The Perfect Ground Power for Military Aircraft

PD System

PowerSource is pleased to feature an interview with Mazen Badr, vice president and general manager for PD Systems' Power Solutions Division. PD Systems specializes in the development and engineering of U.S. military power equipment. Through Boeing and FCX Systems, PD Systems was recently awarded a subcontract to build and supply 110 ground power units (GPUs) over the next five years. The 75-kW units are powered by John Deere PowerTech Plus 4.5L engines and will be used by the U.S. Air Force overseas to supply ground power to military aircraft. Mazen talks about military GPUs and why the jet-fuel compatible John Deere engines are clearly the best choice for the application.

PowerSource: What do people find most interesting or surprising about PD Systems?

Mazen: PD Systems is a Service Disabled Veteran Owned Small Business that has the technical staff and program managers to compete with any large business. Being small allows us to be innovative and flexible in our approach to satisfying the client's requirements. Our strength is taking commercial-grade equipment and working with the manufacturer to engineer it to meet military specifications. Large companies come to us because we are the window to using your (jet-fuel compatible John Deere engines) equipment in military applications.

PowerSource: Tell us about your recent contract.

Mazen: It's a high-profile, fast-moving project because of who is involved in making decisions (Boeing and the U.S. Air Force). From the time we were awarded the subcontract, we had an exceptionally tight schedule to design, develop, and have multiple customer reviews. Normally a project like this would take two years or more to validate, qualify, prototype, and test, but we accomplished this in less than eight months.

PowerSource: Give us some insight into the development of these military GPUs.

Mazen: GPUs supply power to military aircraft when it's on the ground and are used for lights, air conditioning, and aviation system testing. These GPUs meet stringent operational requirements, and there are hundreds of specifications. As an example, the GPU must operate at a temperature as high as 140 degrees Fahrenheit and as low as minus 40 degrees; be sound attenuated; and be built with electromagnetic interference (EMI) safeguards to protect the GPU. The EMI also protects the aircraft it is servicing from emissions the GPU may emit. The GPU is also required to be rugged for harsh environments encountered in military applications including high wind, sand and dust storms as well as loads of ice and snow accumulating on the body of the GPU.

PowerSource: Temperature requirements have become more stringent, correct?

Mazen: Yes, in the past, the military required that components and controls be able to withstand operation in temperatures ranging from minus 25 to 125 degrees Fahrenheit (minus 32 to 52 degrees Celsius). Now the GPUs — and every component — must withstand minus minus 40 to 140 degrees Fahrenheit (minus 40 to 60 degrees Celsius). Because heat rejection is so important, we have to design and build a bigger cooling system while maintaining the tight envelope structure of the unit.

PowerSource: What engine characteristics were you looking for?

Mazen: The biggest task at the start of this was to find an engine that provides enough power to handle the client's stringent requirements. We analyzed, researched, and compared all of the engines and found that John Deere is the only engine in that size and capacity that could run on JP8 fuel. For military applications, that's a requirement without exception and a very important characteristic. Secondly, other important issues were availability and support: How soon I could get the engine and how supportive the manufacturer is to me. Also, engine size and weight are important characteristics for deciding which engine to choose. John Deere engines weigh less than other engines in this category. We also like the engine's ability to work at 140 degrees Fahrenheit (60 degrees Celsius) without derating the engine's capacity. So the John Deere engine met all the characteristics we desired and led to our choosing John Deere.

PowerSource: How would you describe the support that you receive from John Deere?

Mazen: The support we received was outstanding. The delivery schedule of the engines was essential to meet the stringent timeline imposed by the client. The engines were delivered on or ahead of schedule! Both John Deere and Bell Power responded quickly. Both were also very supportive in the technical and engineering qualifications of the engine in making sure that we had the right airflow and housing design, including vents, to ensure operation at 140 degrees Fahrenheit. We shared our design, and Bell Power Systems was able to take our design and perform airflow simulation to make sure we were rejecting enough heat. That was absolutely outstanding.

PowerSource: Bell Power Systems is supplying a complete power unit, correct?

Mazen: Yes, they are supplying what we call a mule — the engine, generator, and cooling system. We ship them the cooling system and alternator and have them build the base.

PowerSource: Is the overseas John Deere dealer network important to your company?

Mazen: Absolutely. I located the John Deere dealers to make sure there was support and service available where these units are going. I was happy and satisfied where the dealers are located and the support our military would receive.

PowerSource: How are the John Deere-powered gen-sets performing?

Mazen: Very well. We haven't had any issue with the engine at all. The John Deere engine is fuel-efficient and is able to work at 140-degrees Fahrenheit (60 degrees Celsius) without modifications. We are very happy with our decision. John Deere and Bell Power both made the difference in making this program a success. I would use John Deere again; it would be my first choice for the future.