[TomcatViP]

Originally Posted by Viper2000

Climb power for the Merlin XX is +9 psi at 2850 rpm. This is the most likely source of your +9 figure.

Pls take a close look at your doc - Merlin XX. I hve here maximum perf calibration with max speed being plotted. It does not look like anything like a climb setting

Oh and it does come from RR..

Originally Posted by Viper2000

Supercharger efficiency depends upon where you are on the compressor map.

I don't see the sense of what your wrote here. You might hve pasted half the sentence from your original doc here

physically given that the SC is accordingly dimensioned (flows and struct) , the heat generated is what will drive the overall efficiency. And what drive away that heat : the flow of air (or air mixture) that is pushed by the impeller blades.

Hence there is a max amount of calorific E that a s/c can work with. Raise the oct -> you'll reach sooner the the max sustainable value

This is why I said that Max boost level hve very little chance to be reachable at an alt where the impeller hve alrdy to compensate for lower air density if the eng was not designed for

etc... etc...

Originally Posted by Viper2000

What you find is that centrifugal impellers are pretty forgiving machines, and will operate over quite a wide range of flows and pressure ratios at any given speed without surging.

Modern supercharger : yes. At the time of BoB hummm that's a pretty acrobatic assumption

Originally Posted by Viper2000

The Merlin XX had a 2 speed supercharger drive gearbox, so 2 compromise speeds were available instead of 1 for the earlier engines. This allowed better overall performance, though it didn't have any direct impact upon peak power.

pls see the above

Originally Posted by Viper2000

In any case, it was an IP licensing thing rather than a case of Farman having specifically produced technology with the Merlin in mind.

I wld hve been pls to see a Farman 220 with 4xMerlins. Damn just to see that huge parasol wing being blown away by the engines airstream

By the way, most patent are cross border documents. There is no shame using a Patent from an other country. Aviation is full of this. let us remind that if Aviation pioneer did not get inspiration from each other all over the world, we wld still cross the pound on steaming boat.

Originally Posted by Viper2000

Merlin without supercharger = Meteor. It would give something in the region of 650-850 bhp. It's quite hard to be concrete because Meteors were generally reconditioned (ie crashed, non-airworthy) Merlins and so they were never going to perform "as new".

Supercharging the eng was meant to keep power at alt (the rated alt) and increased the fighter perfs (smaller engine) where the bomber stream were expected . This is not NHRA supercharging although a direct benefit were a low perf improvement and climb rate to alt.

I hve arldy quoted the Merlin XX data with and without s/c (your 12lb thread)

You'd see that the s/c being driven by the eng shaft use a 7 to 20 % of eng power. Hence teh 1.3k SHP and 1.175k BHP or something like that

Anyhow, the team that did code those FM game have proved superior man skills in the field. I am looking frwd for the next released giving they can work without too much pressure away from 1C SC
(read Spit Complex )
~S