Which country designed the best engines for WWII?

[slaterat]

Kurfurst wrote ;

Well we certainly have a German report with rather precise measurements; as a matter of fact, it is the most detailed report on the Merlin 61 and its aux. systems I have seen so far; the suggestion that Germans were inapt at measuring the weight of an engine has considerable merit in the field of bizarre humor IMHO

Its kind of funny and ironic that you would say that.

Slaterat

[Kurfürst]

Originally Posted by slaterat

Lots of miss information in this thread.

first :
A complete Merlin 60 series engine weighs in at between 1640 and 1660 lbs.
This includes the entire engine, supercharger, intercooler and carb or fuel injection pump. What it does not include are the underwing radiators, two for engine glycol , one for oil and one for the intercooler glycol.

I would like to see the source which is supposed to state that 1640 lbs inlcudes the supercharger, intercooler and carb or fuel injection pump.

Without that, we`re talking in terms of fantasy here.

Originally Posted by slaterat

lets get a fair comparison

a merlin 61/66 27 liters
weight 1640 lbs [includes entire supercharger and intercooler]
hp 1565 at 15 lbs boost
1800 at 18 lbs boost
2000 at 25lbs boost
DB 605 35.7 liters
weight 1584 lbs plus 220 lbs for mw 50 = 1804 lbs
hp 605a 1,475[no mw 50 ?]
605am 1,800 with mw50
605 dc 2,000 with mw50

So what is a fair comparison in comparing peak outputs of the Merlin with Sea level outputs of the DB, quioting 1640 lbs and pretending its full engine weight for the Merlin, dismissing the fact that the Merlin requires an additional intercooler radiator but including the MW system`s weight in case of the DB..?
Not to mention the Merlin`s output of 1800 HP @ +18 lbs is incorrect as well...?

Now as fai comparison as far as engines go,

The bare DB 605A weighted 720 kg, 764 kg complete with accessories, producing 1550 (1410 at 1.3ata) PS peak output; for that it consumed 480 (400) liters/hour.

The bare Merlin 61 weighted 740, 834 kg complete with supercharger and intercooler, to which comes 44 kg for the carburator and 42.5 kg for the intercooler radiator. 920 kg in total. It develops 1550 HP at peak output, at a peak consumption rate of 615 liters/hour.

The propellers, oil tanks, engine bearers are not included in either powerplant weights; and naturally, the Merlin developed more power at altitude, ca. 1000 HP at 9500 meter vs 800 (775) PS in the case of the DB 605A-1; the latter could be however boosted to 1150 PS with use of GM-1 (at 1.3ata/2600 rpm; I have no figures for 1.42ata/2800 rpm, but likely we are talking at about 1200-1300 PS) at the expense of + 75 kg added weight for the GM-1 system.

[Glider]

I must admit that all the data I can find from various places both written and on the web, does give a dry weight of a Merlin 60 series of around 1640 - 1670lb.
The earlier 45 series weighing in at 1430lb again with a slight difference according to the version.

[slaterat]

Kurfurst, you don't know what you're talking about.
Dry weight typically means a "dry" complete engine without coolant ,fuel , or oil. A dry weight DB 605 usually weighs in at 1550 to 1585 lbs.

These are dry weights for merlins

Merlin I/II/III 1320 lbs includes single speed supercharger and carb
Merlin XX 1450 lbs includes 2 speed supercharger and carb
Merlin 61/66 1660 lbs includes 2 speed/2stage supercharger and
intercooler and carb

Can you see the progression? You say that a bare block merlin 61 weighs 1660 lbs but a merlin III weighs 1320 [with supercharger]. Keep in mind its the same bore ,stroke and engine block. Then you go on to say that a merlin 61 weighs in at 2024 lbs? Please Kurfurst just admit you are wrong and save some face and credibility while you still can. A quick check on wikipedia can save you.
If you want a source there are many on the web , I also have several books confirming this. Kurfurst the German source you are quoting is either in error or has been mis-translated.

Try this link WWII Aircraft Performance

Check the article section on development of the merlin.

We both know their power curves changed throughout their development I chose three models of each to demonstrate this. You admit yourself that the merlin developed more power at altitude.

Slaterat

[KrazyKraut]

Yeah that site again. I just read a small part of the "article" on Mk.I vs. 109 E. I especially liked how he put words in Moelders mouth. Selective facts and misinformation.

[Kurfürst]

slaterat,

There is no need to engage with you endless polemics. You`ve made several claims with regards the Merlin engines weight. Support them.

I am quite sure you have made them up. If you`d actually have 'several' books confirming your statements, there would be nothing easier than to just quote them or to post the relavant pages. Instead, you keep repeating the same claim and it gets you nowhere.

As for the Mike Williams site, it has a certain odor when it comes to credibility. It has a wide reputation of selecting its facts to support a certain agenda dear to the author.

In any case, there`s nothing on that site that would support your claims, either.

'You admit yourself that the merlin developed more power at altitude.'

It depends on which DB engine we are speaking of. The Merlin certainly did not develop more power at altitude than the AS and D series of engines.

[Soren]

Juha needs to study the debated engines a bit.

At relatively low boost the DB-603 produced 2,300 PS, and the final versions equipped with MW-50 were expected to reach 2,800 - 3,000 PS.

[Glider]

Originally Posted by Glider

I must admit that all the data I can find from various places both written and on the web, does give a dry weight of a Merlin 60 series of around 1640 - 1670lb.
The earlier 45 series weighing in at 1430lb again with a slight difference according to the version.

For what its worth my main printed source is Janes Fighting Aircraft page 280 -281. It gives a detailed breakdown of the Merlin 61 and a list of weights/performances of the various other types of Merlin.

Some of the sites I visited are: -
http://en.wikipedia.org/wiki/Rolls-R...28Merlin_66.29
http://www.theengineer.co.uk/Article...lin+engine.htm
http://www.spitfireart.com/merlin_engines.html
http://www.unlimitedexcitement.com/P...0%20Engine.htm

They are all very close in detail and from very different sources. The only valid concluion is that the Merlin 61 series weighed in at around 1670lb.

[Kurfürst]

Originally Posted by Glider

The only valid concluion is that the Merlin 61 series weighed in at around 1670lb.

Correct. Without the supercharger and the intercooler.
I am not sure if the carburrator`s weight is included in the 1670lbs/740kg figure.

[Juha]

Soren
now Griffon 65 produced 2035 hp with +18in boost and 2220 with +21 boost.
DB 603A, AA and E IIRC produced 1750-1900 hp.
And N, of which only prototype was ready, 2800hp. And what counts were engines which were used in combat sqns, not some prototypes which were expected to reach xxxx hp.


Juha

[Kurfürst]

Originally Posted by Juha

And what counts were engines which were used in combat sqns, not some prototypes which were expected to reach xxxx hp.

Juha

Speaking of that, how many Griffon 65s were around at the end of 1942, ie. when the 1850 PS DB 603A was introduced, the one you are comparing the Griffon engine?

How many Griffon 65s produced during the war?

I would say the Griffon was a fairly comparable engine to the DB 603A-E series, and the Jumo 213 series - actually the Jumo strikes as the best of these in this size class - only that the Griffon came later and was less available.

[Glider]

Originally Posted by Kurfürst

Correct. Without the supercharger and the intercooler.
I am not sure if the carburrator`s weight is included in the 1670lbs/740kg figure.

Kurfurst
Its an interesting document but if I read it right (and German is not something I am good at) this refers to a Merlin 47 from a Spitfire VI. This was an unusual version, only 100 of which were built specifically for High Altitude work.

Anyway the point is that the Merlin 47 had a dry weight of around 1,450lbs. It looks to me if your document is not referring to a Series 61 engine but a modified Series 45 engine.
One unique aspect of the Merlin 47 was that it had cabin supercharger which may impact on your weights.

If your interested, the Spitfire VI also had an increase in wing area to improve controllability at high altitudes with a span of 40 ft. 2 in. The pressure cabin provided a cabin differential of 2 lb./s. in., reducing apparent altitude from 40,000 feet to 28,000 feet.

[Juha]

Kurfürst
in 42 there were only a few Griffons around but during the war production must have been at least 3000 - 3500, powered at least appr. 650 Firefly Mk Is and IIs plus over 1000 Spit XII, XIV, XVIII, XIX and 21.

[Juha]

BTW
A. C. Lovesey gave as the weight of 2-stage Merlin 1660 lb in his lecture to the De Havilland Aircraft Company Technical Department in Nov 1945.
Source Aircraft Engineering July 1946.

Juha

[Denniss]

Originally Posted by Glider

Kurfurst
Its an interesting document but if I read it right (and German is not something I am good at) this refers to a Merlin 47 from a Spitfire VI.

Document says the aircraft/engine is fitted with the same prop as was used on the Spit VI with Merlin 47. It does not say the data is from a Spit VI or Merlin 47.