Spitfire Mk. IX in Detail
The wing root fillet with solid leading edge visible here was not common for all Mk. IXs. Early production batches powered by Merlin 61 and 63 series engines had a relatively large circular air intake there serving the fuel cooler, a device used to prevent the fuel from boiling at the relatively high climbing speeds of the new fighter. The fuel cooler installation was identical as on the previous Mk. VII high-altitude version. It is not a widely-known feature as it was later removed and none of the surviving Mk. IXs seems to have it retained.
In the same spot, earlier Spitfire
marks had a smaller opening for a gun camera. Because of the
fuel cooler installation, it was initially omitted altogether on Mk. IXs,
and later on moved to the starboard wing fillet.
Close-up on the rear part of the
wing fillet. Note the different style of riveting compared to that on the
The streamlined fairing of the
wing-mounted Hispano cannon.
The abandonment of four-cannon option on the Mk. IX had two consequences. First, the "leftover" wing cannon mount resulted in the short stub outboard of the cannon barrel, plugged with a solid rounded tip. Later on, as it has been realized that the the second cannon bay will never be used, the stub was removed altogether, as seen on this photograph.
consequence was the shape of the upper wing blisters. These blisters were
introduced to provide sufficient room for the ammunition drums of the
Hispano cannon. Initially the "C" wing used a single wide
blister covering the twin cannon bay. As it was realized that only one
cannon was necessary, a new blister was introduced to the Mk. IX
production line. This blister was narrow and elongated, and can be seen on
the wing photograph in The Airframe section of this essay.
The Pitot tube was mounted under the port wing tip.
The initial production Mk. IX had the same undercarriage as the Mk. V and earlier marks. This early type is recognizable by five-spoke wheels and perfectly flat undercarriage covers.
The above photograph shows the mid-production type of undercarriage, which was an entirely new construction. The main legs were not only strengthened, but also raked forward at a steeper angle to counter the increased nose weight. The new four-spoked wheel featured a larger tyre.
Towards the end of the war,
production shifted to three-spoke wheel which can bee seen on many late
marks of the Spitfire.
Another new detail of the updated undercarriage leg
was a forward-facing scissor link over its oleo part - barely
visible here behind the wheel cover. Also the covers differed from the earlier marks,
having a distinctly bulged appearance, necessary as the thicker tyre could
no longer fit into the thin wing when retracted.
A peek into the starboard wheel
well, showing the compact undercarriage retraction mechanism.