Futaba S9251

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*Spec is estimated from brand data.

Technical Specifications

Last Updated: 2026-09-16

Identity
Brand
Product Number	FUTM0221
Category	Hobby
Discontinued	Yes
Performance
Torque	4.8V51.00 oz-inBottom 10%
Speed	4.8V0.07 sec/60°Top 10%
Physical
Weight	2.01 ozAbove Average
Dimensions	L 1.57 in W 0.79 in H 1.46 in
Case Material	Plastic / Aluminum
Drivetrain
Motor Type	Coreless
Gears	Metal
Gear Spline/Teeth	25 T estimate
Rotation Mode	Positional
Rotation/Support	Dual Bearings
Control & Signal
Modulation	Digital
Pulse Width	560-760 µs
Angle Sensor	Potentiometer
Control System	PWM
Electrical & Environment
Operating Voltage	4.8–4.8 V
Water Rating	Water Resistant
Connectivity
Connector	Futaba J

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Disclaimer: Most data is sourced from the manufacturer. Some data is sourced from our loyal community and with the help of AI. We aim for accuracy but are not responsible for inaccurate information.

Compatible Hardware

Amazon eBay

*Spec is estimated from brand data.

Class Comparison

Torque	Bottom 10% Stronger than 4% of 1060 Digital Standard servos at 4.8V
Speed	Top 10% Faster than 92% of 1045 Digital Standard servos at 4.8V
Weight	Above Average Lighter than 70% of 1880 Digital Standard servos

Performance Analysis

Shaft Power	1.35 W
Power Density	0.744 W/in³ More power-dense than 11% of 1768 Digital Standard servos
Torque Density	0.8947 oz-in/g Stronger than 2% of 1053 Digital Standard servos
Torque-to-Volume Ratio	28.16 oz-in/in³ Denser torque than 3% of 1058 Digital Standard servos
Speed-to-Weight	0.25063 (1/sec·g) Faster than 92% of 1038 Digital Standard servos
Speed-Torque Trade-off	3.57 Better balanced than 4% of 1034 Digital Standard servos
Voltage Range Width	0.0 V Wider voltage range than 1% of 1560 Digital Standard servos