Nashorn build with all 3d printed parts - New project

[c.rainford73]

Alwyn looking excellent! I must admit without the servo wire visible I initially had a hard time locating it on your photo very nice

[AlwynTurner]

Well I'm having what the chinese would refer to as an 'interesting' day. I thought the slew motor would be a breeze. It's one of those geared motors, so I duly built a mounting box for it and created an arm to fit on it, got it all fitted and decided to do a test.




The dratted motor runs too fast, it runs at about 3 times the speed I need, and there are no comparable motors in this country, and I've ordered a slower motor from china but that's weeks away.
SO, back to the drawing board. Cunning plan is to build a gearbox so printed out a couple of gears to check the theory.


Ok it looks as though it might work, and I should be able to chop off half the big gear wheel as it's not required to down to designing the gearbox.

An hour now to print it and probably a few bugs to fix and reprint, then time to try again! The light at the end of the tunnel turned out to be a train on fire!

Alwyn

[HERMAN BIX]

Me being the electronics simpleton that I am, could a volume adjuster be used to reduce the 'flow of smoke' to the gearbox & slow it down ?

[AlwynTurner]

Hi Herman, I thought of a few electronic possibilities like putting a resistor in series, but I'll give the gearbox a go, and if that proves mechanically unreliable or problematic, then it's down to the electronic version.

Alwyn

[AlwynTurner]

Finally sorted the problem. After a number of redesigns and reprints, plus in situ modifications, we have a winner!
slew right

slew middle

slew left

and finally painted


Sigh of relief! We don't seem to have an emoji for that.

This is a temporary fix until the slower motors turn up (presumably on the slow boat from China).

The kit will not have the unsightly gearbox, just the servo arm from the motor drive pin so it won't really be noticeable.

Now I can finish off the pretty bits and the prototype should be ready for it's controller board, final fitting, and then it's proper paint job.

Alwyn

[c.rainford73]

Super job looking great!

[Raminator]

Excellent solutions for the recoil/elevation/traverse servos Alwyn, a real testament to your engineering ingenuity. I know these things are difficult enough at the best of times (i.e. when space isn't an issue), but to squeeze that level of automation around a fully detailed gun breech is taking it to a whole other level.

I'm finding it harder and harder to resist one of these kits.

[AlwynTurner]

For those interested here is a view of where the servos were actually mounted. It did involve some structural redesign of the gun carraige which was time consuming but finally successful.


I'm quite surprised (and not a little relieved) that the tiny helicopter servos successfully managed the recoil and elevation jobs.

Alwyn

[philipat]

WOW! MOST IMPRESSIVE!

[AlwynTurner]

After all the hectic design/print/build I decided I needed an artistic break and thought I'd have a bash at a camo design, after all the tank still needs it's proper coat of paint so no worries if it doesn't work.
Here's the result






The lighting and camera aren't really doing it justice as it's actually a lot darker than the pics show.

I don't know whether I like it, I think it may need more green/brown, but I'll take it to MAD on Sunday and get a few opinions/suggestions.

Alwyn