Xfoil for Fixed Wing UAV / Human-Powered Aircraft Design 4 minute read

Why XFOIL Matters

Designing a wing always starts with the same uncomfortable gap:

You can draw a beautiful airfoil shape but how do you know what it does aerodynamically?

For conventional aircraft, that gap is often bridged with wind-tunnel data, empirical charts, or CFD. For small UAVs and human-powered aircraft, those options are either too expensive or too slow to iterate.

XFOIL, written in Fortran at MIT by Mark Drela mit.edu/drela/xfoil, sits precisely in that gap. It provides a fast, physics-based way to go from geometry to aerodynamic coefficients lift, drag, and moment as a function of angle of attack and... read more

PhD Thesis: Afterburner Flame Dynamics 4 minute read

Why Afterburners Are Hard

Afterburners live in a difficult corner of fluid mechanics: high-speed turbulent flow, intense heat release, strong recirculation, and unsteady pressure coupling. A flameholder has to do two contradictory things at once:

  • Create a stable recirculation zone to anchor a flame
  • Do as little damage as possible to pressure recovery and thrust

For vee-gutter bluff-body flameholders, stability comes from the wake. Hot combustion products recirculate behind the gutter, ignite incoming reactants, and sustain a flame even when residence times are extremely short. The same wake, however, is inherently unsteady and sheds vortices that can couple to acoustics and... read more

Propeller Design with XFOIL and QPROP 4 minute read

Why Propeller Design Is Hard

A propeller is just a rotating wing, but that simple statement hides a lot of complexity.

Unlike a fixed wing, every blade section on a propeller:

  • Sees a different relative velocity
  • Operates at a different effective angle of attack
  • Contributes simultaneously to thrust and torque

Designing a propeller therefore requires closing a loop between:

  1. 2D airfoil performance
  2. 3D blade geometry
  3. Integral thrust, torque, and power

This is where XFOIL and QPROP come in. XFOIL provides the sectional aerodynamics. QPROP integrates those sections into a rotating blade model and predicts the global performance.

Together, they form a fast, physics-based path... read more