Ball Tank

scooter · March 08, 2025, 10:32:33 AM

Quote from: zenrat on March 08, 2025, 02:37:57 AMHow about an open top version?
Cut away the upper half of the ball but obviously leave the track arching over the top.
A training tank or maybe an infantry or gun carrier?

Maintenance trainer?

kerick · March 08, 2025, 03:06:20 PM

Every driver and TC wants to drive around sticking their head out!

Captain Canada · March 08, 2025, 04:37:08 PM

The interior details are incredible! For sure having a 'pilot' for scale is a must.

And as an added bonus, your build can also have the best opening bass line.

https://youtu.be/bbr60I0u2Ng

frank2056 · March 08, 2025, 09:13:37 PM

Fred, I was thinking of opening up one of the top holes to add a hatch and vision port, but the hemispheres are very thin plastic. I may try to print one to experiment on.

frank2056 · March 08, 2025, 09:16:55 PM

Quote from: Captain Canada on March 08, 2025, 04:37:08 PMThe interior details are incredible! For sure having a 'pilot' for scale is a must.

And as an added bonus, your build can also have the best opening bass line.

https://youtu.be/bbr60I0u2Ng

I loved that song back in the day. Sharona Alperin is a successful Beverly Hills realtor now!

frank2056 · March 09, 2025, 06:56:06 PM

I felt that the hemispheres looked too smooth, so I experimented adding a casting texture to a styrene rectangle. I mixed some putty with acetone and stippled it on with a stiff brush. In another section, I tried some unthinned primer paint. Finally, I tried it with some thinned Tamiya surfacer. Of the three, the thinned (with denatured alcohol) Tamiya surfacer worked the best. Stippling the hemispheres and the hatches was pretty easy and relaxing work - paint a sector with a layer of surfacer, stipple it, repeat.

Next, I worked on the 37mm gun. Since the gun was originally at the top of the ball, it was difficult to get the ball joint for the gun to point straight forward in it's new forward facing location. So instead, I repurposed one of the machine gun ball joints:

You can see the text strip next to the tank in these pictures.

I also added the driver's sad looking view slit (I may need to fix that) and the second rear facing MG ball joint to the driver's hemisphere:

Tomorrow, more interior mods. I added the foot pedals to the driver's side. With the seat's intended location, the driver would be sitting with his knees up to to his chin. I'll move the seat back by a few mm.

Wardukw · March 09, 2025, 06:59:05 PM

Very cool mate 👌
Liking the new texture and mods

su27rules · March 10, 2025, 03:51:46 AM

Old Wombat · March 10, 2025, 09:01:11 AM

Neat progress, Frank!

Quote from: frank2056 on March 09, 2025, 06:56:06 PMWith the seat's intended location, the driver would be sitting with his knees up to to his chin.

Definitely Soviet/Russian!

frank2056 · March 11, 2025, 07:40:03 PM

I'm almost done with the interior. I removed some of the horizontal bracing to make a space for the crew to move from one side of the vehicle to the other. I added some vertical bracing as well, which (maybe not surprisingly) added quite a bit of stability to the assembly. I also made a wooden floor so the crew can scoot from one side to the other without having to crawl over a hot engine. The seats are just tacked on in this picture:

I realized that the ball tank - with no obvious source of ventilation - would quickly fill with a noxious atmosphere of CO2 and Carbon Monoxide from the engine and gases from the gun firing. Since I moved the gun to the front, the upper gun port was no longer needed. I made a fume extractor/fan assembly out of one of the wheels for the door locks, a trimmed drive wheel from an anonymous tank and I believe the fume extractor from the Tamiya M41 kit. A crew member would turn the wheel to raise the extractor and turn it on. Interior view:

Exterior view with extractor raised. I painted the exterior with Olive Drab:

I still have to finish the main interior and fix nicks and scratches on the white paint and add the gun and ammo to the right hemisphere.

Old Wombat · March 11, 2025, 09:16:20 PM

Fantastic work, Frank! The extraction system is inspired!

Rick Lowe · March 11, 2025, 09:32:55 PM

kerick · March 12, 2025, 06:19:55 AM

This is great fun to watch come together!

NARSES2 · March 12, 2025, 07:04:13 AM

Quote from: kerick on March 12, 2025, 06:19:55 AMThis is great fun to watch come together!

Absolutely

frank2056 · March 12, 2025, 08:20:15 PM

I'll probably start closing up the ball tomorrow or Friday. It's been a struggle not to "improve" on the design (the kit is otherwise excellent except for the seats). I realized that the rollers and rail for the central tire don't form a seal... so this ball would have had a hard time fording a shallow creek. Water would have formed a puddle inside the ball and would have been raining into the interior from above as the tire turned. Visibility out of the Ball was close to zero. Crew positions (even my modified one) are terrible. The list goes on.