Spitfire

We join Dave and Tabitha in Bath to celebrate their tenth anniversary+Dave's 4-0, which is later this year. One of many highlights is a fly-over of the beautiful Submarine Spitfire, pictured. It is one of 44 remaining, and ours the first plane to record a "kill" in the Battle of Britain. Dave's grandfather, who I stand next to during the fly-by's, repaired Spitfires during the war. He recalls the bullet holes that suggested the intensity, and seriousness, of those overhead battles. The Spitfire has a distinctive sound to accompany its unique and elegant design and I learn from our B&B that that drivers pull of the road to watch the spectacle. It is a rare thing indeed to see Britain's most revered aircraft in action.

The Spitfire began with RJ Mitchell's design to meet the Air Ministry specification for a new and modern fighter capable of 251 mph, which netted an open-cockpit monoplan with bulky gull-wings and a large, fixed spatted undercarriage powered by a 600 horsepower Rolls Royce engine. It made its first flight in '34, and despite being airborne, it was a big disappointment to the design team. That year, Mitchell decided to use an elliptical wing shape to solve two conflicting requirements; the wing needed to be thin, to avoid creating too much drag, while able to house a retractable undercarriage, plus armament and ammunition. Beverely Shenstone, the aerodynamicist on Mitchell's team, explained the wing's qualities:

"The elliptical wing was decided upon quite early on. Aerodynamically it was the best for our purpose because the induced drag, that caused in producing lift, was lowest when this shape was used: the ellipse... was theoretically a perfection .... To reduce drag we wanted the lowest possible thickness - to-chord, consistent with the necessary strength. But near the root the wing had to be thick enough to accommodate the retracted undercarriage and the guns... Mitchell was in intensely practical man... The ellipse was simply the shape that allowed us the thinnest possibly wing with room inside to carry the necessary structure and the things we wanted to cram it. And it looked nice."

(source: wiki)