The lack of a four engined bomber

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Topspeed
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Post by Topspeed » 27 Aug 2004 21:40

So a He 177 Greif was a genuine 4 engine bomber right ?


rgrds,

Juke T

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Post by Witch-King of Angmar » 27 Aug 2004 22:41

Huck wrote:
Hop wrote:
Merlins, Allisons were aging designs, small overboosted engines tortured to give the last HP possible. DB605 was from the beginning a larger displacement engine (without having larger external dimensions or weight) producing with ease high power output and being economical at the same time (because of lower revs and higher compression ratio).
Again, you ignore the advantages the Merlin had in high alt performance.

It wasn't until the Db 605 AS the Db could match the Merlin in alt performance.
Incorrect, DB-605A had better high alt performance than Merlin 45, which outnumbered any other Merlin variant used in fighters until '44. DB-605A fitted with GM-1 had aprox 200HP more than Merlin 60 series at high altitude, but saw little use because there was nobody to challenge the superiority of Me-109 fitted with the standard DB-605A. Remember, Me-109 needs less power than Spitfire to achieve the same climb rate and speed, because Me-109 generates less drag and it is lighter.
Then what generated the low service ceiling of most German bombers? plus the general impression is that mainstream German fighters performed badly at maximum ceiling which was nevertheless inferior to a P-51D;

Service ceiling:

German:

Ju-88A-4 (2 x Jumo 211J) - 8,200m
Ju-88G-7 (2 x Jumo 213E) - 8,800m
He-177A-5 (4 x DB-605) - 8,000m
Do-217M-1 (2 x DB-603A) - 9,500m

Allied:

B-17G (4 x Wright R-1820-97 Cyclone) - 10,850m
B-29C (4 x Wright R-3350-23 Duplex Cyclone) -9,710m
(The other Allied mainstream bombers had inferior ceiling to their German counterparts, and I won't quote them here);
In 1943, the Luftwaffe was faced with a desperate need for fighters with better high-altitude performances to face the threat of Allied bombers. By that time, the Luftwaffe was aware of the existence of the B-29, and they were also aware that the existing Fw 190 would be incapable of effectively intercepting this American bomber at the altitudes at which it was supposedly capable of operating. Consequently, Kurt Tank undertook the development of a high altitude version of his Fw 190 fighter to meet the threat. Very early in the production run of the "Dora 9", the original Fw 190A style cockpit canopy was replaced by a blown hood similar to that used on the Fw 190F fighter-bomber.


Tank was convinced that the BMW-801 air-cooled radial would never achieve the required high-altitude performance, and decided that only a liquid-cooled engine would do. Tank proposed that Daimler Benz DB 603 engine be used, but this engine was looked upon with disfavor by the Reichluftfahrtministerium (State Ministry of Aviation, better known as the RLM) for what were basically political rather than technical reasons. Consequently, Tank was told to adapt the existing BMW 801 air cooled radial or use the Junkers Jumo 213 liquid-cooled Vee. As a concession to Tank, he was allowed to work on a DB 603-powered version, but it was made clear to him that it would be only a low-priority project.


Three alternative proposals were considered: the Fw 190B powered by a turbosupercharged BMW-801, the Fw 190C powered by a DB 603, and the Fw 190D powered by a Jumo 213. The Fw 190B and C both ran into an extensive series of teething problems, and, in the event, never entered production. Priority was therefore given to the Fw 190D even though Tank felt that that the DB 603 was a better high-altitude engine than the Jumo 213 and had greater development potential. In addition, it was anticipated that the Jumo 213 would be available sooner than the DB 603 engine, which was still regarded as being "chancy" by the RLM. Tank had always viewed the "Dora" as only an interim type, pending the availability of the DB-603-powered version, which was eventually to evolve into the Ta 152
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Post by Huck » 27 Aug 2004 23:31

Topspeed wrote:So a He 177 Greif was a genuine 4 engine bomber right ?
Yes and no. It was operated like a 4 engine bomber, but the 2 coupled DB605 got a distinct engine designation: DB610.

But unless we want to be completely formal then yes, He-177A was a 4 engine bomber.

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Post by Huck » 28 Aug 2004 01:02

Witch-King of Angmar wrote: Then what generated the low service ceiling of most German bombers? plus the general impression is that mainstream German fighters performed badly at maximum ceiling which was nevertheless inferior to a P-51D;

Service ceiling:

German:

Ju-88A-4 (2 x Jumo 211J) - 8,200m
Ju-88G-7 (2 x Jumo 213E) - 8,800m
He-177A-5 (4 x DB-605) - 8,000m
Do-217M-1 (2 x DB-603A) - 9,500m

Allied:

B-17G (4 x Wright R-1820-97 Cyclone) - 10,850m
B-29C (4 x Wright R-3350-23 Duplex Cyclone) -9,710m
(The other Allied mainstream bombers had inferior ceiling to their German counterparts, and I won't quote them here);


~The Witch-King of Angmar
Hi Witch-King of Angmar,

Short answer to your question is the 2 bombers on top of your list use turbosuperchargers. However as you noticed the German supercharged bombers make a compact block on a honorable 3rd place, above the Allied supercharged bombers.

There were short series of German bombers that used either GM-1 or turbosupercharging and had a ceiling higher than 10000m, such as Ju88S/T, Ju188S/T, Ju388L. I'll come back with more details later.

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Post by Lkefct » 28 Aug 2004 17:37

Not that ALlied or German bombers can drop a bomb accurately from 10,000m.

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Post by Hop » 30 Aug 2004 21:42

DB-605A is a '42 engine V-1650-7 is a '43 engine. Have fun comparing DB-605A with Merlin 45.
In 1942 and most of 1943, the DB 605A had a maximum output of 1290 hp at sea level, 1230 hp at 5800m.

The Merlin XX, from early 1941, could put out 1400 hp at sea level, and was still putting out over 1400 hp (way beyond the max of the Db 605A until late 1943) at 12,000ft.

At 5800m it had an output of 1100 hp.

And this from an engine that was not only a year earlier than the Db 605A, it was 100kg lighter as well.

The Merlin 45 was a lower alt engine, again it much predated the DB 605A, but by the summer of 1942, when the DB650A was putting out a max of 1290 hp, the Merlin 45 had a max output around 1500 hp, again it was 100 kg lighter.

Of course, these comparisons are for Merlins that were 100 kg lighter than the 605, and up to a year earlier.

The Merlin 61 got into service a couple of months after the 605, and it's was equal in weight to the 605.

In the summer of 42, the Merlin 61 put out 1565 hp at around 3400m, 1390hp at almost 7200m.
Completely incorrect. RLM issued such restriction only for the first series of DB-605A -0 and -1. But RLM did NOT decide the operating limits in combat use, only OKL did that. In fact many such RLM orders, sometimes motivated by real supply concerns, sometimes motivated politically, were simply ignored by OKL.
Got any evidence to support that? I'd like to see it. I can provide you with evidence of the derating to 1.3 ata. I've never actually seen the information that proves it was ever increased to 1.42 ata, but someone I trust has, and says it was cleared in Nov 1943.
Among the Me-109 capture by the Soviets in '42, some of them had a throttle pin that blocked the selection of max power setting (the pin could be removed in an emergency), others did not, which means that decision to restrict the use of max power setting was taken at squadron level.
The DB 605 was initially cleared for 1.42 ata, it had to be withdrawn because of engine failures. If a pilot overrode that, he was putting himself at more risk than he was the enemy.

As a matter of interest, does anybody know if that's what caused Marseille's death? He was flying a new 109G.
Romania started to use Me-109 operationally from March 1943. No restriction to use the max power setting was imposed to Romanian crews.
Any proof of that?

Goering was still discussing allowing 1.42 ata in meetings as late as Septemer 1943.
Another thing to consider is that often squadrons from all ww2 airforces were constricted at different times to impose restrictions on the use of max power setting because of the low quality of supplies (either the fuel, oil or various engine components). So that DB-605A was at some point restricted to use the max power setting in some squadrons is irrelevant, the same happend to many engines used by different airforces.
It's not in some squadrons at some stage, it's the RLM and Messerschmitt saying you can cause engine failure if you use 1.42 ata.

This is from 12th June 42, one of the instructions banning the use of 1.42 ata:
A number of cases of breakdown in the DB 605 engine as a result of pistons burning through have occured. The following must therefore be observed.

The Take-off and emergency output with a boost pressure of 1.42 atm. and 2800 revs. may not at present by used. The climbing and combat output with 1.3 atm. and 2600 revs. may in the case of the older engines (for works numbers see below), be used only when operationally essential.
Taken from Air 40/64 from the British National Archives.
Incorrect, DB-605A had better high alt performance than Merlin 45, which outnumbered any other Merlin variant used in fighters until '44.
Source for that, please.
DB-605A fitted with GM-1 had aprox 200HP more than Merlin 60 series at high altitude, but saw little use because there was nobody to challenge the superiority of Me-109 fitted with the standard DB-605A.
GM-1 added around 150 - 200 kg of weight, didn't it?
but saw little use because there was nobody to challenge the superiority of Me-109 fitted with the standard DB-605A.
The Merlin 61 put out a couple of hundred hp more than the DB 605A, even more at high altitudes.
Remember, Me-109 needs less power than Spitfire to achieve the same climb rate and speed, because Me-109 generates less drag and it is lighter.
That's because it's smaller, carried less offensive load (unless you hung gondolas on it), and suffered more from torque and handling problems as a result. And from the Spitfire IX onwards, the Spit usually required less power for the same climb rate. The Spit IX, with 1760 hp, for example, climbs as well as, or better than, the 109K4.
190 gallons of what? MW50 is not a fuel Hop!
No, it's worse than fuel, because it's heavier.

It's still weight you have to carry around, space for a tank, etc.

Or are you worried about the cost of the fuel? The only difference between MW 50 is it's cheaper, and not inflamable. You still have to carry it.

Of course, for the Germans with their fuel shortages, it had an advantage, but not for the allies, who didn't suffer much from a shortage of fuel.
And very important, DB-605DC and DB-605ASC did not need MW50 to achieve 1850HP.
They needed C3, which was in short supply for the Luftwaffe.

The 605 AS had an output of 1270 hp at 8000m, the v-1650-3 about 1340 hp at the same altitude.

The comparable high alt Merlin, the Merlin 70, was somewhat better than that.
210 gallons/hour is the fuel consumption at critical altitude. The fuel consumption for the German engine was given also at the critical altitude.
The fuel consumption for the German engine was given at sea level.
That never happend. Merlins and DB-605 series had similar same power ratings for almost the whole lenght of the war, except at the end when DB-605 was more powerful.
No.

1942 Db 605 1290 hp, Merlin 45 1480 hp, Merlin 61 1565hp

1943 Db 605 1450 hp, Merlin 66 1760 hp

1944 Db 605 1775 hp, Merlin 66 over 2000 hp

1945 Db 605 1970 hp, Merlin V-1650-9A over 2200 hp.
Merlins could compete at the end of the war only when they used the 150 octane fuel.
As the DB could compete only when it used C3 and MW 50.
But as I showed previously the combat units used less 150 fuel grade than the engine factories experimenting with this fuel
Excuse me? You made some claims that the US did not use 150 octane, I posted documents that showed they did. You haven't even commented on that, let alone posted any actual evidence, only an opinion.
proving beyond doubt that the use of 150 fuel grade was nothing more than experimental in Europe.
The documents prove the 8th AF were using it for all their fighters, and that 2nd TAF had also switched over.

The 1.8 and 1.98 ata ratings on the Db were truly rare, being authorised only in 1945, and 1.98 ata (2000 hp) was only used by a small number of units.
I don`t know if between June 1942, and June 1943, would count as 'for most of it`s life'.
Nov 43, afaik, and as far as Butch knows, and you don't seem to want to challenge him on that.
Not to mention in the same time period, two stage Merlins were limited in their boost and output as well, max. allowed being +15 lbs and 1340 HP at SL, very comparable to the DB 605A`s.
The DB 605 power didn't increase much, above sea level. The Merlin did. What was the peak power on the Db 605A at 1.3 ata? The Merlin 61 developed 1565 hp, the Db 605A at 1.3 ata didn't come close o that, at any altitude.
The Merlins you speak of were extremely rare in the field until 1944,
Not really. 350 Spit IXs had the Merlin 61, plus various other Spits (VII, VIII, XI) . Then you have hundreds of Merlin 63 engined Spit VIIIs, IXs, etc, plus fairly small numbers of Merlin 70s.

And the P-51B, of course, with the V-1650-3
when the AS and D engines appeared (early 1944) and were common.In fact these engines were producing about 100HP more at higher altitudes than the most common Merlin 66s.
You mean the high alt Db 605 was producing 100 hp more at high alt than the low alt Merlin 66? Why not compare like with like, and the Merlin 70, the high alt Merlin?
No, it`s still 148 US gallon/hour.

MW 50 was a boosting power required for the maximum powers only, and did not effected range at all, since it wasn`t fuel.
It used space and weight that could otherwise be used for carrying fuel.

Imagine the Mustang if they'd had to rip the rear fuselage tank out to put in an MW 50 tank instead. All of a sudden, no more daylight escort of bombers into Germany.
Strictly by shaft power output, yes. However since the DB had no intercooler, DB 605 power aircraft had less drag and required less power for the same performance;
You are claiming the 109 was faster than the Mustang for the same power?
The two staged Merlins however were already slightly heavier than them to start with.
2 stage Merlins andd Db 605s were almost exactly the same weight.
They required about 30% more fuel to be carried (that means about 200 lbs extra weight already for a 109/Spitfire sized fighter) to get the same range;
Nowhere near. Look at the cruise figures Huch posted, cruise performance is almost exactly the same. Only brief periods are spent at combat power.

Shall I post the range figures from the Aussie docs again?

At low power, the Spit was clearly superior, getting 10 mpg when the 109 got about 8 under similar conditions.

In a high speed cruise, 303 mph for the Spit VIII, 306 mph for the 109 G2, the 109 carrying a small drop tank (total fuel 154 imp gallons) got 5.4 mpg, the Spit VIII, carrying a large drop tank and a lot of internal fuel (total 213 imp gallon) , the Spit got 4.9 mpg.

And the Spit is of course much bigger.
The outdated supercharger control of the Merlins meant that they could only produce high outputs at a very narrow altitude range, only at their FTHs, whereas the DBs produced good power at a very wide altitude range.
A fixed supercharger gear produces better output above FTH too. You don't get any slippage, so less wastage.

That's one of the reasons the two stage Merlins generally outperformed the Db 605s.
The Germans were experimenting early on with intercooled engines, but they never put them into production for this very reason, the extra bulk and weight neutralized the extra power output which was gained, and was much simplier to do without them.
The Mustang seems to have managed OK.
The latest two staged DB 605`s high altitude performance simply paled that of the Merlin, or Griffon was capable of.
Which engine is that, the Db 605L? The engine that may have seen service in up to 2 109s before the end of the war?
Short answer to your question is the 2 bombers on top of your list use turbosuperchargers. However as you noticed the German supercharged bombers make a compact block on a honorable 3rd place, above the Allied supercharged bombers.
The Americans used turbochargers, the Briish in most cases didn't use high alt bombers, but still made some for special purposes.

The Wellington VI, with Merlin 60 series engines, had a service ceiling of over 11,500m, the Lancaster VI, with Merlin 80 series, which became the Lincoln, over 9.000m, and of course the Mosquito B XVI, which was in widespread service, over 10,000m. (The Mosquito XVI recomended profile was begin cruise at 28,500 ft, arrive at target at 29,500ft, at up to 408 mph, all whilst carrying a 4,000lbs bomb.)

Note that these are just supercharged engines with no fancy additives. They did use NO2 injection on some night fighter Mosquitos, with a 30 mph gain in speed above FTH, but I don't think they ever bothered on the Mosquito bombers.

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Post by Erich » 30 Aug 2004 22:01

I am going to back up slightly. Witch King what is a Ju 88G-7 ?

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lack of a ....

Post by Grünherz » 31 Aug 2004 07:09

Hop wrote:

As a matter of interest, does anybody know if that's what caused Marseille's death? He was flying a new 109G.
Hope that I got this quote right. Marseille was returning from a mission when his engine cought on fire. He bailed out but hit the rudder and never opened his parachute. I don't know how this might relate to the engine specifications.
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Post by Witch-King of Angmar » 31 Aug 2004 09:22

Erich wrote:I am going to back up slightly. Witch King what is a Ju 88G-7 ?
Ju-88G was the late nightfighter version of the Ju-88, developed from the Ju-88C. G-7 was the last edition of the G-series, operated from late 1944 to early 1945.

http://users.belgacom.net/aircraft1/avion1/180.html scroll down

http://www.kotfsc.com/thunderbolt/ju-88.htm

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Post by Erich » 31 Aug 2004 14:17

let me point something out............

The G-6 version was the very last of the Ju 88G breed, the link information is quite incorrect. Also there was not an A, B or C models either. I am writing a book on the G-6 and their crews.........the first G-6's to appear were in September of 44 but did not get into front-line units till November and were used till war's end.

Tottles

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Re:

Post by Cantankerous » 15 May 2022 21:24

Huck wrote:
27 Aug 2004 23:31
Topspeed wrote:So a He 177 Greif was a genuine 4 engine bomber right ?
Yes and no. It was operated like a 4 engine bomber, but the 2 coupled DB605 got a distinct engine designation: DB610.

But unless we want to be completely formal then yes, He-177A was a 4 engine bomber.
The only He 177 variant that truly had four engines was the He 177B, of which four prototypes were converted from He 177A airframes and fitted with four individual Daimler-Benz DB 603s. The first He 177B flew in December 1943, and there was also a large four-engine high-altitude derivative of the He 177, the He 274, which was manufactured at the Farman factory in northern France. Although He 177B was considered in some pre-recent books on German military aircraft of World War II to be a cover designation for the Heinkel He 277 long-range anti-ship aircraft project, but Heinkel documents and RLM correspondences (see Smith and Creek 2008 & Griehl and Dressel 1998) make clear that the He 277 was a different aircraft than the He 177B.

References:
Griehl, M., and Dressel, J., 1998. Heinkel He 177-277-274. Shrewsbury, UK: Airlife Publishing. ISBN 1-85310-364-0.
Smith, J.R., & Creek, E.J., 2008. Heinkel He 177 Greif Heinkel's Strategic Bomber. London, UK: Ian Allan Publishing. ISBN 978-1-903223-93-2.

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