Gun Elevation on M22 Locust

Discussion in 'Weapons, Technology & Equipment' started by Don Juan, Sep 17, 2021.

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  1. Don Juan

    Don Juan Well-Known Member

    Another specialised question here, but does anyone know what was the default elevation mechanism on the M22 Locust? The British fitted a free elevation lock on their Locusts, which of course suggests that the Locust employed free elevation (i.e. shoulder control), although I strongly doubt that the Americans adopted this method as a default.

    My suspicion is therefore that either the default was geared elevation, and the British removed the gear in order to facilitate free elevation, OR the Americans fitted an elevation gear that could be disengaged to permit free elevation.

    Does anyone have any insight into this?
     
  2. Christian Fletcher

    Christian Fletcher Well-Known Member

    According to Hunnicut page 484....

    Combination Gun Mount M53 (T55)
    Traverse - manual
    Elevation - manual +30 to -10 degrees by means of a hand wheel & gearbox to an elevating arc.

    Hope that makes sense!
    cheers
     
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  3. Don Juan

    Don Juan Well-Known Member

    Thanks very much! Yes, that confirms what I suspected - default geared elevation.
     
  4. DogDodger

    DogDodger Active Member

    Christian is exactly right. For reference, here's an image of the elevation mechanism from TM 9-724.

    [​IMG]
     
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  5. Chris C

    Chris C Canadian

    Am I right in thinking that the British would have made this change to Locusts they received in 1944?

    And does this represent someone desperately hanging onto the early war idea that free elevation was better because you could fire on the move? (Which experience had shown was not really a good idea in practice)
     
  6. Don Juan

    Don Juan Well-Known Member

    It's a bit of a complex issue that will be explained in a comprehensive book that will (hopefully) be released in the not too distant future.

    But, the short form is that the British Locusts were fitted with Littlejohn adaptors, which adversely affected the balance of the mounting, and so the switch to shoulder control was part of the cure for this.
     
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  7. Chris C

    Chris C Canadian

    Ahhh, that's interesting!
     
  8. Don Juan

    Don Juan Well-Known Member

    Contrary to popular belief, fitting a Littlejohn adaptor was A LOT more complicated than just screwing the adaptor itself to the muzzle end.
     
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  9. Richelieu

    Richelieu Well-Known Member

    This Héritage file reveals that technical issues with the traverse and trunnions had emerged during firing trials in March 1943 which may have informed developments. For the trials it says that “normal geared elevation had been removed and free elevation with lever control fitted”.

    Later reports deal with its vulnerabilities to enemy fire and mines.
     
    Last edited: Sep 19, 2021
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  10. Don Juan

    Don Juan Well-Known Member

    You wouldn't happen to have diagrams of the propeller shaft connections at the clutch and gearbox ends, would you DD?
     
  11. von Poop

    von Poop Adaministrator Admin

    Not really diagrams, but might help a little - glimpses of Driveshaft bits from Roberts's book (same manual).
    Locust 1.jpg locust 2.jpg Untitled-1.jpg
     
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  12. Don Juan

    Don Juan Well-Known Member

    Thanks very much VP!
     
  13. DogDodger

    DogDodger Active Member

    von Poop got all the TM images I saw upon flipping through the relevant sections; there don't seem to be good images of the installed prop shaft connections.
    [​IMG]
    Haven't made it to that one yet. Worthwhile, I presume? :)
     
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  14. Don Juan

    Don Juan Well-Known Member

    Thanks DD. I just wanted to make sure that the prop shaft was effectively the clutch output shaft, and not a separate shaft that was geared from the clutch output shaft I think it's pretty clear that it was the former.

    It was the weakness of the original design of prop shaft that was one of the reasons why the Locust missed Normandy, btw.
     
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  15. von Poop

    von Poop Adaministrator Admin

    It's 'OK'.
    WW2Talk - Book Review - US Airborne Tanks - Roberts

    I wouldn't recommend rushing out & buying, but the sort of thing if you saw it at a discount likely wouldn't massively disappoint.
     
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