Bf-109 Performance Threads

Discussion in 'Old Threads' started by ridato, Mar 28, 2007.

  1. ridato

    ridato New Member

    Joined:
    Mar 11, 2007
    Messages:
    13
    Likes Received:
    0
    Trophy Points:
    1
    Occupation:
    Aerospace engineer
    Location:
    Montréal
    Here a british report for a captured Bf 109E. Very interesting.
     

    Attached Files:

  2. Micdrow

    Micdrow “Archive”
    Staff Member Moderator

    Joined:
    Aug 21, 2006
    Messages:
    7,716
    Likes Received:
    424
    Trophy Points:
    83
    Occupation:
    Manufacture Tech
    Location:
    Wisconsin
    Very cool ridato

    This will be where I add performance documents on Bf-109


    Many Thanks
    Micdrow
     

    Attached Files:

  3. flojo

    flojo New Member

    Joined:
    Jan 9, 2007
    Messages:
    27
    Likes Received:
    0
    Trophy Points:
    1
    The so called take-off and emergency rating (Start- und Notleistung 1.42ata) of the DB605A engine of the early Me109G was forbidden to use until late 1943 afaik. Does anybody know if it was allowed to use so-called climb and combat rating (Steig- und Kampfleistung 1.3 ata) for 30 minutes with these derated engines or was the maximum permissable duration for this power setting also decreased?
     
  4. Hop

    Hop Member

    Joined:
    Jul 11, 2005
    Messages:
    624
    Likes Received:
    17
    Trophy Points:
    18
    There's an English translation of the original German order forbidding 1.42 ata floating around. Try WWII Aircraft Performance

    It says that on older engines, and it gives worknumbers to identify which, the 1.3 ata climb and combat rating must be used only when operationally essential.
     
  5. flojo

    flojo New Member

    Joined:
    Jan 9, 2007
    Messages:
    27
    Likes Received:
    0
    Trophy Points:
    1
    Unfortunately on this page there is only a translation by british intelligence and not the original quote in german. But it would be extremely interesting what "operationally essential" means in this respect. As long as you dogfighting a spitfire - for a brief boost to break away from a fight - use it freely in air combat but not when cruising just to reach your destination faster ???? There is a wealth of possible interpretations.
     
  6. Hop

    Hop Member

    Joined:
    Jul 11, 2005
    Messages:
    624
    Likes Received:
    17
    Trophy Points:
    18
    Well, the fact that aircraft with strengthened pistons did not have the warning about only when operationally essential suggests that there was some risk in running at 1.3 ata in the older engines. It doesn't look like a fixed time limit, but they are only guidelines anyway.

    Basically, if you were prepared to risk your engine blowing you could use it as long as you liked :)
     
  7. flojo

    flojo New Member

    Joined:
    Jan 9, 2007
    Messages:
    27
    Likes Received:
    0
    Trophy Points:
    1
    I found the text you referred to in the section about comparing 109G with Spitfire MkIX. There only older engines were mentioned and that the problem why not to use 1.42 ata was due to pistons burning through. Where can I find the source that newer engines have stronger pistons not making them able to be used safely with 1.42 ata but making the hint to only use 1.3 ata "when operationally essential" obsolete. Is a longer portion of the text available somewhere on Mike William's page?
     
  8. Hop

    Hop Member

    Joined:
    Jul 11, 2005
    Messages:
    624
    Likes Received:
    17
    Trophy Points:
    18
    I'm not sure what's on Mike Williams site, but I have what I think is the complete teleprinter message as a scan (probably from Mike, or Neil Sterling).

    I won't type in the whole thing, but the relevant bits are:

    "The Take-off and emergency output with a boost pressure of 1.42 atm. and 2800 revs. may not at present by used. The climbing and combat output with 1.3 atm. and 2600 revs. may in the case of the older engines (for works numbers see below), be used only when operationally essential." (that's from Mike's site)

    It goes on later:
    "In engines with reinforced pistons the danger of their burning through is not so great as in the older version of the piston, but the takeoff and emergency output may still not be used."

    There's more saying older pistons will be replaced in refit, so I think the problem with 1.3 ata would have disappeared as time went on, unless some new problem occurred.
     
  9. flojo

    flojo New Member

    Joined:
    Jan 9, 2007
    Messages:
    27
    Likes Received:
    0
    Trophy Points:
    1
    Many thanks. I did not realize until now that problems also existed with 1.3 ata for the earlier DB605A engines.
     
  10. Brain32

    Brain32 Member

    Joined:
    Jun 1, 2006
    Messages:
    35
    Likes Received:
    0
    Trophy Points:
    6
    This is the report of bf109 high speed trials original document with translation to english.
     

    Attached Files:

  11. Kurfürst

    Kurfürst Banned

    Joined:
    Mar 13, 2005
    Messages:
    1,076
    Likes Received:
    1
    Trophy Points:
    0
    Occupation:
    legal field
    Location:
    Aquincum, Pannonia Prima
    The captured transmission effectively speaks about the greater wear of the pre-production DB 605A-0 engines, not the serial production DB 605A-1.

    1,42ata appears to have been cleared in 8 June 1943, and used operationally at Kursk, however it seems they were not entirely satisfied and recalled the clearance until Daimler-Benz finally brought a fix in September 1943 by installing oil de-aerators, which seems to be the root of the problem (bubbles forming in oil, reducing lubrication to nil).
     
  12. Kurfürst

    Kurfürst Banned

    Joined:
    Mar 13, 2005
    Messages:
    1,076
    Likes Received:
    1
    Trophy Points:
    0
    Occupation:
    legal field
    Location:
    Aquincum, Pannonia Prima
    The captured transmission effectively speaks about the greater wear of the pre-production DB 605A-0 engines, not the serial production DB 605A-1.

    1,42ata appears to have been cleared in 8 June 1943, and used operationally at Kursk, however it seems they were not entirely satisfied and recalled the clearance until Daimler-Benz finally brought a fix in September 1943 by installing oil de-aerators, which seems to be the root of the problem (bubbles forming in oil, reducing lubrication to nil).

    In any case, all engine and aircraft manuals which still note the ban on Notleistung give 30-minute limit for Kampfleistung just the same.
     
  13. Gatt

    Gatt Member

    Joined:
    Nov 7, 2006
    Messages:
    30
    Likes Received:
    0
    Trophy Points:
    6
    HOP,
    any chance you can scan and post here the original teleprinter message?
    Does anyone has it?
    Thanks for help,
    Gatt
     
  14. Kurfürst

    Kurfürst Banned

    Joined:
    Mar 13, 2005
    Messages:
    1,076
    Likes Received:
    1
    Trophy Points:
    0
    Occupation:
    legal field
    Location:
    Aquincum, Pannonia Prima
  15. Gatt

    Gatt Member

    Joined:
    Nov 7, 2006
    Messages:
    30
    Likes Received:
    0
    Trophy Points:
    6
    Thank you Kurfurst,
    have you ever seen the original of the document?
    Regards,
    Gatt
     
  16. Kurfürst

    Kurfürst Banned

    Joined:
    Mar 13, 2005
    Messages:
    1,076
    Likes Received:
    1
    Trophy Points:
    0
    Occupation:
    legal field
    Location:
    Aquincum, Pannonia Prima
    The German version you mean? No, but I would think it probably exists in BAMA or somewhere..

    However, the British one seems to be a mere translation, and can be found in the PRO (Brit National Archives) in Kew amongst the Me 109G papers.
     
  17. Gatt

    Gatt Member

    Joined:
    Nov 7, 2006
    Messages:
    30
    Likes Received:
    0
    Trophy Points:
    6
    Roger that. We (the Targetware-Target Tobruk MODers) are researching what happened in the Regia Aeronautica and Aeronautica Repubblicana (after september 1943) as far as the 1,42ata, 2.800rpm limit is concerned.

    The DB605A was mounted on the C.205, the G.55 and the Re.2005, however we dont know if and when the limit was canceled. So far, we discovered only one manual, the 1944 G.55's one, without any limitation.

    Regards,
    Gatt
     
  18. yogy

    yogy New Member

    Joined:
    Aug 12, 2005
    Messages:
    7
    Likes Received:
    0
    Trophy Points:
    1
    Occupation:
    Engineer
    Location:
    ER.DE
    The bann on 1,42 ata was released in autumn 1943
     
  19. brewerjerry

    brewerjerry Active Member

    Joined:
    Mar 19, 2007
    Messages:
    449
    Likes Received:
    61
    Trophy Points:
    28
    Location:
    over the hill and far away
  20. Ivan1GFP

    Ivan1GFP Member

    Joined:
    Mar 19, 2008
    Messages:
    636
    Likes Received:
    9
    Trophy Points:
    18
    Hello All,

    What does 1.42 ata manifold pressure correspond to in the US Inches of Hg?
    I believe it is 41.1 or 41.0 inches, but am not sure of the exact conversion factor.

    Thanks.
    - Ivan.
     
Loading...

Share This Page