Graupner C 121 - Micro Servo

Specifications

Source: Most data comes from the manufacturer but some data is sourced from our loyal community.

Last Updated:	2025-08-07
Modulation:	Analog
Torque:	4.8V: 21.00 oz-in (1.51 kg-cm)
Speed:	4.8V: 0.10 sec/60°
Weight:	0.35 oz (9.9 g)
Dimensions:	Length:0.83 in (21.1 mm) Width:0.43 in (10.9 mm) Height:0.83 in (21.1 mm)
Motor Type:	(add)
Gear Type:	Plastic
Rotation/Support:	Bushing
Rotational Range:	(add)
Pulse Cycle:	(add)
Pulse Width:	(add)
Connector Type:	(add)

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The discontinued Graupner C 121 is a high-quality analog servo in the popular 9-gram sub-micro class, upholding the Graupner standard of precision and reliability. As a sibling to the C 111, the C 121 offers a slightly different performance profile, often tuned for a bit more torque or holding power. This makes it an excellent choice for applications that require a bit more muscle, such as the cyclic controls on a 450-class helicopter or the elevator on a park flyer with a large control surface. It provides a solid, confident feel, ensuring that control surfaces are not pushed around by aerodynamic forces.
The character of the C 121 is its precise strength" in a small package. It delivers the extra power needed for more demanding applications but with the characteristic smoothness and reliability of a Graupner servo. It is a popular upgrade for pilots who find that standard 9g servos feel a bit vague or underpowered for their particular model or flying style. It provides a welcome boost in control authority.
In robotics the Graupner C 121's higher torque makes it a very capable actuator for small-scale projects. It is strong enough for building a functional robotic gripper that can hold objects securely or for the primary load-bearing joints of a small walking robot. For any compact robotics project that requires a bit more muscle to perform its task effectively the C 121 provides that power in a reliable high-quality package."