| 35KG·CM STALL | 0.100S/60° NO-LOAD | 8.4V RATED |
| 77G WEIGHT | StainlessGEARTRAIN | 360°TRAVELCustomizable |
Overview
The BLS8135D is the 35 kg·cm brushless servo in the standard 20 × 40 × 38.4 mm case, 77 g. At 8.4 V it swings 0.10 s/60°; drop to a 6.0 V receiver pack and the same servo is 20 kg·cm at 0.14 s.
Stainless steel geartrain on two ball bearings, CNC aluminium case with the fins milled into the sides, 25T-φ5.94 mm output and a POM horn. The mechanical limit is 210°, the dead band 1 µs, and the lead is 300 mm of three-wire cable.
This page covers the PWM build: a standard 50–333 Hz pulse input, 1500 µs neutral and a 3–4 µs dead band. It is the version to pick when the servo hangs off a receiver or a flight controller and you want nothing between the two.
Performance at each supply voltage
| Supply | No-load speed | Peak stall torque | Idle current | Stall current |
|---|---|---|---|---|
| 6.0 V | 0.140 s/60° (429 °/s) | 20 kg·cm (1.96 N·m / 278 oz·in) | 320 mA | 2.8 A |
| 7.4 V | 0.120 s/60° (500 °/s) | 28 kg·cm (2.75 N·m / 389 oz·in) | 370 mA | 3.5 A |
| 8.4 V | 0.100 s/60° (600 °/s) | 35 kg·cm (3.43 N·m / 486 oz·in) | 440 mA | 4.0 A |
Control specification
| Item | Specification |
|---|---|
| Command signal | PWM |
| Amplifier | Digital controller |
| Pulse width range | 800–2200 µs |
| Neutral position | 1500 µs |
| Dead band | 1 µs |
| Rotating direction | CCW (1000–2000 µs) |
| Travel | 360°, customizable |
Mechanical specification
| Item | Specification | Item | Specification |
|---|---|---|---|
| Dimensions | 20 × 40 × 38.4 mm | Case material | Aluminium, CNC |
| Weight | 77 g | Geartrain | Stainless steel |
| Bearings | 2 × ball bearing | Motor | Brushless |
| Output spline | 25T-φ5.94 mm | Horn | Plastic, POM |
| Lead / connector | 300 mm, 3-wire | Mechanical limit | 210° |
| Operating temperature | −15 °C to 65 °C | Storage temperature | −20 °C to 70 °C |
| Ingress protection | Splash resistant (customizable) | Travel | 360°, customizable |
What’s in the box
- 1 × XQ-BLS8135D servo
- 1 × POM horn set
- 1 × mounting screw pack
Optional: metal horn, sold separately.
How to size it
Torque tracks the rail: 20 kg·cm at 6.0 V, 28 at 7.4 V, 35 at 8.4 V, at 0.14, 0.12 and 0.10 s/60°. On a 2S pack that sits near 7.4 V under load, plan on 28 kg·cm and treat 35 as the fresh-pack number.
Stall current is 4.0 A. Four of these on one BEC is 16 A at stall — size the BEC for the worst case, or run a separate servo rail. Brownouts on 35 kg·cm class models are almost always a supply problem, not a servo fault.
FAQ
BLS8135D or BLS8145D?
Same case, same 25T spline, same 20 × 40 × 38.4 mm footprint. The 8145D is 73 g and reaches 48 kg·cm at 8.4 V but draws 5.2 A at stall; the 8135D is 77 g, 35 kg·cm and 4.0 A. Pick on torque headroom versus current budget.
What supply voltage?
6.0 to 8.4 V. The headline 35 kg·cm is the 8.4 V figure; at 7.4 V it is 28 kg·cm and at 6.0 V it is 20.
What pulse range does it accept?
The inspection sheet specifies a 500–2500 µs window (800–2200 µs on the 9130/9150) with 1500 µs neutral, both customizable at order. Feeding it outside that window is out of spec.
Can I drive it from a normal receiver?
Signal-wise yes, but check the supply. This servo wants 8.4–16.8 V, not a 6 V receiver pack, so the power rail has to be separate from the receiver’s.
Other interfaces
Downloads
- XQ-BLS8135D inspection specification (PDF, 722 KB)
Torque, speed and current at each supply voltage, mechanical data, control specification, mounting dimensions. - 2D dimension drawing (image)
Mounting hole positions, case depth and overall height; the same drawing is inside the datasheet.
