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electronic dig?

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Old 07-14-2014, 06:30 PM
  #1
nitrosportsandrunner
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soo, I just picked up a set of redcat RS10 axles/ motors/ esc for $58.

Im thinking up a torsion chassis setup.

I was also thinking that with my flysky GT3c I could do a dig setup.

since it is a MOA setup...can I just rig a switch on the neg (or pos) wire to one motor and use a servo to move that switch on/off? With the switch off, the other motor should still work right?

If that is true, im just wondering what kind of switch I should look for. The redcat motors are 100t 390 size motors, and will run on a 2s lipo....so I don't think the amp draw will be huge. But I don't want to end up with a switch that cant handle the current either.

Thoughts?
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Old 07-14-2014, 06:31 PM
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Also, if anyone has a cheap set of 2.2 crawler tires, or a cheap truck body to sell, please PM me. Id like to keep the whole build under $125.
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Old 07-14-2014, 08:06 PM
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um, been doing some searching and reading what I can find on electronic digs but still a bit confused.

some setups look complex...but I have noticed some "short" the motor which adds some drag brake (beyond the drag of the motor/springs/brushes and low gearing) while others just disconnect the power to/from the motor (free wheeling)

So, I think maybe then I have to rig up 2 switches....thus disconnecting the pos and neg to a motor? I was hoping I could do just one wire to a motor (1 switch, easier rigging to a servo than 2 switches) but maybe this would cause a problem since both motors are wired to the same esc? Would the esc still try to push power to a motor if the neg wire on the motor was disconnected?
Id really like to have a simple, 1 servo, 1 switch setup for a easy dig system but don't want to risk burning up a ESC that will cost $60 to replace!
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Old 07-14-2014, 09:23 PM
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How about 1 servo with 2 switches? Switch 1 is on the negative wire between the esc and the motor. Switch 2 shorts the negative wire to the positive wire. With the servo in position A, switch 1 is closed and switch 2 is open for normal operation. Hit the Dig button, servo moves to position B opening switch 1 disconnecting the motor from the esc while switch 2 closes and shorts the positive and negative wires. Mount the switches next to each other and tie the arms together. Now the linkage is simple since the switches move as one. If they're single pole they'll need to be rotated 180 from each other so one closes while the other opens. If dual pole just make sure you wire them so one opens while the other closes.

Im not not an electrical genius but with 1 wire disconnected I can't see how the esc will get damaged. Melt the switches though and you might end up with a short causing bad things to happen.The motors are wired to the esc in parallel so disconnecting one just means less load on the esc. The motor that is still connected will end up getting more power though so the throttle will feel different.

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Old 07-14-2014, 09:46 PM
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I've actually found you the perfect setup. Best of all it requires no switches and no servo. Basic automotive relays for fog lights and such usually have a 30amp rating (higher is available) as well as a normally open and a normally closed side. So it will act just like the 2 switch setup but with no chance of shorting anything if switch to dig while on the throttle. To control the relay you can use a radio activated switch like this one http://hobbyking.com/hobbyking/store...ay_Switch.html

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Old 07-14-2014, 11:39 PM
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Lol, that was my first thought, I just typed up a big post then realised u all read have lol
there is external DIG controllers

i still think the best way is to hack the gt3. And run those cheap eBay speical ESC with drag brake that I use.... They are only $15 each and are rated to 320a. It will do exactly what u want with the addition of a ton of new features and u will be able to run up to 9 channels.
personally I found 6 is enough, that's 2 for servos, 2 for ESC and 2 for whatever? Lights, smoke, horn? Who knows

honestly u could do the exact same thing I did with DIG and 4ws, I'm happy to help in any I can.
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Old 07-15-2014, 06:49 AM
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ok, should specify my skill....lol
even tho ive been into rc for a long time guys, and can program a radio or esc and generally match any electronics together, knowing how they actually work is another thing. I know ive seen that the gt3c can be hacked, but honestly do not want to do that.
I also know from reading that most prefer to have the option to short the motor or to disconnect it, so it can lock or freewheel. Honestly, I only want the ability to disconnect the rear motor (mainly for climbing steep angles so it doesn't try to "driver under" the front)
So if it is possible to use a single switch to disconnect the pos or neg (does it matter which?) on one motor to allow it to free wheel (there will be an amount of drag from the gearing in the axle) that is what id want to do.
2 esc's and such would allow for more options, but I already have spare servos and a switch shouldn't cost more than $10. I already have the rs10 esc which works well and has drag brake/no-delay reverse. I don't care to buy stuff I don't need.

as it sits, this truck will probly end up looking strange. Im considering a torsion rod chassis, with a scaler body, sitting on MOA axles with 1.9 tires. Weird, right?
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Old 07-15-2014, 07:11 AM
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Hummmmm interesting...
my first thoughts, I don't think that will work to well for climbing.

say a very steep climb, all the weight is on the rear, and the rear has the most traction.
on shaft driven vehicles even tho are 4x4. Going up a steep hill the rear wheels are doing the work.

same deal with a MOA crawler, the rear wheels are doing the majority of the work.
and from experience I've found with MOA crawlers... going up a steep hill there is no weight on the front and if there is a even power split the front wheels will brake traction very very easily compared to the rear.

Example, say u are going up a hill very slowly at 1/5 throttle,
u get to a slightly steeper section that stalls the rear motor,
but as u increase the throttle to 2/5 to get it moving again, the front wheels loose traction free spinning as if they are off the ground while the rears are only just moving.

so cutting the power to the rear motor is going to make it extremely hard to climb.
I don't know if u have ever tried to climb with front wheel drive?? It's basically impossible

ive been playing around with throttle mixing and I can honestly say my moa crawler crawls a lot better with a 60/100 F/R power split.
ie, whatever the rear is doing the front is only 60% of that.

so from what u under stand is I don't really want DIG but u want channel mixing?
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Old 07-15-2014, 08:29 AM
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Quote:
Originally Posted by nitrosportsandrunner View Post
I also know from reading that most prefer to have the option to short the motor or to disconnect it, so it can lock or freewheel. Honestly, I only want the ability to disconnect the rear motor (mainly for climbing steep angles so it doesn't try to "driver under" the front.

as it sits, this truck will probly end up looking strange. Im considering a torsion rod chassis, with a scaler body, sitting on MOA axles with 1.9 tires. Weird, right?
I have no idea what you mean by "driver under". Torsion bar suspension huh? They're not exactly known for having lots of travel but there's no reason why it couldn't be done, should be interesting. I'd consider bending the bars into an Allen key shape and reinforcing the bend. Mount the bars longitudinally and use sway bar links to link the bars to the axle. Packaging may be an issue though and finding the correct material to make the bars for the right spring rate may not be that easy.

[QUOTE=phmaximus;

Example, say u are going up a hill very slowly at 1/5 throttle,
u get to a slightly steeper section that stalls the rear motor,
but as u increase the throttle to 2/5 to get it moving again, the front wheels loose traction free spinning as if they are off the ground while the rears are only just moving.

so from what u under stand is I don't really want DIG but u want channel mixing?[/QUOTE]

i also have no idea what you mean by the last sentence! But you are right about disconnecting the rear motor hurting climbing performance. From what I understand dig is all about turning. I've also heard of the situation you mentioned happening in single esc MOA crawlers where the unloaded axle/motor spins a lot faster than the loaded axle. Does dual esc's help prevent this somewhat?
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Old 07-15-2014, 09:53 AM
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torsion bar wouldn't allow for a lot of travel (flex) but for a 1.9 tire size crawler with a fairly scale body that is fine, you don't want a ton of flex (not the type generally achieved by most MOA crawlers)

Ill try to explain what I mean by "drive under" better. this in when your front tires make it to the top of the rock, but the rears are still at the base of the rock. the front tires will be spinning some, and if they could spin faster might be able to pull the truck up. But when you apply more throttle, the rears, which were not turning before due to the much higher traction, now start to turn. but, instead of driving up, they want to go forward (more traction on the ground then on the face of the rock) and this causes the chassis to want to rotate around the axle itsef......and you end up on your roof. If the rear axle could free-wheel and you could give full throttle to just the front, you would have a chance of the front tires pulling the truck up.

But yes, generally disconnecting (or locking) the rear axle is done more for tight turning than climbing. But with my 1/6 hummer there are times trying to go up a rock that I wish I could have power to just the front tires, as the rears will be trying to lift the front of the truck OFF of the rocks instead of trying to climb up the rock. It is true that some channel mixing (if 2 esc's were used) would likely work better in this situation, but you would be wanting more power to the front than to the rear.
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Old 07-15-2014, 10:01 AM
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along with the torsion bar idea, I am also considering a "pimp cane" type torsion crawler.
The reason the torsion bar idea appeals more, is that the center chassis doesn't twist, giving a place to mount a body.
But I have done a simple torsion crawler before that I was still able to mount a dingo body on (with rs10 axles)

the pics of the torsion bar I found online, the other pics are a rs10 torsion dingo I did couple years back:

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Old 07-15-2014, 05:59 PM
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I get what u are saying but if u are on a hill that's so steep that's the car is about to flip over from wheeling, no way the front would have the traction to be able to pull the weight of the vehicle up. And the mechanical drag from the rear gearbox is going to make things worse

for that situation u are better off increasing the rear anti squat, so under power the rear end raises... Like the 4 link drag cars.... U know the ones that the rear end goes up on acceleration. Or increasing the front weight.

What I was trying to say before, by the sounds u want Chanel mixing more than The DIG aspect.

ill see if I can get a video showing what I mean
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Old 07-15-2014, 06:08 PM
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I'd seriously consider the hack....

all u I have to do is...
buy a kit
solder a 4 pin servo looking connector onto the circuit board
download a programme and a the firmware onto your PC (All for free and links in the instructions on where to get them)
then conect the adaper to the controller and PC with supplied cables.
load the programme and update the firmware.
Then calibrate the controller base settings. Including measuring and inputting the battery voltage, so u will need a basic multimeter

honestly the program looks confusing, but there are great instruction and it's easier than using iTunes lol
all u do is open the file with the programme then click a button up flash the controller, no kidding, it takes around 20 seconds to do.
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Old 07-15-2014, 06:11 PM
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Quote:
Originally Posted by phmaximus View Post
I get what u are saying but if u are on a hill that's so steep that's the car is about to flip over from wheeling, no way the front would have the traction to be able to pull the weight of the vehicle up. And the mechanical drag from the rear gearbox is going to make things worse

for that situation u are better off increasing the rear anti squat, so under power the rear end raises... Like the 4 link drag cars.... U know the ones that the rear end goes up on acceleration. Or increasing the front weight.

What I was trying to say before, by the sounds u want Chanel mixing more than The DIG aspect.

ill see if I can get a video showing what I mean
well, the situation I am trying to describe is when the front tires "crest" the top of the rock but the rears are just at the base. If it was a steep rock taller than the wheelbase of the truck then yeh, the fronts wouldn't pull it up. but if the fronts are now on the top of the rock they will have some pull, especially if the rear is not powered and thus not pulling the fronts off of the rock.

On my 1/6 hummer, there is not much I can do to the rear suspension as the current setup is such that the ride hight is as low as possible. Any other setup would create a high ride height and ruin the look.

I mention the hummer in this thread as I could do the dig to it as well. But for now, I was only thinking of doing it on the rs10 axles/esc I will be getting soon.

Ive been trying to find more pics of torsion rod chassis' but am not coming up with much. are these chassis called by other names? I only know of pimp cane/ torsion/ torsion rod. I need some more pics to get my brain cooking.
I also need to find out where I can get "piano wire". Im sure I can find some online but id like to buy it local if I can. what other uses (or names) does it have?
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Old 07-15-2014, 06:11 PM
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Have a read of this, and see what u think?

http://www.overkillrc.com/GT3B/GT3B%...raft%202.1.pdf
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Old 07-15-2014, 06:13 PM
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Quote:
Originally Posted by phmaximus View Post
I'd seriously consider the hack....

all u I have to do is...
buy a kit
solder a 4 pin servo looking connector onto the circuit board
download a programme and a the firmware onto your PC (All for free and links in the instructions on where to get them)
then conect the adaper to the controller and PC with supplied cables.
load the programme and update the firmware.
Then calibrate the controller base settings. Including measuring and inputting the battery voltage, so u will need a basic multimeter

honestly the program looks confusing, but there are great instruction and it's easier than using iTunes lol
all u do is open the file with the programme then click a button up flash the controller, no kidding, it takes around 20 seconds to do.
Phmax....you have never seen me try to solder! Yeh, technically I can but even after years in the hobby I still suck at it. Motor wires and battery connectors give me trouble....fine spots on a circuit board are even worse for me. I can do it when I HAVE to, but don't want to risk ruining my GT3c (which I love)
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Old 07-15-2014, 06:16 PM
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just found yet another style of torsion chassis, pretty cool:
https://www.youtube.com/watch?v=qiwqCT_0444
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Old 07-16-2014, 05:36 PM
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well, I ended up finding a very detailed video showing how to rig a simple switch to make the RS10 have a dig.
The video also shows that you need to short the motor, as there isn't enough drag from the 390 motor (its been a while since I had a rs10, could have sworn they had more drag than shown in the video)
I have some 9g plane servos, so id just need to find a switch like the one he used.....and then try to solder it all up. If I do it like he did, I will finish it up by covering the connections in plasti dip.

https://www.youtube.com/watch?v=nkJZFfhYWn0
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Old 07-16-2014, 06:15 PM
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Ahh yep, it's super simple to do, but I thought u didn't want that? Because of the brake?
That setup is only going to be useful for DIG turns

dont know about the 5a switch tho
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Old 07-17-2014, 04:29 AM
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Quote:
Originally Posted by phmaximus View Post
Ahh yep, it's super simple to do, but I thought u didn't want that? Because of the brake?
That setup is only going to be useful for DIG turns

dont know about the 5a switch tho
well, without brakes would help going up a hill, with brakes will help with turns. either way I gain a type of advantage. If I go with brakes, now I know exactly how I can do it.

5amp does sound low....but then, it is used on a 70 turn 390 motor. The stock 1800mah nimh battery that comes with a rs10 will get you 20-25 minutes of runtime. These motors don't likely draw very many amps. Plus, when you short the motor doesn't the switch disconnect the ESC leads from the motors' lead, and then connect the motor's leads?
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Old 07-17-2014, 05:33 AM
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Cool, that's gives au a idea on the average current draw but I'd me more concerned with the maximum current draw...
ie. full throttle with a stalled motor.

if it's pulling under 5a it's about on par power wise to a 1/24 with a 150 size motor
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Old 07-17-2014, 06:34 AM
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Quote:
Originally Posted by phmaximus View Post
Cool, that's gives au a idea on the average current draw but I'd me more concerned with the maximum current draw...
ie. full throttle with a stalled motor.

if it's pulling under 5a it's about on par power wise to a 1/24 with a 150 size motor
maybe 5amp is the switch's constant rating? Maybe the burst is much higher?

I still need to find some cheap crawler wheels and a good body to work with....otherwise ill get the axles in a few days and wont be able to start anything. I cant really start building a chassis until I know the wheelbase of the body I am going to use!
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Old 07-23-2014, 11:07 AM
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Nobody mentioned the RC4wd rocker II (2) dig? I used it for ages, works great. There's also the more 'pro' option of the punkrc dig. Both are easy to find from google.
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