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Anyone know how to determine if a Gearbox has enough Torque?

Posted: Fri Feb 08, 2019 3:17 pm
by Tech-Com
I have a 21st Century 1/6 M5A1 Stuart Tank and I want to give it some more speed.

I determined I need 500rpm for the 6mph, which would be 1/6th the true top speed.


The best I can find are 470rpm 12V worm gearboxes.

Rated torque: 2kg.cm; Stall Torque: 10kg.cm

https://www.amazon.com/gp/product/B01GR ... KG47K&th=1

Is this enough to get it rolling? Will it slowly accelerate to top speed of 5.6mph?

Thanks

Re: Anyone know how to determine if a Gearbox has enough Tor

Posted: Fri Feb 08, 2019 11:49 pm
by 43rdRecceReg
Put simply, I have a wooden ramp outside my house leading to the front door (for me and the tanks). If the tanks can get up that, and over the step into the house, then they have enough torque.
Similarly, I have a steep grassy bank (I almost wrote 'Grassy knoll" 8O ) in my Highland hill garden. Again, if they can get up that, they have torque enough. I worry more about when I can't manage it (the hill, that is :D ).
I'm actually thinking about building a mini Aberdeen Tank Proving-Ground in my garden, just for the very purpose of testing pulling power, grip and more. But that's for the future.
Incidentally, and ironically, the original Aberdeen (Scotland), is only about 150 miles from where I live. :D

Re: Anyone know how to determine if a Gearbox has enough Tor

Posted: Sat Feb 09, 2019 1:46 am
by Tech-Com
So after asking around the motor I listed should be able to accelerate it to full speed if the rolling resistance is less than 1.75lb
Maximum thrust would be 8.7lb. I'll have to determine my total weight and the maximum incline this thrust can achieve.

Re: Anyone know how to determine if a Gearbox has enough Tor

Posted: Sat Feb 09, 2019 4:55 pm
by 43rdRecceReg
Tech-Com wrote:So after asking around the motor I listed should be able to accelerate it to full speed if the rolling resistance is less than 1.75lb
Maximum thrust would be 8.7lb. I'll have to determine my total weight and the maximum incline this thrust can achieve.
One of the first tanks I tinkered with, was a Taigen Tiger 1. I assembled it using the trusty Taigen abs/alloy hull you can get from several sources, along with metal tracks, wheels, metal Turret (including the bespoke Airsoft Barrel recoil feature), etc.
It ended up weighing around 16lbs. Using a 4:1 gearbox ( if I recall correctly) also from Taigen, it has no difficulty dealing with any slopes I challenged it with. The Clark TL22 controller, paired with a 4000mAh NiMH
battery, also manage to supply the motors with all the juice the overweight Tiger needs to haul its considerable bulk about. Put simply, configured this way, it has all the torque it needs to do the biz. :thumbup:
No equations needed :D The bank in my garden is probably around 30deg. Steep enough to break my ankle when covered in ice; :thumbdown: but not enough to stop the Tiger. :)
Once again, whilst I have several beefed-up tanks, like many members here, I find even the stock ones can climb and pull pretty well.

Re: Anyone know how to determine if a Gearbox has enough Tor

Posted: Sat Feb 09, 2019 5:07 pm
by 43rdRecceReg
Perhaps I should add that the dynamics of 1/16 models, are going to differ considerably from those built in 1/16 scale. Some 1:6 examples can be incredibly heavy. Scaling weights/power/speed/ component strength (even paint shades) from one scale to another isn't easy. :problem:
I'd advise reading Gary's 1:6 Hetzer thread here to benefit from the decisions, headaches, and solutions he came up with the Power his Hetzer. It's an informative and entertaining thread. :thumbup:
You can also find other 1:6 mod topics on here, but Gary's was practically a scratch build, as opposed to a refurbishment.
viewtopic.php?f=150&t=22899&hilit=gary+Hetzer

Re: Anyone know how to determine if a Gearbox has enough Tor

Posted: Sun Feb 10, 2019 1:14 am
by 43rdRecceReg
You will also find some details on 1:6 Stuarts, , via the 'search' tool here. Just to speed things up a wee bit, one of our most respected members, PainlessWolf, also has the 1/6 Stuart, and you may find what he's written on to be helpful. :thumbup: Hope so.
viewtopic.php?f=150&t=18212&hilit=Stuart+1%3A6+Painless

This scale speed calculator may also come in handy for future reference..
https://www.jbwid.com/art74i.htm