Twin Voyager S12 Incorporates Customer Input And Improves Comfort And Performance

Stemme used the backdrop of AirVenture to introduce its first new motor glider since the S10 came on the market in 1984.

ANN spoke with Wes Chumley, Director of Flight Operations for Stemme USA to get more insight on the features of the Twin Voyager S12, a touring motor glider that combines the comfort and safety of a sport plane and the dynamics of a high altitude, dual seat sailplane.  While the new aircraft maintains many similar unique features to the S10, such as the side-by-side cockpit and folding propeller, the new aircraft incorporates numerous additional features derived from input of existing Stemme customers. 

Stemme has brought to AirVenture the second prototype, produced in Germany, after flying the aircraft on a demonstration tour that began in Miami, with stops as far as San Francisco, before arriving in Oshkosh for AirVenture.

In describing the differences, Wes noted taking recommendations from owners and incorporating a longer wingspan, increasing from 23M to 25M (75 feet to 82 feet) and increasing the glide ratio 3 points, from 50;1 to 53;1.  To handle the longer wings, Stemme widened the landing gear, which also makes it easier to handle on the ground.  Stemme’s unique folding propeller disappears completely into the dome during glide mode and gives the aircraft excellent aerodynamics, a new luggage compartment in the fuselage and an autopilot round out the comfort of this new aircraft. Wes also noted owners really wanted to go from manual to electric trim.  “With trim controls on the yolk, S12 pilots will find it easier to trim in both soaring and power configurations.”

The S12 also has improved the center of gravity, controlled by incorporating a water ballast chamber in the tail.  “If there are two large people, performance increases for both power and gliding using the ballast”.  The S12 includes solar panels that keep the batteries charged to operate avionics when the engine is not operating in soaring mode.

When asked about who buys this aircraft, Wes described two camps. The first are people who are busy, own multiple aircraft and want pure enjoyment, but don’t have a lot of time. “S12 customers can fly a high performance glider without enlisting help from friends and family.  With a powered glider, there is no need for a tow plane.  Wes noted, “S12 pilots can taxi to the runway, takeoff and fly 200 miles to where friends are soaring, and return home under power in time for dinner.”

Wes described the other type of Stemme customer as those who enjoy touring and spend more time under power than most “glider-types” and noted, “the S12 cruises at 120 knots or 140 knots airspeed true at 10,000 feet. The range of the S12 is 945 nm, which allows a high altitude cruise; the S12 service ceiling 32,000 feet, but as the S12 is not instrument certified, the practical limit is 18,000 feet.” On Wes’ journey across the US, he liked to cruise at 12,000 ft.

In March 2016, the European Aviation Safety Agency (EASA) granted type certification for the Twin Voyager S12. Wes recently flew with FAA and notes the U.S. certification is underway. The anticipated price for the S12 Twin Voyager Ultimate Package is $369,000

(Staff images)

FMI: www.stemme.de