Plane & Pilot
Tuesday, January 28, 2014

A Natural Gas To Fly

A Husky takes the alternative route to the skies

At Aviat's AirVenture exhibit area, not far from the Innovations Pavilion, Horn described his reaction to Herrick's pitch. "First I thought, 'Why would I want to do this?' And the answer was, 'Because I can,'" Horn said, as he provided an overview of the program and ticked off the logic and benefits of exploiting CNG. "This could be an interesting way of solving some of these [aviation fuel] issues in a real, viable way in real time. Not in the future, but using things we have today that we can integrate into general aviation," he summed up.

Nodding along with Herrick and Horn, it was difficult not to feel as though one had imbibed the Kool-Aid, too. Could a CNG solution really be that simple? Horn invited Plane & Pilot to fly the aircraft and experience CNG airpower for ourselves.

The Dual Fuel System
On the ramp at Orion Flight Services in the dawn's early light, N15NG looked like the relatively standard blue-and-white Husky A1-C on tundra tires; its one distinguishing feature the bulbous pod on its belly—the faring covering its CNG tank. Aviat test pilot Steve Anderson pointed out that the landing gear on this Husky has been extended four inches and positioned two inches forward of the standard undercarriage, providing more angle of attack on the ground, a design the company has been "toying with offering," he said. On this airframe, it also ensures adequate ground clearance for the CNG tank.

The choice of tank underscores that this is a proof-of-concept application, not a state-of-the-art CNG demonstrator. When Aviat commenced work on the project early this year, "We didn't know anything about CNG," Horn had said at the Aviat display area. One of the lessons soon learned was that CNG storage tanks, now made of composite materials rather than steel, are undergoing rapid advances. The borrowed nine-gallon belly tank on N15NG weighs 70 pounds; a current-generation tank would weigh 40 pounds, little more than half.

The tank can be filled through a valve on the port side, but the faring can be removed, and the tank quickly disconnected and taken to a CNG-fueling facility, if needed. Clearly, a lack of such facilities is one of the infrastructure challenges facing wider use of the fuel; in fact, Horn was concerned about its local availability when he weighed taking on the development program.

Labels: Piston Singles


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