Propellor hub-firing machine guns.

Discussion in 'Weapons Systems Tech.' started by xtberia, Nov 4, 2007.

  1. xtberia

    xtberia New Member

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    Can someone please post a diagram and explain as to how propellor hub-firing machine guns in WW2 aircrafts, used to work?

    :?:
     
  2. Micdrow

    Micdrow “Archive”
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    Drawing shows it all.
     

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  3. Steven Que

    Steven Que Member

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    Hi Micdrow
    I want to know where are these pictures came from?
    That looks so good!
    It show the detail about the weapon system about WW2 fighter very good.
    I can see the machinegun's ammo came from where!8)
    I proud you as my teacher said to me!
     
  4. Micdrow

    Micdrow “Archive”
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    Hi Steve, For those that know me I have a little library of books and manuals. The drawning above came from a Bf-109 manual. The big thing when posting pictures is to size them properly for the forum but also make the legible to read. I have multiple programs for that Adobe Paint, Corel but by far the one I use the most it the paint program that comes with windows XP.
     
  5. Steven Que

    Steven Que Member

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    Wow! you have a little library yourself!
    I always found some data about aircraft from my college's library.
    But I have no much time to visit it.
    I will choose on of my favorite book and copy it's picture and article.
    Maybe one day I will show you my collections!
    :?: How to post some picture with article like yours? These pictures only come from Internet(Http://)? I have some pictures in my fileholder,I don not know how to post!
     
  6. Micdrow

    Micdrow “Archive”
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    You will need a scanner to do that. If you post a small article try and name the books title and auther. One think I seem to be bad about doing. :oops: If you are talking about the Adobe documents then you need adobe acrobat to create these type of documents. Hope that helps.

    By the way its a very small library. Maybe 600 books on various subjects from tanks, ships and aircraft. Not including my aircraft manuals. Most of the books are Hardcover, soft covered and in pdf format.
     
  7. Soundbreaker Welch?

    Soundbreaker Welch? Active Member

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    How many bullets would fire through a propeller at a time I wonder?
     
  8. Steven Que

    Steven Que Member

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    I want to know how to post pictures with article like Soundbreaker's P-51D...
    I am very confused. Is item "Insert image"?:confused:
     
  9. Micdrow

    Micdrow “Archive”
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  10. Graeme

    Graeme Well-Known Member

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    The Mauser MG 151/20 for the Me 109 F-4/R5

    [​IMG]

    And the Mk 103 30mm arrangement for the Do 335 V14.

    [​IMG]

    Both from Cutaway Aircraft of WWII, Argus Books, 1989.
     
  11. Steven Que

    Steven Que Member

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    [​IMG]
    Oh yeah! I see. Thanks~
    [​IMG]
    No cannon in this craft. Because it is Japanese's suicide bomb!
    "BaKa" is meaning "stupied" in Japanese.
     
  12. SoD Stitch

    SoD Stitch Banned

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    Totally depends on the weapon . . .

    I think what xtberia was getting at was how a weapon could fire through a crankshaft. The simple answer was it didn't, it fired through the reduction gear, not the actual engine. The barrel/blast tube usually went above/below the engine between the valve banks, and exited through the reduction gear, which was connected to the actual driveshaft.
     
  13. seesul

    seesul Active Member

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    Steven,

    if you wanna join a picture to your signature, micdrow already gave you an answer. If you ask for loading pictures to your post from your PC, just click on Manage Attachments in post replay or new thread and download pictures you want...
     

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  14. xtberia

    xtberia New Member

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    Sorry folks, I am a bit late in responding to your prompt replies. With very vivid details too, I might add. Many thanks to Micdrow, Graeme and Steven Que.

    Thanks too, to Stitch, for an insight as to how a gun would have fired through the propellor hub. However, without a picture or a drawing to aid in understanding how a reduction gear could have facilitated the entire arrangement, it becomes slightly difficult to comprehend.

    In any case, what I was actually trying to figure out as to how the machine guns could have been synchronized to fire through the propellor without hitting the blades, in the process. [For a more clearer understanding of my question, please could you refer to the Bf109 drawing as posted by Micdrow.]
     
  15. HoHun

    HoHun Active Member

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    Hi Xtberia,

    >In any case, what I was actually trying to figure out as to how the machine guns could have been synchronized to fire through the propellor without hitting the blades, in the process.

    Interrupter gear - Wikipedia, the free encyclopedia

    Note that typically for Wikipedia articles, it features some good stuff (the diagram of a WW1 era interrupter gear) mixed with some deliberate spin-doctoring.

    ("German and Soviet fighter types in particular were slow to abandon fuselage-mounted guns" - the truth is that everyone else "was slow to" adopt electrical synchronization that made synchronization rock. Naturally every air force wanted their guns as close to the centreline as possible to do away with convergence/divergence issues, it's just that it was a technological challenge to develop a reliable, fast-firing, high-firepower, synchronization-compatible gun that would fit neatly into the nose or wing roots of an aircraft.)

    Regards,

    Henning (HoHun)
     
  16. HoHun

    HoHun Active Member

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    Hi Welch,

    >How many bullets would fire through a propeller at a time I wonder?

    With a rate of fire of 13 rounds per second and an engine rpm of 2600 at a reduction ratio of 1:1.685, about two blades would pass by between each shot from one machine gun of the Me 109G.

    I don't know if both machine guns were individually triggered or combined. From the looks of the Me 109E synchronizer cover, it looks as if it had two independend sensors.

    Regards,

    Henning (HoHun)
     
  17. xtberia

    xtberia New Member

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    Thanks Henning. Great article.
     
  18. xtberia

    xtberia New Member

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    Thanks Henning. Great article.
     
  19. HoHun

    HoHun Active Member

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    Hi xtberia,

    Here is another sectional drawing, showing the pneumatical (or is it electric-pneumatical?) system of a British inter-war fighter:

    Vickers-Gun-interuptor-deta

    Regards,

    Henning (HoHun)
     
  20. Tony Williams

    Tony Williams Member

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    Neither electric nor pneumatic, I would assume: I believe that the RAF retained the hydrosonic CC gear (Constantinescu-Colley) from late WW1 until they stopped using synchro guns. This was not hydraulic, by the way, although the transmission media did consist of liquid-filled tubes. Basically, there was a mini loudspeaker at the prop end and a microphone at the gun solenoid. The signal was sent in the form of a sound wave (the speed of sound in a liquid is much faster than in air).

    Incidentally, it is misleading (although common) to call such systems "interrupter gear", which implies that the MG was firing on automatic and was stopped from firing by the synchro gear whenever a prop blade was in the way. Only the very first designs worked that way. For the rest, the MGs were converted to semi-auto fire and each shot was fired individually by the synchro gear as soon as the gun was ready to fire and the prop was out of the way.

    Losses in rate of fire depended on the synchro system and on the gun mechanism. The best was the German electric system, which lost only around 10% of the RoF. The worst was the US .50 BMG which lost around 40%. Most were around 25%.
     
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