RC Tank Warfare community hobby forum

I'm glad that I don't have the problem of worrying about the return roller issue on the Cromwell as well Roy I'm going to try and figure out how to and also the best position to possibly fit the dampers to the first and last roadwheels to give them a little more strength in these major areas

Cheers, Lee.

Let me know how the dampers work out. I’m still considering using them on each wheel

Model Builder 4 wrote:I'm glad that I don't have the problem of worrying about the return roller issue on the Cromwell as well Roy I'm going to try and figure out how to and also the best position to possibly fit the dampers to the first and last roadwheels to give them a little more strength in these major areas

Cheers, Lee.

I'm working on the recoil mechanism currently, Lee. I think the Comet will run as it is, but I'll return to the suspension weakness in due course. In the meantime, I thought you might like to know that I found a good source for springs- one where you can actually specify the type and size you need.They're custom made, in other words- and value for money. Christian's spec for springs is something like: S= 0.50 mm (wire gauge) D=5.0mm (Outside Diameter)
and overall length of 11.9mm. The ones I ordered here are slightly longer, and a tad stronger. I also bought an assortment of compression springs- many of which will fit comfortably within the twin walls of the Comet's hull. I may simply double up on the four 'corner' springs...as a quick solution.

Here's the web link for the supplier. The springs also turned up next day- so, that also has to be a good recommendation
https://springsandthings.me.uk/product- ... n_springs/

Thank you very much for the link Roy looks like a great site for useful bits and pieces and also very reasonable prices as you say . I have just taken a look and I am thinking of getting these ( 12mm x 5.4mm x 0.8mm ) hopefully these will work out and offer a bit more strength and tension

Cheers, Lee.

Model Builder 4 wrote:Thank you very much for the link Roy looks like a great site for useful bits and pieces and also very reasonable prices as you say . I have just taken a look and I am thinking of getting these ( 12mm x 5.4mm x 0.8mm ) hopefully these will work out and offer a bit more strength and tension

Cheers, Lee.

Great. Yes, Lee, so long as the spring has a diameter less than 6mm, it will fit snugly in between the two plates!

Setting aside the soft suspension issue for a while, my main concern is to fit a recoil and elevation system into the turret. After that, the turret ring and traverse unit will be the next challenge.
Here are the basic components I have to fit. The gun will be shortened and drilled to accommodate the HL recoil shaft. Then, I have to fix the frame of the recoil unit to the gun tube and mantlet.
When they elevate/depress together properly, I can then work out the optimum position for the elevation unit, which will be situated beside it.

Gun will be adapted (shortened and reamed out) to fit onto the sliding recoil breech.

Working out where the cuts, and joints should be. This is tricky, as I want the gun to have the correct profile in battery, whilst allowing ample room for the recoil unit to move unhindered.
When that all works, the recoil unit you see in this pic (in a StuG 111), will end up positioned next to the Comets' new recoil. The activation arm of the recoil will move in the channel fixed to the side of the recoil frame. That's after the correct mountings are made for the elevation unit.


This is going to be a slow and painstaking process, as I don't own a lathe (yet!). The chuck of a steady drill will be the ersazt holder for cutting/reaming/polishing.
The original 'breech' unit (clamp on the gun tube for a servo- perhaps) provided by Christian will be dispensed with.

The springs I ordered arrived today Roy, very quick delivery as you said I opted for a set of 12 x 5.4 x 0.8mm, they seem a lot stronger than the one's I had with the kit, in fact I think using them on every suspension arm may be a bit overkill so I will try them on the first and last suspension arm's to begin with as this is where i feel they would be mostly needed due to the extra weight, I will see how these work out and go from there

Cheers, Lee.

Model Builder 4 wrote:The springs I ordered arrived today Roy, very quick delivery as you said I opted for a set of 12 x 5.4 x 0.8mm, they seem a lot stronger than the one's I had with the kit, in fact I think using them on every suspension arm may be a bit overkill so I will try them on the first and last suspension arm's to begin with as this is where i feel they would be mostly needed due to the extra weight, I will see how these work out and go from there


Cheers, Lee.

Slow and methodical, Lee- that's the way. Use the beefier ones on the foremost and rearmost arms!

I could do with a decent mini-lathe. Still, a decent electric drill, with a versatile chuck, can be a reasonable substitute. That's if it's held firmly in a stand, or workmate/workbench (I have a good old Bosch Workmate).

I could have drilled and tapped the barrel, to replace the sliding breech that's fitted to the servo arm. However, it wouldn't have been quite long enough. So, what I did was to shorten the barrel, and drill it out to accept the sliding servo breech. Thus:

Barrel shortened, and reamed out to accept sliding breech.



I guess for mechanical purposes, the servo breech is offset. What I intend to do, is to fit appropriately sized stryene blocks (fluted slightly on the inside, to grip the gun tube slightly) either side of the guntube. Then I intend to use the tapped holes in the recoil frame, that had held the trunnions, to compress the styrene agains the guntube- thus fixing the recoil to the guntube. Hopefully...
Hmmm...what Scotsman wrote "'The best laid schemes o' mice and men.."

Ultimately, the reocil framw needs to be fitted this way up, in order to allow the eleavtion unit to be fitted on the left side of the gun. I have checked to see whether the recoil arm would be obstructed by the turret roof, when it's all in place- and shouldn't be an issue.

In order to get a decent, and realistic, amount of elevation I've had to shorten the recoil frame. I always knew this would be the case. After all, there are no guidelines or instructions for this: it's up to the builder to figure out what will work, and what won't. Now, on full elevation, the recoil passes through the turret- floor without hitting it. All good.
One tricky design conundum to solve: the recoil arm movement requires the barrel to be slightly offset. This means the frame will have to be offset too, because of the lack of symmetry.
Here's the gun, and recoil, now in the optimum position (gun is in battery):

From below, you can see that I've had to fashion some styrene spacers to create the correct offset.

The packing pieces are actually bonded to another piece of styrene beneath the barrel. It's the tight fit I was looking for, but it will also be pinned, and locked against the gun tube with small screws passing through the original trunnion holes. The gun tube now supports the entire recoil breech, and attaches it to the Mantlet.
Here's the gun on full elevation, unobstructed by the turret floor. Phew...

You can see the channel, on the left of the breech, where the elevation arm will run. That's going to be the next big challenge.