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Thread: Allison V-1710 Supercharger Impeller

  1. #16
    Senior Member kool kitty89's Avatar
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    Admiral, looking through the data (as well as some articles on the P-39/P-63) many of those 2-speed engines you refer to are actually the early 2-stage versions. (lacking intercooler) It is mentioned in the engine description, though only one impeller size is mentioned.

    The -45 (F7R) is the same as the -39 (F3R) of the P-40D/E but with the auxiliary supercharger stage, 9.5" impeller listed. (for aux stage?) It apears to be the first (at least in the F series) to use the auxiliary stage. The -47 (not mentioned by you) is similar but of the E series with extention shaft and remote reduction gearing. (XP-39E/XP-76 and XP-63) The -93 was used on the production P-63A.

    I'm not sure about the -57 model though, according to the chart it had a 2-speed supercharger with "Birmann impeller" of 10.25" and was used on the F-5A, P-38F, and XF-5D lighning. (the altitude ratings of this engine would indeed seem to corespond to a slingle stage 2-speed engine, though the use on the Lighting would seem odd -except perhaps for testing purposes)

    The -97 apears to be a single-stage two-speed model, this time with the larger 10.25" supercharger. It seems to be mislabeled in featuring a turbocharger in the charts. The first of the G series.

    The 101 was an F series engine with auxiliary supercharger and carburetor between the stages.

    The 109 was another E series engine similar to the -93 but with carb between stages, modified crankshaft, and different supercharger gearing with significantly better high altitude performance.

    I think the 111 is a mislabeled turbocharged engine as the altitude performance is far too high and the supercharger (9.5") gearing is fairly low. (though strangely 2 speed figures are given) And since it was the engine of the P-38L.

    The 131 is similar to the -97, G series with single stage 2-speed 10.25" supercharger.




    The G series sees the introduction of the 10.25" impeller. All of the F series (except for the odd F11R -57) have the 9.5" impeller. It also apears that early 2-stage F models may have a 9.5" impeller for the aux stage as well.
    Last edited by kool kitty89; 12-08-2008 at 02:00 AM.

  2. #17
    Senior Member Elvis's Avatar
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    Quote Originally Posted by kool kitty89
    Admiral, looking through the data (as well as some articles on the P-39/P-63) most of those 2-speed engines you refer to are actually the early 2-stage versions. (lacking intercooler) It is mentioned in the engine description, though only one impeller size is mentioned.
    KK,

    If only one impeller is used, doesn't that make it a single stage system?


    Elvis

  3. #18
    Senior Member kool kitty89's Avatar
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    Only one size is mentioned, but if the impellers of both stages were identical it may not have been listed. (some of the data seem to have been listed rather confusingly, only two gear ratios seem to be listed as well)
    Hence my comments in the last paragraph.

    Such engines specifically mention an auxiliary supercharger.
    Last edited by kool kitty89; 12-08-2008 at 02:07 AM.

  4. #19
    Senior Member Elvis's Avatar
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    Good point.
    Thanks.


    Elvis

  5. #20
    Senior Member kool kitty89's Avatar
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    Another thing to note is that nearly all the models listed are odd numbered, virtually no even numbered models are listed. This doesn't really matter for the V-1710 as most, if not all of the models actually used on aircraft (even prototypes) were odd numbered. The same would go for the V-1650 with the -1/3/7/9 being used operationally.

    However for several other engines (ie R-1820, R-1830, R-2800, R-2600) this means many of the models used on operational aircraft (not to mention prototypes) were even numbered. (like the R-1820-40 of the F2A, the R-1830-76/86/90 of the F4F and R-1820-56 of the FM-2)
    Last edited by kool kitty89; 12-08-2008 at 05:24 PM.

  6. #21
    Senior Member Elvis's Avatar
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    Wouldn't that simply be a fact of those lists.
    They match engines that were actually used in service....so maybe the even numbered Allisons were experiementals and thus, don't relate?

    ....JMHO

    Something else this thread reminded me of.
    Have you seen this before? - Allison V1710 Engine
    Relates more to usage in Unlimited Hydroplanes, but some good info on the history of the engine.
    Might not neccessarily help you, in regards to this particular thread, but it emlightened me to some facts about its history that I was unaware of prior.



    Elvis

  7. #22
    Senior Member kool kitty89's Avatar
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    That wouldn't explain the listed radial engines though.

  8. #23
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    I think you may find clockwise rotation engine is odd number and anticlockwise even numbered

  9. #24
    Senior Member kool kitty89's Avatar
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    No, at least not for the V-1710 (not sure about the radials)

    The V-1710-29 was the F2L model, the -53 was the F6L, the -55 was the F10L, the -77 was the F15L, the -91 was the F17L, and the -113 was the F30L. (all are also P-38 engines)

  10. #25
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    US Engines in WW2

    Production of aero-engines for US armed services required that engines for the ARMY had ODD dash numbers and engines for the NAVY had EVEN dash numbers.

  11. #26
    Senior Member kool kitty89's Avatar
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    Thank you. (that would explain it) There doen't seem to be a similar Navy engine article, but there's a lot more info here: Reference

  12. #27
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    Actually Red Admiral, Dan Whitney in his superb book Vee's for Victory is right and you are wrong. You are wrong in your interpretation of the Model Designations of U.S.A.F. Aircraft Engines table and wrong in discrediting a book you have obviously not ever even opened.

    The -45, -93, -109 and -101 Allisons are two stage engines with a single speed gears driving the main stage and another set of single speed gears driving a variable speed hydraulic clutch for the auxiliary stage.

    the -111 uses a single speed mechanical supercharger along with a GE turbocharger in the P-39.

    The one and only experimental -57 used a two speed single stage "mixed flow" "Birmann" (named for the designer) supercharger from the Turbo Engineering Company of New Jersey. Like the experimental Birmann turbochargers TEC produced in very small numbers for the U.S. Navy during the Second World War performance was about equivalent to designs already in mass production.

    The -97 was a late war experimental single speed single engine with a 10.25 inch diameter supercharger. Either 7.48:1 or 9.60:1 supercharger gears were used depending on the altitude performance required. Only three or four were produced.

    The -131 was a true two speed single stage engine produced in very small numbers (less than ten engines total) for the stillborn Douglas XC-114 and YC-116 in 1946. The Allison designation was V-1710-G-3R not V-1710-C3 as stated in the U.S.A.F. Aircraft Engines table.

    Dan Whitney documents several other experimental single stage two speed 1710s in Vee's for Victory. Altogether of the more than 69,000 1710s that were produced by Allison less than thirty had single stage two speed mechanical superchargers.

    Before reading Vee's for Victory I considered the Allison 1710 a second rate engine compared to the Roll-Royce Merlin. Rolls-Royce received millions from the British goverment to develop the Merlin while Allison received hollow promises from the USAAF. That's the real reason the Merlin became a better engine than the 1710.

    Red Admiral if you ever make the effort to read Vee's for Victory you will be enlightened.

  13. #28
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    Actually Red Admiral, Dan Whitney in his superb book Vee's for Victory is right and you are wrong. You are wrong in your interpretation of the Model Designations of U.S.A.F. Aircraft Engines table and wrong in discrediting a book you have obviously not ever even opened.
    One official primary source says one thing, a secondary source says another. From what you've said the primary source isn't clear and the two gear ratios listed are for both parts of the unit. However for other two speed engines the notation is exactly the same. I was hardly discrediting the book, just that the available information said differently. I've heard good reviews of Whitney's book, and if I ever see a copy at a reasonable price I'd probably get it.

  14. #29
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    Red Admiral first let me apologize for the tone of my previous post. I got a little excited when I saw your comment that Dan Whitney was wrong. Veeís for Victory is simply a fantastic book from a very talented author. Dan Whitney did an incredible amount of research and in my opinion deserves to be recognized as the authority on the Allison 1710.

    This isnít a case of a primary source and a secondary source saying two different things. What you call the primary official source, Model Designations of U.S.A.F. Aircraft Engines and what you call the secondary source, Dan Whitneys' Vee's for Victory, are in agreement except for one copy error and one typo in the Model Designations of U.S.A.F. Aircraft table. You simply have misinterpreted what the information in the Model Designations of U.S.A.F. Aircraft Engines table means.

    For example in the -45 row the Aircraft Engines table notes in the Description column that the -45 has an auxiliary second stage supercharger and in the Supch (Supercharger) column lists Geared, 9.5, 8.1:1, 6.85:1. Somehow you interpret that information to mean a single stage two speed supercharger. Vee's for Victory has much more information on the -45 which has a 9.5 inch primary stage supercharger driven by a 8.1:1 ratio gear set and an auxiliary supercharger driven by a 6.85:1 gear set driving a hydraulic variable speed clutch.

    If you understand the information in the Model Designations of U.S.A.F. Aircraft Engines table it is obvious that the -45 is not a single stage two speed engine.

    Similarly the -93, -101 and 109 are two stage engines which, if you had the luxury of being able to refer to Veeís for Victory you would know, have some minor variations to the basic two stage primary and auxiliary supercharger equipped -45.

    The -111 is a turbocharged engine used in Lockheed Lightning variants. I believe the Geared, 9.5, 8.1:1, 7.23:1 information in the Supch column is simply a copy error from the -109 and 109A information.

    The -57, -97 and -131 are indeed single stage two speed engines. Both sources agree on the details except for the typo in the Aircraft Engines table that designates the -131 as a V-1710- C3. The -C3 was a very early engine with the military designation V-1710-5 (XV).

    Your original post gives the impression that there were significant numbers of single stage two speed 1710s. On careful examination of the eight variants listed by you as single stage two speed engines only three can be classed in that category. The production of those three variants was less than two dozen total. So I think that I can say with certainty that single stage two speed 1710s were a minor footnote in the complex history of this interesting engine.

  15. #30
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    For example in the -45 row the Aircraft Engines table notes in the Description column that the -45 has an auxiliary second stage supercharger and in the Supch (Supercharger) column lists Geared, 9.5, 8.1:1, 6.85:1. Somehow you interpret that information to mean a single stage two speed supercharger.
    The list isn't consistant with itself. To me, that means a 9.5" diameter impeller with two gear ratios. If we look at the V-1650-1 which is a single stage two speed engine, its listed as 10.25", 8.150:1, 9.490:1 in the same manner as for the V-1710-45 but meaning something else. For two stage engines it usually gives both impeller diameters. Its only with more information its possible to see differently.

    Is there any mention of post-war use of V-1710s for hydroplane racing in Whitney's book? I occasionally hear claims of 4000hp+ which seem doubtful.

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