Subsonic Wind Tunnel Test Section
Provides controlled airflow at V_inf = 30 m/s with flow angularity < 0.1 degrees.
Aerospace & Aeronautical Engineering / Aerodynamic Drag Polar
FREE TO EXPLORELABORATORY 04 · AEROSPACE & AERONAUTICAL ENGINEERING
Direct Force Balance Measurements and Aerodynamic Drag Polars
Measure lift and drag forces simultaneously on a wing model using an external 3-component strain-gauge balance to determine parasite drag coefficient C_D0 and induced drag factor k. Explore interactive wind tunnel simulation, flight dynamics, and aerospace engineering telemetry.
AERODYNAMICS · PROPULSION · FLIGHT DYNAMICS
Your virtual aerospace engineering laboratory.
TOTAL DRAG COEFFICIENT C_D—
FLIGHT & TEST CELL TELEMETRY
Ready to sample with C_L^2 = 0.36 dimensionless.
Adjust C_L^2, then execute aerospace trial.
Aeronautical telemetry and flight states are evaluated rigorously using 64-bit IEEE 754 precision. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support high-fidelity aerodynamic modeling.
Aeronautical assumptions and boundary condition limits
Parabolic polar relationship C_D = C_D0 + k * C_L^2 is valid strictly for attached flow prior to the stall boundary. The linear regression of C_D against C_L^2 yields an induced drag factor k = 0.0450 and parasite drag C_D0 = 0.0180 with R^2 > 0.999999.
Aeronautical apparatus & wind tunnel sensors.
External 3-Component Strain-Gauge Balance
Measures aerodynamic normal force, axial force, and pitching moment via calibrated Wheatstone bridges.
Finite Wing Model (AR = 6.0)
NACA 0012 rectangular wing planform with span b = 600 mm and chord c = 100 mm.
Automated Angle-of-Attack Actuator
Pitches wing model through precision stepper motor from -4 to +16 degrees with optical encoder.
Dynamic Pressure Pitot-Static Sensor
Continuously records reference dynamic pressure q_inf to normalize forces into non-dimensional coefficients.
Balance Signal Conditioning Chassis
Amplifies strain gauge microvolt signals with 24-bit delta-sigma converters and digital filtering.
FOLLOW THE METHOD
A reason behind every step.
Measure lift and drag forces simultaneously on a wing model using an external 3-component strain-gauge balance to determine parasite drag coefficient C_D0 and induced drag factor k. Standardized parameter settings: 0.04, 0.16, 0.36, 0.64, 0.81, 1.0 dimensionless.
01
Tare Weight and Balance Calibration
Execute zero-flow weight tare across all balance load cells to eliminate gravity tare moments across the pitch range.
02
Wind Tunnel Velocity Baseline
Start the wind tunnel and bring test-section speed to V_inf = 30 m/s, stabilizing dynamic pressure at q_inf = 551 Pa.
03
Zero-Lift Alignment Verification
Set angle of attack to alpha = 0 deg and confirm that measured lift on the symmetric wing is zero within balance tolerance.
04
Systematic Drag Polar Sweep
Step the model through angles of attack corresponding to C_L^2 = 0.04, 0.16, 0.36, 0.64, 0.81, and 1.00.
05
Force Resolution to Wind Axes
Resolve measured normal and axial balance forces into wind-axis lift L and drag D using measured pitch angles.
06
Drag Polar Plotting and Regression
Plot C_D versus C_L^2, perform linear regression to determine parasite drag C_D0 and induced drag factor k, and compute (L/D)_max.
YOUR NOTEBOOK · 0 OBSERVATIONS
Turn measurements into aerodynamic insight.
Points are your recorded observations. The solid regression line validates Aerodynamic Drag Polar mathematical scaling.
LINEAR REGRESSION FIT · y = mx + b
C_D = C_{D0} + k C_L^2 \implies C_D = m \cdot (C_L^2) + b
| # | Lift Coefficient Squared C_L^2 (dimensionless) | Total Drag Coefficient C_D (dimensionless) | Lift Coefficient Squared C_L^2 | Total Drag Coefficient C_D | Remove |
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