Tuesday, February 21, 2012
Gipps Airvan: Don’t Call It A Caravan
This innovative Australian single emphasizes the principle that less really can be more
|The step for the rear door doubles as an armrest for the backseat.|
The fuel system is almost disarmingly simple. There's an on-off pull control on the upper-left panel that goes full-in for "run," full-out for "stop." Fuel is either on or off. Though there are two conventional wing tanks; there's no selector. The Airvan feeds fuel symmetrically from both tanks. On the ground, there's a simple valve in each wing that precludes overboarding fuel if the airplane is refueled and parked on a slanted ramp. (Twenty years ago in Libreville, Gabon, on a trip to South Africa in a Caravan, I lost about $300 worth of fuel when I parked the airplane with one wing slightly downhill on a slanted ramp and neglected to turn off the fuel selectors.)
The Airvan's strut-braced wing employs a modified USA 35B airfoil (reminiscent of the Piper Cub) with a mild 2½ degrees of dihedral and 2 degrees of incidence. Total area is 208 square feet, which generates a wing loading of about 20 lbs./sq. ft. High wing loading is usually indicative of a smoother ride in turbulence.
Moving back to the empennage, the vertical tail is swept, and there's a ventral fin installed below the horizontal stabilizer. Morgan told me the flight tests for anti-spun characteristics were performed by the National Test Pilots School in Mojave, Calif., and the ventral was a result of those tests.
The Gipps GA8 specifies one notch of flaps for takeoff, and you can maintain that setting all the way to cruise. Morgan said flight tests revealed a slight climb advantage with flaps extended, plus a better view over the nose.
Furlong and Morgan designed the GA8 with a flat floor and a quick-change interior that allows you to add or subtract seats in a flash. We left out two seats in favor of mountain bikes and camping gear.Our test airplane was the turbo model that delivers 40 inches of manifold pressure on takeoff and provides a gratifying shove in the back on power-up. Put the left lever against the panel, and the Airvan responds with more enthusiasm than you might expect. The airplane flies off at about 55 knots and starts uphill with a strong positive rate, if not an aggressive one. Book spec is just over 900 fpm at sea level, and certified ceiling is 20,000 feet.
On the way to cruise height, you can't help but notice the visibility. Every seat offers an excellent view. There are windows everywhere, over a dozen in all, including two eyebrow skylights at top cabin above the pilot and copilot. If you need to maneuver in a tight canyon or fly a close-in pattern, the eyebrows give you a look into the turn. The flight crew sits well forward of the wing-leading edge, so normal turns allow you to keep track of the runway threshold on base and final.
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Labels: Piston Singles