Ideal propeller pitch angle

The speed at the propeller tip at 6,400 rpm (maximum engine speed) is close to Mach 0.51, which is within the safe range. The 2.58:1 reduction gear is essential—without it, at 6,400 rpm with a 135-cm rotor diameter, the tip would already exceed Mach 1.2.

If the propeller is fixed-pitch, the optimal design point should be adjusted to match the most common cruise speed. If the Rotax 582 normally operates in the 5500–6200 rpm range during cruise, a pitch angle of 16°–18° provides the ideal balance between static thrust and cruise efficiency.

You can adjust the cruising speed and the radius in the calculator to see how the angle changes.

Ideal Propeller Pitch Calculator

Propeller Pitch Calculator — Rotax 582
Aeronautics — Geared Propeller

Rotax 582 · B Gearbox (2.58:1) · Four-blade propeller ⌀135 cm

Engine RPM
6400
maximum
Propeller RPM
2481
@ 6,400 rpm engine
Top speed
175
m/s
Mach tip
0.51
@ISA 15°C
Passing angle β — at the selected % radius
—
Adjust the settings below
β= φ + α
φ= arctan(Va / ωr)
α≈ 4° (angle)
Go—
ωr—
φ—
// Flight Parameters
Cruising speed 100 km/h
Calculation Point (% Radius) 75%
// Breakdown of the calculation
Propeller diameter135 cm
Total Radio0.675 m
Radio to %0.506 m
Reduction ratio2.58 : 1
Tangential velocity (ωr)—
Feed Rate (Va)—
Geometric angle φ—
α incidence4.0°
EFFECTIVE PITCH
—
REL. UPDATE J
—
STATISTICAL EFFICIENCY.
—
// Position on the passband spectrum
10°15°20°25°30°35°
Very low / low thrust
Optimal UL/LSA Range
High risk of overmotorization
Your calculated angle
// Reference for typical ranges
Usage β (75% radio) Geometric pitch Status
Takeoff / Climb 14° – 16° 60–70 cm low
Cruising speed 90–110 km/h 16° – 19° 70–85 cm optimal
Maximum speed 20° – 24° 85–100 cm high
Your current settings — — calculated
Rotax 582 · B gearbox 2.58:1 · ⌀135 cm four-blade propeller · α = 4° (Clark-Y / NACA 4-series airfoil)
Propeller Pitch Calculator — Rotax 582
Aerodynamic Design Tool
Angle β @ 75% radius
Type B Gear Reducer · 2.58 : 1 (defect)
Result — selected configuration
Angle β — operating range (5° – 40°)
5°10°15°20°25°30°35°40°
Mach at the tip — recommended limit 0.85
0.00.20.40.60.81.0
Complete Comparison — All Configurations
Shovels Diameter Propeller RPM V-peak (m/s) Mach tip Stride (cm) Angle β J Ratio Status
Note: β calculated at 75% of the radius (standard reference station). Angle measured from the plane of rotation. Geometric pitch = forward speed / propeller RPM. J = advance ratio = V / (n·D). Assumed speed of sound: 340 m/s (sea level, 15°C).