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

[Crumpp]

the "maximum continuous rating" of every engine as the design goal

It is the design goal. Maximum continuous is the power the engine is designed to develop and maintain.

It represents 100% of the power capability of an aircraft engine. Anything over that is an overload condition and will shorten the life of the engine.

Typically you see overload capability in take off ratings, sometimes climb ratings, and in emergency ratings.

It is the power the engine can produce at 100% capability that is the primary focus.

[NZtyphoon]

Originally Posted by Crumpp

It is the design goal. Maximum continuous is the power the engine is designed to develop and maintain.

It represents 100% of the power capability of an aircraft engine. Anything over that is an overload condition and will shorten the life of the engine.

Typically you see overload capability in take off ratings, sometimes climb ratings, and in emergency ratings.

It is the power the engine can produce at 100% capability that is the primary focus.

Originally Posted by 41Sqn_Banks

However I don't think Crumpp claims that the Merlin was limited to +4 1/2 boost at any time, if he does he will certainly provide a document to support this claim. I think he consider the "maximum continuous rating" of every engine as the design goal and uses this value to compare different engines. He's free to do so. Others consider the maximum power, and some may use the takeoff power. It doesn't matter, the engine remains the same.

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

Originally Posted by Crumpp

You are talking about running the engine at 3 times its original design maximum capacity. Really guy? You think just changing the fuel did that?

I asked:

Originally Posted by NZtyphoon

So you think the Merlin was designed to run at about 400 hp?

Originally Posted by Crumpp

If that is what the engine produces at maximum continuous...YES.
Get a Spitfire Mk I POH and read the maximum continuous rating. That is the maximum power the engine is designed to safely and reliability produce.
Mixture control Normal = +4 1/2 lbs at 2600rpm

So he is trying to claim the Merlin III's maximum designed continuous power rating was +4 1/2 lbs at 2600rpm, and about 400hp.

[41Sqn_Banks]

Originally Posted by NZtyphoon

So he is trying to claim the Merlin III's maximum designed continuous power rating was +4 1/2 lbs at 2600rpm, and about 400hp.

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. Sometimes Minimum Take-off Rating (this is at maximum allowed take-off boost with minimum allowed RPM, which is only important for fixed propellers).

Maximum continuous rating (1,15ata 2000 PRM) of DB601A was 810hp (@0km) to 860hp (@5km). As the maximum output is almost the same we can assume that the Merlin has a comparable power at continuous rating.

Here is the (not so serious) protocol from the design meeting at Rolls-Royce when they thought about their new high performance fighter engine. Engineer A is a daredevil, he likes fast, loud and dangerous stuff. Engineer B is a square and a careful engineer, he likes reliably stuff.
Engineer A: "I think with that design we should get 1,100hp maximum output. That's a great improvement compared to the 700hp of the Peregrine. Image how fast our fighters will fly with that. What do you think?"
Engineer B: "Hmm ... yes this should give about 800hp at a reasonable engine life of 100 hours between overhaul. I'm cool with that."
Engineer A: "Yeah whatever ... So we define our design goal as 1,100hp maximum and 800hp continuous output. Deal?"
Engineer B: "Deal! Let's do it!"

Later at Air Ministry ...

Engineer B: "This is our new engine design. We estimated it will will produce 800hp ..."
Engineer A: *facepalm*
Air Ministry: "What? The Germans build engines with 1000hp maximum output! You are useless!"
Engineer A: "May I interrupt? The 800 hp is the continuous rating, the maximum output will be 1,100hp."
Air Ministry: "... OK now that sound good. We want 900 engines delivered in 3 month. ... Oh and next time just tell me the maximum output. At Air Ministry we like fast, loud and dangerous stuff."

While leaving Air Ministry ...

Engineer A: "I told ya!"
Engineer B: "..."

[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.

[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?

[winny]

Originally Posted by Osprey

ISBN number please?

Britain's War Machine: Weapons, Resources and Experts in the Second World War - David Egerton
Hardcover: 464 pages
Publisher: Allen Lane; First Edition edition (31 Mar 2011)
Language English
ISBN-10: 0713999187
ISBN-13: 978-0713999181

It's on Amazon.
EDIT:
Here's the page I was refering to.



It then goes on to explain the sources of this fuel.
Kurfurst will hate it but the stock figures are from Gavin Bailey's paper..

[Crumpp]

I don't know where you are from Crump but there's no such thing as a standard day in England.

All - righty then....

[Kurfürst]

Originally Posted by winny

Kurfurst will hate it but the stock figures are from Gavin Bailey's paper..

Actually I like Gavin Bailey's paper.

It says 100 octane was introduced to 'select' Squadrons in May 1940, and I cannot find any statement or reference in it or anything that would support the every-last-Hurricane-even-in-Northern-Scotland-was-running 100 octane theory.

Though as others has noted the paper is more concentrating on dispelling the 'myth' of dependency of US 100 octane fuel supplies, argues to downplay the significance of extra performance of 'US 100 octane' versus the extra performance by the addition of 'pure British' CSP units, and has overall quite a bit of anti-american tone, perhaps due to nationalistic grievance about the UK becoming a sort of a US satellite state after the war.

Of course here I refer to real Gavin Bailey, not the forum nick registered 'gbailey' who turned up very shortly after NZTyphoon's arrival, who refused to confirm his identity upon request, refused to respond to direct questions, and claimed that the only 100 octane fuel the Germans had in the BoB was from captured British stocks eventually went ape and behaved in such a childish fashion - much like for example as if he were a university student in his 20s and pretending to be someone else - that the thread had to be closed and his posts had to be moderated.

[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: