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concept · 12 min read
G-factor pilot's guide
How many Gs did you really pull in that thermal?
On this page
What the Hell is a G-Factor Anyway?
Why Should I Care?
The Physics (Don't Run Away, It's Quick)
The Basic Formula
Two Ways to Pull Gs (Both Equally Uncomfortable)
1. Vertical Acceleration (The Pull-Up)
2. Lateral Acceleration (The Turn)
How We-Fly Computes Your Gs from IGC Files
The Problem: IGC Files Are Not G-Meters
Step 1: Smooth the Noisy Data
Step 2: Compute Vertical Velocity (First Derivative)
Step 3: Compute Vertical Acceleration (Second Derivative)
Step 4: Convert to Vertical G-Factor
Step 5: Compute Ground Speed and Turn Rate
Step 6: Convert to Lateral G-Factor
Step 7: Combine Vertical and Lateral Gs
Step 8: Compute Statistics
The Fine Print (Important Caveats)
1. IGC Data is Low-Resolution
2. Pressure Altitude vs GPS Altitude
3. Smoothing Hides Reality (But That's OK)
4. These Numbers Are NOT Certification-Grade
Validation & Sanity Checks
One Last Thing: G-Factor Doesn't Lie, But Context Matters
Final Thought
References
1. FAA Pilot's Handbook of Aeronautical Knowledge (PHAK)
2. Aerodynamics for Naval Aviators
3. Introduction to Flight (8th Edition)