XR-7 Propulsion Module Technical Specification

Document ID: ARROW-SPEC-2026-0142 Classification: PUBLIC Revision: 3.2.1 Last Updated: 2026-02-02

---

1. Overview

The XR-7 Propulsion Module is a high-efficiency brushless motor assembly designed for sustained autonomous flight operations in variable atmospheric conditions. This document defines the technical parameters, operational limits, and integration requirements for deployment in Arrow platform configurations.

Parameter	Value	Unit	Tolerance
Rated Power	2,400	W	±2%
Max Continuous Current	45	A	—
Peak Current (10s)	62	A	—
KV Rating	170	rpm/V	±5%
Operating Voltage	44.4–58.8	V	—
Mass (bare motor)	438	g	±3g
Stator Diameter	56	mm	±0.1mm
Stator Length	30	mm	±0.1mm

2. Performance Characteristics

2.1 Thrust Curve

Measured at sea level, 15°C, 1013.25 hPa with standard 22×7.2 propeller.

Throttle	Current	Power	Thrust	Efficiency
25%	8.2 A	410 W	1.82 kg	4.44 g/W
50%	18.6 A	930 W	4.21 kg	4.53 g/W
75%	32.4 A	1,620 W	6.89 kg	4.25 g/W
100%	48.1 A	2,405 W	9.34 kg	3.88 g/W

2.2 Thermal Limits

CAUTION: Exceeding thermal limits will trigger automatic power derating. Sustained operation above 95°C stator temperature will result in permanent degradation.

• Maximum Stator Temperature: 120°C
• Maximum Bearing Temperature: 85°C
• Recommended Operating Range: -20°C to +45°C ambient

3. Mechanical Interface

3.1 Mounting Pattern

The XR-7 uses a standard 4-bolt radial mounting pattern compatible with Arrow Universal Motor Mount (AUMM) specification.

        [FRONT]
           ○
     M4×0.7  19mm
    ○───────────○
    │           │
    │     ●     │  ← Shaft centerline
    │   (∅8mm)  │
    ○───────────○
         19mm
        [REAR]

Bolt Specification:

• Thread: M4×0.7
• Length: 12mm minimum engagement
• Grade: 12.9 or equivalent
• Torque: 3.2 N·m ± 0.2 N·m

3.2 Shaft Details

Feature	Specification
Diameter	8.00 mm h6
Length (exposed)	22 mm
Thread	M8×1.0 LH
Keyway	3×3 mm, 12mm length
Material	4140 steel, hardened

4. Electrical Interface

4.1 Power Connections

Three-phase winding connection using 4mm gold-plated bullet connectors.

Phase A ──[YEL]──●
Phase B ──[ORG]──●  → ESC Input
Phase C ──[RED]──●

4.2 Sensor Interface

Optional hall sensor package available. 6-pin JST-SH connector.

Pin	Signal	Description
1	VCC	5V supply (10mA max)
2	GND	Ground reference
3	HA	Hall A output
4	HB	Hall B output
5	HC	Hall C output
6	TEMP	NTC thermistor (10kΩ @ 25°C)

5. Quality Assurance

5.1 Acceptance Criteria

Each unit undergoes the following validation sequence:

1. Visual Inspection — Surface defects, winding integrity, bearing alignment
2. Electrical Test — Phase resistance (±3%), inductance (±10%), insulation (>100MΩ @ 500VDC)
3. Dynamic Balance — G2.5 or better per ISO 1940-1
4. Run-in Test — 30 minutes at 50% load, thermal stability verification
5. Final Inspection — Dimensional verification, documentation package

5.2 Traceability

All units are laser-marked with:

ARROW│XR-7│SN:YYWW-NNNNN│LOT:XXXXXX

• YY — Year of manufacture
• WW — Week of manufacture
• NNNNN — Sequential unit number
• XXXXXX — Production lot identifier

---

Document Control

Rev	Date	Author	Description
3.2.1	2026-02-02	Systems Engineering	Updated thermal limits
3.2.0	2026-01-15	Systems Engineering	Added sensor interface
3.1.0	2025-11-20	Propulsion Team	Initial release