RC Tank Warfare community hobby forum

Looking at the incredible detail of the gun breech etc., I am fully expecting to see an empty shell case being ejected, when the gun recoils!

And it was all going so well (up until today).

So I started planning on how I was going to fit the necessary servos/motors for slew/elevation/recoil and decided to begin with the recoil. Hmmmm.... it's a bit cosy under the gun carriage, but never mind. I finally (after about 4 abortive attempts) managed to design and print a rack and pinion for the recoil so now to try and fit it.

Tight fit doesn't even come close to describing it, we are talking millimetre gaps and I'm using the smallest servos I could find. These ones were designed for a helicopter.




The problem is that yes the recoil servo fits, but there's no space under the gun carriage for the elevation servo, so that is going to have to fit on the left of the gun mount with the rotating part poking through the gun support and servo arm being underneath the gun carriage.

That means a redesign and reprint of the gun support and shield part so a good few hours redesign and print work ahead. At least I have managed to salvage some of the component bits.

And it was all looking so pretty too..... Never mind it will all work out in the end.

Alwyn

'The best laid plans of mice and men aft gang aglae' as the scots say. The rack and pinion approach to the servo was a complete bust. I commissioned my Turborix 2.4g tx/rx which has been sat in a box for 18 months and plugged in the recoil servo and... found that the maximum throw I could get with the largest wheel I could fit in the available space was.... wait for it...about 1 centimetre if I was very lucky.

And this was after several hours designing and fitting a servo box in exactly the right place etc etc etc....

After much gnashing of teeth and a modicum of bad language, I put on my heath robinson hat and did some experimenting (i.e. bodging) and behold, the good old-fashioned approach, the servo arm with a piece of bent wire.


Bingo, eureka, etc. Works a treat and gives the necessary length of throw.

So one servo down, elevation servo to go (which will be handled in the same way) plus the gun slew motor to figure out.

Light is at the end of the tunnel.
Alwyn

Awesome work! Love the build and all of the 3d printed parts.

Magnificent work. I was wondering is the barrel able to take an LED to provide a muzzle flash?

Thanks Philipat although I've used most of a reel of filament so far!

Richard yes the barrel has a 40mm brass tube right through specifically for the muzzle flash and also for the battle flash if wanted.

At the moment I doing the 'one step forwar and two back routine though. I just get the recoil sorted and then find the recoil arm fouls the front shield when the barrel is elevated! Hmmmm... back a couple of steps and move things around!

But I'm getting there!

Alwyn

Looking forward to seeing the end result. I have complete confidence in your abilities.

Jeeeezus, makes my tribulations seem insignificant !!

After a frantic couple of days of blood, sweat, tears, anger, frustration, exhilaration, and finally exhaustion, humpty is back together again! The elevation/recoil interferance had me stumped, and then I vaguely remembered that the Nashorn was limited on elevation. After a quick check of my documentation I confirmed that the Nashorn was limited to -5 degrees and plus 15 degrees elevation, and I was getting plus 18 degrees so no need for further adjustments!!!
So now the recoil and elevation servos are fitted and tested and will just need final adjustment when I get a controller board. At the moment it looks like it might have to be a TK22 because I've well and truly blown the budget getting components and supplies for the kits, but I would really like an IBU2 plus. Maybe after I've built and sold a few kits.

The elevation servo is barely visible on the left of the gun carriage but it isn't too obvious. the recoil servo is completely hidden under the gun carraige. That just leaves the slew motor which is going in the engine compartment and will be positioned just below the basket on the rhs of the cab with a servo arm and a wire connector to the gun base.





Well onward with the build.
Alwyn

That looks absolutely magnificent.