Which country designed the best engines for WWII?

[Kurfürst]

Originally Posted by Juha

But in what RR was good was to squeeze many hps/l.

Juha

Indeed - the question is what is it good for to squeeze many HP from a given displacement.. it has no practical gains, apart from looking good in company selling brochures. The Griffon for example may have been in the displacement class of the 605, but in size and weight it was rather an equivalent of the 44,5 liter DB 603s or the 35-odd liter Jumo 213s.

[Juha]

Now Griffon was some 170 kg heavier than DB 605AM but gave some 200 hp more power and if one add the weight of MW50 system which was. IIRC, essential for DB 605 AM to attain some 1800 hp, DB system was only appr. 70 kg lighter.

60 series Merlins were some 15 kg heavier than DB 605 AM but again when the weight of MW50 system was added Merlins were appr 85 kg lighter. So?

DB was shorter, IIRC, that's true.

Juha

[red admiral]

The HeS-011 is a good example of how far the Germans were in this field.

Good argument. The Germans were ahead because they produced a handful of examples of an engine that never produced anywhere close to its designed power. The allied jets were far ahead of the German ones in production in every area apart from thrust/frontal area. For that there is the Metrovick F.2 series which comfortably beats the German engines in every regard.

Kurfürst, do you have any information on the fuel consumption of DB series engines compared to the Rolls-Royce ones? The only data I've seen puts the DB series about 10% worse than the Merlin and Griffon.

The Merlin itself had some great development, going from 10300hp to 2640hp in 5 years.

With UK radials there is only Bristol in the picture. Most resources had to be spent on manufacturing and upgrading the Hercules (it was in more dire supply than the Merlin) instead of the Centaurus, which probably would have come into service around 1941/42 otherwise. The Centaurus was a great engine with a very good installation.

[KrazyKraut]

Originally Posted by red admiral

Good argument. The Germans were ahead because they produced a handful of examples of an engine that never produced anywhere close to its designed power. The allied jets were far ahead of the German ones in production in every area apart from thrust/frontal area. For that there is the Metrovick F.2 series which comfortably beats the German engines in every regard.

Yeah right
Too bad they were never used. Unlike the oh-so inferior German jets.

[red admiral]

Usage has nothing to do with the design. The Germans used their axial jets that were inferior to the Metrovick type because they had no choice. The British did have the choice, with their centrifugal types which were easier to build and maintain. The Metrovick F.2 is superior in every way to the 003 and 004 (it was used on the SRA.1 before that was cancelled, and developed into the Sapphire) even without talking about the turbofan F.3 and F.5 versions.

[Kurfürst]

Originally Posted by red admiral

Usage has nothing to do with the design. The Germans used their axial jets that were inferior to the Metrovick type because they had no choice. The British did have the choice, with their centrifugal types which were easier to build and maintain. The Metrovick F.2 is superior in every way to the 003 and 004 (it was used on the SRA.1 before that was cancelled, and developed into the Sapphire) even without talking about the turbofan F.3 and F.5 versions.

I wonder what on Earth do you base that... wishful thinking perhaps?

Specs Jumo 004B / Metropolitan - Vickers F-2
First test flown: March 42 / June 43
Thrust 880 kgf / 817 kgf
Weight 719 kg / 692 kg
Diameter : 810 mm / 835 mm
Lenght 3860mm / 3251 mm

Given the specifications, the Jumo was a slightly superior engine.

Of course your wishful approach carries away you to the post-war F-2/4 type, which was enlarged compared to the F-2, and nowhere near ready for production: it only begun bench testing in 1946 and it was just passing its 100 hour tests in 1946.

The Jumo 004 completed those in 1943. Which is the major difference between the two. The Jumo 004 was there. The Metrovick axial jets were nowhere near being ready for production and combat application.

Originally Posted by red admiral

Kurfürst, do you have any information on the fuel consumption of DB series engines compared to the Rolls-Royce ones? The only data I've seen puts the DB series about 10% worse than the Merlin and Griffon.

Yes I have. Which is why I wonder where on Earth did you see specs stating the opposite..

Originally Posted by red admiral

The Merlin itself had some great development, going from 10300hp to 2640hp in 5 years.

I seriously doubt the latter figure. Perhaps on a bench pad, but thats an entirely different figure alltogether.

Originally Posted by Juha

Now Griffon was some 170 kg heavier than DB 605AM but gave some 200 hp more power and if one add the weight of MW50 system which was. IIRC, essential for DB 605 AM to attain some 1800 hp, DB system was only appr. 70 kg lighter.

60 series Merlins were some 15 kg heavier than DB 605 AM but again when the weight of MW50 system was added Merlins were appr 85 kg lighter. So?

DB was shorter, IIRC, that's true.

The DB series (AM/ASM/DB/DB/DC) could develop 1800 HP without MW 50 with use of C-3. MW-50 was a sort of internal and/pr charge cooling for them, in the same manner as the intercooler in the Merlins/Griffons, which needs to be added into the comparison.

It was a fairly bulky system, making neccesarry adding:

- the inter/aftercooling unit of 32 kg weight
- an extra radiator for the intercooler weighting 42 kg,
- and 6.2 dm2 additional cooling frontal area (drag)
- cooling liquid (unknown quantity, perhaps 10-20 kg extra)

The weight peneleties of the sysytem are rather like the complete MW-50 system on the Bf 109, however the intercooler on the Merlins neccesitiated adding a radiator of the size equivalent of the 109G`s oil cooler (6.5 dm2, 8.5 on high alt (AS/D) versions), with considerable drag penalty.

This is for the Merlin 61; I think it is reasonable to believe the Griffon`s intercooling needs were considerably higher (given its enormous supercharger and the sheer size of its radiators).

All in all, when you look at it, the Merlin 60-series engines required a total of 154 kg cooling radiators alone to be installed, as compared to the DB 605A/AM`s of 87 kg. That was equivalent of a missing 70 kg that didn`t need to be lifted by the engine`s power.

So, for when one for example makes a comparison between the say DB 605 (at 720 kg dry weight without accessories), and the Merlin 60series engines (740 kg w/o accessories), one also has to take into account the different weight of the the cooling systems. Ie. on the Merlin there`s an additional 186 kg from the coolant, oil, and intercooler radiators and intercooler unit (as in the Spitfire IX), compared to the 87 kg extra from the oil/coolant radiators of the DB 605A (as in the 109G).

This does not include yet the supercharger unit (61 kg) and the carburator (+42 kg) of the Merlin 61; I am not sure of the DB 605, but I am sure OTOH its supercharger was much lighter, even on the AS engines, and probably the injection system is already included, as there is no seperate carbburator.

Then there is the question of propeller; higher powered engines require larger, and thus heavier propellers to absorb the power. In case of the DB 605A, a three bladed, light alloy VDM prop (complete with hub and all) would weight 170 kg; the 4 bladed Rotol, complete with hub weighted 181 kg.

Then there`s the question of fuel effiency of course. In case you`d need say 25% more fuel to achieve the same range, at the ca 500 kg total fuel capacity of the 109G/Spitfire, we are already talking about +125 kg needed to achieve the same range.

[Juha]

Kurfürst
IIRC 60 series Merlins were appr. 100 kg heavier than Merlin 45 and 50, so I think the second stage of supercharger and the intercooler were included in the weights of 60 Series Merlins. They were an integral part of the design, in fact the essence of it. Of course intercooler needed fluid and extra cooling capacity.

Now I cannot remember how it was with 605s, IIRC a couple years ago there were still some conflicting info on the need of MW50 with C3, but if you refer to use of C3 as cooler as well as fuel, ie injecting extra C3 into eye of supercharger to act as a cooler, IMHO that ruined significantly the fuel efficency of 605.

Juha

[Kurfürst]

Its always a question what is included - bare engine only or what else.
In any case, the German intel report notes these weights (M61):

Motor komplett (einschlißlich Lader und Endkühler, jedoch ohne Kühlflüssigkeit) 834 kg (Motortrockengewicht 740 kg)
... (weight of other items, cover plates, bearers, prop, oil/coolant tank listed)

Einzelgewichte:
Lader 61 kg
Endkühler 32 kg
Vergaser 44 kg

Curiously : Trockegewicht 740 kg + Lader 61 kg + Endkühler 32 kg = 833 kg ~ Motor komplett.


So 740 kg is probably without the supercharger, intercooler and carburator, 834 kg with the supercharger and intercooler, but still without the carburator.

As for the DB 605D, the design could put out 1800 PS w/o any additional booster injection. Its clearly noted in its manual. The MW-50 manual for the G-14 also seems to imply that MW-50 was not absolutely neccessary, unless only B-4 fuel was available. By default C-3 was specified. MW-50 was described as internal coolant.

In fact there are some curves for the 605G (ie. AM`s maiden name) showing output w/o MW-50 at slightly over 1700 PS peak. Basically thats the same as the Merlin 66 at +18, at less weight.

Less if we consider the cooling system, and much less if we also consider consumption (to produce ~1700 HP came with a consumption of 680 liter/hour on Merlin 66, and 1800 PS (wet) with 560 liter/hour on the DB 605AM. 1700 PS is perhaps less, perhaps the same..

Kurfrst - DB 601, 603, 605 datasheets - DB 605 AM

[red admiral]

I wonder what on Earth do you base that... wishful thinking perhaps?

Your information is wrong. The F.2 was initially rated for 1800lbf in 1942, this rising to 2500lbf in 1943. The engines were running for over 200 hour stints (as opposed to 10 hours of the 004). Fuel consumption was around 1.10lb/lbf-hr in the early engines, decreasing to 1.05 in the F.2/4 as opposed to around 1.60 in the 004.

Yes I have. Which is why I wonder where on Earth did you see specs stating the opposite..

Please post, link or give the source then. The variety of figures for the DB series range from 0.474 to 0.451 (lowest for DB 603A-G). For the Merlin I've got 0.45 and 0.42 for the Griffon. I hardly think the figures come from nowhere.

EDIT: I just found a nice graph of the Merlin X showing an sfc of 0.42 (ish, its off a graph)

I seriously doubt the latter figure. Perhaps on a bench pad, but thats an entirely different figure alltogether.

2640hp is well documented from a RM.17SM engine on test in 1944. Maximum service use was around 2200hp from 100-series engines on 150PN without ADI. The higher figures were with ADI and higher boosts.

Merlin 61 weight of 1640lb includes two stage supercharger, intercooler and carbs. Weight increases slightly on later versions (70 and 100 series) with different accessories and some increased strengthening.

[Juha]

Kurfürst
interesting info on Merlin 61 but a bit odd. Firstly, Price wrote in Late Marques Spitfire Aces that second stage and intercooler increased the weight of Merlin by 200lb which is almost the same as the weight difference between 1-stage and 2-stage Merlins. To be sure one should consult RR Aero Engines book, but I don’t have that.
More importantly, the weight table of P-51B & C Empty and Basic Weights gives
.
.
.
Engine (incl. accessories) 1670 lb
Engine controls 30 lb
Propeller 483 lb
Starting 25 lb
Cooling 663 lb
Lubricating 101 lb
.
.
.
Pyrotechnics 6 lb
Altogether 7325 lb, that w/o fuselage fuel tank

Nowhere in the list there is supercharger or even less carburettor, which were so integral to Merlin, that I would have surprised if they were mentioned separately.

On 109G-14, to my understanding in essence it was late 109G-6 with MW50 system installed. Why to put the system (and its weight) in a type, if it wasn’t essential to its powerplant?

Juha

[Kurfürst]

Originally Posted by red admiral

Your information is wrong. The F.2 was initially rated for 1800lbf in 1942, this rising to 2500lbf in 1943.

Source please.

Originally Posted by red admiral

The engines were running for over 200 hour stints (as opposed to 10 hours of the 004).

Source please.

In any case you appear to be comparing apples and oranges, ie. bench test times for the development-stage, hand-built Metrovick jet prototype vs. the TBO which you`ve made up for the Jumo 004B production engine, out of which ca 8000 were produced (actual TBO was anywhere between 25 and 50 hours).

Anyway, the Jumo 004B completed several 100-hour bench tests in 1943, the precedessor Jumo 004A (which used high grade materials) had a TBO of 250 hours.

Just to put things into context.

Originally Posted by red admiral

Fuel consumption was around 1.10lb/lbf-hr in the early engines, decreasing to 1.05 in the F.2/4 as opposed to around 1.60 in the 004.

Source please.

Originally Posted by red admiral

Please post, link or give the source then. The variety of figures for the DB series range from 0.474 to 0.451 (lowest for DB 603A-G). For the Merlin I've got 0.45 and 0.42 for the Griffon. I hardly think the figures come from nowhere.

You made a claim. Its you who will have to support that claim, and not me having to disprove it.

Originally Posted by red admiral

EDIT: I just found a nice graph of the Merlin X showing an sfc of 0.42 (ish, its off a graph)

Lets see it.

Originally Posted by red admiral

2640hp is well documented from a RM.17SM engine on test in 1944.

If it is well documented it will be ease for you to document it for us, too.
In any case, the thing you wish to impress us seems to be a brief bench test, 15 mins or so IIRc, of an engine under development and far from entering service.

Well DB already pushed the DB 601 to 2700 HP in 1939 for racers, these achievements being as much if not more material to the subject as the brief bench runs you come up with.

Maximum service use was around 2200hp from 100-series engines on 150PN without ADI. The higher figures were with ADI and higher boosts.

Source please.

Merlin 61 weight of 1640lb includes two stage supercharger, intercooler and carbs. Weight increases slightly on later versions (70 and 100 series) with different accessories and some increased strengthening.

You made that up didn`t you.

[Kurfürst]

Originally Posted by Juha

Kurfürst
interesting info on Merlin 61 but a bit odd. Firstly, Price wrote in Late Marques Spitfire Aces that second stage and intercooler increased the weight of Merlin by 200lb which is almost the same as the weight difference between 1-stage and 2-stage Merlins. To be sure one should consult RR Aero Engines book, but I don’t have that.
More importantly, the weight table of P-51B & C Empty and Basic Weights gives
.
.
.
Engine (incl. accessories) 1670 lb

Question is, what accessories are included in that 1670 lbs? Your source doesn`t make it clear.

Originally Posted by Juha

Nowhere in the list there is supercharger or even less carburettor, which were so integral to Merlin, that I would have surprised if they were mentioned separately.

Superchargers are not integral to the engine, they are seperate subsystems of the powerplant. Thats why they are usually not included in the weight of the engine.

In any case, the German report I have is rather clear how much the Merlin 61 weights. Motor komplett (einschlißlich Lader und Endkühler, jedoch ohne Kühlflüssigkeit) 834 kg

On 109G-14, to my understanding in essence it was late 109G-6 with MW50 system installed.

Correct. To be even more precise, its a G-6 with MW-50 in which the MW-50 is put under pressure with compressed air tapped from the supercharger (in the G-6 with MW50 it was done via seperate pressure bottles).

Why to put the system (and its weight) in a type, if it wasn’t essential to its powerplant?

Juha

I would say because it was beneficial in many ways. It provided apprx. 100 PS extra power to the powerplant even at the same manifold pressure, it enabled that the same output could be achieved with lower grade fuels as well, and it provided internal cooling to the engine, greatly decreasing its cooling needs (which in the end meant that there were no extra cooling loss, in fact the engine seems to be developing less heat at 1800 PS than previously at 1300 PS).

[Juha]

Hello K

"Question is, what accessories are included in that 1670 lbs? Your source doesn`t make it clear."

You are right but as it is the calculation of the Empty weight of P-51B/C and it's so accurate that it gives items as light as 6 lb and it doesn't give separately anywhere the weight of the 2nd stage or intercooler, they must have included in engine weight. Empty weight is empty weight of flyable a/c. After tallying Empty weight the table went to disposeable load alternates beginning from pilot, then oil, fuel, ammo etc and all adds up to gross weight. IMHO its clear that engine weight incl. the weight of the 2nd stage and the intercooler. Somewhere in empty weight there must be the weight of the 2nd stage and intercooler included, because they were not given separately and engine is much more natural place for that than fuselage, tail, wing, landing gear etc, isn't it.

Juha

[red admiral]

Sources are

The Development of Jet and Turbine Aero Engines by Bill Gunston for the stuff on the Metrovick F.2. The F.2 engines were flying in a Meteor prototype and a Lancaster, not sitting on a bench.

Merlin fuel consumption from The Case for the Carburettor, a short report from March 1941. Figures were provided by RAE tests.

Merlin power levels can be found from The Development of the Rolls-Royce Merlin from 1939 to 1945 by AC Lovesey or RRHT's booklets. The RM.17SM wasn't a race engine (race Merlins taken to over 3000hp in hydroplane racing), it was the high altitude version of the 100 series engines. 2640hp was the maximum attained on tests with 35lb boost 150PN and ADI. 2350hp 9might be 2380 I can't quite tell) 30 minute rating without ADI. 2200hp at 30lb boost. These were from type tests and approval tests in 1944.

Merlin weights can be found in the above and in A British Masterpiece by G. Smith (this deals with the Merlin XX but gives total weights)

I have sources for all the factual statements I previously made. They are not made up as you seem to think. Your point of view seems to be set firmly in concrete though, so I doubt you'll accept this.

[Kurfürst]

Originally Posted by red admiral

Merlin fuel consumption from The Case for the Carburettor, a short report from March 1941. Figures were provided by RAE tests.

Specifics? What rating, what Merlin, what RPM, what altitude?

For example, the Merlin 66 thirst for avgas is noted at 154 Imp. gallon/h (=700 liter/h) at +18 lbs (1705 HP).
The DB 605D would produce 1800 at 615 liter/hour.

Merlin power levels can be found from The Development of the Rolls-Royce Merlin from 1939 to 1945 by AC Lovesey or RRHT's booklets.

I am familiar with the Lovesley article. Its rather propagandic and contains many factual inaccuracies. For example it claims 2000 HP was accomplished for the Merlin 66 in 1943; in reality only two Spitfire IX LF Squadrons were doing operational trials with this rating in 1944; in 1945 it was attempted to be standardized for the 2nd TAF, but was withdrawn after a month or two due to a steep rise in fatal accidents.

The RM.17SM wasn't a race engine (race Merlins taken to over 3000hp in hydroplane racing), it was the high altitude version of the 100 series engines. 2640hp was the maximum attained on tests with 35lb boost 150PN and ADI. 2350hp 9might be 2380 I can't quite tell) 30 minute rating without ADI. 2200hp at 30lb boost. These were from type tests and approval tests in 1944.

2640 HP for the extent of a 15 minute bench tests... Immaterial to our discussion IMHO.

Merlin weights can be found in the above and in A British Masterpiece by G. Smith (this deals with the Merlin XX but gives total weights)

I`d like to see the source wheter it makes the same claims as you do. Reminder, you claimed that

'Merlin 61 weight of 1640lb includes two stage supercharger, intercooler and carbs.'

I have quoted a German report from 1943 which makes it quite clear it doesn`t. 1640 is a bare engine. No supercharger. No intercooler. Not even the sizeable carburator is included.

I have sources for all the factual statements I previously made. They are not made up as you seem to think. Your point of view seems to be set firmly in concrete though, so I doubt you'll accept this.

I accept verifiable information. But so far, there`s very little.

Jumo 004 (Wiki, I found it to match my other sources, and I am a lazy typer

The first prototype 004A ran in spring 1940, and in January the following year was brought up to full thrust, 4.2 kN. Vibration problems with the compressor blades delayed the program at this point, until a new stator design by Max Bentele solved the problem. With the new stators in place the engine developed 5.9 kN in August, and passed a 10-hour endurance run at 9.8 kN in December. The first flight test took place on March 15 1942, when a 004A was carried aloft by a Messerschmitt Bf 110. On July 18, one of the prototype Messerschmitt Me 262s flew for the first time under jet power from its 004 engines, and the 004 was ordered into production by the RLM to the extent of 80 engines.

The 004A was strictly a test-bed, unsuitable for mass production due to its solid, and thus heavy, construction and considerable use of expensive high-temperature metals in the "hot section". For production, the 004B turned to air cooling instead, using hollow turbine blades made of inexpensive steel, cooled by compressed air "bled" from the compressor. The first production versions weighed