1941: the best V-12 engine

Discussion in 'Aviation' started by tomo pauk, Oct 1, 2012.

  1. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Out of the V-12 that were in production (so no prototypes, nor one-offs, but at least 500 produced) in 1941, what one should be considered as the best? The contender need to have plenty of power, both for take off and at altitude, while being of decent reliability (meaning it's really powering planes in flight), and suitable for the mass production. Weight size do matter, a lighter smaller engine for the same power has the edge. In case you thin that a special feature of an engine should adds 'points', please post about that. You can also state your champion and a runner up, making sure that you elaborate your choices.
     
  2. Shortround6

    Shortround6 Well-Known Member

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    You only have four choices.

    Allison

    Merlin

    DB 601

    Jumo 211.

    Reliability and durability are already the subject of dispute and "suitable for the mass production" is also in dispute with few good numbers really available. Due to some rather large discrepancies in official "exchange rates" of currency just quoting the "cost" of an engine and using the exchange rate to claim one is cheaper than other and so is easier to produce is not a good argument.

    Surprisingly (or not :) ) the four contenders are very close in physical size (length, width and height) and more importantly, in weight. Power out put in 1940/41 is still fairly close as the Allies haven't taken full advantage of the better fuel to really push the manifold pressure yet.
     
  3. DonL

    DonL Banned

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    #3 DonL, Oct 1, 2012
    Last edited: Oct 1, 2012
    At 1941 I think it was a very closed match between the Merlin 45 and the DB 601E as best produced V-12 engine in numbers.

    One out of this two engines.

    Edit.

    The Allison lagged too much at altitude through it's single stage supercharger.
    The Jumo 211 was too large and too heavy for it's performance output at this time.
     
  4. Juha

    Juha Well-Known Member

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    Of those two I'd pick up 601E. Maybe I'm biased because I really like 109F-4.

    Juha
     
  5. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Hi,
    While I do agree that RR and DB were evenly mathched, why would we consider the 211 as too large to heavy for the power it was delivering?
     
  6. DonL

    DonL Banned

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    Jumo 211 F: 1340PS

    lenght: 2172,5 mm
    width: 804mm
    height: 1053mm
    Dry weight without intercooler 720kg

    DB 601E: 1350PS

    lenght: 1722mm
    width: 739mm
    height: 1027mm
    Dry weight without intercooler 610kg
     
  7. Shortround6

    Shortround6 Well-Known Member

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    May I ask where those numbers come from as a few of them don't seem quite right. Unfortunately some sources mix lengths of engines with and without propeller shafts and some accessories, like starters and generators.

    There is little doubt that the Jumo was a bit wider and higher but length and weight seem a bit off. I am not saying the Jumo was shorter or lighter but but 450mm longer and 110kg heavier?
     
  8. DonL

    DonL Banned

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  9. gjs238

    gjs238 Well-Known Member

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    Which of the 1941 engines were 2-stage supercharged?
     
  10. wuzak

    wuzak Well-Known Member

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    Perhaps he means the low critical altitude of the Alison.
     
  11. GregP

    GregP Well-Known Member

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    The Allison didn't have a low critical altitude. It was about the same as all other single-stage single-speed supercharged engines. The Allison was designed with a turbocharger as the high-altitude component and it was removed by the USAAF from the P-39 and P-40 due to lack of turbochargers for all planes. Theyw ere saved for the bombers and the P-38 only. Unfortunately for my love of the Allison, even WITH the turbocharger, it still had issues in 1941 that were corrected by early-to-mid-1943, but were not yet fixed in 1941.

    So I'd have to pick the DB 601 inverted V-12 by virtue of it's fuel injecttion rather than a carburetor. Of course, if picked, I'd mandate an elctric starter!

    If you delete the electric starter, I'd pick the Merlin. Fuel inject the Merlin and I'd pick it first. Of course, if you improve the Merlin, then I'd get tio fix the intake and carburetion issues with the Allison, too ... so it stands for me as DB 601 if electric starter equipped and Merlin if not. By the way, the electic starter for the DB 601 was and IS a bolt-on item, not a big "fix." Of course, they'd also have to fit a battery, but that also is not a big problem or a large weight gain.
     
  12. wuzak

    wuzak Well-Known Member

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    Greg, the Merlin 45 was a single speed single stage supercharged engine, and its critical altitude was 5-6000ft more than the Allison's.

    P-40 was never intended to have the turbo. It was designed from the outset to take the altitude rated engine. Or the altitude rated engine was created for the P-40.

    The P-39's turbo installation was woeful, and the aircraft was probably too small for the systems.
     
  13. GregP

    GregP Well-Known Member

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    Don't buy it Wuzak.

    5 - 6000 feet is not important when you have 15,000 - 20,000 foot ceiling and you need 25,000 - 35,000 feet. Neither one was sufficient for Europe and BOTH were OK for the PTO and MTO.

    Don Berlin was allowed to build ONE turbocharged P-40 and it flew VERY well at 30,000+ feet. It was never adopted, but Don intended it to be a turbo unit after the first few ... but was never allowed to do so. The XP-39 turbo unit WAS woeful, but the P-63 fixed all that and was a VERY good high altitude fighter that was about 12 mph slower than the P-51D at the P-51D's best altitude. At many other altitudes, the P-63 was faster, rolled better, climbed better, and turned better. Of course, it still had the abysmal Oldsmobile cannon ... and that was just plain awful, but was never the fault of the airframe.

    The performance numbers were not the 39" of MAP usually used in tests, but 59"+ inches of MAP used when the engine was allowed to be run correctly. Look at the available P-63 graphs and you will see it plainly. Look at 10,000 feet - 20,000feet, and 30,000 feet. The best top speed will vary and the P-63 with the Aux supercharger stage didn't have the dogtooth in the speed graph that the 2-stage Merlins had. It had ONE top speed, not two. It also handily out-climbed the P-51D.

    However, once the similarity to the P-39 was seen, teh USAAF didn't take the P-63 seriously. The Soviets DID and used it VERY effectively. Wish WE had.
     
  14. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Thanks. BTW, should we consider the DB601E as a 1350PS machine in 1941?

    Mech supercharger V-1710s did have low critical altitude. Those were equipped with carburetors (Stromberg PD-12K)of 24,4 sq in of throat area, matching the supercharger inlet. The early mech supercharged V-1710s have had the PD-13 carb, with 41,3 sq in throat area, but the ducting was narrowing down to those 24,4 sq in, to match the supercharger inlet. Contrary, the V-1650-1 was featuring the PD-16 carb, with 38,3 sq in, and no narrowing down after that. So basically the V-1710 featured a restrictor, that was 'stealing' critical altitude.
    It was estimated by Allison that it would take them 1 to 2 years to redesign the supercharger inlet area, so that idea was discarded
    source: Vee's to victory, pg. 325
     
  15. wuzak

    wuzak Well-Known Member

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    Which wasn't sufficient for the ETO? 15-20,000ft ceiling?

    P-40E's ceiling was 29,000ft and Spitfire V's 35,000ft.

    The extra 5-6000ft critical altitude made a large difference to the performance at altitude.


    When was the turbo P-40 built? They'd already built a turbo V-1710 version of the P-36 - the X/YP-37.


    The P-63 was significantly bigger than the P-39, but did not have a turbo. It didn't have the XP-39's air:air intercooler either, using either a liquid:air intercooler (like the Merlin's) or none (used ADI instead).

    The P-63 relied on Allison's 2 stage development, which took some time.
     
  16. wuzak

    wuzak Well-Known Member

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    Just comparing the P-40E and Spitfire V tests at wwiiaircraftperformance.org.


    P-40 Performance Tests
    Spitfire Mk V Performance Testing

    From these it can be seen that the P-40E's best speed was 342mph @ 11,400ft and 340mph @ 15,300ft.
    The Spitfire V's speed at 10,000ft was 331mph, at 15,000ft it was 351mph and at 20,000ft it was 371mph.


    Climb wise the P-40E's maximum rate of climb was 2400ft/minute at 10,000ft. At the same altitude the Spitfire V's RoC was 3250ft/minute, and at 20,000ft the RoC was 2440ft/min.

    So 5-6000ft of difference in critical altitude can make a lot of difference.
     
  17. DonL

    DonL Banned

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    The DB 601E had 1350 PS emergency power at 2700 rpm and 1,42 ata and
    1200 PS "fighting" power at 2500 rpm and 1,30 ata.
    Official sources differ at the clearance of the emergency power (1350PS) mostly claim end of 1941.

    The DB 601E with the Bf 109 F-4 had it's best outputperformance at 6200m (20341 ft) with max speed of 660 km/h (410 mph) at 1,42 ata 2700rpm
    At 8000m (26246 ft) the DB 601E with the Bf 109 F-4 was still at 649 km/h (403 mph) at 1,42 ata 2700rpm

    With steig und Kampfleistung normal (fighting) power at 1,30 ata and 2500 rpm/ Bf 109 F-4:

    Best outputperformance at 6200m (20341 ft) with max speed of 635 km/h (395 mph)
    At 8000m (26246 ft) max speed was 620 km/h (385 mph)

    Source Kurfürst:
    Kurfürst - Mtt. AG. Datenblatt, Me 109 G - 1. Ausführung
    Kurfürst - Mtt. AG. Datenblatt, Me 109 G - 1. Ausführung

    This is a much much better altitude performance then the P40 with an Allison with single stage, single speed supercharger.
     
  18. Jabberwocky

    Jabberwocky Active Member

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    Those are the headline acts, to be sure, but you've got a couple of other acts at this festival as well. From Russia there is the AM-35 and the M-105P (a much reworked and enlarged H-S 12Y rated up to 2700 rpm and a very solid 1200-1250 hp), you've also got the wonderful Italian Isotta Fraschini Delta, a 27 liter air cooled V12 capable of around 700-800 hp.

    I'm not enough of an expert to pick the engines apart technically, but the sound of the Merlin makes the hair on the back of my neck stand up, so I'll choose it on that alone.
     
  19. fastmongrel

    fastmongrel Well-Known Member

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    Does anyone know when the Ford V 12 would have been available if development had continued. Done a bit of googling and cant really find any info on it, was it a possibility for 1941.
     
  20. fastmongrel

    fastmongrel Well-Known Member

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    Apart from the negative G problem which I believe was sorted during 1941 with a bodge and cured later with the Bendix type carb what advantages did fuel injection have over a carburettor. As far as google will tell me the only Merlin to have fuel injection was the M120 tank engine did RR ever build fuel injected Merlins to try the technology out. There must have been plenty of DB and Jumo engines to examine and copy so what work was done on fuel injection in Britain during wartime.
     
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