Mustang X

In 1942, Rolls-Royce converted four Mustang Is into Merlin testbeds. I have seen drawings and photographs of these aircraft, but I still have some questions.
First, does anyone know if these were known as the Mustang X as in "experimental" or as Mustang "ten" as in the Roman numeral?
Second, what was the purpose of the enlarged nose intake? Did it house a supplemental radiator or an enlarged oil cooler or ducts for the Merlin's supercharger or a combination of these?
Third, the propeller and spinner appear different from those used on production Merlin Mustangs. To me, they look a lot like the units used on the Spitfire VIII or IX.
I'd appreciate any information anyone might have on these points.
Reply to
Loading thread data ...
formatting link

formatting link

"Rolls-Royce Mustang Mk.X
Five prototype conversions only two Mustang Mk.I airframes were initially trial fitted with Rolls-Royce Merlin 65 engines in mid-late 1942, in order to test the performance of the aircraft with a powerplant better adapted to medium/high altitudes. The successful conversion of the Packard V-1650 Merlin-powered NAA P-51B/C equivalent rendered this experiment as superfluous. Although the conversions were highly successful, the planned production of 500 examples was cancelled."
Reply to

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.