HAMPTON-- NASA researchers have just completed a series of flights to study the effects of alternate biofuel on engine performance, emissions, and aircraft-generated contrails at altitudes typically flown by commercial airliners.
The Alternative Fuel Effects on Contrails and Cruise Emissions (ACCESS) experiment involved flying a NASA Dryden Flight Research Center DC-8 airplane as high as 39,000 feet while an instrumented HU-25C Guardian aircraft, based at NASA's Langley Research Center, trailed behind at distances ranging from 300 feet to more than 10 miles.
'This lets us vary aircraft separation to examine the changes that occur in exhaust plume composition as they mix in the air. It also allowed us to study the role aircraft soot emissions and conditions play in the formation and growth of contrail ice particles,' said NASA ACCESS scientist Bruce Anderson.
During the flights, the DC-8 engines were powered by conventional JP-8 jet fuel or a 50-50 blend of JP-8 and an alternative of fuel of hydro-processed esters and fatty acids produced from camelina plant oil.
More than a dozen instruments mounted on the Guardian jet characterized the soot, gases and ice particles streaming from the DC-8.
Alternative fuels cost as much as $18 per gallon compared to standard jet fuel that can cost $4 per gallon.