Aviat Unveils Bi-Fuel CNG Husky A-1C at Oshkosh


Bi-Fuel Airplane Could ‘Dramatically Reduce the Cost of Learning to Fly’

Wyoming’s Aviat Aircraft and the Minneapolis-based Aviation Foundation of America will unveil the first piston-powered aircraft that can operate on compressed natural gas (CNG) and aviation gasoline at AirVenture 2013 this week in Oshkosh, Wisc.

CNG, being far, far cheaper than $6/gallon avgas, could make it easier for student pilots to build their requisite hours, says Aviat Aircraft, which is unveiling a bi-fuel Husky piston single at Oshkosh.

The modified Husky A-1C – “America’s favorite taildragger” – has been fitted with a single Type IV fuel cylinder from Hexagon Lincoln. The aircraft’s 200-horsepower, four-cylinder Lycoming aircraft has been modified with a 10:1 compression ration and to run on either compressed natural gas or avgas “with the flip of a switch.”

“Among the many advantage of using CNG are fuel cost savings, cleaner burning fuel and no lead emissions,” Aviation Foundation of America president Greg Herrick says in Aviat’s announcement. “I’m impressed with how Aviat readily agreed to tackle this project, working with a team of engineers and craftsmen within the aviation and natural gas industries.

 “The result is a sophisticated solution which can be readily applied to a variety of piston powered aircraft,” Herrick said.

Regarding the choice of a Type IV fuel cylinder, “The newer generation tanks are of course preferred due to the lighter weight,” Herrick says. “A lot of progress is being made in tank technology, for example the new 3M tanks just now going into production.”

CNG power is up to 80% less expensive than the national average of $6-per-gallon aviation gasoline, Aviat says. And, there is no lead in CNG. Lead “is currently a significant issue with aviation gasoline.”

Engine oil remains significantly cleaner, therefore improving engine life, Aviat says, while aircraft performance is enhanced as CNG typically burns 138 octane versus the 100 octane of avgas.

“One aspect we’re particularly excited about is the opportunity to dramatically reduce the cost of learning to fly,” Herrick says. “If a flight school installs a simple CNG refueling station it can cut the cost for the student’s fuel, perhaps by thousands of dollars. And the fuel is available where ever there is a natural gas line. If a training plane uses 10 gallons per hour, the cost of fuel alone could be reduced by $40 to $60 per hour.”

The CNG is the same natural gas used in homes and offices everywhere. Home, business and industrial CNG filling equipment is available today, with home units projected to be selling for around $500 by 2014 with larger and faster-filling equipment costing more.

“While adapting our standard Husky aircraft into this dual fuel configuration was not without challenges, it was well worth it,” Aviat Aircraft president Stu Horn says in his company’s announcement.

 “The performance and ease of operations have exceeded our expectations,” he notes. “This is a remarkable proof-of-concept airplane.” It is, however, limited to single-pilot operation with both the 9.2-gas-gallon-equivalent CNG and 52-gallon 100LL tanks filled to capacity, when it can carry a 220 lb. pilot and 70 lbs. of gear. The CNG tank weighs 95 lbs, and structural modifications add another 10 lbs.

The Aviat Husky CNG flew more than 1,000 miles from Aviat’s headquarters in Afton, Wyo., to Oshkosh. Flight endurance at 65% power setting is approximately seven hours.

Aviat estimates that In a production environment, the bi-fuel dual CNG option could add between $12,000 and $15,000 to the base price of a gasoline powered aircraft.

The CNG gas tank is mounted beneath the Husky’s fuselage


The Husky’s gear legs are extended to accommodate the CNG tank.

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