Licence built DaimlerBenz V12s, what was the problem

Discussion in 'Aviation' started by fastmongrel, Dec 13, 2015.

  1. fastmongrel

    fastmongrel Well-Known Member

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    #1 fastmongrel, Dec 13, 2015
    Last edited: Dec 13, 2015
    Another thread started me on this train of thought. What was it that meant that the licenc built DB engines never seemed to live up to the engines built by the Germans. I can find three companies Alfa Romeo, Kawasaki and Aichi that built DB engines and plenty of claims they werent as good as the original but no info on why that was.
     
  2. tomo pauk

    tomo pauk Creator of Interesting Threads

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    From what I can gather, the Aichi Astuta was the one with problems, Kawasaki and Italian produced engines were okay. Aichi was to produce engines for the Navy needs, the Kawasaki for Army.
    The Kawasaki-own development, the Ha-140, seems to ba a problematic engine too, leading to the installation of the radial engine in the Ki-61 airframe that become the Ki-100.
     
  3. stona

    stona Well-Known Member

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    I've not seem it claimed that the Italian built engines performed worse than the German built ones. They were interchangeable and at least some pilot's notes I've seen give the same instructions for both (as far as I can tell with my limited Italian).
    I've seen it claimed that the Italian engines had a higher output, but this is, I think, due to a misunderstanding of which version of the Daimler Benz engine was being produced under licence.

    I can't comment on those built in Japan.

    Cheers

    Steve
     
  4. fastmongrel

    fastmongrel Well-Known Member

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    Spent a while on google and English language info on Japanese and Italian engines is frustratingly sparse. I am only going on fragments but it seems the Japanese models had problems with crankshafts, crank bearings and lubrication.

    All the information I have found on the Aichi Atsuta V12 could be written on the back of a stamp with a marker pen.
     
  5. davebender

    davebender Well-Known Member

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  6. GregP

    GregP Well-Known Member

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    When I was working out at Joe Yancey's shop, we had a fellow come in who talked a bit about the Japanese version. Seems that after the war several Ki-61s made it over here and got tested by our pilots. One of the Ki-61s was being flown by one of the test pilots and had an engine problem. This particular test pilot was also a mechanic. He nade the rather unusual choice to remove the engine and look at it. What he found was that there are oil passages in the main block, but the Japanese had failed to drill a couple of them into the nose case. So ... the engine ran fine until the oil in the nose case all got returned to the tank but never got replaced. Then the engine would run for some 30 - 40 minutes while getting hotter all the time, until failure happened.

    Now this tale is heresay, but should not be hard to validate, assuming one has access to an Atsuta engine. Obviously, I don't. Since that time, I have heard this same assertion several times, but no confirmation from any source.

    So it sort of remains an interesting possibility that probably should be investigated, but which may never actually be so. I repeat this here for information only but don't claim it to be fact since I don't know. Whatever the reason, the Japanese were never able to field a good liquid-cooled V-12 in WWII.

    I haven't ever heard or seen any big complaints about the Italian versions, but have read they generally produced about 100 or so less HP than the German versions. Why this should be is anyone's guess. I'd hazard a guess that engine plans don't exactly show all processes steps and it could be that the finish on one or more parts was simply not quite the same. In a 1,475 HP, 100 HP is significant, but not greatly so. The addition of another 100 HP in, say, a Regianne Re.2005 might have made a small difference in performance, but would never have influenced the number of them produced.
     
  7. tomo pauk

    tomo pauk Creator of Interesting Threads

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    I would not be so sure that Italian-produced DB 60X produced less power than it's German counterpart. The difference might lay in that the Italians (and Japanese) produced the DB 601Aa, the small letter 'a' meaning 'ausland', or 'for foreign country'. The 'Aa' was making 1100 PS, or 100 PS more for take off than the 'A', and at rated height of 3.7 km power was 1100 PS. Above 4 km, the 'A' was a bit better (all altitudes are for no ram).
    The 'Aa' of German production seem to went in the fighter-bomber versions of the both Bf 109 and 110.
     
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  8. GregP

    GregP Well-Known Member

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    It's what I have read over many years, Tomo. That said, you could be right. The many items I have read on it mentioned a bit less HP, but I don't recall them dwelling on the exact model of engine the "Tifone" was supposed to be. The slightly less HP was mentioned. I may have to go back and look that up since your observation may account for it.
     
  9. GrauGeist

    GrauGeist Well-Known Member

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    The "Tifone" was the DB605 manufactured by Fiat as the RA.1050
     
  10. Aozora

    Aozora Well-Known Member

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    According to Nicholas Millman in Ki-61 and Ki-100 Aces https://ospreypublishing.com/ki-61-and-ki-100-aces

    The Ha-140 that was supposed to power the Ki-61 II series had improved inlet flow, strengthened supercharger, higher compression and a water-methanol injection system; it suffered from excessive vibration, main bearing failures and oil leaks.

    All in all, the Ha-40 and Ha-140 had potential, but both were underdeveloped. Added to that, New Guinea must have been the worst possible place in which to debut both the engine and the fighter en-masse. It was at the end of a very long supply chain, and no thought seems to have been given to having a cadre of properly trained mechanics to support the Ki-61.
     
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