These sizes have never made any sense to me as I had an e flite apprentice which had a 1500mm wing but Horizonhobby say its a 15 size, it was electric so who knows! (15-size, 840Kv brushless, 30A ESC, 3S 3200mAh)
I think the sizes come from the older balsa models so the pilot knew which size internal combustion glow engine to use, though it was and still is common for pilots to fit a BIGGER engine :D
- 15in;400mm / 31in;800mm (Micro)
- 36in;914mm / 38in;980mm (Mini)
- 47in;1200mm (25 Size)
- 55in;1397mm;Middle / 58in;1480mm;H9 (40 Size)
- 62in;1574mm;DasUgly / 66in;1680mm;Dra (60 Size)
- 120 Size
- 160 Size
A ‘stick’ is a shoulder wing sport / trainer model aircraft originally designed by Phil Kraft in 1966, his was called the Das Ugly Stick and had a round cowl.
“The original concept of the Ugly Stik was to design a radio controlled aircraft which could be built in an absolute minimum of time. Its purpose was towards a flying test bed for new proportional control developments and an all around shop airplane which could be used as a loaner for visiting flyers, testing repaired equipment, and any use which required an airplane which could be considered as expendable.”
Notable difference between the Das Ugly and a modern Ultra stick is the shape of the tail, the flat trailing edges on the ailerons and elevator & it has no cowling.