[WIP] BuWizz Ripsaw Tank with Turret

[JLiu15]

Hey guys, I'm starting a smaller project here with the aim of maximum playability. Currently I'm waiting for a huge Pick-A-Brick order to arrive for my New Flyer XD60 project, so I've decided to do a small project in the meantime, especially since I haven't published anything since January.

This will be a small and simple ripsaw model equipped with a two-missile turret, using new missile elements from the Robot Inventor set. The model will probably be modular, with the body and chassis largely built modularly and connected together when finished. Currently I have the turret and some of the body built. The turret can also raise and lower, but unfortunately cannot rotate as the BuWizz unit only has 4 ports (and two will be taken by the drive motors). As for the drive motors, I plan to use 4 L motors with one connected to each sprocket, although I might also go with one RC motor per track. Overall, I see this model as an upgrade from my Lime Tracker of 2017, as this one will be driven by the more powerful L motor and feature BuWizz.

I think this will be a fun little MOC to drive around. It's nice to build something else after months of work on a single project, and it'll be a great way to pass the time as I wait for parts to arrive for that project.

Photos:

[992bricks]

Looks great, and sounds like lots of fun. I like how you have used the newer missile turrets from the Robot Inventor set instead on the older ones and I am looking forward to how your mini project goes on in the near future!

 

[Gray Gear]

Sounds like a fun little project!

But why would you bother to model a Turret in the first place, if you already know it will not be able to rotate? I'd go with a "Jagdpanzer" (Tank Destroyer) style superstructure. Take a look at the StuG III, Jagdpanzer IV or even the Jagdpanther 

I would especially recommend to place the battery box somewhere low between the tracks to lower the center of gravity. It would also allow you to drop down the missles a few studs, and it would look much nicer too.

[vascolp]

Hi,

Instead of one port for firing and one for raise/lower, why not a port for a gearbox and the other port for the action? I mean, a gearbox with three outputs, three functions: raise/lower, fire and rotate?

Space might be a problem... and a chalenge...

[JLiu15]

On 8/3/2021 at 6:46 PM, 992bricks said:

I like how you have used the newer missile turrets from the Robot Inventor set instead on the older ones and I am looking forward to how your mini project goes on in the near future!

Thanks! Part of the reason behind this project is to test out the newer missile turrets from the Robot Inventor set :)

On 8/4/2021 at 3:13 AM, Gray Gear said:

But why would you bother to model a Turret in the first place, if you already know it will not be able to rotate?

I mean, it's better than nothing, and adds more functionality than just driving which would get boring after a while.

On 8/4/2021 at 3:51 AM, vascolp said:

Space might be a problem... and a chalenge...

Yes. For such a small MOC, I don't think incorporating a gearbox will be easy. It'll probably take up the entire space in the rear.

[Gray Gear]

24 minutes ago, JLiu15 said:

I mean, it's better than nothing, and adds more functionality than just driving which would get boring after a while.

I didn't say to skip the gun, I just suggested to not mount it in a turret. Like a Tank Destroyer style body. Alternatively a ATGM vehicle could work as well, because It would make the missles look more fitting than on a tank, and you could fit a lot more ;)

[JLiu15]

UPDATE 8/10/21

I've built the chassis of the model. It features 2 RC motors (1 driving each track) and a suspension system. Reinforcing it was a bit difficult, but with some cross bracing it held up pretty well in my tests. So far, this thing goes crazy fast, and this is with my BuWizz low on battery. I was concerned that there won't be enough torque (as the rear sprockets are connected directly to the RC motors' outer outputs), but it manages to climb obstacles pretty well too.

Finding the right track tension was a challenge here. It couldn't be too loose, as it would fall off the sprockets especially given the speed, or too tight, as it would cause excess friction or even warp the sprockets' attachment. I have came up with a setup that uses differently sized sprockets in the front and rear, and it's actually the smaller sprockets that are driven. I think this would also give the model slightly more torque than if I had used the larger sprockets in the rear. Note that the road wheels and return rollers will be attached later.

Lastly, I also made a small change to the body. The BuWizz is no longer mounted here. It'll be mounted lower in the chassis to lower the center of gravity, but probably face-up to prevent dirt from potentially damaging it.

If you guys have any suggestions for me, please let me know.

Photos:

[JLiu15]

UPDATE 8/12/21

The majority of the body is now finished and attached to the chassis. I was concerned that the weight of the body (although it's not exceedingly heavy) would worsen the performance, but I tested it and the performance was pretty much unchanged, which is good. I feel like I could've done a better job with the body, but I tried to be a little more liberal with applying body panels rather than making it look like a box on wheels. The addition of the cab section and tracks should also improve the looks, as right now it's kinda boring with just part of the body and no tracks. The BuWizz is still in the cab area, but positioned lower in order to lower the center of gravity. At this point, all that's left to do is the cab area and some final touches, and the model is complete.

If you guys have any suggestions for me, please let me know.

Photos: