Terminology and engine data

[sibboh]

I'd like to open a new post. I don't know if there was a similar discussion in the past. But i'm new in this forum.

The argument could be summarize:
"Terminology (and meaning) of engines data in different languages and countries"

The problem is very important for interpretations about:
aircraft performances
tecnical history
research history
political history (how elite chose to finance, or not, research... in one or different branch)

Infact in the past when i read something about aircraft performances i didn't understand why some fighter had an engine with great power output but the same or worst performances than fighter with an engine with lower power output. So i began to study engines data. In Italy there are very few data about engines. Also for italian engines. And many aircraft historians use the engines data incorrectly. Only one example: when many authors write about Me109E they supply the extreme engine power output for DB601: 1175 PS, but this is limited for only takeoff and 1 minute. Instead if they write about italian aircraft with italian engines, they supply the normal continuos power output! Like for Isotta Fraschini Asso XI (then L.121) with 900 cv (not hp) normal continuous engine power output.
This is a similar difference between running and walking, or between fondle and beat!
I began to collect data. But i found terminology differences. But also different meanings. For example for the power output endurance.
The Merlin normal power output (International rating. Is there an exact definition about international rating? Is it endurance decisive in definition?) i found that could be used for 30 minutes for the first versions or 1 hour in the following versions.
Germans were very accurate, and there are more data about power endurance. Italians used (and use) expecially normal continuous power (but when they write about engines from other countries they use emergency power without explaining limitations). French terminology is similar to italian terminology. US and british terminolgies are similar (even not the same).
So i'd like to bring order about that. And i like possible help from other people.

Here below different terminology. And i post an example. There are errors yet. And i use cv, meters and atas and not bhp, feets, psi or mmhg. But i have other versions (these are incomplete yet). It's important to create a system to collect and compare data.

View attachment Radial WWII 38,67 L 87 octane engine.pdf


English terminology:

W.E.P. (War Emergency Power)
Emergency
Emergency maximum
Take-off or T.O.
Maximum output
Combat power rating
Military
Rated
Rated output
Climbing
International rating
Normal
Cruising
Cruise
Continuous maximum
Maximum climbing conditions
Maximum cruising conditions
Climb Combat
Max. Cruising
Economical Cruising

German terminology:

Höchstzulässige Dauerleistung
Wirtschaftliche Dauerleistung
Sondernotleistung (W.E.P. ?)
1' erhöhte Kurzleistung
Abflugleistung
Startleistung (take-off output)
Kurzleistung (short-term output/rendimento di breve durata)
5' Kurzleistung
Kampfleistung (combat output/rendimento di combattimento)
30' erhöhte Dauerleistung
Dauerleistung (continuous output/rendimento continuo)
Sparsamer Dauerflug (cruising/crociera)
Höchste Dauersparleistung
empfohl. Reiseleistung (sparsamer Dauerflug)

abflug = partenza, decollo/take-off
leistung = prestazione, rendimento, performance, potenza/output, performance
am boden beim abflug = a quota zero al decollo/take-off at zero (at ground level, at zero quota)
in bodennahe = a quota zero (a livello del suolo)/at zero (at ground level)
dauernd = costante/continuo = continuous
Notleistung = massima di emergenza/ maximum emergency
Abflugleistung = rendimento al decollo/take-off output
Kurzleistung = potenza a breve (termine)/short-term power
kampfleistung = potenza di combattimento/combat power
Sondernotleistung = Potenza di emergenza speciale = special emergency power
Höchstzulässige = massimo/a = maximum
Dauerleistung = potenza continua/continuous power
Sparleistung = potenza economica (di risparmio)/ economic power (saving?)
Wirtschaftliche = economica
Dauerflug = durata di volo/endurance
Sparsamer = economico
Sparsamer Dauerflug = volo continuo economico/ economic cruise

Example:
Pressure Pressure
ATA (DB 605DB) ATA (DB 605DC)
At ground level:
Sondernotleistung 1,80 1,98
Start- u. Notleistung 1,80
Steig- u. Kampfleistung 1,45 1,45
Höchstzulässige Dauerleistung 1,35 1,35
Sparleistung 1,15 1,15
Leerlauf --- ---

At altitude:
Sondernotleistung 1,80 1,98
Start- u. Notleistung 1,80
Steig- u. Kampfleistung 1,45 1,45
Höchstzulässige Dauerleistung 1,35 1,35
Sparleistung 1,15 1,15
Notleistung --- ---

 

[tomo pauk]

I cannot but congratulate you for the effort to tabulate the data. What kind of help do you need - the data is easy to find about US, UK, Japanese, German and Soviet engines. Not so easy on French and Italian.

About the nomenclature:
-'Notleistung' (last of the German power regimes you've listed) is a 'part' of "Start und Notleisdtung"
-'Sondernotleistung' is the 'Notleistung' with anti-detonant injection, whether MW-50 or C3 is used as ADI; US equivaletn being 'WER wet' for liquid cooled engines, and WER for air-cooled engines
-'Emergency' and 'Emergency maximum' should be equivalents of 'Military', mostly seen on early war engines, prior the certification of WEP rating started
-'Combat power rating' is, in most cases, equivalent of WER
-there was also 'WER wet', the US term applicable for liquid cooled engines using ADI (used in P-63 in ww2,); despite using ADI, the WER rating was never termed as 'WER wet' for the air-cooled US engines. The liquid-cooled US engines have had WER (we might call it 'WER dry'), lower power than 'WER wet'.

 

[sibboh]

Thanks, tomo pauk! And thanks for definitions... I know only WEP.
The situations is more complicated than i thought!
But kampfleistung, for example, was a combat power. But limited to 30 minutes, and not like Allied military output, generally limited to 5 minutes. These are problems. And i think to reality. It was very important during dogfight.
Well, i have other data tables, even if i'm interested principally in the period between the late '30 and the beginning of WWII, 1943 for the end. Probably because Italy loose the war in 1943. But also because i want to see the state of art at the beginning of the war. The whole developments during the war it depends on the knowledge at the and of 1930s.
I need a great quantity of data. Expecially time endurance in different engine output conditions. But i have time. It's a long term work, for me.
I know, for example, that some power output could be used only for 1 minute, other for only 3 minutes, 5 minutes, 30 minutes etc... And I want also understand the real continuous (without limits) power output. Italian engines lacked for great emergency and combat power. Or there aren't data about this. But i've seen that continuous power output weren't so different. Apart for availability of high grade octane fuels. Allied engine were more racy (i don't know is the word is correct... sorry for my english). Expecially respect to italian engines. But basal output (continuous) are similar. In the table about european radial engines with 38,67 l displacement we can see that english Bristol Hercules have highest rpm at take-off and emergency or combat conditions. But only for a short time.
I need expecially time limitations. Pressure at different conditions etc...
I need a definition about "International rating". Is there an exact definition about international rating? Is it endurance decisive in definition?
The work is very gigantic! But for me, almost in Italy, is very important. And could be help everyman interested in aviation. Because if i had problems to understand some data, i think the same for the others aviation fans.

 

[tomo pauk]

The 'Kampfleistung' is a 'part' of 'Steig und Kampfleistung', ie 'Climb and Combat power'. Therefore it is not an direct translation of any term in English language. Both the RPM and manifold pressure were always lower than at 'Start und Notleistung' (= 'Start and Emergency power'). Hence the big difference at duration (30 vs. 5 or 3 minutes).
We have no engine rating of US or British engines that is a 100% equivalent to the 'Steig und Kampfleistung'?

US engine data (many engines were in prototype stage, though):
http://www.enginehistory.org/ModDesig/SecI.pdf
DB-601/605 engines:
Kurfurst - Your resource on Messerschmitt Bf 109 performance
Japanese engines are discussed several times in this sub-forum, and there are translated tables also available here.
The data for plenty of British engines can be found at:
WWII Aircraft Performance
I'll try to dig out the translated data about Soviet engines, and for BMW-801 A-C-D-S.

 

[JtD]

We have no engine rating of US or British engines that is a 100% equivalent to the 'Steig und Kampfleistung'?

Actually, the British usually gave a "climb" rating for their engines, usually limited to 30min - 1 hour. Imho this is 100% equivalent, it even shares the name. It should be mentioned that this roughly translates to "rated power" as used in US documents, which can be seen when you compare British and US manuals for the same type. The Soviet in their lend lease aircraft / engines typically referred to this setting as "nominal power", as did the Japanese if the translations are to be trusted.

 

[tomo pauk]

From Spitfire V manual, available in this forum:

The 'Climb' power is allowed for an hour, yet, the 'Combat' power is allowed for 5 minutes, while featuring far higher boost and 5% more RPM. So the German term 'Steig und Kampfleistung' (Climb and Combat power) does not have a direct British equivalent in name and duration? The 'Combat' rating being the equivalent for WER. Eg. 67in of MAP was war emergency rating for the V-1650-3:

Now, the British do not have the direct equivalent for US term 'military power', in this case 15 min rating at 61 in MAP.

The US engine tables use term 'normal rated' as the equivalent for 'maximum continous', ie. no time limit.

 

[tomo pauk]

Soviet Klimov engines, BMW-801 D and -C (note that ram effects the altitude and power).

added: some radials, Soviet data.

 

[tomo pauk]

The Japanese engines have their own sticky topic in this sub forum, and quite the job have members done about that

The BMW-801A, from Do-217, Aug 1941:

 

[sibboh]

WOW!!! An incredible amount of data!!! Thank you very much, tomo pauk and JtD! I also have a lot of data. But I have to rearrange them.
Infact i already know kurfurst.org and WWII Aircraft Performance
I have also "US engine data" (www.enginehistory.org/ModDesig/SecI.pdf). I don't know how to quote (mention) it. For bibliography...
But i didnt know the following data that you have posted. I will read them slowly and carefully!
I have other problems at ht e moment. And first of all i want to show them.
In "US engine data" i noticed that for Packard V-1650 (RR Merlin) there are continuous output ratings. They are around 1000 bhp (with a maximum of 1200 for V-1650-23). And with 100/130 grade fuels.
I think that there is a mistake for V-1650-1 with 1800 bhp continuous. Infact it's higher than take off and military, but it's absurd. Probably it's a typing error, and i think that the real number was 1080 bhp. It might be likely.
But what i want to tell it's another thing. I have different Merlin data from Manuals (from Merlin II) and from "British Piston Aero-Engines and their Aircraft" written by Lumsden.
In this very important (at least for me) publication i found many informations. But, at least for Merlins, there is no continuous power output informations. I know RPM and boost. The same for Merlin II and III manuals. British were not interested in that information. In "US engine data" instead there aren't infos about combat Merlin conditions. So I crossed the data. But i lacked for the first Merlin versions.
About V-1650-1 (similar to Merlin 22A/28) i know that take-off and military rpm were 3000, combat rpm (Lumsden refers to "Normal, Continuous Climb (Rated) Power". But it wasn't really continuous! But limited for 60 minutes) were 2850, continuous rpm were 2650.
Between Lumsden publication and "US engine data" there are some differences.
Lumsden Maximum Power (Emergency, Combat, 5 Minutes) probably corresponds to Military engine ratings (in "US engine data"). And they have the same RPM. But different power ratings!
Lumsden "Normal, Continuous Climb (Rated) Power" have a similar power ratings to Military engine ratings (in "US engine data"). But the first at 2850 RPM, the latter 3000 RPM.
Continuous output (in "US engine data") are lower than Lumsden "Normal, Continuous Climb (Rated) Power". And RPM are different: 2650 and 2850.
Is it possible that Packard V-1650 engine was a less pushed engine than Merlin (versions: XX to 28)?
Moreover in the first Merlin versions (Merlin I, II, III and X): take-off rpm were between 2850 and 3000 (depending on the version), military rpm were 3000, combat and climb 2600 (that in the first Merlin versions had a 30 minutes time limit, as the german "Steig- und Kampfleistung"). And what about the continuous? Is it the "Maximum climbing conditions" or "Maximum continuous cruising conditions" (from the Merlin II III manual)?
Maximum climbing conditions: +6.25 psi and 2600 rpm
Maximum continuous cruising conditions: +4.5 psi and 2600 rpm
V-1650-1 continuous output was lower than combat/climb output. I suppose the same for Merlin I to XII.
I surmise that continuous power output in first Merlin (I to X) versions could be around 900 bhp (from the Power Curve scheme, but not graph, in: "British Piston Aero-Engines and their Aircraft" at pages 203 to 207). But i have non data about it.

Now i post another scheme about 1937-1940 EUROPEAN V12 ENGINES (87 grade fuel).
There are time limitations (or supposed). No pressure data, nor RPM.
Power output are given in CV (cavallo vapore, the same as german PS, but not anglosaxon bhp/HP), and Altitudes in meters (m).

And this is the Bibliography:

RR Merlin II Engine Overhaul 1938 - with Mk III updates through to June 1941, Historybytesback, e-book museum archive

"Notice technique des moteurs 12 Y" - Société Française Hispano-Suiza

Alec Lumsden, 1994, "British Piston Aero-Engines and their Aircraft", Airlife Publishing

"Relazione Tecnica e Norme di Montaggio e Regolazione dell'Aeroplano Caproni 135 - 2 Motori I.F. Asso XI Rc 40 (Spinto) - bombardamento" - Aeroplani Caproni, Milano - Taliedo (Italia)

Ministero dell'Aeronautica - Direzione Generale delle Costruzioni e degli Approvigionamenti - Istruzioni per l'uso dei motori Isotta Fraschini: "AS. XI R. C. 40 D.", "AS. XI R. C. 40 S.", "AS. XI R.2 C. 40 D.", "AS. XI R.2 C. 15 D." - Soc. An. Fabbrica Automobili Isotta Fraschini - Milano - 1937 - anno XV

 

[sibboh]

8 and ) became 8) ... damn!!!

 

[sibboh]

Did Russians use metric horsepower (л. с. - Лошадиная сила - Loshadinaya sila) or HP? I think the first, isn't it?
Metric horsepower (http://en.wikipedia.org/wiki/Hp):
German Pferdestärke (PS)
Italian cavallo vapore (cv)
French chevaux (ch)
Dutch paardenkracht (pk)
Swedish hästkraft (hk)
Finnish hevosvoima (hv)
Norwegian and Danish hestekraft (hk)
Hungarian lóerő (LE)
Czech koňská síla
Slovak konská sila (k or ks)
Bosnian/Croatian/Serbian konjska snaga (KS)
Bulgarian "Конска сила"
Macedonian Коњска сила (KC)
Polish koń mechaniczny
Slovenian konjska moč (KM)
Romanian cal-putere (CP)

 

[sibboh]

I begin to hate emoticons!!!

 

[Shortround6]

In US terms the "maximum continuous" was just what it says. The maximum amount of power the the engine was rated for with NO time limit. You could keep it at that setting for as long as the fuel lasted without EXTRA maintenance procedures or notes in the log book. It was a bit different than maximum cruise only in that it used more fuel.

The British sort of skipped this rating. They gave a max power (usually 5 minutes), a "climb" rating (usually 30 minutes) and a "cruise" rating usually the max power while running in a lean condition. NONE of these ratings required any notes or extra maintenance procedures. Combat or "emergency" power levels were also 5 minutes but did require notes in the log book, shorter overhaul times, more frequent spark plug inspection/replacement, etc.

The Americans also started with a max power or Military rating ( usually 5 minutes) but skipped the British "Climb" and went to max continuous which was described above but sometimes limited to one hour. You do have to watch maximum cruise because sometimes it is listed at rich mixture and sometimes at lean mixture. As the war went on and they added "emergency" or War" ratings the time was usually 5 minutes, at this point SOME engines got their Military power time extended to 15 minutes.

The British and Americans sometimes didn't approve the same upper boost limits at the same time. Sometimes if ever. What the squadrons "used" might be different that what was "approved".

So, unfortunately, some of the ratings, while close, do have slightly different conditions which can affect the rating.

 

[tomo pauk]

Good catch, siboh, the 1800 HP for the V-1650-1, max continuous (or any rating), is a typo.

Any luck we could see the original tables graphs for the Issota engines?

 

[sibboh]

WOW!!!! The data grow up!!!

Thank you Shortround6 for the clarifications. Are very important for me. This confirms some of my impressions!
The "Maximum continuous cruising conditions" in Merli II III manual is "normal rich mixtures".

@tomo pauk, the v-1650-1 table is wonderful! If i could have a table like this for every engine... the work i have in my mind could be easier!
Yes, i want to post images and full manuals.
Infact today I was watching again the Isotta Fraschini engine graphics. And i thought again about the table that i posted today. I think that could me more mistakes than i previous expected. So i want to ask you what do you think.

This is a 1937 manual from Isotta Fraschini.

View attachment Motore Isotta Fraschini Asso XI RC40 (CA327) 1937.pdf

This other is Alfa 128 RC 18 manual

View attachment Manuale Istruzioni Motore Alfa Romeo 128RC18 1942.pdf

I have other manuals but they are bigger (everyone more than 70 MB)

 

[sibboh]

Isotta Fraschini Asso L.121 RC.40 data are very few, are scattered across multiple sources (and not always well denominated. Confusion about power derive from ignorance about different output conditions. And i don't know the original sources). The same for Isotta Fraschini Asso L.122 RC.50.
One example from an italian magazine.
In the magazine "Il Corriere dell'Aviatore", n. 1-2/2010 (this is the link: http://www.aeroclubcomo.com/LinkClick.aspx?fileticket=z/cR+IacQNY=&tabid=216&language=it-IT) you'll find an interesting but brief article titled: "Gli ultimi progetti dell'ing. Giovanni Pegna. I Caproni CA153, 154, 155, 156 e 155II" at page 24 to 26.
At page 25 there is a table with aircraft project characteristics. CA155 with IF L 121 engine and CA155II with IF L 122 engine. But the power output for IF L 121 is wrong: the same like the latter. (The L 121 was the Caproni Ca.165 engine. A biplane fighter with a very good speed, with 465 kmh top speed). In the text there are other engines data.
For example Alfa 135 RC.32. They give some informations about this engine.
Take-off: 1500/1600 cv (not very accurate)
1200 cv at 5000 meters. But in the table 1 is 6000 meters !?! And this isn't the rated altitude that is 3200 mters. Infact RC 32 means Riduttore (Adapter) + Compressore (supercharger) + 32 (x 100 = 3200 meters: rated altitude).
L. 121 RC.40 rated altitude was 4000 m
L 122 RC.50 rated altitude was 5000 m
etc...

 

[wuzak]

In US terms the "maximum continuous" was just what it says. The maximum amount of power the the engine was rated for with NO time limit. You could keep it at that setting for as long as the fuel lasted without EXTRA maintenance procedures or notes in the log book. It was a bit different than maximum cruise only in that it used more fuel.

The British sort of skipped this rating. They gave a max power (usually 5 minutes), a "climb" rating (usually 30 minutes) and a "cruise" rating usually the max power while running in a lean condition. NONE of these ratings required any notes or extra maintenance procedures. Combat or "emergency" power levels were also 5 minutes but did require notes in the log book, shorter overhaul times, more frequent spark plug inspection/replacement, etc.

I think the British had a "Normal" rating, which was the equivalent of Max Continuous.

Also, in some aircraft performance data sheets/test reports British aircraft have cruise for the consitions of maximum economy, maximum weak mixture and maximum rich mixture (which would, I guess be the normal rating).

 

[tomo pauk]

...

@tomo pauk, the v-1650-1 table is wonderful! If i could have a table like this for every engine... the work i have in my mind could be easier!
Yes, i want to post images and full manuals.
Infact today I was watching again the Isotta Fraschini engine graphics. And i thought again about the table that i posted today. I think that could me more mistakes than i previous expected. So i want to ask you what do you think.

This is a 1937 manual from Isotta Fraschini.

View attachment 229825

This other is Alfa 128 RC 18 manual

View attachment 229826

I have other manuals but they are bigger (everyone more than 70 MB)

Thanks for the files.
I'll attach tables charts I have, and look forward to anything you can post, too - tables, charts, manuals etc
Don't know how good/bad Internet connection you have, the bigger files can be hosted at dedicated net services, I use mediafire.com for that. Do not despair about mistakes, they are present even in original documents and books. Sure enough, the less mistakes, the better

 

[tomo pauk]

Trying to read a bit about the engines, I've just found out that Fiat A.74 was able to make 960 HP at 3000 m 'in case of emergency, during few minutes'. You can read the manual here, the 960 HP is mentioned at the bottom of the pg.6 of the manual, ie. at the page 11 of the overwiev:

FIAT A.74 MR Parte 1

Curiously, the link was provided by the English language Wikipedia article about the engine, and there such power level is not mentioned (870 being the max there); Italian language Wikipedia declared the 960 HP as maximum.

 

[tomo pauk]

Excerpt from the manual about the FIAT A.74 RC 38 S 8)