HENFOIL
An airfoil knowledge base for HENFOIL, in reading order: geometry and forces, analysis and design, boundary layers, theory and computation, then named families, wind-tunnel method, geometry repair, optimization, and the workflows that keep a polar traceable. Product field guides sit after the lessons. These are teaching notes, not certification reports.
220 articles · 38 topics
Product
HENFOIL and HENSYNTH product notes: what each workspace adds, who it is for, and what it does not claim.
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.
Aircraft and propulsion
A trainer section is judged on a gentle stall, a moment a simple tail can trim, and behavior with a rough leading edge. Cruise lift-to-drag is a later column.
Aircraft and propulsion
A flying-wing section has to trim at a positive lift coefficient without a tail. Reflex, sweep and the center of gravity do that together. The section moment is necessary and not sufficient.
Aircraft and propulsion
A propeller blade is a stack of sections. Each radius has its own speed, Reynolds number and inflow angle. A wing polar pasted along the whole blade is the wrong map.
Aircraft and propulsion
A wing-borne electric VTOL section lives in at least three problems: a high-lift transition, a quiet cruise, and a structure thick enough to carry people. No single polar covers all three.
Aircraft and propulsion
At altitude the density drops. Chord Reynolds number can be low even when true airspeed is high, and Mach number can rise at the same time. The section has to be chosen for both.
Aircraft and propulsion
A slow mapping airplane lives at a high lift coefficient and a low Reynolds number for a long time. Evaluate the section at the loiter condition, including a rough leading edge and a mild stall.