Early PR Spitfires

Hi All.
I am able to answer the question above following the BP Defiant route.
Thanks to Richard Franks at Valiant Wings Publishing who replied to me .

'Pretty sure this is the intake/exhaust for the starter motor that is
mounted on that side of the engine - the intake allows the air to be drawn
in at the front as the starter motor is used, then exhausted out the back -
in flight, the air just goes through it front to back'.

S Spitfire pr1v Well, I'm certainly no expert but I'm pretty sure the starter motor on the Merlin III, as with most other Merlins I've seen, was on the starboard side below the magneto. The motor was connected to an angle drive that also enabled a hand crank to be used to start the engine. The starter motor is seen below in this example of a Merlin III at the Science Museum in London (pic source Rolls-Royce Merlin III | Large Scale Planes). To 8 oclock of the red exhaust cover is the magneto (large cover in silver). Below the magneto you can see the circular drive unit for the hand crank (also covered in silver) and below that, in a dark aluminum colour, is the starter motor.



Logic would beg the question as to why a starter motor, which is used only for a few seconds at the beginning of a flight, would need its own dedicated air intake?

The location of the scoop that you refer to is very near the generator which, on the Merlin III and all others I've seen, is mounted on the port side. The link that I posted above shows this unit and, coincidentally, also mentions a cooling intake for it, though the intake would appear to be too far forward to coincide with the one in your picture.

Pictures of the various PR Is in The Spitfire Story by Alfred Price show the scoop present on the IC, IE, and IF but, oddly, the one picture from the port side of the ID shows no intake there. According to Price, the ID entered service after the E and F so apparently, something came up to warrant the deletion of the scoop.

I glanced through the "bible" - Morgan and Shacklady's tome - and I got no further on this.

You are right Crimea _River. Thanks for the really extensive research/info and photos.
I did some researching myself last night on the Merlin III and like you have come to the same conclusions as it not being the starter motor etc. I agree with you about the position of the extra intake on the port side.
The PRIVs (D) were factory fitted with Merlin 45s and were specifically designed and built as recon aircraft.
Oh dear, back to the drawing board.....
Perhaps we are back to cooling a larger generator or some specialist electrical kit needed for PR "converted" electrics, attached to the side of the Merlins III /XII?

Spitfire pr1v said:

You are right Crimea _River. Thanks for the really extensive research/info and photos.
I did some researching myself last night on the Merlin III and like you have come to the same conclusions as it not being the starter motor etc. I agree with you about the position of the extra intake on the port side.
The PRIVs (D) were factory fitted with Merlin 45s and were specifically designed and built as recon aircraft.
Oh dear, back to the drawing board.....
Perhaps we are back to cooling a larger generator or some specialist electrical kit needed for PR "converted" electrics, attached to the side of the Merlins III /XII?

Click to expand...

Or maybe it was fitted with a larger generator to drive the Defiant turret and PR spitfires being low volume used the same and they require the increased cooling whether you use a lot of power or not?

S Spitfire pr1v I assume that you are not a member at Britmodeller. If that's the case, if you go through the thread I posted earlier and can confirm that the question was not asked and answered there, I will post your question there. There are lots of pretty knowledgeable people on that site.

Crimea_River...Thanks . I did post a similar question on Britmodeller and got some response but nothing conclusive from one of the members, I thought the opposite to you and knew there are lots of knowledgable people on this site.