Snowwolflair wrote:It could be done with an inductive coupling (think electric toothbrush charging), but probably beyond the capabilities of most modellers.
HERMAN BIX wrote:As the breach is an opening device, could a barrel light be powered by a button battery, triggered by the breach opening movement to make a contact in a circuit , and accessed by the opening breach for battery changes ?
Of course, its easy for me to say, no hope of being able to do it myself !
Thank you gentlemen. These are good ideas. I'll put this dilemma aside for now pending investigations and decision.
Continuing with the build, the sighting apparatus.
I found no wartime pictures with close ups on the sighting instruments. This is a capture from a video found on Youtube. Not much help.

- 1/16 RC US 155mm Gun Motor Carriage M12 - Build
- Capture.JPG (96.08 KiB) Viewed 1547 times
Academy did not really do a good job in this area. The whole shield and sighting instruments are simplified and full of ejection pin marks. The round hub for the gears does not have the right shape. As i am not sure i will finish the 1/35 kit, i have just assembled the parts to get some clarity on this area.

- 1/16 RC US 155mm Gun Motor Carriage M12 - Build
At least, it provided some ideas for the sights to reproduce instead of leaving the area empty on the 1/16 model. Notice the triangular shape behind the shield, with thickness grossly exaggerated and lack of back rivets for the ones on the other face. Still, dimension and positions for what is there was most welcome.

- 1/16 RC US 155mm Gun Motor Carriage M12 - Build
- Capture3.JPG (97.98 KiB) Viewed 1547 times
This is the same area on the surviving M12, showing the complexity and where improvements can be made. We can see the structure of the main arm and everything that is there. Sadly, the scopes were not installed.

- 1/16 RC US 155mm Gun Motor Carriage M12 - Build
Of the whole area behind the shield, these are the only parts that Vandra provides. A 3D printed hub for the gun elevation/rotation with the crank wheels, and a simplified arm devoid of any sighting apparatus or details. It is annoying when you pay for a kit, and when the area is complicated, the vendor just ignores it...

- 1/16 RC US 155mm Gun Motor Carriage M12 - Build
The Vandra hub is a bit too small but was reused. It needs a thicker base for attachment to the gun mount.

- 1/16 RC US 155mm Gun Motor Carriage M12 - Build
- Capture6.JPG (86.62 KiB) Viewed 1547 times
The arm needed to be redone with proper dimension and shape.

- 1/16 RC US 155mm Gun Motor Carriage M12 - Build
The shape of the arm need to be aligned so that when the scope is mounted at the tip, the view needs to go through the small hole in the shield.

- 1/16 RC US 155mm Gun Motor Carriage M12 - Build
After one day of plasticard and tube cutting, this is my best effort at reproducing the sighting apparatus from the few pictures and angles on the M12 book. My goal was not to spend a month doing a perfect scale rendition, i do not have enough photographic reference material for that. But it certainly fills the hole with a fair representation.

- 1/16 RC US 155mm Gun Motor Carriage M12 - Build
Sighting apparatus is installed but removable as it is part of the pin that allows the gun barrel to be dismounted. Rivets were also added to the back of the shield, aligned with the items in the front of it.

- 1/16 RC US 155mm Gun Motor Carriage M12 - Build
continuing on following post.