Wasn't an FR Mk IX just a conventional, armed Spitfire Mk IX with an oblique camera fitted, rather than a full-on PRU job? I can't think why the cockpit would be laid out any differently
The significant role designator FR, for Fighter Reconnaissance, implies that the aircraft carries defensive armament as apposed to PR, for Photo-Reconnaissance, which are unarmed. The main role of the FR type is tactical reconnaissance flying at low and medium altitude where it is thought more likely they would encounter enemy fighters, hence the reason for retaining some defensive armament.
A number of examples of what is known as the FR.IX were produced. They were mostly modified in the field to undertake the tactical reconnaissance role. Several examples were flown in France, Holland and Germany during late 1944 and into 1945. Used for low and medium altitude photography below the cloud base they were painted pink. Each was equipped with a single camera looking to port and retained four machine guns in the wings.
Before any PR.XIs were produced, a number of F.IXs were modified by removing their armament and installing photographic equipment similar to the PR.IV. At least three existing F.IXs, BS338, BS339 (F.Vs converted to F.IXs by Rolls Royce at Hucknall) and BS473 were equipped with camera systems at Vickers Armstrongs' Worthy Down facility during October 1942. BS338 was delivered to 541 Squadron on 30th November 1942. Subsequently 15 F.IXs were similarly converted on the assembly lone. They probably all had the enlarged oil tank under the nose but lacked the wet-wing tanks and needed to carry external fuel tanks to extend their range. These aircraft were designated PR.IX (factory type 374). BS497 was the first of these. Apart from the 15 converted F.IXs, a single PR.IV (EN263) was apparently modified to PR.IX standard. The most famous PR.IX missions were the preparations for 617 Squadron's Dambuster raid. During February and March 1943 the first PR.IXs entered service in the Mediterranean, EN153 was the first to reach Malta. Eventually all these PR.IXs were converted to PR.XI standard.
When the Mk IX was introduced in 1942, the R3002 IFF set was fitted as standard on all fighters. This used two aerials located between the tips of the tailplane and fuselage. In early 1943 the IFF system was changed. Modification 801 dated 12th January 1943 contianed the instruction to introduce R3067 (radio) MK. III IFF (all marks). Photographs show the old system remained in use until mid-1943. After that a single rod aerial was fitted under the starboard wing near the aileron.
FR.IX MK716 'X' of 16 Squadron. Painted pale pink, the serial number and 'X' were probably Roundel Red.
16 Squadron Spitfires at Bayeux, autumn 1944. In the foreground FR.IX MK915 'V'. Painted pale pink and fitted with a 50 gallon torpedo tank. In the background PR.XIs in PRU Blue Individual aircraft letters appear to be applied in white on all the Spitfires.
Enlargement shows IFF rod aerial.
EN149, one of the 15 F.IXs converted to PR.IXs. Similar in appearance to early production PR.XIs and often confused with them, the fixed tailwheel gives it away.
