Discover XQ-Power Servos in Our eBay Store!
Shop Now
Technical Specifications
Last Updated: 2026-07-28
|
Identity
Performance
Physical
Drivetrain
Control & Signal
Electrical & Environment
Connectivity
Origin
Preferences are saved automatically.
Weight
Dimensions
Torque
Speed
Current
Temp
Wire
| Identity | |
| Brand |  |
| Product Number | 8521 |
| Category | Hobby |
| Discontinued | Yes |
| Performance | |
| Torque |
6.0V
41.70 oz-in
3.00 kg-cm
0.3 N-m
4.8V
34.70 oz-in
2.50 kg-cm
0.2 N-m
|
| Speed |
6.0V
0.12 sec/60°
500.0 deg/s
83.3 RPM
4.8V
0.16 sec/60°
375.0 deg/s
62.5 RPM
|
| Running Current | (add) |
| Stall Current | (add) |
| Physical | |
| Weight | 0.64 oz18.2 g |
| Dimensions |
L 1.18 in W 0.51 in H 1.24 in L 30.0 mm W 13.0 mm H 31.5 mm |
| Case Material | (add) |
| Drivetrain | |
| Motor Type | (add) |
| Motor Drive | (add) |
| Gears | Plastic |
| Gear Spline/Teeth | 25 T estimate |
| Shaft Size | (add) |
| Rotation Mode | (add) |
| Rotation/Support | Single Bearing |
| Backlash | (add) |
| Control & Signal | |
| Modulation | Digital |
| Direction | (add) |
| Rotational Range | (add) |
| Mechanical Limit | (add) |
| Pulse Cycle | (add) |
| Pulse Width | (add) |
| Neutral Position | (add) |
| Dead Band | (add) |
| Refresh Rate | (add) |
| Angle Sensor | (add) |
| Control System | PWM |
| Programmable | (add) |
| Signal Voltage | (add) |
| Electrical & Environment | |
| Operating Voltage | 4.8–6 V |
| Power Source | (add) |
| Regulator Type | (add) |
| Temperature | (add) |
| Water Rating | (add) |
| Certification | (add) |
| Idle Current | (add) |
| Connectivity | |
| Connector | JR (Universal) estimate |
| Wire Length | (add) |
| Origin | |
| Country of Origin | (add) |
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.
Performance Analysis
| Shaft Power | 0.40–0.64 W |
| Torque Density | 1.9066 oz-in/g Stronger than 28% of the 219 Digital Mini servos in the database |
| Torque-to-Volume Ratio | 46.50 oz-in/in³ Denser torque than 17% of the 224 Digital Mini servos in the database |
| Power Density | 0.861 W/in³ More power-dense than 14% of the 425 Digital Mini servos in the database |
| Speed-to-Weight | 0.34341 (1/sec·g) Faster than 54% of the 220 Digital Mini servos in the database |
| Speed-Torque Trade-off | 5.55 Better balanced than 31% of the 223 Digital Mini servos in the database |
| Torque Gain per Volt | 16.81%/V More voltage-responsive (torque) than 61% of the 190 Digital Mini servos in the database |
| Speed Gain per Volt | 27.78%/V More voltage-responsive (speed) than 95% of the 190 Digital Mini servos in the database |
| Voltage Range Width | 1.2 V Wider voltage range than 37% of the 288 Digital Mini servos in the database |
Quick Actions
Similar Active Servos
Reviews of Robbe FS 550 BB
Be the first to review!