Fuels Team Plans Super Hornet Biofuels Flight Test
Naval Air Systems Command fuels team
is gearing up for biofuels flight tests in an F/A-18 Super Hornet
at Patuxent River, Md., by next spring or summer, according to
NAVAIR's fuel expert. Rick Kamin, Navy fuels lead, explained that
before "biofueling" the plane, the team will first conduct
laboratory and rig tests at Pax River, followed by static engine
tests with the Super Hornet's F414 engine on a test stand at the
Lynn, Mass., facility of manufacturer General Electric. The static
tests will take place "probably in the December-January time
frame," Kamin said.
The NAVAIR fuels team is also getting ready to kick off a
similar effort to test and certify biofuels for use on ships.
The upcoming tests are part of a larger effort to test and
certify promising biofuels in support of the Navy's energy strategy
to enhance energy security and environmental stewardship, including
reducing greenhouse gas emissions.
"Our major goal is a drop-in replacement" for the Navy's
petroleum-based fuels, Kamin said. "The field won't know the
difference."
Fuels derived from plants are considered carbon neutral. Burning
them doesn't increase the net amount of carbon dioxide in the
atmosphere because the carbon they contain was originally absorbed
from the air as the plants grew.
NAVAIR has asked for 40,000 gallons
of JP-5 jet fuel from bio-based feedstocks in a request for
proposal (RFP) issued by the Defense Energy Support Center. Initial
laboratory analyses and rig testing will consume 1,500 gallons; the
static engine tests, 16,500 gallons; and the flight tests, 22,000
gallons. The feedstocks targeted are not used for food.
Kamin said fuels received from the JP-5 RFP may include those
made from oils produced by plants such as camelina, jatropha and
algae.
"We won't know for sure what we're going to get until the
procurement process is completed," he said. The contract signing is
expected to take place this month.
Camelina, also known as gold-of-pleasure or false flax, is in
the same family as rapeseed, the source of canola oil. Often
considered a weed, camelina is cultivated today for the high
quality oil its seeds produce, both for human consumption and
conversion to biodiesel. Jatropha is a tough woody plant that can
grow in arid conditions unsuitable for most food crops. Its seeds
produce oil that's unfit for human consumption but can be converted
to fuel.
Algae can be grown in vats or ponds under controlled conditions
that maximize output and harvesting efficiency. Algae's oil is
produced within individual cells. Oils harvested from the plants
are refined into fuel with conventional petroleum refinery
processes.
Two commercial biofuels that will not be tested are ethanol, now
blended with gasoline, and biodiesel. Ethanol is unsafe for
shipboard use because it ignites too easily, and its lower energy
content would significantly reduce aircraft range.
The biodiesel sold commercially today consists of
oxygen-containing compounds called esters. Although they burn well,
esters absorb water too readily to be suitable for the Navy's
maritime environment.
For the upcoming static and flight tests, the biofuels will be
mixed in a 50-50 blend with conventional petroleum-derived jet fuel
to provide the necessary specification properties. Biofuels are not
as dense as conventional jet fuel, have less lubricating ability
and contain no aromatic compounds, a group of chemical compounds
able to penetrate the rubberlike materials that make up gaskets and
seals.
"Aromatics are critical for seal swelling," Kamin noted. "The
easiest way to get these properties back in is with a blend with
petroleum-based fuels."
Kamin emphasized that the Navy will not be producing any
biofuels itself. Fuel for all military services is purchased by the
Defense Energy Support Center.
"We're responsible for fuel specification requirements. Our main
responsibility is to test and certify the alternative fuels for
inclusion in our specifications," he said.
The fuels team will initially apply three categories of standard
tests to the fuels received in response to the RFP: analytical
chemistry – using instruments such as a mass spectrometer to
determine chemical composition and structure, "wet chemistry"
– determining the fuels' response in specific chemical
reactions and rig test properties such as water separability, to
determine how the fuels will react in aircraft and in conditions
typical of Navy operating conditions, which include long-term
storage.
"Storage stability is a unique military and Navy requirement not
required in the commercial world," Kamin noted.
"We're trying to certify by families, to come up with a spec for
an approved class of feedstocks, such as oil shale, petroleum,
hydrotreated renewable or coal," he said. The specifications of
each family will be determined initially through the full battery
of chemical analysis, physical properties, static engine tests and
flight tests.
The Navy plans to have test and certification completed on the
most promising alternative fuel candidates no later than 2013,
Kamin said. As each candidate is approved for use, it will be added
to the Navy's JP-5 (aircraft) and F-76 (ship propulsion fuel)
specifications. Once in the specification, the Defense Energy
Support Center can buy the fuel to meet Navy requirements from the
lowest-cost provider. Actual usage in the fleet will depend on
industry production capability. [ANN Salutes Robert Kaper, Naval
Air Systems Command Public Affairs]