The Eagle Aircrafts Viper SD-4 is set to disrupt, if you ask Wayman Luy. It’s aggressively priced, he said, and available in either SLSA, ELSA or as an Experimental kit build airplane. And you can have one in three to four months if you order now. Plus, with a peppy Rotax 914 iS in the demo model brought to Sun ’n’ Fun by Wayman Aviation, this pilot discovered that the Viper SD-4 is just plain fun to fly. Ergonomics are a delight for such a small airplane. Though the semi-reclined, well-cushioned seats are fixed, the rudder pedals have an innovative flip button that allows a two-inch extension, making it possible for this five-foot pilot to reach the stops. Three EFIS screens (two Dynons and a panel-docked Garmin 695) light up just before the liquid-cooled Rotax purrs to life.
On application of full power and release of the hand-controlled brake, the airplane comes off the grass runway at Sun ’n’ Fun’s Paradise City in about 800 ft with two FAA souls and about 19 gallons of fuel at a balmy outside air temperature of 75 degrees F. Climb-out with the three blade composite prop at 5200 rpm was a brisk 900 fpm; at 5,000 rpm and 70 knots it was 500 fpm. Cruise was 4500 rpm, producing hands-off stable flight at 95 knots. The aircraft’s pitch and bank feels balanced, even in slow flight. A responsive electric pitch and rudder trim assists in keeping control feel fingertip light throughout even slow flight or steep turns. Stalls with and without flaps are simple straightforward affairs, with a minor burble and soft break, followed by a natural pitch down, which aids in recovery.
Throughout maneuvering flight I marveled at the excellent visibility through the canopy (thoughtfully tinted on top to keep the greenhouse effect to a minimum). The large window vents in the canopy and eyeball vents on the panel helped the cabin stay cool, as well. Landing was textbook, with greasers easy to manage if you are willing to let the airplane slow down below 60 knots.
The aircraft demoed at Sun ’n’ Fun 2017 retails for around $125,000 according to Luy, and is available for sale from Wayman Aviation located at Opa Locka Airport, in Miami and North Perry Airport, Fort Lauderdale, Florida.