RC Tank Warfare community hobby forum

Hi Rob if the springs are a tight fit on the pins they will resist the drop-down effect anyway but a nice simple effective design.

Alwyn

Thanks. There's elegance in simplicity. As you say, the tracks should keep the springs from pinging out of the two locating pins. I'd considered using the shock absorber type fitting from the Pz111, but you only get 4 per set, and I would need 10.

Took three attempts to get the mantlet right so that elevation would would smoothly. What looks ok in a CAD drawing doesn't always translate to the real world. This will all be smothered with Milliput to give a rough cast finish, so detail wasn't an issue on the print settings. There is a cavity for the IR led to slot in behind the machine gun hole.

I did a set of suspension retainers, so I'll glue those on soon.

Lower hull almost done, will reprint return rollers and idlers as they are a bit ropey.

Lovely build Rob, It just gets more stunning. See you solved the problem of suspension dropping down with stopper blocks. Great piece of design work.

Alwyn

AlwynTurner wrote:Lovely build Rob, It just gets more stunning. See you solved the problem of suspension dropping down with stopper blocks. Great piece of design work.

Alwyn

Have to agree, Alwyn. I'd envisaged a set of internal retaining springs, weaker- of course- than the load bearing ones. Or, perhaps, internal clips like the ones found on old clothes pegs
modded to prevent the arms dropping too low. But that would have been fiddly, and servicing the suspension= post build = is likely to be fiddly too, on the Comet as well as the Cromwell. That sandwich of 'metal' could to be hard to access, if a component breaks internally (as it was, apparently, on the full-size models). Wibb's solution looks simple enough to avoid access niggles.

I can get to the suspension internals by unbolting a suspension arm, though the parts are all rock solid so unlikely to break anytime soon. I could have done it the same way using HL suspension arms, drilling and pegging the upper side, and making styrene blocks and pegs to go inside the hull. The springs were as cheap as chips, got them off Ebay from a place that quotes diameters, and they cut them to length.

Had a marathon printing session this morning, put my heart in my mouth and printed a one piece turret. Top notch finish, the lines you can see are more filament colour changes than ridges, its all pretty much silky smooth. 5.5 hours to do that little part... The acid test was placing the mantlet on the front, printing parts separately is always a risk as they may not be mm perfect in size, but these two are good.

I am learning as I go along, and persistently trawling the net for info. The Cromwell/Comet hull is a bit of a nightmare all round, nothing is what it seems, and if I get one bit wrong that rest won't be right. Blueprints are useless as they don't show the bits that I need to see in order to construct a model with a removeable upper hull.

Fantastic Rob, I would have been VERY nervous of the 5.5 hrs print but great design. Please post a link to the spring supplier as I battle getting springs of the right dia/length.
Alwyn

Here you go, if you search in his shop he has all sorts of diameters etc

http://stores.ebay.co.uk/FirstCompressi ... 7675.l2563

You're certainly the pathfinder/ Avant grade/ recce.unit here!. Your problems/solutions are our gain.... I'll be home next week in Scotland, and if you should need any dimensions off my (currently flat-pack) Cromwell kit, or any photos, you're more than welcome to them. The kit comes with a limited PDF but, like you, I'm going to have to devise some of my own fittings. Even Christian's metal suspension arms come in two pieces. They appear to be sliced down the middle (cross-sectioned). At first, I thought he'd sent two sets of arms: but no. I guess they have to be bonded together to form complete arms, but none of this appears in the PDF
Thanks for the eBay spring link by the way I'd even considered using the M26 type shock absorbers as my main suspension units )integrated in the sandwich, though), but getting hold of them might be difficult.
Amazed that you can print a whole turret..