The G103 Twin II (originally designated the G 118) is a high-performance two-seat

sailplane A glider or sailplane is a type of glider aircraft used in the leisure activity and sport of gliding (also called soaring). This unpowered aircraft can use naturally occurring currents of rising air in the atmosphere to gain altitude. Sailpla ...

manufactured in Germany by Grob Aircraft. The aircraft is of

T-tail A T-tail is an empennage configuration in which the tailplane is mounted to the top of the fin. The arrangement looks like the capital letter T, hence the name. The T-tail differs from the standard configuration in which the tailplane is ...

configuration, and is fitted with upper-surface airbrakes and a non-retractable undercarriage. Of

fiberglass Fiberglass ( American English) or fibreglass ( Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cl ...

construction, it is designed for training, high performance cross-country racing and simple

aerobatic Aerobatics is the practice of flying maneuvers involving aircraft attitudes that are not used in conventional passenger-carrying flights. The term is a portmanteau of "aerial" and "acrobatics". Aerobatics are performed in aeroplanes and glide ...

flying.

Design and development

The G103 Twin II (a.k.a. the Twin Astir 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. Approach control is by top surface Schempp-Hirth type airbrakes. The G103A Twin II Acro variant features strengthened mainspar caps and steel control pushrods which permit greater aerobatic performance. The G103 also has a

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approved modification kit for all-hand control for handicapped operation. The

Royal Air Force Air Cadets The Royal Air Force Air Cadets (RAFAC) is a volunteer-military youth organisation sponsored by the Royal Air Force that manages both the Air Training Corps and RAF Sections of the Combined Cadet Force. The organisation is headed by a former serv ...

acquired 100 Twin II Acros (known in service as the Grob Viking T1) in 1984/85 to replace the aging

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gliders of the RAF Volunteer Gliding Schools. A total of 549 were produced before it was succeeded in production by the G103C Twin III in 1989.

Operational history

Records

On 28 September 1981 the Twin II took the world Out & Return record for two-seat sailplanes (1000.88 km/ 621.92 miles). The aircraft (N424GL) was flown out of the Ridge Soaring Gliderport, Pennsylvania, USA, by pilot Thomas Knauff and crew, Rob Gannon. On May 14, 1996 the Twin II G103A took the Pennsylvania State Open Multi place class; Distance around a Triangular Course/Speed over a Triangular Course of 100 km; Pilot David F. Bradley, Sr. Passenger Jim Vincent. and the Pennsylvania Sports Class; Distance around a Triangular Course of 100 km; Pilot David Bradley, Passenger Jim Vincent.

In-Flight Limitations

In 2003 Service Bulletin 315-64/2 reduced the maximum admissible airspeeds and prohibited aerobatic flight. This was due to reports that the design of the fuselage may not have been sufficient to sustain limit loads during certain maneuvers and during flight at certain speeds. Grob completed further investigations into the effects of certain flight conditions on the fuselage structure and the development of corrective procedures. Further static strength tests were conducted to verify the safety margin of the fuselage. The results of these tests restored the original flight speed limitations and maneuver operations for the Twin II and allowed the Twin II Acro only basic aerobatic maneuvers (spins, lazy eights, chandelles, stall turns, steep turns, and positive loops). An approved modification, when incorporated, restores full acrobatic status to these sailplanes.

Operators

; * Argentinian Air Force ; *

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; *

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for Royal Belgian Air Cadets ; *

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Gliding Centre ; *

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www.raf.mod.uk Retrieved: 13 December 2009 (For the

) ; *

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Specifications

References

sailplanedirectory.com

Grob G 103 Twin II POH

External links

Johnson R, A Flight Test Evaluation of the Grob G103 Twin II, Soaring, Feb 1983

Homepage of Grob Aircraft AG

A PDF information guide based on the Flight Manual, from Adelaide Soaring Club
{{Grob aircraft 1980s German sailplanes Grob aircraft T-tail aircraft