SUPERMARINE Spitfire —

Commemorative Spitfire at Colindale RAF Museum, London.

Placque says MK I -- problem is MK-I had a two blade, fixed pitch prop, no wing canons -- just the 303 machine guns.

Spitfire Mk I: http://www.airpages.ru/eng/uk/spitf1.shtml http://www.airpages.ru/eng/img/spit_2.shtml

Type code SPIT

Powered by a 990 hp Rolls-Royce Merlin C with DH two-bladed fixed-pitch wooden propeller, unarmed prototype K5054 first
flown at Eastleigh on March 5, 1936. Successively fitted with 1,035 hp Merlin F and 1,030 hp Merlin II and with full
armament of eight 0.303-in (7.7-mm) machine guns, before being written off on second day of World War II, September 4, 1939.

Supermarine Spitfire I: Initial production version, built to Specification 16/36; first contract placed June 3, 1936.
First aircraft flown May 14, 1938, with 1,030 hp Merlin II; Merlin III introduced at 175th aircraft. Early aircraft with two-bladed Airscrew Co wooden propeller; three-bladed metal propeller soon standardised - DH two-position, then DH or (few only) Rotol constant speed unit. Entered service August 1938 with No 19 Sqn at Duxford and nine squadrons operational by September 1939, with ten more by mid-1940. Designation Supermarine Spitfire IA adopted retrospectively in 1940

Even the big boys get it wrong.