Plane & Pilot
Tuesday, January 28, 2014

A Natural Gas To Fly

A Husky takes the alternative route to the skies

The patchwork of farms and wetlands disappearing in all directions below made it hard to believe the world's largest gathering of airplanes was being celebrated just a few miles away. More astonishing was that the alternative fuel powering the airplane's 200 hp Lycoming was more efficient, safer and cleaner than avgas, and also costs under a buck a gallon. "Why isn't everyone using this?" one had to wonder. Oh, yes: because the proof-of-concept fuel system on this certificated aircraft makes it the only one in the world that can use the plentiful and readily available alternative fuel—as of now.

A Here-And-Now Alternative Fuel
The quest for a 100LL avgas alternative has become general aviation's Holy Grail, sending academic research teams, large companies and basement tinkerers searching for a philosopher's stone that can transmute batteries, biomass, sunlight or a host of pie-in-the-sky technologies into the gold of efficient, affordable, nonpolluting flight. So, it was a surprise to see a here-and-now solution to the avgas crisis, whipped up in six months' time, fly into AirVenture this year virtually under the radar, like Fred MacMurray's flubber-powered Model T landing on the White House lawn in Disney's classic The Absent-Minded Professor.

Not to cast aspersions on the venerable Aviat Husky, the platform for this avfuel innovation, by comparing it to a Model T. But like that one-off automobile from the movies, this Husky's novel power source could usher in a new era in how we get around the skies. Developed by Afton, Wyo.,-based Aviat Aircraft, the Husky's manufacturer, and Minneapolis-based Aviation Foundation of America (AFA), the experimental Husky unveiled at Oshkosh is the first dual-fuel piston-powered aircraft that can operate on either compressed natural gas (CNG) or aviation gasoline (avgas).

Aviat's experimental Husky can operate on either compressed natural gas (138 octane) or standard 100LL avgas.  It's outfitted with a nine-gallon belly tank that can be filled through a valve, or it can be disconnected and brought to a CNG-fueling facility.
The CNG power is the real potential game changer: CNG is homegrown, plentiful and cheap (about $0.86 per gas gallon equivalent, or GGE). It's 90% less polluting, it's less flammable and causes less engine wear than avgas, and it's 138 octane, so CNG can provide more power than 100LL. Oh, and it weighs less, too: 5.66 pounds GGE versus 6.02 pounds pg for avgas. As for compatibility with existing technology, other than putting in high-compression cylinders to burn CNG more efficiently, the A1-C's stock 200 hp Lycoming IO-360-A1 D6 is unchanged. It can operate entirely on CNG, but as that fuel isn't readily available at airports, the dual-fuel system allows the pilot to select the fuel source, which can be changed at any time, on the ground or in flight.

The N15NG was on display in front of AirVenture's new Innovations Pavilion, and AFA president and GA advocate Greg Herrick, who initiated the project, was watching the crowd around the Husky and "seeing people's reactions" when I stopped by. Of course, CNG powers many municipal ground transportation fleets, and if you have a heater in your hangar, CNG likely powers that, as well, Herrick noted. He said about a year before, he began wondering if CNG could power airplanes. "I posed the question on blog engineering sites, and people said 'yes' and 'no.'" Herrick concluded he'd need a committed OEM behind the project. "I immediately thought of Stu [Horn, Aviat Aircraft owner and president]."

Labels: Piston Singles


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