Flying Skies with Coal Mix Fuel
August 5, 2010
- Army helps Air Force effort to test Alternative power for Black Hawk
Recent flight testing on a Black Hawk helicopter at Redstone Arsenal proved to engineers Matt Boenker and Dale Cox something they already believed in - a U.S. helicopter can fly on an alternative fuel mix of 50 percent coal and 50 percent jet fuel.
A May 19 flight demonstration test conducted at the Redstone Airfield in support of Air Force research efforts further proved the viability of using an alternative synthetic fuel in aircraft - this time a Black Hawk helicopter.
"This was the first time a Black Hawk had flown on alternative fuel. It's a little bit groundbreaking. This is also the first time the Army has been involved in a test of this kind,"
said Matt Boenker, a contractor working for Avion in support of the Aviation Engineering Directorate-Propulsion, Aviation and Missile Research Development and Engineering Center, and principal engineer for AMRDEC's Alternative Fuel Program.
Dale Cox, the subsystem's team chief for the Alternative Fuel Program, has long been convinced that the Army can save fuel costs and gain efficiencies with the use of alternative (synthetic and bio) fuels. And, thanks to the recent Air Force test, Boenker and Cox are hoping to get closer to obtaining funding to research the use of alternative fuels by Army rotary aircraft.
"The Navy, Army and Air Force are all interested in alternative fuels," Boenker said. "We were involved in helping with the Air Force certification effort to certify the H-60 aircraft (Black Hawk to the Army and Pave Hawk to the Air Force) to fly on this coal-jet fuel mix.
"This is not an Army program and this test does not qualify or certify this fuel for Army aircraft. But it was a demonstration by the Air Force that this could be done. We need a lot more testing to use this on Army aircraft. We are now pursuing funding for that testing."
The process of turning coal into fuel was discovered in the 1920s by German scientists Franz Fischer and Hans Tropsch, and today is referred to as the Fischer-Tropsch or F-T process. During World War II, the F-T process was used by Nazi Germany and Japan to fuel aircraft and the war effort. After the war, research on the F-T process was continued in the U.S. by German scientists as part of Operation Paperclip. During the economic isolation caused by apartheid, South Africa began using the F-T process to meet its energy needs using both natural gas and coal.
"Since the mid-1990s, South Africa has used its alternative fuel at the Johannesburg International Airport," Cox said.
"About four years ago the secretary of the Air Force mandated that all Air Force aircraft be required to use alternative fuel by 2016. The Air Force has set up a certification office at Wright-Patterson Air Force Base, and they have a staff of about 30 who are certifying Air Force aircraft to use alternative fuel."
Researching and certifying the use of alternative fuels is a major emphasis within the Department of Defense. DoD is the largest single consumer of fuel in the U.S. with aviation fuel making up the largest portion of fossil fuel consumed by DoD, according to a 2007 Department of Defense report. In fiscal 2005, DoD consumed roughly 125 million barrels of oil (about 1.2 percent of the nation's total). About 74 percent of that was used to power mobility vehicles - Air Force aircraft, Navy ships and Army ground vehicles. Of that, about 52 percent was used for aviation fuel. In 2006, DoD consumed about 340,000 barrels of oil per day, according to the Office for Defense Research and Engineering.
A tri-service effort involving the Air Force, Navy and Army is ongoing to test the use of alternative fuels. The Air Force has taken the lead in this effort due to its commitment to purchasing at least half of all its fuel for its continental U.S. fleet from domestic alternative fuel sources by 2016.
Although research has shown that F-T fuel runs cleaner than the standard JP-8 (Jet Propellant 8) fuel, there are concerns with the flight characteristics of the F-T fuel in its pure form.
"The Air Force is not trying to certify straight F-T. There are no aeromatics in the F-T fuel that keeps the O-rings expanded," Boenker said. "With the constriction of O rings, you will have fuel leaks. That's why we have to use a 50/50 mix of JP-8 fuel and F-T fuel. But, even with a 50/50 mix, you cut in half the amount of JP-8 fuel that you need."
Prior to the May 19 testing at the Redstone Airfield, Air Force contractors briefed the AMRDEC engineers and Redstone Test Center pilots on all testing that has been completed with the JP-8 and F-T mix. The AMRDEC and RTC employees reviewed flight tests and material capability tests, and accepted the risk of flying with this new fuel blend.
"We were convinced there were no issues at all," Boenker said. "Our guys really had no reservations in using F-T fuel because it's flown in so many different aircraft."
On May 19, a series of three flight tests at the Redstone Airfield confirmed for the Air Force that F-T fuel can power a Black Hawk. The first flight test, using the original form of JP-8 as fuel, was conducted to confirm all systems on the Black Hawk were performing properly. In the second flight test, JP-8 was used in one engine while the F-T/JP-8 fuel was used in the second engine. Once that flight was confirmed a success, a third test flight using F-T/JP-8 fuel in both engines was conducted.
"F-T fuel and biofuel meet all the standards as a JP-8 fuel, they are just produced from a different source and in a different process," Cox said. "They have the same characteristics as a JP-8. During our testing, the F-T fuel was confirmed as a drop-in fuel, a fuel you can drop in and don't have to make any adjustments for."
Since the Air Force test used an Army helicopter, AMRDEC was instrumental in conducting inspections before and after the flights.
"We wrote the processes to inspect the aircraft with the alternate fuel," Boenker said. "We checked specifically for leaks and seeps, and any abnormalities. We were responsible for the air worthiness of the flights. The pilots saw no difference between running straight JP-8 and this fuel."
The Black Hawk was one of the last aircraft that the Air Force needed to certify with the JP-8 and F-T fuel mix. But, while the Air Force is well on its way to meeting its 2016 requirement, the Army has yet to do its own testing with alternative fuels.
"We still have a testing requirement," Boenker said. "We haven't started testing, especially in regards to the long-term effects on an engine. We have quite a bit of work to do with Army aviation to qualify this fuel."
Even though the coal-to-fuel process has proven to be successful, Cox and Boenker said efforts into using renewable sources - such as Algae (in ponds and renewable in 14 days), and the Camelina and Jatropha plant - are better solutions to providing alternative fuels.
"Coal as a feed stock for alternative fuels is not renewable. Biofuels use renewable feed stocks. Plant based and animal based sources are renewable," Boenker said. "There are even studies involving converting chicken fat from chicken plants into biofuel. Anything that has carbon can be used as a biofuel."
Research involving the use of corn, sunflower seeds and soybean as alternative fuel sources has been discouraged, Boenker said, because they are food sources.
The Navy and Air Force are now doing research into the use of Jatropha and Algae as biofuels. Recently, the Air Force completed a test that used biofuel in an A-10 Thunderbolt II ground attack aircraft. The Navy is working on testing biofuel in an F-18 aircraft.
"These fuels are extremely expensive because they are produced in very small amounts," Cox said.
Any work done in the area of alternative fuels is good for the U.S. fuel industry. As the alternative fuel industry grows, mass production will increase and costs should decrease. Proving that alternative fuel technology can provide high performance results in both military and private aircraft and vehicles is the first huge step toward jump starting this new, cleaner industry, Boenker and Cox pointed out.
"It's all about pushing awareness," Boenker said.
"Pushing awareness" is also about encouraging private companies to invest in manufacturing processes for alternative fuels.
"Fuel using coal is not readily available," Cox said. "It's a supply and demand thing. No demand, so no supply. There are very few sources for this alternative jet fuel. The next big hurdle in this program is developing sources of supply."
The F-T fuel used in the May 19 test flights was purchased from South Africa. The Defense Energy Support Center is working with U.S. companies such as Rentech of Mississippi to develop supply sources for alternative fuels.
Pushing toward creating U.S. sources for alternative fuels will, in the long run, be a good move for the military and for the U.S. economy, the two engineers said.
"We don't want to be dependent on South Africa or any of the oil producing nations for our fuel," Boenker said.
Boenker and Cox also hope awareness will lead to funding for the stand-alone engine testing on T700 and T55 engines used in Black Hawk, Chinook and Apache helicopters, and for flight demonstration testing with alternative fuels.
"One essential test is the endurance test where we run the engine with this alternative fuel and then we tear down the engine and look at all the internal parts to see if there is any degradation," Cox said.
As engineers, Boenker and Cox know it will take time to conduct Army tests on the use of alternative fuels in aircraft. But, as U.S. consumers, both are excited about the significance of these tests in terms of broadening the use of alternative fuels.
"This is an exciting industry," Boenker said. "We are very excited about what research and testing of alternative fuels can mean for not only the Army but also for the U.S. economy."
The following Team Redstone and Air Force employees supported the program during the planning stage, the actual flight testing at RTC, and post test of this new fuel: Jim Hesson, John Burkhead, Level Lesley and Emmett Garret, Redstone Test Center; Anthony Vahl, Gary Brammell, Daniel Bryant and Charles Berry, Army Aviation Test Directorate, Redstone Test Center; Dale Cox
, Curtis Stevens, George Bobula and Matt Boenker, Aviation Engineering Directorate; Gary Smith, Army Fuels Division; and Walter Bagnal, Mark Bates, Craig Howell, Brad Strong, Daryl Corsentino, Jeff Eblen, Wayne Durosko, Steven Powers, Leo Starvetsky, Betty Rodrigues and Heather Haskin, Air Force Alternate Fuels Division.
"A program of this size cannot be put together without the incredible team effort of us all," Boenker said.