Burkhart Grob Glider aircraft modelsChoose a model to review its registered fleet, specifications, and aircraft currently offered for sale.G103C Twin Iii SL — 5 registeredG 103 Twin II — 34 registeredG-109B — 29 registeredG-103A Twin II Acro — 28 registeredG103C Twin Iii Acro — 7 registeredG103 Twin Astir — 4 registered