Was the Spitfire Area-Ruled?

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SUMMARY

The Supermarine Spitfire, designed in the mid-1930s, exhibited characteristics of area ruling, particularly in its fuselage design, which may have contributed to its superior performance in high-speed dives during World War II. The tapering of the fuselage behind the engine banks aligns with the principles of the Area Rule, first identified by Otto Frenzl in 1943 and later formalized by Whitcomb in 1951. Although the design was not intentionally created with area ruling in mind, it likely helped mitigate compressibility effects, enhancing the aircraft's aerodynamics. Historical accounts, such as those in Pierre Clostermann's "The Big Show," illustrate the Spitfire's impressive speed capabilities in extreme conditions.

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Alan1000
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Was the Spitfire "area-ruled"?

Any aerodynamicists out there?

The Supermarine Spitfire, designed in the mid-1930s, supposedly enjoyed the highest mach rating of any propellor-driven fighter in World War 2. Even the Mustang, with its state-of-the-art laminar flow wing, could not match the Spitfire in the dive.

While looking at a photo of a Spitfire recently, it occurred to me that it had a somewhat area-ruled fuselage. If you look at a picture taken from slightly above, you can see that immediately behind the engine cylinder banks, roughly in line with the wing leading edge, there is a substantial tapering-off of fuselage cross-sectional area. This continues for some distance, then, behind the point of maximum chord thickness, the cockpit canopy causes cross sectional area to increase once more.

This "area-ruling" was presumably not designed as such, because the concept hadn't been thought of then (as far as I know). But how significant was it, I wonder, in delaying the onset of compressibility effects?
 
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The Area Rule was first noticed by Otto Frenzl at Junkers in 1943.
In 1951 in the USA it become the Whitcomb Area Rule.
https://en.wikipedia.org/wiki/Area_rule#History

I suspect Mitchell intuitively reduced the fuselage section at the wing so as to improve and not interfere with the lift of the wing.

In the book “The Big Show” by Pierre Clostermann, there is a report of two Strato-Spitfires, with pressurised cockpit canopies bolted down, in a vertical dive from 43,000 feet in pursuit of a photo-reconnaissance Messerschmitt Bf 109G.

“The Hun made full use of his GM-1 booster [Nitro injection] and kept his lead. At 27,000 feet my A.S. indicator showed 440 mph, i.e. a true speed of 600 mph. I had both hands on the stick and I leant on the controls with all my strength to keep the aircraft in a straight line. The slightest swerve would have crumpled up the wings. I felt my Spitfire jumping all the same, and I could see the paint cracking on the wings, while the engine was beginning to race.”
 

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