RC AMX-13 (Maker Faire: done!)

[Fluburtur]

Alright, I made the turret ring and it is sort of working.

The inner and outer races arent exactly smooth so I have to work the file a bit, also I might end up running it without the balls because it doesnt need them to stay center and that will be handy when I need to open it, just needs to have grease everywhere.
Also im out of plastic again so it will give me some time to design the rest.

 

[SlingShot]

Pretty amazing printing project

 

[Fluburtur]

I completed the turret ring and lower turret assembly

It is a bit janky but it works, now I have to to more work on the hull and start re-designing the tracks

 

[Fluburtur]

Alright, I spent a few hours to re-design basically 90% of the parts related to the tracks, that means another week of non stop printing.
There was a whole bunch of issues, the main one was that the little lugs on the track links are supposed to be halfway to the middle and not outside, let me illustrate:

This is how the tracks of the real AMX-13 look

Adn this is how mines were designed

Spot the Issue? That by itself wouldnt be too bad but the tracks also have a lot of sideways flex that makes it easy to ride off the wheels, the new tracks look like this:

Also on the real one, the rear and front gear rides outside of the lugs and the road wheels are inside, this way there is presure from both sides to keep the tracks aligned. Which means that I re-designed all gears.

The road wheels being thinner, I can make them in one piece which makes life much easier. I can now remove them with only one screw and also remove the arm with one screw pointing out (and not up like the old design) which means I can swap an arm without having to go inside the tank.

The new road wheels will also have a strip of 2mm thick EVA foam around them like the real tank which has rubbers, I doubt it will make the tank produce less noise but it should be a tad smoother at least.

Overall a lot of good changes, the new design should be reliable but it will take ages to print all that.
I ordered a new printer with a larger volume so I will probably wait for it to print the new parts (im printing test parts right now, production parts will wait) so in the meantime I will try to get back to working on the Falken.

 

[kilroy07]

I finished assembling most of the gearbox, it still lacks the bearings and it has a temporary motor which is 900kv instead of 400 but I was able to test it.

It sounds terrible because of the mostly hollow plastic gears but it actually runs quite smooth

Tanks sound terrible (in real life) so it’s spot on! 😂

Great job!

 

[Fluburtur]

I got new ESCs that have both forward and backward propotionnal throttle (ie: quads esc) so it means the tank will now drive much more smoothly and even rotate on itself, of course not for now because both tracks are off until I put on the new ones.

I also spent a while in inav to configure all the crap up, steering is all set up properly and even turret stabilisation (which the real AMX-13 didnt have)

 

[Fluburtur]

I installed the slip ring of the turret ring and crimped on all the connectors, it can now spin 360° while keeping contact with servos in the turret without getting all tangled up

 

[Fluburtur]

Something I have been saying for a while is that strenght is in the design, especially in 3d printing. More often than not fancy materials wont help your part strenght but better design will.

Point in case, I just opened the 3d printed gearbox of the tank to inspect it after about 6km of driving and some not so gentle operation. I had noticed the central gear (the most loaded part of the tank) was pretty loose so I was expecting the bearing made with airsoft BBs to be whack, as it turns out it is not the case.



This is the upper part of the gear, the printed axle part of the gear broke but the bearing being rather large kept the gear align and even spin pretty smooth


Lower part of of the gear, the bearing being much smaller got some damage when it broke and it was wobbling pretty bad but still working. It couldnt get off axis too much because of the upper bearing.

Printing this particular part with more perimeters and infil will probably solve this problem or at least make the part more durable, for your information it was printed with only 2 perimeters and 5% infill as are most parts of the tank.

Btw the rest of the gear had no wear or damage.

 

[Fluburtur]

I got one of the new tracks completed so I put it on, it seems to work well.

 

[Fluburtur]

Im done printing the new tracks, while the new drive gears were printing I tested it a little.

No sign of throwing a track, when the new gears are there and the batteries charged I will take it on a 3km drive to see how well it works

 

[Fluburtur]

Yesterday I went for a drive with the tank, the 3km path I did before and had no issues.

the new tracks and drive gear work perfectly well

then today, I went to drive in my back garden a bit and then showed it to my friend, he tried to drive it and the left drive wheel just fell off because the carbn fiber axle was totally shredded (also broke 3 suspensions axles, no big problem)

So I guess I need new gear axles.

 

[Fluburtur]

Alright, I have been a bit quiet but im still working on stuff
Earlier today I took the tank to a test drive with a friend and we stopped by a small sakte park and got some cool shots

I have a lot more so I will try to put together a nice video

 

[Fluburtur]

 

[Fluburtur]

I was tired of waiting for the new printer so I built the turret today

The elevation servo is too weak to move the turret up and down because the barrel is really heavy so I will try putting counterweight on the back, thankfuly this tank doesnt have to fly.

 

[Fluburtur]

Well that was two days of good work, built the turret and painted the tank

 

[cranialrectosis]

Is that an LED in the muzzle of the barrel?

This really is excellent work. I learned a ton reading this thread today. Thank you for posting.

 

[Fluburtur]

No, I havent put any lights yet. The barrel will remain empty because I have plans for it later.
Until then, have this

 

[Fluburtur]

Well, another day of driving the tank

 

[Fluburtur]

Today was a garage sale in my town and I got a nice flugelhorn


Oh yeah, also I had the tank
I charged my big 7000 mah li-ion pack to test the run time on that and it is like 3 hours, it amused plenty of peoples and a small kid even got to ride the tank so it was fun, didnt have any major issue either.

 

[jakexie6]

Nice flugelhorn! Do you play trumpet? Also, that tank seems pretty sweet, 3 hours of runtime...now all you need is to add some solar panels and you could go across the country with it! Are you planning to add a bb gun or water gun etc. to the barrel? I would love to see something like that.