Model thrust from propeller dimensions and RPM. Review pitch speed, power draw, and thrust ratio. Tune inputs before launches to reduce avoidable setup mistakes.
| Motor KV | Voltage | Current | Prop Size | Efficiency | Weight | Estimated RPM | Estimated Thrust |
|---|---|---|---|---|---|---|---|
| 950 | 14.8 V | 38 A | 11 x 5.5 | 82% | 1350 g | 11541 | 1175 g |
| 1100 | 11.1 V | 32 A | 10 x 6 | 80% | 1100 g | 9768 | 786 g |
| 720 | 22.2 V | 52 A | 13 x 6.5 | 84% | 2400 g | 13427 | 2465 g |
This RC plane thrust calculator helps model how a motor, battery, and propeller combination may perform before a real-world test. Many builders know KV, voltage, prop size, and current, but still need a quick way to connect those values to estimated thrust, pitch speed, and thrust-to-weight ratio. This page brings those numbers into one place.
The calculator uses loaded motor speed, a static thrust coefficient, propeller diameter, air density, and slip-adjusted pitch speed. That approach gives practical planning numbers for workshop comparisons. It is especially useful when choosing between propeller sizes, comparing two battery voltages, or checking whether a new build is likely to feel underpowered.
Static thrust matters most during launch, climb, and low-speed acceleration. Pitch speed helps estimate how fast the model may travel once moving efficiently. Power loading adds another useful view because watts per pound often reveal whether a setup fits trainer, sport, or aerobatic goals. Together, these outputs create a balanced engineering snapshot.
This tool is still an estimate, not a substitute for a wattmeter, tachometer, or thrust stand. Prop brand, blade shape, ESC timing, motor condition, and field elevation all influence real performance. Use the result as a screening step, then confirm the final setup with safe ground testing.
1) Loaded RPM
Loaded RPM = Motor KV × Voltage × Efficiency
2) Static Thrust
Thrust = Ct × ρ × n2 × D4
Where: ρ = air density, n = revolutions per second, D = prop diameter in meters, Ct = estimated static thrust coefficient based on pitch-to-diameter ratio.
3) Pitch Speed
Pitch Speed = ((RPM × Pitch × 0.0254) ÷ 60) × (1 − Slip)
4) Input Power
Input Power = Voltage × Current
5) Thrust-to-Weight Ratio
Thrust-to-Weight = Static Thrust (g) ÷ Plane Weight (g)
6) Power Loading
Power Loading = Input Power ÷ Aircraft Weight in pounds
It compares estimated static thrust with aircraft weight. A higher ratio usually means stronger climbs, shorter takeoff runs, and more responsive vertical performance.
No. Static thrust is estimated while the aircraft is not moving. In-flight thrust changes with airspeed, prop unloading, and changing aerodynamic conditions.
Ideal pitch speed assumes the prop advances perfectly every revolution. Real props slip in air, so the calculator reduces speed using the slip percentage input.
Blade shape, airfoil, hub geometry, and manufacturer design all change performance. Two props with the same diameter and pitch can still behave differently.
Use a realistic loaded value, often between 75% and 90% for many setups. If unsure, start conservatively and compare against real tachometer data later.
Yes. Higher altitude reduces air density, which lowers static thrust. You can reflect that by entering a lower air density value for your flying field.
Not ideally. This calculator is aimed at propeller-driven RC planes. EDF systems follow different performance behavior and deserve a separate fan-based model.
No. Use it for planning and comparison. Final propeller and battery choices should still be confirmed with current checks, RPM measurements, and safe ground testing.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.