RC Helicopter Head Speed Calculator
Estimate theoretical rotor head speed from motor KV, battery voltage and the total gear reduction between motor and rotor head.
Power
Nominal pack voltage, e.g. 44.4 V for a 12S LiPo.
Drivetrain
Every reduction stage between motor and rotor head multiplied together.
Result
Theoretical head speed
2,128RPM
rotor speed
Motor RPM (no-load)
23,532RPM
Total reduction
11.06: 1
Theoretical figure — stay inside the head-speed limits set by your model, motor, blade and drivetrain manufacturers.
Formula
- 1.
Theoretical Motor RPM = KV × Voltage - 2.
Theoretical Head Speed = Motor RPM / Total Reduction Ratio
Worked example
- 1.Inputs: 530 KV motor, 44.4 V (12S nominal), total reduction 11.06:1.
- 2.Motor RPM = 530 × 44.4 = 23,532
- 3.Head speed = 23,532 / 11.06 ≈ 2,128 RPM
Assumptions and limits
- Real head speed is lower under load and depends on voltage sag, governor settings and motor efficiency.
- Always stay inside the rotor head speed limits set by your model, motor, blade and drivetrain manufacturers.
- Do not use this figure to exceed a rated head speed — it is a paper estimate, not a safety check.
Related tools
Guides and concepts
FAQ
Is head speed the same as motor RPM?
No. The rotor head turns through a reduction drivetrain — head speed is motor RPM divided by the total reduction ratio.
Why is my actual head speed different?
Voltage sag, motor efficiency, load and governor settings all pull real head speed below the theoretical figure.
Assumptions
- No-load motor RPM is used (KV × voltage).
- Total reduction ratio covers every stage between motor and rotor head.
- Governor behavior and motor efficiency are not modeled.