| 75KG·CM STALL | 0.110S/60° NO-LOAD | 8.4V RATED |
| 88G WEIGHT | StainlessGEARTRAIN | 360°TRAVELCustomizable |
Overview
The BLS8175D is the 75 kg·cm end of the standard-size brushless range: same 20 × 40 mm footprint as the 8135 and 8145, but 40 mm deep and 88 g, because the geartrain and the motor behind it are bigger. At 8.4 V it delivers 75 kg·cm at 0.11 s/60°.
Two details separate it from the smaller models. The output is a 25T-φ7.96 mm spline — larger than the φ5.94 used on the 48 kg·cm build, so horns do not cross over — and the box includes a 7075 aluminium CNC horn rather than a POM one, which is the right call at this torque.
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 | 0.170 s/60° (353 °/s) | 53 kg·cm (5.20 N·m / 736 oz·in) | 320 mA | 6.0 A |
| 7.4 V | 0.140 s/60° (429 °/s) | 65 kg·cm (6.38 N·m / 903 oz·in) | 370 mA | 7.5 A |
| 8.4 V | 0.110 s/60° (545 °/s) | 75 kg·cm (7.36 N·m / 1042 oz·in) | 440 mA | 9.0 A |
Control specification
| Item | Specification |
|---|---|
| Command signal | PWM |
| Amplifier | Digital controller |
| Pulse width range | 800–2200 µs |
| Neutral position | 1500 µs |
| Dead band | 2 µs |
| Rotating direction | CCW (1000–2000 µs) |
| Travel | 360°, customizable |
Mechanical specification
| Item | Specification | Item | Specification |
|---|---|---|---|
| Dimensions | 20 × 40 × 40 mm | Case material | Aluminium, CNC |
| Weight | 88 g | Geartrain | Stainless steel |
| Bearings | 2 × ball bearing | Motor | Brushless |
| Output spline | 25T-φ7.96 mm | Horn | 7075 aluminium, CNC |
| 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-BLS8175D servo
- 1 × 7075 aluminium horn
- 1 × mounting screw pack
How to size it
Torque is 53 kg·cm at 6.0 V, 65 at 7.4 V and 75 at 8.4 V, at 0.17, 0.14 and 0.11 s/60°. The 8.4 V figure is the one on the box; on a loaded 2S pack plan on 65 kg·cm.
Stall current runs 6.0 A at 6.0 V, 7.5 A at 7.4 V and 9.0 A at 8.4 V. Two of these on one BEC is 18 A at stall — if the receiver resets under load, the supply is the problem, not the servo. Use a rail rated for the stall current, not the idle current.
FAQ
BLS8145D or BLS8175D?
48 kg·cm versus 75, 73 g versus 88 g, 38.4 mm versus 40 mm deep. The 8175D also changes the spline to φ7.96 mm and ships with a 7075 aluminium horn. If your linkage and horn set are built around a φ5.94 spline, staying on the 8145D avoids redesigning the arm.
Will my existing 25T horns fit?
Check the centre diameter. 25T splines are not all the same size — this one is φ7.96 mm, where the 8135D and 8145D are φ5.94 mm. A φ5.94 horn will not seat on it.
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-BLS8175D inspection specification (PDF, 821 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.
