Aerospace design blog — airfoil lessons & notes

How-to

Field guides for HENFOIL features and HENSYNTH loops — geometry, requirements, synthesis, Mission, Performance, Trades, Optimize and Reports.

Airfoil fundamentals

Chord, camber, thickness, NACA names, angle of attack, and how shape creates lift.

Airfoil analysis

Polars, Reynolds and Mach number, L/D, drag, pitching moment, and how to compare sections.

Airfoil design

Choosing, drawing, and optimizing a section for a UAV or another real mission.

Advanced aerodynamics

Boundary layers, stall types, roughness, icing, pressure plots, and airfoil noise.

Airfoil applications

Wind turbines, electric aircraft, CFD, and the step from a 2D section to a 3D wing.

Airfoil geometry

Coordinates, chord, camber, thickness distribution, leading-edge radius and named NACA profiles.

Lift and drag

How to calculate CL and CD, read the lift slope, zero-lift angle, CLmax and the best angle.

Analysis methods

Lift curves, low Reynolds number, Cp plots, potential flow, convergence and compressibility.

Design and modification

Editing a section, parameterization, design variables, optimizers and a comparison matrix.

Applications and validation

HALE and racing aircraft, altitude, gliders, wind-tunnel tests and checking a computation.

Boundary layers

Thickness, laminar bubbles, adverse gradients, transition, roughness and skin friction versus pressure drag.

Stall and flow control

Stall type, post-stall polars, slats, flaps, vortex generators and dynamic stall.

Coordinates and numerics

Bad points, interpolation, resampling, panel methods, resolution and why two codes disagree.

Operating conditions

Reynolds-number sweeps, temperature, yaw, critical Mach, shocks and off-design flight.

Design workflows

Databases, CAD sketches, performance maps, high-lift selection and the step from a polar to a wing.

Geometry models

NACA camber lines, 5-digit and 6-series sections, coordinate equations, CST and Bézier curves.

Aerodynamic theory

Thin-airfoil lift, the lift slope, the Kutta condition, circulation and the aerodynamic center.

Computational methods

Panel methods, viscous coupling, XFOIL settings, failed polars, CFD meshes and RANS.

Stability and integration

Pitching moment and stability, tailplanes, flaps, control surfaces and finite-wing effects.

Specialized applications

Solar UAVs, human-powered aircraft, wind-turbine stations, small electrics and performance maps.

Airfoil families

Clark Y, NACA 23012 and 4415, symmetric thicknesses, and Eppler and Selig low-Reynolds-number sections.

Flow phenomena

Pressure recovery, leading-edge suction, camber and zero lift, compressibility corrections and three-dimensional flow.

Wind-tunnel testing

Balances and wakes, data reduction, uncertainty, oil flow, pressure taps and a validation workflow.

Geometry processing

Self-intersections, area and ordering, transforms, DAT to DXF, and a quality check before the loft.

Optimization and workflows

Robust and multi-point design, surrogates, machine learning, morphing sections and an automated analysis loop.

Geometry parameters

Leading-edge radius, thickness ratio, trailing-edge thickness, reflex camber, and comparing two sections.

Performance reading

Best lift-to-drag angle, glide ratio, reading lift with drag and moment, hysteresis, and polar trade-offs.

Analysis workflows

Reynolds-number sweeps, consistent databases, sensitivity, outliers, solver benchmarks, and reproducible reports.

Aircraft and propulsion

Trainers, flying-wing UAVs, propeller blades, electric VTOL, high-altitude flight, and slow mapping aircraft.

Research methods

Uncertainty, Bayesian search, physics-informed models, flow control, bio-inspired sections, and digital twins.