Born: United States of America
Primarily active in: United States of America
From Leadership Profile: Vertiflite September/October 2012
Edwin P. Birtwell, Vice President & General Manager, Turboshaft Engines, GE Aviation
At the GE Aviation plant in Lynn, Massachusetts that made the T700s, T64s, and T58s powering most US military helicopters, Ed Birtwell leads a team that knows more than engines. “We’ve been able to develop, mostly in Lynn, a turboshaft expertise – people who know helicopter systems,” he explains. “They know how to integrate engines into helicopters and some of the unique aspects of the rotary-wing environment – the controls for the interface, the severity of the helicopter environment, the dust, and the dirt. We’ve learned to design the engines to survive in that kind of environment.” Lynn nevertheless represents only the tip of the GE engineering iceberg. “We have a huge skill-set of people and R&D dollars spread across the enterprise. That’s a big strength of the engineering team that we have. We’ve also grown the turboshaft business significantly over the last couple of decades.”
Military T700s in Army Black Hawks, Apaches, Navy Seahawks, Marine H-1 Zulus and Yankees, Air Force Pave Hawks, and Coast Guard Jayhawks continue to evolve. Commercial CT7-8 spinoffs found early success in the S-92, and Mr. Birtwell notes, “We’ve been branching out and getting onto additional applications. We’ve got the CT7-8 on the AW101, the NH90, more recently on the AgustaWestland 149 and 189, and the Bell 525. We’ve also seen a shift in the offshore oil market. We’re seeing oil companies planning to increase drilling rigs by over 20% in the coming years, so a lot of airframers are responding to this.”
Birtwell came to GE Lynn from helicopter airframer Sikorsky Aircraft. “After Connecticut for a couple of years, my wife and I decided we wanted to move back to the Boston area. I interviewed with GE who was the maker of the T700 for the Black Hawk. I went in there thinking ‘I’ll try this out for a couple of years.’ That was 1976, and I’m still here.”
Birtwell was recently elected as the Secretary/Treasurer of the AHS Board of Directors, taking office on July 1, 2012. He has been an AHS member since 1985.
Born in Newton, Massachusetts, Ed Birtwell grew up in Glen Ellyn, Illinois without strong aviation or engineering influences. “I always liked airplanes – what kid doesn’t? I guess I had a special interest in what I found myself better in, which were the math and science courses in high school.” A favorite uncle was a Notre Dame alumnus, and Mr. Birtwell acknowledges, “Notre Dame people are typically pretty vociferous boosters of the university. Growing up in the Chicago area, it wasn’t too far away, and as I got to become a football fan, Notre Dame was pretty important.”
University studies ultimately took an aerospace turn. “I went in as an intended math major, freshman year,” recalls Mr. Birtwell. Honors-level math courses were in the Notre Dame College of Science. “I found that mathematics at that level is not much about numbers at all. It’s more about philosophy. I decided I wanted to change out of math to something more pragmatic, and that led to the engineering side. Notre Dame had a good aerospace department, and I had always loved flying. The idea of learning how to make things fly was really appealing.”
Satisfying college years led the young aerospace engineer to advanced studies back east. “While I was at Notre Dame, my family moved back to Boston. I looked around the Boston area for a graduate school and applied to MIT where I got a research assistantship that paid the tuition and living expenses. I worked there on a magnetic balance and suspension system wind tunnel. You could correlate the currents moving through the magnets and measure all the aerodynamics without any interference from a support mechanism. It was an amazing system.”
With a Master of Science degree in aeronautics and astronautics, Ed Birtwell sought industry jobs. “I looked at what was available and interviewed at Sikorsky, Boeing and McDonnell Douglas – fixed-wing and helicopters. When I went on the tour during my interview at Sikorsky, I got absolutely fascinated by helicopters. To see these machines in person and think through how complicated they are and what special capabilities they have got me really fascinated.” Sikorsky also provided an intriguing systems perspective. “I was hired in as a survivability specialist who covered the gamut, from detectability – audio, visual, radar, IR – to ballistic vulnerability and crashworthiness. It was the time of the original UTTAS [Utility Tactical Transport Aircraft System] competition for what became the Black Hawk.
“I had a lot of fun. I really loved the products. I loved learning about the technical side, how the rotors are designed, how you control these things, how you calculate vibration from the rotorhead down through the structure, how you calculate fatigue life. In the particular job I had, you were evaluating entire system effects.” Mr. Birtwell adds, “Also, while I was working there, the engine for the UTTAS was prescribed to be the T700. I didn’t learn a whole lot about how the engine worked, but I did learn that there was enormous respect in Sikorsky for the T700 product. That led into where I went next.”
An interview at GE in Lynn won Ed Birtwell a mechanical design position on the TF34 turbofan then on the fixed-wing S-3 Viking and A-10 Warthog. “I wanted to round out my experience, to really get into the nitty-gritty of what does it take to design parts. That got me into the analysis that goes into designs, material tolerances, the supply chain and how parts are made.” A subsequent systems integration assignment on the F404 fighter turbofan in 1984 led to an application engineer’s job on the T700 turboshaft. “That job entailed working on the integration of the engine in helicopters, as well as some sales support. I’ve been associated with the T700 ever since.”
When Ed Birtwell entered the T700 business, the T700-GE-700 was already in production for the Black Hawk, the -701 for the Apache, and the -401 for the Seahawk. “We were also developing a Hover Infrared Suppressor System for the Black Hawk – the HIRSS – and I was responsible for that.” More powerful T700s were soon in development – the -701C for UH-60L Black Hawks and -401C for later Seahawks. The same period saw the introduction of digital electronic controls for the T700. “I’ll tell you one thing about helicopters and engines – the integration is really important. It’s a different world from what my fixed-wing friends have to deal with.” Mr. Birtwell explains, “Fixed-wing, the pilot can control the engines directly. In a helicopter, the pilot flies the cyclic and collective and pedals, and the engine’s got to anticipate the power you need to maintain rotor rpm. We really have to understand the helicopter rotor, transmission, and driveshaft so that we can build in the right control model into our software. Not only that, we have to understand how the pilots are flying them.”
The Army chose to put the more powerful -701C engine on radar-toting AH-64s. “On the H-60, they had upgraded the transmission to take the higher power of the -701C. On the Apache, they hadn’t. We found some integration issues when we tried to put it on the Apache,” reflects Mr. Birtwell. “We could produce a lot of power, but when the power could exceed the transmission easily, the pilot had to catch it. We had to do some real innovation on the control laws to moderate how the engine responds right around the transmission limit. It took us some time to do that, but in the end, the engine responsiveness was super, and the pilots really loved it, which is the main thing.”
T700 successes fueled investment in commercial CT7-8 for the S-92. The -8 engine has since topped 3,000 shp, twice the output of the original T700 in the same footprint. The company-funded development also underscored the difference between military and commercial engine markets. “The commercial market is very focused on cost. They also tend to fly much more – if you compare commercial flying rates with peacetime military, it’s an order of magnitude higher. That means the aftermarket service cost factors are very significant. We have to make sure we design engines that not only have good and low operating and support costs, and be willing to guarantee this to the customer.”
Commercial advances return military enhancements. “We found ways to take some of the technologies from the dash-8 commercial engine and fuse them back into the T700 to make it more durable,” notes Mr. Birtwell. “We developed a program called the -701D just in time for Iraq and Afghanistan. We were able to extend the Time on Wing operating in that environment.”
GE Lynn has several technology streams to improve and expand its turboshaft line. Last year, it consolidated development of the Army Advanced Affordable Turbine Engine demonstrator and the Navy/Marine GE38 into a new Advanced Turboshaft/Turboprop Programs group. Compared to the T700, the 3,000 shp AATE aims for 25% lower specific fuel consumption, 60% better power-to-weight ratio, and 35% lower operating costs. Mr. Birtwell explains, “The Army is interested in taking that technology into an engine to replace the T700 in the Improved Turbine Engine Program (ITEP).” He adds, “We’re putting technologies into this AATE engine that will satisfy this requirement. We’ll also be able to infuse these technologies into the T700 to make the T700 more efficient and more powerful.
” Meanwhile we are developing the GE38 engine for the Marine Corps CH-53K. This engine has topped 7,500 SHP,” notes Mr. Birtwell. “Last year we won the Army FATE – the Future Affordable Turbine Engine Program. What FATE is doing is providing us the test bench to work through the technologies for us to be able to grow and improve the GE38.”
GE Lynn meanwhile leverages other products such as the big GE90 turbofan and F414 fighter engine to provide technology for its turboshafts, “We are heavily matrixed,” notes Mr. Birtwell. “We have one engineering organization that works on the breadth of GE enterprise engines. A lot of the technologies are very similar.
“We’re developing new materials continually, but we are working particularly hard on the ceramic matrix composite materials for hot sections. The ceramics will be able to take a lot more temperature. We’re also evaluating a distributed control concept where you take some of the major computational aspects of the control and distribute them into some of the major LRUs [Line Replaceable Units] to simplify the wiring and also simplify the FADEC box itself.”
GE Lynn meanwhile seeks to replenish its workforce. “I think we all recognize the criticality of having good, strong engineering talent.” Mr. Birtwell concedes, “We do have people with a lot of experience who either have retired recently or are about to, so we have stepped up programs to deal with that. We have an absolutely great program for entry engineers called the Edison Engineering Program. We bring in new engineers, put them on assignments for nine months at a time, along with an educational program that will enable them to get a good feeling for what areas they’re likely to pursue in their careers.
“Another popular program is the Junior Officer Leadership program where we bring in folks from the military. We also have a very strong internship and co-op program with colleges and universities – not just in the Boston area but all over the country. We’ve also adopted a local middle school here where we have people from the plant volunteer, so we get the kids from a very early age interested in the things that we do.”
Mr. Birtwell notes, “GE wants to get beyond the engine, whether in propulsion systems or electrical power generation. Where I think we need to focus is on the applications. As I look at the helicopter/rotorcraft industry, I’m asking what kind of vertical lift programs do our customers need in the future? There is the JMR/FVL [Joint Multi-Role/Future Vertical Lift] effort going on. How is our military customer, in particular, going to get their arms around what this needs to be?
“If you can conceptualize this well enough, I think we can achieve better technical solutions once we understand what the goals are,” concludes Ed Birtwell. “I think if you look at the end-system goals, we as an industry could come up with some better efficiency/synergy with how we attack those requirements. Having associations like AHS is important because they can bring people together in this dialogue. I think the Vertical Lift Consortium is a great idea. You can’t visualize those capabilities unless you know where the customer wants to go.”