Dang you Lukas...IS-7 build.

[HERMAN BIX]

Sure is an example of the proverbial "brick S-house" !!
A deft touch on that idler adjuster Mr Tankme, clever work.

[tankme]

The IS7 is an impressive animal. I used to play WOT and it is a formidable opponent.

As for smoothing 3D printed parts, I can recommend this stuff. Just paint it on, its self levelling, wait for it to dry, and bingo, a gloss finish. It's great for tanks as if it is not sanded you get a slightly smooth cast finish. If you want parts super smooth it is easily sanded. You can paint straight over it.

I have turned some rough prints into very presentable models using it. It also strengthens fragile parts which is a bonus.

https://www.youtube.com/watch?v=GSKxycs3kPg

I have some of that Smooth On XTC-3D I did try it once on the wheels of the IS7. Even with me spreading it out in a tray like they recommend, the cure time was really fast. One coat on the wheels of the IS7 definitely wasn't enough and it dried before I could even get it put on all the wheels. That was just on the outer wheels and just on the center area I can't sand. I may need to do it again, but I didn't want to put it on too thick or it would kill all the detail.

Sure is an example of the proverbial "brick S-house" !!
A deft touch on that idler adjuster Mr Tankme, clever work.

Thanks. I actually was sitting there looking for an M3 based turnbuckle all over the place and I was like...hey, I have a whole slew of standoffs over there...

[wibblywobbly]

I have some of that Smooth On XTC-3D I did try it once on the wheels of the IS7. Even with me spreading it out in a tray like they recommend, the cure time was really fast. One coat on the wheels of the IS7 definitely wasn't enough and it dried before I could even get it put on all the wheels. That was just on the outer wheels and just on the center area I can't sand. I may need to do it again, but I didn't want to put it on too thick or it would kill all the detail.

I found that spreading it on card made it dry faster too. I kept it in the pot, and used a little less hardener. It stayed fluid that way.
The trick was to only use small amounts on a small brush, or use a foam pad. It would tend to pool in recesses, so I just kept brushing it out until only a thin film was left. This isn't a tank, but the prints were incredibly fragile, and quite rough. I couldn't sand them without breaking ribs etc. The resin made them stronger, and covered some pretty rough areas.

[tankme]

I just had to order some parts for my latest project so I dusted this puppy off and brought it back to the bench for a bit tonight. I had some issues with track alignment which is why the tracks and wheels were originally removed. The idler was misaligned so all of that got resolved, the wheels got re-attached, and the tracks were fitted. Before I finish the detailing work I think I need to slap some electronics in it and give a test run. Trying to finish my CompTIA Network+ cert this week so it may be a few days before I get back to it again.

[HERMAN BIX]

jeez I'd love one of those in my life

[tankme]

I just started printing a friend for it...an IS-4...

[tankme]

So I've been messing around with this build. I had a TK-50 laying around (albeit with Tiger I soundset) that I installed for testing of this beast. I thought I might not be happy with the performance of the 280 motors that came with it and unfortunately I was right. I did plan ahead and bought a 370 motor/gearbox to use on the existing gearboxes. That didn't quite work out the way I planned. The new gearmotor had zero torque. I thought well maybe I can take the 280 gearbox off and put it on the 370 motor. The result kinda worked. The new combo had a lot of torque, but was way too slow (even slower than the 280 gearmotor combo). Now I don't want a speed demon, but the IS-7 was capable of about 35mph or around Sherman speeds. This had lead me in a different direction for gearboxes.

I tried a traditional mid/low HL type gearbox and it was way too high to clear the upper once installed - NO GO.

I had a mid/low enclosed CNC set of gearboxes for another project...they wouldn't fit side to side as the motor length was too long - NO GO.

Then I saw my all metal PZ3 sitting on the other bench and remembered it had the really low profile Mato gearboxes in it. I pulled one of the gearboxes and did a test fit. Height is good, length is good, width is good...shaft is too short. Some quick searching shows me they make a long shaft Mato gearbox and even some Taigen/Torro ones with the same layout as the Stug/PZ3 gearboxes. I think the Taigen/Torro black steel gear ones are discontinued and they didn't seem to be all bearings. From what I saw they only had bearings on the final output shaft. That's disappointing. My ultimate question is, does anyone know of a place (besides Torro) that has a Mato Stug type gearbox with a long output shaft (like the ones below)? I guess my other option is to buy the mid/low long shaft Mato gearbox and a Stug gearbox to swap the shaft between them.

https://www.aliexpress.us/item/32568024 ... 1131078451

I don't want to buy anything directly from Torro as they are charging $80 USD for shipping which is more than the items I wanted to buy.

Other suggestions?

Derek

[DrupeluRC]

Hey, there are different gearboxes for that particular motor size in China, i will try to dig out some links, but yea it feels slow compared to other tanks, but if you take the scale and re-calculate, it is more or less closer to reality.

[tankme]

Lukas,

I was actually able to fit the Mato Low/Low gearboxes in there. I just had to swap for the longer shafts. I don't have a pic of them installed yet though. I bought a High/Low set that said it was for the Jadgtiger (longer shafts) and I swapped shafts with the Low/Low set in my Mato PZ3. Then I installed the high/low gearboxes in the PZ3 with the short shafts. All worked out exactly as planned.

Derek

[tankme]

So I did make some progress on this guy as I mentioned in the last post. I was able to finally mount the barrel permanently or semi-permanently as I used a small hex head screw to hold the muzzle brake on. I drilled a small hole in the barrel by the mantlet to keep the rest of the resin barrel from shifting on the brass inner sleeve. The brass inner sleeve has two holes holding it onto the recoil mechanism. I wanted to ensure that I could take part the barrel assembly if I needed to for maintenance or repair. The mantlet has two fasteners under the dust cover holding it to the recoil mechanism.



The dust cover itself is glued and mechanically connected to the turret via hex head bolts. I do think I'm going to redo the barrel side of the cover with smaller fasteners closer to the original design. The ones on it were the only ones I had at the time. I broke the MG barrel off while messing with it, but it should glue right back on. Plus I have some fiber optic rod I can re-enforce it with.



Made some progress with the interior also. I 3D printed a speaker box and contoured the bottom to the dimensions of the IS-7 hull. I sized it so that the upper hull aluminum supports just clear it. When the upper and lower are mated it keeps the speaker from moving side to side. There is a speaker mount in the turret, but I ended up not using it as the Visaton FRS7S speaker wouldn't fit in there. I've done a preliminary mock up of the electronics as I had a TK-50 with Tiger sound set in the parts bin. I will eventually put a different sound set on the board. The gearboxes were scavenged from my Mato PZ3. I bought some long shaft Mato gearboxes to back fill into the PZ3. All I had to do was swap the short PZ shafts for the longer shafts in the new gearboxes to get everything to line up correctly. Despite being a very long tank, it has a pretty low profile hull. Preliminary motion tests were very good. Now I just need to finish up the wiring, finish a few more details, and finish adjusting the turret ring to line up with my lowering mod I did. I did test the recoil and elevation functions and they are good to go.