HS-788HB Servo


The Hitec HS-788HB servo is based around the long-time favorite, the HS-785HB. This new model was created with a 25 tooth output spline in order to conform with the majority of the hobby servo market.   Similar to its 24 tooth cousin, this model is able to rotate multiple turns while retaining positioning feedback. Conventional servos are typically limited to a maximum of 180 degrees, which, in the steering mechanism of a remote controlled car, is plenty. Many other applications demand more than conventional servos can provide. The HS-788HB has an underdriven potentiometer so the distance it moves in relation to the output shaft is less. This allows the output shaft of the servo to turn nearly eight full rotations before the outer limits of the potentiometer are met. The final output shaft of the servo is supported by a pair of ball bearings and the gears are constructed of Karbonite plastic to provide excellent wear resistance.  

The HS-788HB servo comes with a dual spool style winch pulley for those who wish to install in a pull-pull setup. The included servo horn screw has aggressive threads and a 2.5mm socket head drive so that you can tighten the horn onto the servo without concern of rounding out the head.  The included servo mounting hardware (grommets, eyelets and screws) can be discarded when mounting in a goBILDA servo mount but can be used when mounting to wood or plastic structures, where vibration dampening is needed.

How Far Will This Servo Rotate?

The answer to this question is partially dependent on what you are using to control the servo.
Click for a quick video explanation.

With an Average Radio System:
3.92 Turns
Your average transmitter and receiver will output a relatively narrow PWM signal range.

Radio System + Travel Tuner:
7.85 Turns
Adding a Servo Travel Tuner to your radio system setup will allow you to achieve wide PWM signal ranges.

Wide Signal Controllers:
7.85 Turns
Controllers such as the Servo Commander, Arduinos, and Raspberry Pi servo hats can usually send a wide signal.

Tech Tips


Output Shaft Style H25T Spline
Voltage Range 4.8V ~ 6V
No-Load Speed (4.8V) 1.68 sec/360°
No-Load Speed (6.0V) 1.38 sec/360°
Stall Torque (4.8V) 153 oz-in (11.0 kg.cm)
Stall Torque (6.0V) 183 oz-in (13.2 kg.cm)
Travel per µs 1.570°/μsec
Pulse Amplitude 3-5V
Operating Temperature -20°C to +60°C
Current Drain - idle (4.8V) 8mA
Current Drain - idle (6.0V) 8.7mA
Current Drain - no-load (4.8V) 230mA
Current Drain - no-load (6V) 285mA
Continuous Rotation Modifiable Yes
Direction w/ Increasing PWM Signal Clockwise
Deadband Width 8 μsec
Motor Type 3 Pole Ferrite
Feedback Style 5KΩ Potentiometer
Output Shaft Support Dual Ball Bearings
Gear Material Karbonite
Wire Length 11.81" (300mm)
Weight 3.42oz (97g)
Wire Gauge 22 AWG
Max PWM Signal Range 600-2400μsec
Max Rotation 2826°
Servo Size Large

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