Stability and Control characteristics of the Early Mark Spitfires

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Slow down and tell me where you get the 78.54 MAC on that sheet.

Do you know what percentage MAC is??

The reason the NACA used percentage MAC is because they did their own weight and balance analysis.

The ONLY number that is comparible...is the percentage MAC!!!

MAC as measured by RAE:

19.5+8.4 = 27.9/84 = 33.2%

NACA CG as flown = 31.4% MAC

The NACA flew the Spitfire with the CG 1.8% MAC FORWARD of the aft CG limit as defined by Supermarine.

If you want to use your 78.54 in MAC with our most narrow aft CG limit...

CoG range 5.4"-7.9" aft of datum point, no inertia device needed

(19.5 + 5.4) / 78.54 = 31.7% MAC

NACA CG as flown = 31.4% MAC

The NACA flew the Spitfire with the CG .3% MAC FORWARD of the aft CG limit as defined by Supermarine.