Build the perfect water cooled engine

[P-40K-5]

Allied P-40 losses for the day were four, including one that was most likely due to AAA, as well as one heavily damaged and written off on landing and several others that were damaged and repaired.

Against this, there were Luftwaffe claims for 19 P-40s and one Spitfire.

Since a few experts and enemy fighter pilots doubted
the veracity of these claims, maintaining that there wasn't
even 26 aircraft in the air, here is the tally sheet from 1 September,
which was verified by the enemy:


Oblt. Marseille 0826 hrs, a Curtiss, SE of Imayid.
0828 hrs, a Curtiss, SE of Imayid.
" 0835 hrs, a Curtiss, SE of Imayid.
" 0839 hrs, a Curtiss, SE of Imayid.
" 1055 hrs, a Curtiss, SE of Alam Haifa.
" 1056 hrs, a Curtiss, SE of Alam Haifa.
" 1058 hrs, a Curtiss, SE of Alam Haifa.
1059 hrs, a Curtiss, SE of Alam Haifa.
" 1101 hrs, a Curtiss, SE of Alam Haifa.
1103 hrs, a Curtiss, SE of Alam Haifa.
" 1105 hrs, a Curtiss, SE of Alam Haifa.
Oblt. Marseille 1747 hrs, a Curtiss, SE of Imayid
Oblt. Marseille 1753 hrs, a Curtiss, SE of Imayid

it can be stated with certainty that the claims made by
Marseille and the entire JG 27 were correct. No one was
given credit for a kill without at least one eyewitness confirming
it.

 

[Lighthunmust]

..... I couldn't help but think of this....

He lies like an eyewitness. - Nietzsche

.....which leads me to this.....

Research in cognitive psychology in social psychology, as well as in the philosophy of science and in other fields seems, however, to indicate that the reliability of visual reports are often much overrated. - Wikipedia

Food for thought.

 

[P-40K-5]

page 197, The Life Story of the "Star of Africa" by FRANZ KUROWSKI (Translated from German by Don Cox).

 

[Jabberwocky]

Since a few experts and enemy fighter pilots doubted
the veracity of these claims, maintaining that there wasn't
even 26 aircraft in the air, here is the tally sheet from 1 September,
which was verified by the enemy:


Oblt. Marseille 0826 hrs, a Curtiss, SE of Imayid.
0828 hrs, a Curtiss, SE of Imayid.
" 0835 hrs, a Curtiss, SE of Imayid.
" 0839 hrs, a Curtiss, SE of Imayid.
" 1055 hrs, a Curtiss, SE of Alam Haifa.
" 1056 hrs, a Curtiss, SE of Alam Haifa.
" 1058 hrs, a Curtiss, SE of Alam Haifa.
1059 hrs, a Curtiss, SE of Alam Haifa.
" 1101 hrs, a Curtiss, SE of Alam Haifa.
1103 hrs, a Curtiss, SE of Alam Haifa.
" 1105 hrs, a Curtiss, SE of Alam Haifa.
Oblt. Marseille 1747 hrs, a Curtiss, SE of Imayid
Oblt. Marseille 1753 hrs, a Curtiss, SE of Imayid

it can be stated with certainty that the claims made by
Marseille and the entire JG 27 were correct. No one was
given credit for a kill without at least one eyewitness confirming
it.

So nice of you to selectively leave out the sentence directly under the claims list:

"Unfortunately, a list of official records on this day was not available to the German side at the time".

It can be said, with certainty, that the JG 27 claims are overinflated, as were almost all fighter claims of the war.

The UK/Commonwealth units - Hurricanes and Spitfires of 1, 238 SAAF and 92 RAF squadrons, P-40s of 2 and 5 SAAF - lost 16 aircraft between them in the day, plus two written off later due to damage for a total of 18.

Against this we have JG 27's claims for 24 (26?).

Roughly a 2:3 ratio, which is broadly similar to that of Luftwaffe day-fighter units in the ETO.

Post-war, the USAAF concluded that (in 1944 at least) that the percentage of kill claims awarded by the Lufftwaffe "varied systematically with the rank of the pilots". The lower down the hierarchy you were, the less likely a pilot was to be awarded a kill.

While a staffel captain may indeed be more likely to hit his target and recognise when it is a 'kill', the USAAF found that "it is surprising that hits and fires in the target do not appear to affect the granting of claims".

Something to think about.

 

[Readie]

..... I couldn't help but think of this....

He lies like an eyewitness. - Nietzsche

You are absolutely right Steve,if you ask 100 people who saw an incident you will get 100 different version of the same event.
If people are under pressure to appear to be successful, i.e on the losing side, then the truth gets even more distorted.

Cheers
John

 

[Gixxerman]

@ wuzak

Daimler Benz DB604.jpg

Thanks for that, last time I looked there was a fair bit on the Jumo 222 but there didn't seem to be much info on the 604.

 

[Readie]

So Gentlemen, are we all agreed that the Merlin was the most iconic, versatile, useful and 'perfect liquid cooled engine' ?
Others come a mere second to Rolls Royce's masterpiece.
Cheers
John

 

[Lighthunmust]

So Gentlemen, are we all agreed that the Merlin was the most iconic, versatile, useful and 'perfect liquid cooled engine' ?
Others come a mere second to Rolls Royce's masterpiece.
Cheers
John

John your worship of the Merlin is going to have me and perhaps others speculating that your descendants in centuries to come will worship the rusted hulks of Merlins as though they are relics equal in importance to the parts of "The True Cross" and the bones of the Saints.

 

[wuzak]

Just been doing some numbers on the Vulture.

The standard power was 1780hp @ 2850rpm with +6psi boost (from Wiki). That equates to a BMEP of 1316kPa/191psi. Compare that to the Merlin XX with 100 octane fuel from mid 1940, +15psi boost, giving 1480hp @ 3000rpm for a BMEP of 1634kPa/237psi.

Now, if we can get that BMEP from the Vulture, still at 2850rpm, the power that could be extracted would be just over 2200hp. If we can get it to spin to the Vulture's design speed of 3200rpm then 2480hp is the result.

Later in the war the 70 series engines were built and gave 1710hp @ 3000rpm at +18psi. That is a BMEP of 2888kPa/274psi. At 3200rpm the Vulture at that BMEP would give 2867hp.

Now, the Vulture had the same bore spacing as the Merlin, so the bore could have easily been upped from the standard 5in/127mm to the Merlin's 5.4in/137.2mm, and the stroke kept the same at 5.5in/139.7mm. That would take capacity to 3023cid/49.5l, and power using BMEP of 2888kPa/274psi and 3200rpm to 3344hp. The extra capacity wouldn't change the weight of the engine much.

Mk66 Merlins were rated for 2000hp low level with PN150 fuel during 1944. That gives a BMEP of 2209kPa/320psi, which equates to 3353hp with the standard bore, and 3911hp with the 5.4in bore.

The last war time development of the Merlin was the RM.17SM. It was cleared for 2200hp @ 3000rpm just prior to the end of the war. That is a BMEP of 2429kPa/352psi. For the Vulture that equates to 3688hp/4302hp for standard/larger bore.

So, the Vulture probably had quite a lot of potential for development, had RR got past the reliability issues, which is whay it was rated so low in the first place, and had the resources to develop it as much as the Merlin, as well as doing the Merlin and Griffon improvements. And it would have weight not much more than a Griffon, and less than a V-3420.

 

[wuzak]

Vulture weighed around 2450lb/1111kg, and would have been reduced to around 2200lb/1000kg when the epicyclic reduction gear was used. Compare that with around 1650lb/748kg for the Merlin 61, 1980lb/900kg for the Griffon 65 and 2360lb/1070kg for the Sabre.

The air-cooled engines of similar power potential (ie over 3000hp) would be the R-4360 at somewhere between 3400-3900lb/1542kg-1769kg, the Wright R-3350 with turbocompounding at 2670lb/1211kg for the basic engine plus approximately 500lb/227kg for the compounding components, for an all up weight of around 3170lb/1438kg.

The Vulture would, of course, need a radiator and coolant. If that equates to 600lb/272kg the installed weight would be 3050lb/1383kg for the version that was in service, or around 2800lb/1270kg for a version with epicylic reduction gear.

 

[Readie]

John your worship of the Merlin is going to have me and perhaps others speculating that your descendants in centuries to come will worship the rusted hulks of Merlins as though they are relics equal in importance to the parts of "The True Cross" and the bones of the Saints.

You could be right Steve.

Amongst the many historical artefacts of England, the Mary Rose, the soaring cathedrals, Mallard and I K Brunel's work the Spitfire and the RR Merlin will still be admired in the centuries to come.

King Arthur, his knights Merlin sleeping in an English hill waiting to ride out and save England at her time of greatest need is a legend I love.
There are many places where 'the hill' is supposed to be but, on a stormy day Tintagel on the Cornish coast is very atmospheric.

Merlin did fly and save us in WW2...so, maybe there is a connection after all.

Cheers
John

 

[wuzak]

With the liquid cooled engine there are several options as to where the radiators fit - under the nose, under the fuselage belly, under the wings, wing leading edges, etc.

A popular option for the Germans was to use an annular radiator, which also enabled an in-line to be bolted up to an airframe originally designed for a radial (or vice versa).

The problem I see is that a V12 aero engine could get quite lonely inside a housing of the diameter of a radial.

That is designed to fit a space for a BMW 801, which is smaller in diameter than most of the allied big (powerful) radials.

I have picture of the V-1710 installation in the XB-38, bolted up to the bulkhead desiged for a Wright R-1820 and it looked to have planty of space around.

An X engine would suit the annular radiator more than the V12.

Still, I wonder if the XB-38 had been designed with annular radiators in a bolt up QEC module if it would have been more favourably received. The XB-38 used engines from a P-38, with underslung intercooler and leading edge radiators between the engines. The XB-39 did use a QEC, but with a chin radiator.

One Tempest was trialed with an annular radiator:

Ducted

and unducted

One Fury prototype (Griffon power) had an odd arrangement

That design was further refined for the Shackleton
http://upload.wikimedia.org/wikiped...leton_with_Saunders-Roe_airborne_lifeboat.jpg

 

[wuzak]

Compare the Jumo 213 with annular radiator with the tightness of the BMW 810 packaging

 

[wuzak]

Another DB604 picture

And a spec sheet for German engines, this page including DB604

Numbers specified:
2660hp @ 3200 rpm for sea level/take off, 1.42 ata boost
2410hp @ 3200 rpm @ 20,600ft, 1.42 ata boost

Climb and Combat
2270hp @ 3000 rpm for sea level, 1.3 ata boost
2120hp @ 3000 rpm @ 21,600ft, 1.3 ata boost

Max Cruising
1830hp @ 2800 rpm for sea level, 1.15 ata boost
1860hp @ 2800 rpm @ 20,000ft, 1.15 ata boost

Weight 2380lb/1080kg.

What was the reason it was dumped? Were there problems with the engine, or was it a case of spending resources on other engines, like the 601, 603, 605 and their coupled versions?

 

[wuzak]

Compare the DB 604 with the DB610 - a coupled pair of DB605s.

Max Power
2870hp @ 2800 rpm for sea level/take off
2560hp @ 2800 rpm @ 25,000ft

Climb and Combat
2550hp @ 2600 rpm for sea level
2400hp @ 2600 rpm @ 24,200ft

Max Cruising
2100hp @ 2300 rpm for sea level
2040hp @ 2300 rpm @ 23,000ft

Weight 3460lb/1569kg for C, and 3540lb/1606kg for D (opposite rotation).

So, the engine is slightly more powerful than the DB604 (200-300hp), but weighs more than 1000lb/454kg more, is wider, probably just as tall, but possibly not as long.

 

[gorizont]

Compare the DB 604 with the DB610 - a coupled pair of DB605s.

Max Power
2870hp @ 2800 rpm for sea level/take off
2560hp @ 2800 rpm @ 25,000ft

Climb and Combat
2550hp @ 2600 rpm for sea level
2400hp @ 2600 rpm @ 24,200ft

Max Cruising
2100hp @ 2300 rpm for sea level
2040hp @ 2300 rpm @ 23,000ft

Weight 3460lb/1569kg for C, and 3540lb/1606kg for D (opposite rotation).

So, the engine is slightly more powerful than the DB604 (200-300hp), but weighs more than 1000lb/454kg more, is wider, probably just as tall, but possibly not as long.

And what about DB-604 dimensions? I never learnt them - I haven't found a single source there they were discribed.

 

[wuzak]

And what about DB-604 dimensions? I never learnt them - I haven't found a single source there they were discribed.

Performance numbers are in post #214 (ie three posts ago).

There is a wiki entry for the 604: Daimler-Benz DB 604 - Wikipedia, the free encyclopedia

Cylinder dimensions are bore 135mm x stroke 135mm.

 

[gorizont]

Performance numbers are in post #214 (ie three posts ago).

There is a wiki entry for the 604: Daimler-Benz DB 604 - Wikipedia, the free encyclopedia

Cylinder dimensions are bore 135mm x stroke 135mm.

I've seen it. No common recource gives its external dimensions as far as I checked.

 

[wuzak]

I've seen it. No common recource gives its external dimensions as far as I checked.

According to this page there is a DB604 in the Flugausstellung L.+P. Junior museum.

They may have the info, or could run a tape measure over it.

I cannot speak, read or write German, so could anybody enquire on our behalf?

 

[tomo pauk]

With the liquid cooled engine there are several options as to where the radiators fit - under the nose, under the fuselage belly, under the wings, wing leading edges, etc.
A popular option for the Germans was to use an annular radiator, which also enabled an in-line to be bolted up to an airframe originally designed for a radial (or vice versa).
The problem I see is that a V12 aero engine could get quite lonely inside a housing of the diameter of a radial.

That is designed to fit a space for a BMW 801, which is smaller in diameter than most of the allied big (powerful) radials.

The outer diameter of the annular radiator of the Jumo 213 DB 603 was substantially smaller than the outer diameter of the cowling of the BMW 801. The cowling of the 801 was designed as a tight fit anyway, installation employing fan to cover the cooling issues because of such a fit IIRC.