Spitfire III - questions

[Graham Boak]

The Spitfire Mk.III was designed to take the Merlin XX, as this was expected to be the standard next-generation Merlin. I know of no reference suggesting the prototype first flew with any other engine, although the Merlin X was discussed for early production aircraft in the case of delayed production of the Merlin XX.

The wings were clipped by 3.5 feet of each tip, giving a quoted span of 33ft 8in. Following disappointing flight trials, the aircraft was refitted with a standard wing, but by then the decision had been made to cancel production. This was partially due to the number of changes required to fit the longer engine into the Spitfire, including changes in the undercarriage geometry, which would lead to lower production numbers. (The Mushroom Monthly book is wrong is suggesting the Mk.III was the same length as standard Spitfire.) Many of the lesser improvements suggested for the Mk.III found their way into later production Mk.Vs.

Look in Spitfire The History for a fuller history of the Mk.III.