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Merlin ignition timing variations

 
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smoore



Joined: 11 Jan 2011
Posts: 2
PostPosted: Wed Jan 12, 2011 18:37    Post subject: Merlin ignition timing variations Reply with quote
The R-R Merlin series II, III, IV and X engines' fully advanced ignition timing was 45 degrees BTDC, but on later configurations of the engine like the -22 and the -24 the exhaust ('B' bank) magneto is advanced by a further 5 degrees to 50 degrees BTDC, while the inlet magneto ('A' bank) remains at 45 degrees BTDC. Does anyone know the reason for this? Is it to avoid detonation by giving the exhaust side flame-front a definite lead over the inlet side's to avoid excessive compression of the unburnt charge in the hottest area of the combustion chamber?
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