1/10th Comet or 1/16th Cromwell

[bikerdude]

Hi all, firstly I'd like to say that I have no connection to either of these sites, I'm just looking for opinions...

I've found the files for the 2 tanks in the title, a 1/10th scale Comet, or a 1/16th scale Cromwell. To my very untrained eye, they look very much the same apart from the turret/gun, but I'm struggling to decide which to go for. I think I prefer the turret/gun on the Cromwell, but the idea of 1/10th scale does appeal to me, something a bit more impressive driving around the fields and through the woods, plus the extra internal space for bigger batteries to keep it going for longer, so I'm leaning towards the Comet. Having said that, the availability of parts to fit a 1/16th scale tank would be a great help.
The Comet files are only £20, the Cromwell are closer to £60. Has anyone here built either of these, or built a different model but from files from either of these vendors?

Cromwell: https://cults3d.com/en/3d-model/various ... tank-model

Comet: https://www.3dprintedtanks.com/comet2/#&gid=1&pid=2

Any help or advice is greatly appreciated,

Thanks,

Derrick

[tankme]

The Cromwell is done by one of the users on this site and it's a very nice print in 1/16. It's probably the best Cromwell you will find to print or to buy as it is better than Hooben's Cromwell from what I have seen of both. The Comet on the other hand looks very good except for all the texture on the prints. That would drive me nuts, but other than that I think the Comet looks good also. The Comet is basically a different turret on a Cromwell chassis, but I personally haven't done a lot of research on the two tanks so others may be able to come up with more differences between the two tanks.

[43rdRecceReg]

I think you'll find that the Cromwell is the handiwork of Tomas '50koruny'- a member here. This was the excellent development thread for it:
viewtopic.php?f=23&t=31651&hilit=printable+Cromwell
I've never printed a tank, but I have built the Cromwell and the Comet. If I were to print one, I'd be happy with Tomas' design and files.
The hull of the Comet was slightly longer and wider than the Cromwell it's based on. This was to accommodate the larger turret ring, needed to cope with the 17-Pounder gun turret. In reality, the 77mm HV gun used was based on the 17-Pounder but had a shorter barrel.
The Comet also had return rollers. They're absent on the Cromwell. Personally, I think the Comet is a better looking tank than the Cromwell, but I do like the fact that the huge rivets holding the plate armour to the frame of the Cromwell turret, make it look like a Dalek.

[bikerdude]

Thanks for the replies. The surface finish on the Comet is something I think I'd be able to address with the ironing setting, failing that some filler primer and a light sanding. However I still can't decide which to go for, I think the larger scale may be easier for me as my 1st scratch build (if you can call it that, printing the bits and gluing together), but I do much prefer the turret on the Cromwell and (now that it's been pointed out to me) I prefer the lack of return rollers.

I'll probably end up buying both sets of files, and then deciding which to do 1st once they've downloaded.

[bikerdude]

Decision has been made, I've bought and downloaded the files for the Comet. I now need to order some of the recommended filament, and get the print settings sorted for it before I can make a start on this project. Looking forward to it and hopefully the kids will be able to help with the build.

[43rdRecceReg]

Decision has been made, I've bought and downloaded the files for the Comet. I now need to order some of the recommended filament, and get the print settings sorted for it before I can make a start on this project. Looking forward to it and hopefully the kids will be able to help with the build.

You can build the Comet without return rollers. I have photos of a prototype Comet without the rollers, and it performed well over obstacles without them. There you have your precedent.

[bikerdude]

Decision has been made, I've bought and downloaded the files for the Comet. I now need to order some of the recommended filament, and get the print settings sorted for it before I can make a start on this project. Looking forward to it and hopefully the kids will be able to help with the build.

You can build the Comet without return rollers. I have photos of a prototype Comet without the rollers, and it performed well over obstacles without them. There you have your precedent.

Funny you should say that, I had no idea about that but I was wondering whether to just not add them and call it a hybrid Cromet or developmental prototype...

[43rdRecceReg]

Well, here's proof positive. I also used this book during my Comet build thread.
Voila, one Comet without return rollers:

[bikerdude]

Well, here's proof positive. I also used this book during my Comet build thread.
Voila, one Comet without return rollers:

Thanks, I'll have a look for that book. I'll omit the return rollers initially, but with a view that if I have issues of it throwing a track on rough ground I can later add them in to see if some extra tension will help. It's a problem I've had on each tank we've had, except for my old HL Bulldog with metal tracks.



I also have a question RE. 3D printing tanks. I've had a look through the instructions for the Comet and it says I will need 5kg of PLA. I always thought PLA was supposed to be brittle, and so not especially suited to something like an RC tank where it will take knocks and bumps? Also, I can't seem to find it now, but I'm sure when I had a look before, it suggested using ASA, which I've not used before but from what I've read would probably be more suited. Has anyone got any ideas or suggestions?

[bikerdude]

I'll probably start a proper build thread for this when I've got enough bits to actually start building. At the moment I've managed to print 2 pieces of the hull, I turned on the ironing option so it's quite a nice smooth finish on the top layer. Problem I have is that the printer is in the garage, in the back corner, blocked in by a load of other stuff, so getting to it is a bit of a pain. It also means that I can't keep an eye on the prints, so I went out to get the 1st piece and found that it had been under-extruding and the piece was useless! The piece I was printing today has started warping on the bed, but I don't want to stop it as I'd put a load of the suspension parts on the same file and they're coming out well.