Hello all,
I tried this inquiry first on Britmodeller, but didn’t get very far, so I’m trying it out on you lot!
Can anyone fill some gaps in early Merlin numbering? Here’s what I’ve got:
I – original production type, used only in Fairey Battle (?)
II – first major production: Hurris, Spits, Battles, etc [Note, I’m not really concerned about production applications, just including for reference]
III – improved II, universal shaft to take either Rotol or DH variable-pitch props
IV – I’ve seen mention in relation to (some) Whitley IV production, unless that was an error?
V – ?
VI – ?
VII – ?
VIII – Coffman starter, for Fulmar
IX – ?
X – first 2-speed supercharger version
XI – ?
XII – 100 Octane “developed III”, Coffman starter, used only in Spit Mk.II, though some consideration (during 1939) of use in Hurricane
any “teens”?
XX – 100 Octane, 2-speed supercharger (improved blower)
Let’s stop there, in order to keep it somewhat manageable. Note that the designation “Merlin XX” seems to first appear in May ’40, so that gives us an end-date to work with. I’m thinking there may have been a jump from X (or XII) to XX, but I imagine the earlier numbers were at least potential variants, otherwise I don’t see how we’d end up with VIII and XII. I have observed that numbering was somewhat fluid, so that during planning/development they might refer to a configuration as one number (Merlin 22) but while firming up production plans it might become another number (Merlin 60). I have intentionally not brought in the other system (RM3SM, for example) but if anyone cares to elaborate on that it’s fine by me!
Thanks,
bob
By: Versuch - 3rd July 2012 at 04:19
Merlinpete…you nailed it …two breathers on the other side.
The best bit is I bought from old postcard and stamp shop…
asked If he had anything aviation related…he walked out
the back and returned holding it saying…Something Like This!
You just never know.
Cheers Mike
By: MerlinPete - 2nd July 2012 at 14:36
I was told this was ex Battle….I dont know how they knew, its
just the rocker cover…is it?
D32963 is an A bank cover for engines produced after 1945, when they reintroduced the Rolls-Royce name on them.
It has two breather ports on the opposite face, which were not present on early ones.
You were right in thinking you can`t tell which specific mark of engine a basic rocker cover was used on if you have no other information.
Makes a change from being told it`s Spitfire anyway.
Pete
By: Arabella-Cox - 2nd July 2012 at 14:21
I was told this was ex Battle….I dont know how they knew, its
just the rocker cover…is it?
Later mark. Battle would have an early Merlin mark, with a 4-digit D number.
By: HP111 - 2nd July 2012 at 13:59
“British Piston Aero-Engines And their Aircraft” devotes around 16 pages to the subject. Not sure how easy it is to get hold of a copy these days.
It fills in your list slightly, for instance:
Merlin V
Converted MkIII with a non-standard propellor shaft. Used on Hawker Henley.
By: Versuch - 2nd July 2012 at 13:37
I was told this was ex Battle….I dont know how they knew, its
just the rocker cover…is it?
By: Seafire - 2nd July 2012 at 12:11
Letters and numbers
Right, the initial development configurations ran through the alphabet to ‘G’ at least. But it is the “production”* Mark numbers I’m specifically wondering about. (Hmm, that makes three systems used on the Merlin at one time or another…)
* By production I mean that system, not versions actually put into production.
Thanks,
Bob
By: knifeedgeturn - 2nd July 2012 at 11:48
They started off using letters A,B,C etc.
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July 2, 2012 at 11:11 am