The Viking TMk1 aircraft is a conventional high performance 2 seat tandem glider of Glass Reinforced Plastic (GRP) monocoque construction, manufactured by Grob Aerospace. The aircraft is of T-tail configuration, and is fitted with a non retractable undercarriage and upper surface Schempp-Hirth type airbrakes.
The Viking, known in the Civilian World as the G103 Twin II is the successor of the original G103 Twin Astir with a nose wheel and a fixed six-inch main gear fitted behind the center of gravity - The main wheel is equipped with a hydraulic brake. Modified ailerons produce a substantially improved roll response compared to the previous model. The Viking has had some minor modifications from the civilian variants to make it suitable for Air Cadet flying.
The Viking can be launched either by winch or by aerotow from a powered tug aircraft. At 615 VGS, all launching is done by winch, and typically will achieve around 1000ft above airfield level. Normal launch speeds are between 55-60 knots, and once trimmed after the launch the aircraft is flown at 50 knots for the majority of time. For the normal range of aircraft weights, approach speeds are 55/60 knots, dependant on wind conditions on the day. The Viking is able to land in a crosswind component of up to 11 knots.
The Viking is also permitted to carry out a limited number of aerobatic manoeuvres subject to crew qualification. These include loops, chandelles, and lazy eights. The aircraft is very manoeuvrable and up to 98 knots has airframe acceleration limits of +5.7g to -3.7g, although operationally these are restricted to lower values to preserve airframe life.