How to Evaluate Airfoils for Small Electric Propeller Aircraft

Two airfoils on one energy budget

Battery energy is the range. Drag of the airplane and inefficiency of the propeller both spend it. The wing section governs profile drag at the cruise lift coefficient. The propeller blade sections govern how much of the electrical power becomes useful thrust. Picking a wing airfoil and ignoring the prop, or stretching the wing section out to the blade, answers one of the two problems.

For the wing, compute Re from cruise speed and chord, and CL from wing loading and dynamic pressure. On a small trainer or a light electric two-seater those Reynolds numbers are often lower than the light-aircraft habit the airfoil was named in. Run the polar there, clean and tripped, and read L/D and moment at the cruise CL. Thickness still has to hold a spar and, sometimes, the battery. A thin laminar section that forces a heavier wing can lose the range it appeared to win.

The propeller is a radial family

How to evaluate without mixing the books

1. Write a wing card: Re, Mach, cruise CL, tripped and clean CD, CM, CLmax.
2. Write a blade card at two or three radii, with local Re and local Mach. Do not copy the wing CD onto the blade.
3. Estimate airplane drag from the wing polar plus induced drag, as in the performance-model lesson. Estimate thrust from the blade sections with a propeller method. The range comes from both.
4. If the wing and the prop were selected from the same famous 12% section, that coincidence is not a design. Re-read both cards at their own Reynolds numbers.

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Where this sits in the series

In simple words: what this page is for

A small electric airplane has a wing section at a modest Reynolds number and a propeller section at a different one. Battery energy makes both drags expensive, and they are not the same airfoil.

This lesson exists because section decisions fail when geometry, method labels and selection reasons are scattered. How to Evaluate Airfoils for Small Electric Propeller Aircraft helps you keep a clean trail from shape to polar to choice.

Why the topic matters

Engineers lose time when a title sounds clear but the page only sketches the idea. This article expands How to Evaluate Airfoils for Small Electric Propeller Aircraft so you can answer three questions without jargon: what is the idea, when do you use it, and how do you check it in a HENDOI product.

Read the sections above for the core definitions. Use the steps below to move from reading into a real project trail you can share with a teammate.

How to apply this in HENDOI

In practice: create a HENDOI account or log in, open HENFOIL, bring a section in (create, import DAT, or digitize), pass the geometry gate, climb the analysis ladder only as far as the decision needs, then compare and archive. Every calculated number should keep its method label.

When the section choice is ready for the aircraft, continue in HENSYNTH for mission, compliance and trades. Same account. Same plans.

What this page will not claim: a teaching polar or geometry note is not a flight-Re certificate. HENFOIL labels methods so you know what you bought. Tunnel data and professional judgement still sit outside any single software run.

Checklist before you leave this page

• Can you state the idea of How to Evaluate Airfoils for Small Electric Propeller Aircraft in one sentence?
• Do you know which product owns the next action — HENFOIL or HENSYNTH?
• Will every number you keep carry a method label or a stored-run source?
• If you are new here, have you opened Register or Login?

Related reading on this site

• Active Flow Control on Airfoils: Suction, Blowing and Synthetic Jets
• How Adverse Pressure Gradients Affect Airfoil Boundary Layer Separation
• What Is the Aerodynamic Center of an Airfoil? Location, Meaning and Applications
• What Is Airfoil Aerodynamic Efficiency Across a Range of Flight Conditions?
• All HENDOI blog articles
• HENFOIL product page
• HENSYNTH product page
• Pricing — Student, Professional & Team
• FAQ
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• Previous: Wind turbine airfoils along the span
• Next: High-lift, low-speed and short-takeoff airfoils
• Index: all HENFOIL airfoil lessons

These pages teach the ideas. They are not wind-tunnel data and not a certification analysis. When a number matters, compute it at a stated Reynolds number, Mach number and transition setting, and keep the method label on the result. In HENFOIL that production polar is a VIC polar — see the analysis ladder and the polar field guide.