RE: futaba 5101 need spec info
Go to futaba-rc.com click analog servos and then click on discontinued servos near the bottom.
Servo # Dimensions Length x Width x Height in. Connector Type Weight oz. Torque oz.-in. Speed Replacement
S5101 1.52 x 0.77 x 1.36 J 1.4 55.60 0.24/60 S9001