Trying to learn about M20 Azimuth Indicator

[RedArrow2016]

I had this piece of great history here and I am trying to learn what this did here, and I can not seem to find any information as of late here. I know people on the G are great and have a lot of history when it comes to things. But first question I have is what does this go to? Is this for a Sherman or a Patton or a Stuart Tank? And secondly I have not seen or found any photos of where this goes in the tank if this is for a tank. Thanks again and I look forward to all the help on here for this.

Many blessings and may God be with you always...

[Packhow75]

Nice item

As far as I recall...

Azimuth indicator is used to allow tank to be used for indirect fire missions.

For normal artillery piece the gun will be zeroed in onto ranging posts (gun sight is aimed at these posts because the actual target is not available... trigonometry is used to ensure the shell lands on target).

Normally there will be two aiming posts used - making the assumption that at some point during a fire mission one of the aiming posts may be obscured by the gun carriage... so the gunner can use the second post to aim at.

Inside the tank, the Azimuth Indicator is used to track the turret rotation away from the zero line (start point) such that the gunner can correctly aim the gun and set the elevation to land the shells in the right place.

Prior to installation of the Azimuth indicator, the gunner used markings on the traverse handwheel to calculate the traverse.

Tim

[W. Winget]

page 54 of this article discusses Tank guns as Artillery (note it talks of the M20 periscope, but the details of laying the azimuth in on the vehicle for multi-vehicle battery use were identical)
https://books.google.com/books?id=I0BEA ... or&f=false

Several old beatup restorable one's went for $250 (or were asking price) from Italy back in 2014:
viewtopic.php?t=231044

There is a manual on these: TM 9-1731D AZIMUTH INDICATOR M20 M21 TANKS GUN CARRIAGES 1945 MANUAL SHERMAN somewhere out there

Fits the Super Sherman, M18, M36 (I suppose the M19 earlier version fit the same way and in late War they were upgraded so earlier Shermans likely could use it as well)



the M41 tank took the M31 Azimuth Indicator, but if you look at it I'd bet it bolts right in and would fit the bill on someone that's missing one...till they found the right M31 model...


A $42 copy of the manual (other reprints were 4 Pounds Sterling)
https://aotp.com/product-category/x-eph ... l-manuals/

V/R W Winget

[RedArrow2016]

Well thanks for the help and time and the photos here that means a lot to me here trying to learn about this.

[RedArrow2016]

I look at all the links here and thanks again for sharing this with me here. I never knew so much about this piece of history and it is a really neat piece and to understanding it made it fun for me here. Many blessings again and take care.

[Poniatowski]

Hi,
Do you still have this? If so, could you please tell me what its diameter is? I've fired tanks from these many times, but never measured one.

Thanks!
Ron