Written by Tiger April 25, 2006, 17:52:00 PM1359 ViewsRating: (1 Rates)Print
The Spitfire MkIII...
Next was the more significant, albeit, technical only development, the MkIII. Only one aircraft was ever built, really only as an experimental prototype for Merlin engine development.. The requirement, to produce more horse power at increased height, resulted in an engine with a two speed supercharger producing 1280 hp. Much later on, as part of a different development, a Merlin 61 was also fitted. The wings were 'clipped' thus the wingspan was reduced by 6 ft, the canopy was cleaned up for better streamlining. A retracting tail wheel was introduced along with minor other refinements which eventually found their way onto later Mk aircraft. The knowledge and experience gained with this aircraft was to come to fruition later on.
330 and 348
15th March 1940
30ft 6 ins ( 9.30 m ) (Clipped) 36ft 10 ins (11.23m) (standard)
30ft 4ins ( 9.25 m )
11ft 5ins (tip of prop. Tail down ) (3.48m)
Two-speed, single-stage 1280hp (954 kW) (plus 12 lb/sqin boost) Merlin XXI. Later tested with two-speed, two stage 1565 hp (1167 kW) Merlin 61.