Superchargers?

Discussion in 'Aviation' started by tomo pauk, Feb 24, 2014.

  1. tomo pauk

    tomo pauk Creator of Interesting Threads

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    What I'm after is this: is there a one-stop on-line reference around? Specifically, I'm interested about supercharger systems used in piston engines, from late 1930s to late 1940s. Preferably, with as small flag-waving as possible :)
     
  2. Shortround6

    Shortround6 Well-Known Member

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    I am not even sure there is a one stop print reference :)

    You can certainly find books with chapters on supercharger theory and formulas but actual details of individual superchargers seems to be pretty spread out.

    The Merlin was pretty prolific as far as superchargers go, with a variety of gear ratios and different sized impellers (at least 4) and at least 3 different inlets on the single stage superchargers alone. Maybe somewhere there are documents with supercharger maps or charts for all the variations.

    Same with a number of other companies. The superchargers were modified over time with not only different sized impellers but different numbers of 'blades', the geometry of the inlets changed, the number and shape of the inlet vanes changed and the diffuser changed even for superchargers that kept the same nominal impeller diameter. These changes could affect air flow and efficiency even at the same gear ratios. These records may or may not exist in company records anymore.
     
  3. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Guess you're on the money there. I'm a bit more interested in applications, than in theory, but will look at anything decent that I can learn from.
     
  4. Balljoint

    Balljoint Member

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  5. tomo pauk

    tomo pauk Creator of Interesting Threads

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    A worthly reading. Guess I'll try to make a set of articles about supercharger systems of ww2 :)
     
  6. Shortround6

    Shortround6 Well-Known Member

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    This site may have a fair amount of the information you need. Unfortunately it may be scattered through a number of threads. :(
     
  7. rinkol

    rinkol Member

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    You can find a number of NACA reports on superchargers and various other aeronautical topics in the NACA archive on the NASA web site (I tried posting a link, but this was forbidden for some reason). In some cases, these are translations of foreign documents.
     
  8. OldSkeptic

    OldSkeptic Active Member

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    Read Stanley Hookers biography "Not much of an Engineer", put quite few equations in there.
     
  9. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Thanks for feedback, people.
     
  10. Shortround6

    Shortround6 Well-Known Member

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  11. Balljoint

    Balljoint Member

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    Apparently NACA was tasked with improving the supercharger performance but found the engine itself was lacking. Just an opinion, but it would seem that the engine may have been unlike their previous experience with radials and turbocharging.

    http://history.nasa.gov/SP-4306/ch2.htm
     
  12. tomo pauk

    tomo pauk Creator of Interesting Threads

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    I take it you mean this, from the NACA's page:

    Am I the only one that finds this except misleading?
     
  13. gjs238

    gjs238 Well-Known Member

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    There were several misleading statements in that document.
     
  14. Balljoint

    Balljoint Member

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    Two things struck me as pregnant. I had thought that the Allison supercharger problem was the result of Allison’s lack of corporate funds and lack of military concern. But Arnold was apparently on top of the matter and requested the NACA effort. However, the NACA guy Pinkel was a turbo man with good results on the B-17 but at sea as to how to package and drive a supercharged inline engine. It may be reading a bit too much into a few lines, but not at least replicating and adapting the extant Merlin supercharger tech meant the escort P-51 was delayed. It should have been doable.
     
  15. m37b1

    m37b1 Member

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    I'd call it a bit misleading, or at least in need of expanding on. The basic mechanics of the reciprocating assembly of the Allison, were very much the equal of the Merlin. I'd say the combustion chamber was actually superior on the Allison. I'll never take any of the excellence away from the Merlin, but that statement really needs to be backed up with detail.
     
  16. Shortround6

    Shortround6 Well-Known Member

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    Something to remember is that Army power plant division thought that the IV-1430 hyper engine was the "answer" to the liquid cooled engine question for quite some time. Continental simply built bits and pieces to Army specifications. Some of the Army "experts" had a lot of prestige and pride invested in the hyper concept. How much of this transferred over to the NACA I don't know.
     
  17. tomo pauk

    tomo pauk Creator of Interesting Threads

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    Fine points there.
    We might see that failure of the IV-1430 was never mentioned in the article, yet Arnold's condemning comments about US engines' manufacturers can be read easily:

    In late 1942, both UK and Germany were trying to develop the engines that were neither small, nor light (Sabre, Griffon, Centaurus, DB-603, Jumo 213/222, BMW-802). The USAC/USAF never put much faith before 1942 in two-stage engines either - why all of the sudden accusing the manufacturers for not designing the stuff the main costumer isn't asking for? If there was no USN and P&W cooperation, the P&W 2-stage ('highly supercharged') engines would've likely never existed. Even Wright produced 2-stage variant of the R-2600, though just as prototype (prototypes?).
    Contrary to that, USAC/USAF favored turbo, and that does not mean small, and by extension, does not mean light. Insistence for turbo meant that engine-stage compressors were of modest size, too.

    That is dated as of "3 November 1941".
    The R-2800 was at that time (and any other time) a far better engine than BMW-801. In late 1941, the lack of fuel injection was not a thing holding back the R-2600, but a better layout of exhaust, that was solved mid-war. The 801 was somewhat smaller, but R-2600 was far more reliable, despite some Curtiss muddling.

    Here is the reply (dated 11 December 1942) from P&W to the Arnold's accusations of 14 October 1942, a footnote from same web site:

     
  18. Shortround6

    Shortround6 Well-Known Member

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    Kind of a case where the right hand didn't know what the left hand was doing. You are not going to build "small" (1200-1400 cu in engines) that are "highly supercharged" without fuel well in advance of the plain 100 octane stuff the US was using in 1940 and into 1941. It is also a bit amusing in that both the Lycoming 1230 and Continental 1430, which had the most Army input (read meddling ) weighed about the same as the Allison and, at least in length, were significantly longer.
     
  19. OldSkeptic

    OldSkeptic Active Member

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    Thank god for Roll Royce then. It was powerful enough and tough enough (under the great Hives) to ignore that nonsense from idiots.

    People, especially Americans (who have a talent for reinventing history), underestimate how important RR was to creating the Merlin Mustangs. The USAAF didn't want it, NA had some vague ideas but were trying to survive against official obstruction from the USAAF (it's only customer really was the British). The Air Ministry didn't want it (especially Portal) , MAP didn't want it, there were official instructions from those to RR to NOT DO IT, Hives ignored them and told it team to go ahead... hence the Merlin Mustang X... which was a god send to Arnald trying to get some, against endless US and UK opposition, a decent LR fighter.

    To be fair I think NA then stuffed up because it took nearly another year to produce the P-51B... it would have been much better to just slap Merlins into P-51As and get them out of the door fast (like a Spit V to Spit IX thing). So instead of P-51Bs arriving in late '43 in very small numbers could have been lots of P-51x's in say March/April 43... but hey Govt/corporate politics....heck the Merlin X was superior to the (much) later P-51B....at least it had guns that fired....

    Thinking about it it would have been much smarter to ship P-51 shells across to the UK and let RR convert them....since NA took soooo long to produce a fast, but fairly average and buggy plane, with rubbish and unreliable guns and crappy vision (and a tendency to lose tails). RR was far better at that sort of thing and as master of mass production could have (given their clout with the UK Govt, not even Portal would dare to cross swords with RR, though he did quite happily do that with Arnold) converted heaps of them to become superb planes long before they actually did.
     
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  20. tomo pauk

    tomo pauk Creator of Interesting Threads

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    <gets popcorn>.
     
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