A rather nice animation of the piston motion of a Merlin; although the crankshaft arrangement is pretty universal for a V-12 it is interesting to me how strange the motion of the centre four pistons looks when you actually see it.
By: MerlinPete - 11th June 2011 at 15:09
[QUOTE=Creaking Door;1757479]Sorry, with you now; you meant the Griffon crankshaft is different from the Merlin, not a different arrangement of throws. (And thanks for taking the trouble to post the drawings).
No, I meant the arrangement of the throws!
Have another look at the drawings.
The direction of rotation doesn`t determine the arrangement of the crankshaft, or the counterweights necessarily. The Rover Meteor uses the same crankshaft as a Merlin but rotates the opposite way.
Pete
By: Creaking Door - 11th June 2011 at 01:29
The Merlin and Griffon firing orders are completely different.
Yes, you’re right; I can’t get a similar firing pattern (ignoring numbers) no matter how hard I try (but it is late).
By: QldSpitty - 11th June 2011 at 00:53
Heres a Sakae 21
http://picasaweb.google.com/Shinpachi2009/Shinpachi3DCGWorksEnginesNakajimaSakae21
He also has some merlin stuff.
By: Creaking Door - 11th June 2011 at 00:52
Surely the firing order is effectively the same; just the numbers are different because of the different direction-of-rotation (and mirroring of the crankshaft)…..if you see what I mean?
By: Avro Avian - 11th June 2011 at 00:34
The Merlin and Griffon firing orders are completely different.
Merlin: 1A-6B-4A-3B-2A-5B-6A-1B-3A-4B-5A-2B
Griffon:1A-4B-3A-2B-5A-1B-6A-3B-4A-5B-2A-6B
Hence they sound quite different.
Check this out for other engines. 🙂
By: Creaking Door - 11th June 2011 at 00:31
Hard to explain, so here are the drawings!
Sorry, with you now; you meant the Griffon crankshaft is different from the Merlin, not a different arrangement of throws. (And thanks for taking the trouble to post the drawings).
The engines rotate in opposite directions for a start…
I knew about the different direction of rotation but despite that the overall arrangement of the crankshafts is identical (but mirrored?), and identical to the Junkers Jumo 210 and Daimler-Benz 600 and their developments. I wonder if there is any V-12 aero-engine that doesn’t follow this crankshaft arrangement?
By: RPSmith - 10th June 2011 at 20:16
I, and I assume all the other delegates, enjoyed a computer generated film of a Griffon internals operating at the RRHT AGM a couple of months ago – it was superb (sound as well).
Roger Smith.
By: Arabella-Cox - 10th June 2011 at 19:46
Merlin vs Griffon
The engines rotate in opposite directions for a start, CD.
Anon.
By: MerlinPete - 10th June 2011 at 18:35
Hard to explain, so here are the drawings!
There are also two different crankshafts for the Griffon, but I can`t remember how they differ, the 57/58 had a different one to the earlier versions.
It`s now 6:30 and I`m still at work, time to go home I think!!
Pete
By: Creaking Door - 10th June 2011 at 14:17
…the Griffon crank is different to the Merlin.
Really, how so? I’d assumed the Griffon was just a scaled-up (smaller ;)) version of the Merlin (with the camshaft drives at the front).
By: MerlinPete - 10th June 2011 at 14:12
Nice! I certainly can`t knock the detail, looks just right to me.
In theory there are at least three arrangements of V12 crankshaft, the Griffon crank is different to the Merlin.
I would guess that most or all automotive V12s use the same pattern as each other.
Pete
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June 10, 2011 at 1:58 pm