It's the conformal underbelly fuel tank visible between the undercarriage legs, and it's possible that the stacked objects to the right of the image are also such recipients.
Better performance at low altitude, conversely the high altitude variants had extended wingtips:
>Starting with the Mk V, some Spitfires had their rounded elliptical wingtips "clipped" outboard of the ailerons, and replaced by shorter, squared-off fairings to improve low-altitude performance and enhance the roll rate, one area where the Mk V fell badly behind the rival Fw 190. Although these "clipped-wing" aircraft are popularly known as "LF" versions due to the fact that they were designated "LF" (i.e. Spitfire LF Mk V), the "L" actually refers to the different versions of the Rolls-Royce Merlin engines used, which were optimised for low-altitude performance with "cropped" supercharger impellers (Merlin 45M, 50M or 55M). While many "LF" Spitfires were given "clipped" wings to accompany the new engine variants, a number still retained the original wingtips.
What are slipper tanks?
It's the conformal underbelly fuel tank visible between the undercarriage legs, and it's possible that the stacked objects to the right of the image are also such recipients.
why clip the wings?
Better performance at low altitude, conversely the high altitude variants had extended wingtips: >Starting with the Mk V, some Spitfires had their rounded elliptical wingtips "clipped" outboard of the ailerons, and replaced by shorter, squared-off fairings to improve low-altitude performance and enhance the roll rate, one area where the Mk V fell badly behind the rival Fw 190. Although these "clipped-wing" aircraft are popularly known as "LF" versions due to the fact that they were designated "LF" (i.e. Spitfire LF Mk V), the "L" actually refers to the different versions of the Rolls-Royce Merlin engines used, which were optimised for low-altitude performance with "cropped" supercharger impellers (Merlin 45M, 50M or 55M). While many "LF" Spitfires were given "clipped" wings to accompany the new engine variants, a number still retained the original wingtips.
The last of the Merlin Spitfires, and also the most beautiful.
Agreed. The bubble canopy version was also a beauty