Asiatam StuG IV conversion kit...

[PainlessWolf]

Good afternoon!
Sir, you have done a bang up job in reconfiguring the breech to work with the Taigen unit. I completely agree that a bit of streamlining of their unit ( quite a bit ) is called for so as to work better with a casemate type vehicle.
regards,
Painless

[c.rainford73]

Roy some really smart engineering you have thereReally impressed

[43rdRecceReg]

I've been distracted with a few domestic repair jobs lately. Spring looked like it was on the way, and even flora and Fauna seemed to think so too. But Winter keeps coming back.
Generally, the effect of Spring is for me to reach for the toolbox or paintbrush. Given today's downpour, and promise of another freeze, I turned to the StuG's recoil unit as a good way to pass time.
Someone else mentioned problems with a poorly soldered piece of kit lately. Well, this Taigen/Asiatam recoil-elevation unit must have been connected up by someone with an aversion to solder- as the motor connectors barely had any.
The white and blue leads, that are meant to connect to the turret on/off switch, both fell off on day one. Then the puzzling green wire also fell off, leaving no indication of where it had been. Finally, a red wire also detached itself.

StuG IV recoil unit missing electrical leads

I really can't see a good reason to connect this unit to an on/off switch. It makes more sense with an airsoft unit; but here it's a case of unnecessary bits of wiring. So, I added a bit red wire to the red wire that had detached itself from the the Elevation motor '+' terminal, bonded them both to the + terminal, and then connected the red jumper wire to the + on the recoil motor. This means that instead of having a 'safety' inline switch for the positive supply to two motor positives, a short red wire now shares the + feed between the motors, and makes the original white and blue leads redundant. They're in the bin.
The mysterious green wire is actually a negative/ground connector for the recoil motor. I re-soldered it in place. I had a pic of another recoil unit where this lead had been black, and that's how I worked out where it should go.
Quite why 'green' should appear as a negative colour instead of black, I really don't know.

StuG IV recoil wiring solution

It wouldn't make sense to shoehorn this all into the StuG, only to find faults later. I shall also connect all the main circuits/functions up to the MFU and test them before installing them It's a mighty tight squeeze in there...
as Neil Young might have said.. so..i don't want to do it twice..

[43rdRecceReg]

I made some recoil unit support brackets from spare sprue frames. The two I've made will be bonded into the casemate. After that, the unit can be screwed to the supports. Doing it this way should provide access later from the (detachable) casemate roof, and from below via the upper hull.

StuG IV support and retaining brackets for recoil unit

Here the brackets have been bonded into the casemate roof ridge with two part epoxy.
Looking at the recoil unit, which is loosely in the desired position, you'll see that I've drilled into the L/H gun trunnion, and put a 1.5mm brass bolt in there. The bolt is to act as a locking key in the elevation arm, once the arm has been bonded to the trunnion.
While the recoil arm should now just about have room enough to operate, it will still have to enter the breech by about 10mm, and that could lead to problems with sticking and obstruction, even though I have opened the breech out about as far as it can go.
Anyone contemplating using this Asiatam StuG kit, should give a good deal of thought to the fact that the kit appears to have been designed with a 'static' status in mind. Why? Well, because there's no obvious, nor any easy way of mounting any kind of gun operating system (Airsoft, IR etc) in the upper hull.
My plan is to shorten the recoil arm so that it can travel 19mm (full stroke) before entering the breech. I'm thinking of screwing an operating arm to the end of the barrel, so that no part of the mechanism will be proud of the barrel itself, and the screw itself will be short enough to allow the xenon flash cable to pass down the barrel unhindered. But that's for later, when the plan takes shape. As usual Click to ENLARGE the pics..

Stug IV- recoil retaining supports bonded in place

Here I've drawn the rough shape I need to cut out of the elevation arm, in order to bond it to the gun trunnion. The circle of styrene has the the diameter of the trunnion and cut out of it, so as to act as a template for the arm.
The shape of the locking key 1.5mm bolt also appears in the silhouette on the elevation arm. I'm making it up as I go, but in principle, it should work. ..I think

Mod for elevation arm

The doodle on the arm is a tad crude, but the finished thing should be a precision fit on the trunnion...and hopefully clear up any unintended gobbledegook . Often there are no accepted terms here for scratch made parts, so it's necessary to approximate them from known engineering terminology..