Inaccurate performance data for BOB fighters in COD comparing to RL data

[lane]

Originally Posted by 41Sqn_Banks

I don't know if power at maximum continuous rating was 400hp, I've never seen a value for it. Rolls Royce always give International Rating, Maximum Rating and Maximum Take-off Rating.

Test certificates on fairly early Merlin II/III running on 87 octane show:

Rated power 990 b.h.p. at 2600 r.p.m. 12,250 feet at 6 1/4 lbs/sq.in. boost
Maximum power 1030 b.h.p at 3000 r.p.m. 16,250 feet at 6 1/4 lbs/sq.in. boost

The power curves at 12,250 feet give 829 b.h.p. at +4.2/2400 with Merlin II No.2855 and 822 b.h.p. at +4.2/2400 with Merlin III No.7491.

Merlin II installed in K.9787

Merlin III installed in N.3171

See also Merlin II & III ratings as shown in the The Merlin in Perspective, (Rolls-Royce Heritage Trust, Derby, 1983)

[41Sqn_Banks]

Power curves of Merlin XX:

[Crumpp]

Not so long ago Crumpp claimed that the Merlin was only capable of generating 400hp...


Quote:

Baloney, re-read what I wrote. IF that is what it produced at maximum continuous...

Operative word being IF....

In the english language, IF denotes a conditional clause or supposition.

As for posting any pages, I am on a laptop. My old Desktop is getting repaired and going to my daughter. I have a new desktop being built but it will be a week or so before it is ready.

[Crumpp]

If you look at Banks chart, you will see that Merlin XX is a ~625 hp at 4 1/2 lbs at sea level on a standard day.

On a summer day, it would considerably less at ground level on most airfields in England.

Why? Engine power is a function of atmospheric density. That is why superchargers were invented to slap a band-aid on that fact to try and overcome it.

Of course, some one will stand up to defend their gameshape and think I am slighting their favorite cartoon.

NO, I am only pointing out that Banks chart is a good one for you guys to understand how engines work in airplanes. It is a fact that the 100% power capability of the Merlin II and III is 4 1/2lbs MS gear as listed in all the Pilots Operating Notes.

[Robo.]

Originally Posted by Crumpp

NO, I am only pointing out that Banks chart is a good one for you guys to understand how engines work in airplanes. It is a fact that the 100% power capability of the Merlin II and III is 4 1/2lbs MS gear as listed in all the Pilots Operating Notes.

If you intend to stick to this logic that's fair enough. As long as the engines in the sim produce correct amount of power at either of these settings used in real life, e.g. +6.25lbs. or +12lbs. as it is the case of early Merlins, I am happy.

MS gear is not Merlin II or III related btw. No matter how you look at it, the final result is exactly the same. And so is the reality that at this moment, what the title of this thread says is true, unfortunately.

[41Sqn_Banks]

Originally Posted by Robo.

If you intend to stick to this logic that's fair enough. As long as the engines in the sim produce correct amount of power at either of these settings used in real life, e.g. +6.25lbs. or +12lbs. as it is the case of early Merlins, I am happy.

MS gear is not Merlin II or III related btw. No matter how you look at it, the final result is exactly the same. And so is the reality that at this moment, what the title of this thread says is true, unfortunately.

Yes it's all fine. Changing the definition doesn't change the engine.

+4.5 is 100% ...; +6.25 is 108% ...; +12 is 138% of "maximum continuous" boost
+4.5 is  92% ...; +6.25 is 100% ...; +12 is 127% of "all out/climb/take off" boost
+4.5 is  72% ...; +6.25 is  79% ...; +12 is 100% of "emergency" boost

[Osprey]

Originally Posted by winny

There's a book called "Britains war Machine" that I found last night. It contains a section devoted to the supply, use and production of 100 octane fuel.

It explains the whole Trimpell (Trinidad - ICI - Shell) refinery set up and says that the "shortage of 100 octane is a myth"

It's available as an e-book.

ISBN number please?

[Osprey]

Originally Posted by Crumpp

If you look at Banks chart, you will see that Merlin XX is a ~625 hp at 4 1/2 lbs at sea level on a standard day.

On a summer day, it would considerably less at ground level on most airfields in England.

Why? Engine power is a function of atmospheric density. That is why superchargers were invented to slap a band-aid on that fact to try and overcome it.

I don't know where you are from Crump but there's no such thing as a standard day in England. We have a hosepipe ban here, yet as I write it's chucking down a ton of rain - typically British.

According to your logic the German engines are also affected, so they must be producing loads of power over in standard France but by the time they arrived in sunny England they were down to a couple of hundred HP.

[41Sqn_Banks]

Originally Posted by Crumpp

If you look at Banks chart, you will see that Merlin XX is a ~625 hp at 4 1/2 lbs at sea level on a standard day.

I don't think you are reading the chart correctly. If you following and extending the line of +4.5 boost to sea level the rpm is decreasing at the same time which gives lower bhp.

However I've found a better source for the power of Merlin XX. It has a max. economic cruise rating of +4 boost and 2,650 rpm which gives 800bhp at sea level and 900bhp at FTH MS gear. Reference: http://www.wwiiaircraftperformance.o...x-curve-c1.jpg

So even if we assume that the Merlin III and XX are comparable (I wouldn't do it, to much guesswork in it but anyway ...) this would give for the Merlin III between 800 and 900bhp (which is achieved at lower boost but slightly higher rpm) from sea level to FTH, which is supported by the 830bhp (which is achieved at lower boost and lower rpm, so actual power is higher) given by lane.

BTW: The Maximum cruising rating is +7 boost and 2,650 rpm which gives 1000bhp at sea level and over 1100 at FTH MS gear.

[Seadog]

Originally Posted by Crumpp

NO, I am only pointing out that Banks chart is a good one for you guys to understand how engines work in airplanes. It is a fact that the 100% power capability of the Merlin II and III is 4 1/2lbs MS gear as listed in all the Pilots Operating Notes.

What complete $#^&%@!

100% power is full throttle, full boost, just like any IC piston engine.