RotorCalculator is an engineering tool for rotorcraft and rotary-wing aerodynamic performance analysis based on classic Blade Element Momentum Theory (BEMT).

Designed for aerospace engineers, researchers, UAV/drone developers, and students, RotorCalculator delivers fast, rigorous rotor performance calculations directly on your Android device with zero cloud dependency.

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KEY CAPABILITIES & PHYSICS
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• BLADE ELEMENT MOMENTUM THEORY (BEMT)
Combines blade element strip theory with momentum conservation to resolve induced inflow across the rotor disk.

• INFLOW CLOSURE MODELS
Choose between classic inflow approximations:
- Uniform Inflow
- Coleman
- Coleman-FG (Forward-Flight Glauert)
- Drees Linear Inflow

• COMPRESSIBILITY & TIP-LOSS CORRECTIONS
- Prandtl-Glauert Mach number compressibility correction
- Sissingh and fixed blade tip-loss models
- Numerical Vectorial integration of profile drag across all azimuth stations

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APPLICATION MODULES
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1. GEOMETRY
• Factory rotor presets: Sikorsky UH-60 Black Hawk, Bell 206 JetRanger, Bo 105, Robinson R44, and DJI Drone
• Create, clone, customize, and save unlimited custom rotor configurations
• Instant planform metrics: Solidity (σ), aspect ratio (AR), disc area, blade area, root/tip chord, taper ratio, and linear blade twist
• Complete JSON import and export via the native Android Storage Access Framework

2. FLIGHT CONDITIONS & TRIM
• Hover, axial climb/descent, and high-speed forward flight
• Dual flow representations: advance ratio (μₓ) or horizontal speed (Vx); angle of attack (α), climb speed (Vz), or axial advance ratio (μz)
• 6 coupled Trim Condition pairs:
- Ω + θ₀ (RPM and Collective Pitch)
- Ω + T (RPM and Target Thrust)
- Ω + C_T (RPM and Target Thrust Coefficient)
- θ₀ + T (Collective and Target Thrust)
- θ₀ + C_T (Collective and Target Thrust Coefficient)
- T + C_T (Thrust and Thrust Coefficient)
• Standard atmospheric model: altitude, temperature, density, and sound speed

3. RESULTS & DIAGNOSTICS
• Clean, standardized 3-column engineering layout: Quantity | Value | Unit
• Forces & Torques: Thrust (T), In-plane H-force, Profile H₀, Induced Hᵢ, Side force (Y), Shaft torque (Q)
• Power Breakdown: Total power (P), Induced power (Pᵢ), Profile power (P₀), Parasite power (P_par)
• Non-dimensional Coefficients: C_T, C_Q, C_P, C_H, Figure of Merit (FoM)
• Section & Flow Diagnostics: Retreating blade tip Mach number, advancing/retreating tip speeds, total axial speed (V_z,tot), and 75% radius section angle of attack and inflow angle
• One-tap toggle between SI and Imperial units with custom decimal precision

4. PARAMETER SWEEPS & CURVE FAMILIES
• Interactive parameter sweep plots across advance ratio (μₓ) or forward speed (Vx)
• Compare inflow models side-by-side on the same chart
• Hover collective trim mode with custom delta pitch curves
• Interactive crosshair readout
• Data table view with instant CSV and high-resolution PNG export

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BUILT FOR PROFESSIONALS
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• 100% Offline: All aerodynamic numerical solvers run entirely on your device. No internet connection, account, or cloud sign-in required.
• Adaptive Dark, Light, and Midnight themes designed for high readability in field and laboratory environments.
• Built-in Physics Reference Manual explaining all symbols, equations, sign conventions, and literature citations (Johnson, Leishman, Stepniewski).

RotorCalculator provides engineering-grade analysis within the validity envelope of blade element momentum theory.