also a lot of stuff that you can’t do — geometries to avoid,” Littles said.

While inspection might be a challenge, Robertson said a smaller part count is also “fantastic when you think about reliability.”

She recounted that in 2012, NASA decided to make components for a prototype engine to demonstrate additive manufacturing. Managers saw a 30 percent reduction in cost and part reduction from 250 to six, she said.

NASA also sees some limits to additive processes.

“If you have a part rotating at 90,000 rpm, you’re probably going to have to do machining to clean that up,” Robertson said.

Overall, “There are a lot of challenges that remain,” Robertson said. “We sometimes found that quality would follow people, rather than a company. Right now, additive is still an art.”

Video

All 2016 AIAA Propulsion and Energy Forum Videos