Kodiak AEV 3 Armoured Excavation Vehicle

[AlwynTurner]

Hi Rob, I would love to get details of the motors in case a future build requires something similar, any chance you could share details and pics please? regards Alwyn

[wibblywobbly]

Your wish is my command Alwyn,

http://www.ebay.co.uk/itm/350884416139? ... EBIDX%3AIT

They are a lot smaller than they look in the pic.

I have been researching 3D printers and printing, and came to the conclusion that they are a double edged sword. Some think that if you have a printer then you can magically print anything you want for free. It's not quite that simple, not by a long shot.

[AlwynTurner]

Thanks Rob, those are really titchy motors, with that gearing though they look pretty mean. Good luck with the build and lots of pics please? Alwyn

[wibblywobbly]

I have never built anything like this before, so it was whistling in the dark...but it works!

The whole thing is styrene, even the thread that the output shaft sits in.



The other sections are all built, it's just a matter of installing the motors etc.

I am slowly coming to realise that if I invested in a 3D printer, and took the time to learn how to design parts, I could have had this whole excavator job in scale, with housings for the motors, and everything lined up perfectly...my next tank may well be a printer...

RobG

[AlwynTurner]

Hi Rob that looks absolutely brilliant! The motor use is fantastic, I thought you were going to turn something with them but using a screw operation means its working exactly like a hydraulic ram - inspired thinking!. Does it draw much power - thinking battery life in minutes here if you were using these all across the arm and bucket . This model is going to be amazing and I will follow progress with great interest. Lots of pics please? Alwyn

[wibblywobbly]

They are tiny 6v motors, but as they are geared, they can pull quite well. The trick was to make everything out of styrene on the arm, it has kept the weight to an absolute minimum. I won't know until the whole arm is complete whether the first motor will lift everything above it. Its a shame, but I haven't seen any larger motors with the same geared and threaded shaft attached.

Battery life should be ok, the excavator won't be used much, and even when it is there isn't much movement required on any motor to move the arm or bucket by a comparitively large amount. It was only by reading up on how diggers work that I realised that the bucket is dropped open, but it is the arm holding it that scoops on the return stroke, and then the bucket rotates to pick up what it has collected.

After all this is done, I still have to make and install a dozer blade??

RobG

[PainlessWolf]

W.W.
I understand that I am the 'some' that you were refering to up in your previous post. I am glad to see that you understand the possibilities as well as the limitations of 3D printers. I spent some eleven years mastering a skillset in 3D design software to build tradeshow booths in vr for clients and even back then I thought that the possibilities were amazing! This was over a decade before I even heard the words ' 3D printer'. ;o). The expenses in time to learn how to create a piece then the monetary outlay for a decent device and the various types of materials required to feed it can be considerable. When I look at something like Woz' Lee\Grant or sublime creations like a working human heart, I am still completely floored by the possibilities. Following along!
Regards,
Painless

[wibblywobbly]

Now there's a coincidence, my brother is a director of a company that designs and builds exhibition stands, the big stuff etc for the aerospace industry. He also does TV and movie props, BBC etc, and the equipment that circus performers use, he sells all over the world. One his customers is Batman Live:



He also does me free stuff like some powder coated barriers for the front of my house, lolol.

Anyway, back to the build, I now have three motors on the arm, just waiting for a couple more motors to arrive. It isn't a replica of the original arm, as that uses hydraulics, and I have limited movement on the threaded bars on these motors.

[PainlessWolf]

Good Morning,
You've put the degrees of movement that you have to very good use, Sir. Your brother does some amazing stuff there! I worked for Image Industries\Laarhoven Design back in the day as their Colorado based Graphics Dept. *chuckles* Following along with the Build.
regards,
Painless

[wibblywobbly]

The motors that I was awaiting arrived, and I now have an operating turntable. I still need to install one to lift the entire arm, though this should be fairly easy.

The way that the electrics will operate is a bit challenging.

Two of the arm sections will be powered from the tank drive sockets on an RX18, this means that both will run in the same direction for lift and lower, but pushing the stick sideways will make them run in opposite directions, so I will get quite a bit of control off one stick. I tested that part and it works well.

I can use the turret rotation circuit for the turntable.

This leaves the control for one arm, and the elevation motor only runs one way on an RX18?

I have an IBU2 that I will use for propulsion, and operating the dozer blade, the dozer blade will work off the IBU2 elevation circuit, so I can't use it for the excavator arm.

This leaves me with using turret rotation on the IBU2 to operate the arm, or installing an RC switch that may not yet have been invented that will allow me to flick a switch on the IBU2 tranny, and reverse the polarity on the power to the motor, that way I get two way travel on this missing link.

I will still be left with controlling the motor that lifts the entire arm....

The other option is to make a recycling crank to operate the bucket, that way a one way motor will be ok.

Right, now that I have frazzled everybody's brains, these are the latest pics, I actually managed to get some detail done in between playing with everything else. I kicked myself this morning when I looked at it. I spent ages making the smoke launchers...why the heck didn't I just buy the HL sprue........