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Technical Specifications
Last Updated: 2026-10-23
Weight
Dimensions
Torque
Speed
Current
Temp
Wire
| Identity | |
| Brand |  |
| Product Number | BBR-BMS-A921+ |
| Category | Hobby |
| Performance | |
| Torque |
8.4V
209.74 oz-in
15.10 kg-cm
1.5 N-m
7.4V
184.74 oz-in
13.30 kg-cm
1.3 N-m
6.0V
150.01 oz-in
10.80 kg-cm
1.1 N-m
|
| Speed |
8.4V
0.05 sec/60°
1,200.0 deg/s
200.0 RPM
7.4V
0.06 sec/60°
1,000.0 deg/s
166.7 RPM
6.0V
0.07 sec/60°
857.1 deg/s
142.9 RPM
|
| Physical | |
| Weight | 1.20 oz34.0 gBelow Average |
| Dimensions |
L 1.398 in W 0.591 in H 1.142 in L 35.5 mm W 15.0 mm H 29.0 mm |
| Drivetrain | |
| Motor Type | Coreless |
| Gears | Metal |
| Gear Spline/Teeth | 25 T |
| Rotation/Support | Dual Bearings |
| Control & Signal | |
| Modulation | Digital |
| Neutral Position | 1520 µs |
| Dead Band | 1 µs |
| Refresh Rate | 333 Hz |
| Control System | PWM |
| Electrical & Environment | |
| Operating Voltage | 4.5–8.7 V |
| Power Source | 2S Li-Po / 2S Li-Fe |
| Connectivity | |
| Connector | JR (Universal) estimate |
| Origin | |
| Country of Origin | Taiwan |
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.
Class Comparison
| Weight | Below Average Lighter than 19% of 505 Digital Mini servos |
Performance Analysis
| Shaft Power | 3.96–7.76 W |
| Power Density | 8.220 W/in³ More power-dense than 95% of 482 Digital Mini servos |
| Torque Density | 4.4121 oz-in/g |
| Torque-to-Volume Ratio | 158.99 oz-in/in³ |
| Speed-to-Weight | 0.42017 (1/sec·g) |
| Speed-Torque Trade-off | 10.50 |
| Voltage Range Width | 4.2 V Wider voltage range than 95% of 405 Digital Mini servos |
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Reviews (1)
Includes 1 review aggregated from around the web.
There are very few reviews for this servo on the web. An RC Universe forum user trying Blue Bird for the first time in a small glider says the servos seem very smooth and quiet so far.
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