Engine Comparison:

Discussion in 'Engines' started by enven, Oct 26, 2007.

  1. enven

    enven Member

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    Daimler-Benz DB 605AS (109g14) V.S. Packard Merlin V-1650 (P51b)

    Looking at the raw power of both, it seems that the P.Merlin V1650 had a boost (Pun intended) on the DB605...it seems though, having the raw power that the merlin has with what the 605 lacks; made up for the 605 in ceiling altitude...

    For every meter both planes climbed the DB 605 seemed to have ran more efficient...

    My question is:

    What were the factors that caused the DB 605 to perform 'better' at higher altitudes, and why did the Merlin 'weaken' due to the latter?

    (Am I wrong?)
     
  2. Kurfürst

    Kurfürst Banned

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    This comparison doesn't make me any sense; of course the V-1650-3/7 is a more powerful engine than the DB 601E, at all altitudes, but then : the 601E was introduced in mid-1941 into service, the V-1650-3/7 in early-mid1944. The contemporary would be the DB 605AS and D engines.
     
  3. enven

    enven Member

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    It was actually 1943...I did make a typo with the German Engine..as for Altitude, I had the idea that the air would cause the engine to have trouble...
     
  4. mad_max

    mad_max Member

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    There is so many variables that there is not a single easy answer. As for the 1650 (esp. in
    the B model) it depends if it the -3 or the -7 series. The -3 was the "high" altitude engine
    and the -7 was the "medium" altitude engine. They would have different flight envelopes.

    Are the performance numbers your looking at using 100, 100-130 or 100-150 PN fuel?

    Those are some things you need to specify before a comparision can start.

    Of course what can be said now is the engines are two different breeds. The 1650 uses
    a 2 stage 2 speed supercharger that is gear driven. The 605AS/D uses the enlarged
    single stage supercharger from the 603 combined with a fluid coupling. Both have their
    advantages and disavantages.

    The 1650 uses a lower compression ratio with higher boost pressures whereas the 605
    uses higher compression ratios with lower boost ratios. As I understand the theory is
    both had relatively the same combustion chamber pressures, but I'm not an engine man.;)

    The 605 has direct fuel injection into the cylinders...still the best way to get efficiency, plus
    with injection the fuel is atomized by pressure; thus lower volatile fuels can be used.
    The 1650 use what is call an injection carburator and the fuel is helped with atomization by
    going through the supercharger.

    The 1650 is a 27.02 liter engine and the 605 is 35.7 liters.

    That is the beginnings to an answer.

    From what I have read and studied in overall performance
    I'd be more inclined to say the 109 had the upper hand at lower alt. (20-23k) and the Pony
    had the upper hand over 25k. Really I feel they were pretty evenly matched aircraft and
    the one that had the advantage usually won the battle.

    IMHO and FWIW
     
  5. enven

    enven Member

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    Thank you very much; next time I ask a question I will have a bit more details/research involved.


    Thanks.
     
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