Merlin Differences / Performance

[R Cubed]

How were the HP increases achieved in the different models of Merlin, I am aware that there was different octane ratings and that the water/glycol % of coolant allowed for a cooler engine rather than 100% glycol made a difference.

Were there any mechanical engine alterations Compression Ratio ? ignition timing ? valve size changes ? Supercharger pressures ? different cams ect and how did this affect the engine performance.

[Rich W]

Lots of small changes to the shape of the cylinder heads and other parts, but the biggest power gain was in the supercharging. There was a redesign of the shape of the impeller and it's ducting which made it more efficient. It was then again changed to make it a two stage two speed supercharger - which gained it 300hp at 30,000ft.

[Pzkpfw-e]

IIRC, the Merlin 61 introduced the 2-stage supercharger.

http://www.wwiiaircraftperformance.org/merlin-lovesey.pdf

Any use?

[Topdog]

Thinking of making the 105 into a self propelled gun are you? Just strap a Merlin to it.

[R Cubed]

Thinking of making the 105 into a self propelled gun are you? Just strap a Merlin to it.

 

 

Now now come on that would be silly :cool2:

[R Cubed]

Lots of small changes to the shape of the cylinder heads and other parts, but the biggest power gain was in the supercharging. There was a redesign of the shape of the impeller and it's ducting which made it more efficient. It was then again changed to make it a two stage two speed supercharger - which gained it 300hp at 30,000ft.

 

The shape of the cylinder heads, is that when they changed the valve steam angle from the 45 deg valve angle to the flat head so the valve steams were parallel to the cylinders ?

[R Cubed]

Were any of the later Merlin parts which did not meet air worthy standards get used for the Meteor range of engines ?

[Adrian Barrell]

The first Meteors were built from sub-standard and reworked Merlin parts.

 

I have found Packard Merlin banks on Meteors so parts certainly got used but that would only have been early on, once Rover took over production it was probably all Meteor only production.

[Richard Farrant]

Were any of the later Merlin parts which did not meet air worthy standards get used for the Meteor range of engines ?

 

If you want to learn more about the development and production of Meteor engine, then you should seek out a book published by the Rolls Royce Heritage Trust, No.35 in their Heritage Series, called "The Rolls Royce Meteor - Cromwell and other applications".

[Rich W]

The shape of the cylinder heads, is that when they changed the valve steam angle from the 45 deg valve angle to the flat head so the valve steams were parallel to the cylinders ?

 

I don't know as all my dealings are with it's bigger brother the Griffon.

 

I do know that various design of cylinder head are more sought after if you want more power, with the 500 series and later Merlin heads being the most sought after. RR were after a good chunk of the civil market and kept developing the engine post war for power and longevity.

 

Regards,

 

Rich