I just went by my LHS and he showed this one from Hobbico
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HCAM0312 CS-160 Digital High Torque/High Speed 2BB $45.00 spped was .0.17 and 110kg or ozboth at 4.8 v but he said with my 4s system on the Backdraft It would be 6.0v which would give me 0.14 speed and 131kg or oz........... I am giving myself an education in servos I did'nt really want..
Hobbico servo link http://www.hobbico.com/radioaccys/hcam1000.html