Airplane manufacturer Aviat Aircraft, Inc. and Minneapolis-based Aviation Foundation of America, Inc. will unveil the first bi-fuel, piston powered aircraft to operate on both compressed natural gas (CNG) and aviation gasoline, at this week’s AirVenture 2013 which takes place in Oshkosh, Wis., from July 29 through August 4. The Aviat Husky CNG will be on display outside the Innovations Pavilion.
“This is a remarkable proof-of-concept airplane,” said Stu Horn, president of Aviat Aircraft. “While adapting our standard Husky aircraft into this dual fuel (1) configuration was not without challenges, it was well worth it. The performance and ease of operations have exceeded our expectations.”
The Aviat Husky CNG, which flew more than 1,000 miles from Aviat’s headquarters in Afton, Wy., to be at AirVenture, can be powered by CNG or 100LL aviation gasoline with the flip of a switch. It is a standard Aviat Husky A1-C that has been fitted with a CNG fuel tank in addition to its standard aviation gasoline tanks with a capacity of 50 gallons. The aircraft is powered by a 200 h.p., four cylinder Lycoming aircraft engine with a cruise speed of 143 m.p.h. The flight endurance at 65 percent power setting is approximately seven hours.
With the exception of the CNG fuel tank and associated fuel controls, the only modification made to the engine, a Lycoming IO-360-A1 D6, was the installation of new pistons to increase the compression ratio from 8.50:1 to 10:1.
From Concept to Reality
Greg Herrick, president of the Aviation Foundation of America approached Aviat’s president in early 2013 with the idea of building an aircraft to demonstrate the advantages natural gas can offer general aviation aircraft.
“Among the many advantage of using CNG are fuel cost savings, cleaner burning fuel and no lead emissions,” said Greg Herrick, president of the Aviation Foundation of America. “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.”
Compressed natural gas power is up to 80 percent less expensive than the national average of $6-per-gallon aviation gasoline. There is no lead in CNG, the presence of which is currently a significant issue with aviation gasoline. It is also a much cleaner burning fuel, reducing smog pollutants by 90 percent and reducing CO2 emissions by 30 percent. Engine oil remains significantly cleaner therefore improving engine life, while aircraft performance is enhanced as CNG typically burns 138 octane versus the current 100 octane of aviation gasoline.
“One aspect we’re particularly excited about is the opportunity to dramatically reduce the cost of learning to fly,” added Herrick. “If a flight school installs a simple CNG refueling station they can cut the cost for the student’s fuel, perhaps by thousands of dollars. And, the fuel is available wherever 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-$60 per hour. This would make it economical for a flight school to install CNG refueling equipment on site, and even switch to 100% CNG aircraft as most training flights are in the general vicinity of the airport.
The Husky’s gasoline capacity is 52 gallons of 100LL, 50 of which is useable. In this demonstration aircraft both the CNG and 100LL tanks may be filled to capacity and still carry a 220 lb. pilot and 70 lbs. of gear.
(1) The natural gas vehicle industry typically refers to a fuel system that uses two fuels separately as bi-fuel and two fuels together as dual-fuel.)