That's a seriously heavy duty hub! Should take a beating and last for years.

The equation for bite depth is: D = V * 2 * Pi / (N * W)

Where:
D = maximum bite in metres
V = the maximum bot speed in metres
N = number of teeth
W= the disk's angular velocity in radians per second

If you hate working in radians as much as I do, the results for 2,800 RPM and 3 teeth are 7.14mm @ 1m/s and 21.83mm at 3 m/s
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yay! thats the best feeling when it spins for the first time!

@Nick thanks man, that's exactly what I was looking for, they sound like decent figures, yep that is pretty serious looking hub

@Cpnwolfe, hell yeah! looks well balanced too.

With all the new and improved spinners this year, the spectators are going to get a supercharged show
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

have you done weight calculations?
That is a lot of Al you have sitting there.
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Mechanical engineers build weapons, civil engineers build targets

Yes trying to knock some weight out of it now, the nuts and bolts/bearing that hold it all together weigh a bit and the disc is 3kg iirc. The drives/esc's/ntm/rx/battery come close to 3kg going to be very tight.

Going to run Red wheels with a bearing mount/tz85's/dlux 100A sbec/2x rs550's/NTM 580kv/5S 5Ah nanotech battery may have to drop to a 4S 2.65Ah for weight reasons, will lose some significant power, safe to say bitten off a bit more than I can chew atm.

EDIT: With the disc/pulley component (including the axle/bearings) @5kg & the internals +3kg leaves less than 5kg for the chassis/armor/disc mounting towers......cutting it fine concerned about "dead space" in the bot taking up weight allowance.

Fail Safe

Mental bot works just the way it should safety lights / switch / and rx/tx fail safe - throw the bot into a 360 degree spin and shut down the radio and the bot stops dead every time.

When the NTM 580 is connected to the dlux 100A http://www.hobbyking.com/hobbyking/store/__16367__turnigy_dlux_100a_sbec_brushless_speed_controller_w_data_logging.html on a bench test and the fail safe action is taken the motor continues to spin? also if the motor is spinning then brought to a stop and the radio turned off the motor starts up! anyone know what is happening in this situation that is occurring? New to Brushless

On another note the programming box and data logger work a treat ( I'm sure the above issue is due to something I have not set correctly ) over a 3:40 run on 5S the motor spun to 12368 RPM, and got to 32 degrees C in a ambient setting of 30 degrees C.

The RX has a failsafe which may be set to a default position when it has lost signals.

I would suggest you reset it.

Without knowing RX I can't tell you exactly how to but it is usually based on the channel position when you bind the RX.

STeve
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Steven Martin
Twisted Constructions
http://www.botbitz.com

Last edited by marto on Wed Sep 24, 2014 9:18 pm; edited 1 time in total

Cheers Steve, it was a binding issue sorted

Inertia test spin up - 5S, Dlux 100A esc w/data logging NTM 580kv - spin up test data - @1/4 - 1/3 throttle approx* yielded 2600RPM @27A @20V - ...interesting results picture speaks a thousand words, Miles has some video I think

Spin up video - 2600RPM figures quoted in previous post were from a different test, belt needs to be tightened.



in the vid it's very over weight, here the biz front plate is removed, sitting at 14.4kg atm not sure I'll make the cut. looking at removing all the material in front of the towers, and cut the sides down to just in front of the gearbox mount removing the wheel support. Then using some 1mm ali for the front lol

....the towers still need bracing with some rebar, seems for everything I'll take off I need to put back on as weight somewhere else.








Last edited by Tim on Mon Sep 29, 2014 2:44 am; edited 1 time in total

awesome as. spins hard.

Here's what i reckon for weight saving -

The drills are super wide which is gunna add tons of weight via the size of the frame. If you can compact that all down then theres at least half a kilo to be saved there.

Chop the top of the box section arms down as far as you can. Anything above the axle is dead weight.

But most of the weight is in those massive hubs. The belt doesnt need to be that far from the blade. Half the distance would be fine i reckon. If that assembly is made much narrower then you can make the frame narrower too.

Drill or lathe the hell out of them as well. Must be at least a kg of dead weight in there

Good progress
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Thanks Glen credit also to Miles for the lathe work

quote:

---

spins hard

---

Having just put 2 brand new 18V Rockwell drills in Mental running on 4S with tz's, and connecting everything backup, making sure polarities are correct ect. gave it a test drive on the bench (wheels not on the ground/spinning freely)

After about 90-120 seconds the left wheel consistently stops? (8 times in a row!) I figure this is the thermal cut out programmed into the tz's (I'm using the code from Launchpad, I'm not a programmer I just flash the tz via ISP cable and send it the brushed file.) there's nothing wrong with the tz's, drove perfectly a day ago, the only new variable in the equation is the motors....I should also add it's 34 degrees Celsius indoors here with the fan on.

Also that's without it's armor so I'm guessing under load that run time will come down dramatically, could it be that the drills are just not run in? any ideas anyone?

Note:- Inertia has been put on hold due to weight/design issues, so this is my only bot and now it doesn't want to play just days before the Nats!

Edit:- Once the motors stops for whatever reason, if I turn the bot off then back on again it runs straight away? not very useful in a combat situation.

cheers tim

The motors should be drawing very little current under no load, so maybe the left motor has a lot of internal friction? Is the left motor harder to turn by hand than the right motor? What happens if you switch the ESCs - does the problem stay on the left side? Does the left side ESC get noticeably warm compared to the right side?
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion