The SDD Greenley is an enlargement of the very successful Super Duper (SD) Greenley and has been especially designed for 100cc motors to tow the biggest gliders.Due to the ever increasing size of the gliders requiring aerotowing it was felt that a larger version of the SD Greenley tug was needed to enable a bigger motor to be fitted. The superb flying qualities of the SD Greenley have been maintained in the new larger design by close attention to detail and weight saving.Designed by John Greenfield, the SDD Greenley uses the same form of simple sheet construction for the fuz and tail surfaces as the SD Greenley but features a 2 piece built up wing to aid transportation and storage.The model has a 100" wingspan and a flying weight of around 9.0 kg depending on which motor and exhaust system is fitted.

The combination of the SDD airframe and a DLE 111cc motor have proved to be more than capable of towing the largest gliders on the UK scale glider scene.