sweetdiesel
aka SouRGassssssss
Supporter
What is it and why do I want it? When do you guys use it the most in your rigs? Front dig vs rear dig? 3 position dig vs 2 position? Inquiring minds (building a clod based crawler/basher) want to know. 
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CharliesTheMan
Gone - bye bye.
Dig is basically controlling one axle independent of the other axle. On a rig with clod axles, all you have to do is run an ESC to each motor, and have a nice radio system, and you can run 4WD or control the axles independently. Dig serves a few purposes. On the 2.2 rigs with driveshafts (like my axial rigs) we only use dig on the rear wheels, so I'll explain that in the most detail. With dig, we can run the vehicle in 4wd, front wheel drive with the rear freewheeling, and front wheel drive with dig (rear wheels locked). One huge advantage of dig is with steering. Picture trying to turn a regular 4 WD crawler in a circle, and then imagine locking the rear wheels, so that the front wheels drive the truck and pivot around the rear axle. You're turning radius can be cut in half. This is very useful on tight courses, because you lose points for backing up.
Another big function of dig with with crawling obstacles. When you take a crawler and climb something verticle, once you're completely vertical, the rear axle wants to push under the front axle, causing the truck to flip over backwards. When you are only pulling with the front axle, you lose this effect of the rear axle trying to drive under the front axle, and you can get the rig much more vertical this way. You can also lock the rear axle to load the suspension. If you're crawling a vertical obstacle and the weight of the truck wants to flip is over, you can lock the rear tires and pull the truck up and over the obstacle with the front tires.
There are other functions of dig but those are some of the main uses.
There are different kinds of dig setups, and those require different radios. There are digs that connect to the transmission, like the VF (now DNA) dig, digs that are attached to the driveshaft, and then what I mentioned about running two motors and ESC's and controlling them seperately. I haven't run a clod based rig so I don't know a lot about how to go about setting up dig on them the best way. I'll use the digs that I use for an example. They bolt to the rear of the transmission, and act as a housing. Then you have a seperate servo that selects the position of the dig shaft, which goes into the unit and makes the magic happen. For this, you have to have a three position third channel. This is for 2WD with freewheel, 2WD with dig, and 4WD. The Nomadio and DX3R systems have three position third channels, and you can very easily mod a TQ3 with the correct switch.
Another big function of dig with with crawling obstacles. When you take a crawler and climb something verticle, once you're completely vertical, the rear axle wants to push under the front axle, causing the truck to flip over backwards. When you are only pulling with the front axle, you lose this effect of the rear axle trying to drive under the front axle, and you can get the rig much more vertical this way. You can also lock the rear axle to load the suspension. If you're crawling a vertical obstacle and the weight of the truck wants to flip is over, you can lock the rear tires and pull the truck up and over the obstacle with the front tires.
There are other functions of dig but those are some of the main uses.
There are different kinds of dig setups, and those require different radios. There are digs that connect to the transmission, like the VF (now DNA) dig, digs that are attached to the driveshaft, and then what I mentioned about running two motors and ESC's and controlling them seperately. I haven't run a clod based rig so I don't know a lot about how to go about setting up dig on them the best way. I'll use the digs that I use for an example. They bolt to the rear of the transmission, and act as a housing. Then you have a seperate servo that selects the position of the dig shaft, which goes into the unit and makes the magic happen. For this, you have to have a three position third channel. This is for 2WD with freewheel, 2WD with dig, and 4WD. The Nomadio and DX3R systems have three position third channels, and you can very easily mod a TQ3 with the correct switch.
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chip cross
Hardcore RCTalk User
I have front and rear dig with one ESC and two motors on a Berg (same thing as a clod) it's all in how you wire the rig. I am using a DX3R, 1 Mamba Max ESC,2 Team brood racing motors,and a Spektrum micro servo for front and rear dig. And the greatest thing is no stinking drive shafts and zero torque twist :
This is how you do it.
:This is how you do it.
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CharliesTheMan
Gone - bye bye.
Yeah I knew you could do it, but I sure couldn't explain the above diagram in words lol.
Chip what about freewheel, does it not exist with a berg type rig?
Chip what about freewheel, does it not exist with a berg type rig?
chip cross
Hardcore RCTalk User
Yes, you can freewheel but thats a lil trick that I will take on my grave.I can't tell you everything I know
Lessen
Super Awesome!
Supporter
As far as crawling, I'm a fish out of water but I know I can configure my 3PK for 2 or 3 position 3rd channel as well. I would imagine the M8/M11 could too, as well as the 4PK. Basically, any high end computer radio will do it.
sweetdiesel
aka SouRGassssssss
Supporter
- Thread starter
- #7
Thanks for the great information! I now understand the function of the rear dig but what would be the situation where a front dig is required? What are the drawbacks of running dual brushless motors/escs since running a single esc with two brushed motors seems to be more common? As Lessen pointed out, I should be able to mix the channels and lockout the esc powering the rear axle with my 3PK.
chip cross
Hardcore RCTalk User
-brushless is not the answer for everything a good handwound motor will be fine btw 35 to 45 turn. Belive me I love brushless speed demons.
-front dig is when you lock up the rear tire and dig the front, you would be suprised what rear dig can do for you.
-I am not sure about the 3pk, but if you use the above diagram that I posted you can have front and rear dig if your 3pk has a 3 postion 3rd channel
CharliesTheMan
Gone - bye bye.
Lessen, I'm sure that you can run the motor on the axle setup by mixing channels and controlling with the ESC. You can setup a sequence with the 3PK to use a few switches and work a tranny dig, but it's a complicated sequence to learn and remember, and nothing like a regular 3 position 3rd channel. I did a lot of research on this because I already had a 3PK and wanted to use it for dig. This is on a dig where I needed a 3 position switch, so I don't know about using the ESC's for your dig setup since I haven't done it that way. Someone like you could probably run the sequence fine, but for me, when I'm in a competition where time is of the essence, and one wrong move or dig in the wrong gear can cause me to flip over and maybe cost me the competition, I need to be able to hit the definitive switch and move on, not try to remember what order to hit two or three buttons, which is the only way that I've seen anyone be able to run dig on a 3PK. I'm not advanced with it like you guys are though, I just did a lot of research trying hard to find a way not to spend $300 on another radio when I had a 3PK.
Also, I'm hoping the 4PK has a normal 3 position 3rd channel like the DX3R. I like my DX3R, it feels good since it doesn't have but 4 batteries, but the screen doesn't have a backlight and I really don't like that. If anyone finds out for sure if the 3rd and fourth channel has a 3 position switch, I would really appreciate it. I've been wanting to look into it, but with this new business venture, two jobs, and school, all of my time off and spare time from the first job goes into designing, developing, and testing my crawler parts.
SD, I use to be nothing but brushless and LiPo, until I got my hands on some really nice brushed motors. I had two Novak goats, and then I tried some John Robert Holmes brushed motors on a mamba with 3S LiPo. Needless to say, both of the goats were for sale in a week, and now I run nothing but the holmes motors with a mamba max. The 7 turn cobalt puller motors are by far the best crawler motor on the market, and after doing a good bit of testing with one, it's the only motor that I'll run if the chassis has room for it. The Holmes Hobbies handwound 540 motors are just as nice, and by far the smoothest electric motors that I've ever seen. I now have two 7 turn puller motors, 2 35 turn handwound crawler motors, and a holmes outrunner motor. The problem with the outrunner motors is the cogging. Cogging is a lot different in a crawler than it is in a brushless basher. It shows up in a much more signifigant way, and a lot of people don't like the outrunner motors because of that. With the goats, I didn't have cogging, but the low speed throttle input and the startup routine was NOTHING like that of the mamba max with the holmes motors. Also, with the mamba you have the programming features, which I think are more important in my crawlers than in my bashers and race rigs. Here's the link to holmes hobbies. Sweetdiesel, with your knowledge of electric motors, you should call John Robert Holmes if you have any questions. His customer service is great and he's a wonderful guy to call up and shoot knowledge back and fourth with.
http://holmeshobbies.com/home.php?cat=17
Also, I'm hoping the 4PK has a normal 3 position 3rd channel like the DX3R. I like my DX3R, it feels good since it doesn't have but 4 batteries, but the screen doesn't have a backlight and I really don't like that. If anyone finds out for sure if the 3rd and fourth channel has a 3 position switch, I would really appreciate it. I've been wanting to look into it, but with this new business venture, two jobs, and school, all of my time off and spare time from the first job goes into designing, developing, and testing my crawler parts.
SD, I use to be nothing but brushless and LiPo, until I got my hands on some really nice brushed motors. I had two Novak goats, and then I tried some John Robert Holmes brushed motors on a mamba with 3S LiPo. Needless to say, both of the goats were for sale in a week, and now I run nothing but the holmes motors with a mamba max. The 7 turn cobalt puller motors are by far the best crawler motor on the market, and after doing a good bit of testing with one, it's the only motor that I'll run if the chassis has room for it. The Holmes Hobbies handwound 540 motors are just as nice, and by far the smoothest electric motors that I've ever seen. I now have two 7 turn puller motors, 2 35 turn handwound crawler motors, and a holmes outrunner motor. The problem with the outrunner motors is the cogging. Cogging is a lot different in a crawler than it is in a brushless basher. It shows up in a much more signifigant way, and a lot of people don't like the outrunner motors because of that. With the goats, I didn't have cogging, but the low speed throttle input and the startup routine was NOTHING like that of the mamba max with the holmes motors. Also, with the mamba you have the programming features, which I think are more important in my crawlers than in my bashers and race rigs. Here's the link to holmes hobbies. Sweetdiesel, with your knowledge of electric motors, you should call John Robert Holmes if you have any questions. His customer service is great and he's a wonderful guy to call up and shoot knowledge back and fourth with.
http://holmeshobbies.com/home.php?cat=17
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Timmahh
RCTalk Addict
i too have been wondering what exactly DIG Is. Great explination guys! basically its a disconect for front or rear axle so it has no drive ability. i can see where this could be helpfull in some places.
i have been thinking bout the crappy steering ability being locked 4WD. i think i have found a possible option to help with this, but it will take some time to design and work out. my idea is similar in the fact it will use a couple servos, but not be associated with the drive train at all. as i get more thought/tests and ideas. i ll start to share if it looks like a viable option.
i have been thinking bout the crappy steering ability being locked 4WD. i think i have found a possible option to help with this, but it will take some time to design and work out. my idea is similar in the fact it will use a couple servos, but not be associated with the drive train at all. as i get more thought/tests and ideas. i ll start to share if it looks like a viable option.
Lessen
Super Awesome!
Supporter
maybe I'm confused about this "3 position" 3rd channel. Is it a sequential 2 directional switch in which there is a "left", "center", and "right"? Meaning you have to pass through "center" if you're going from "left" to "right"? Or is a a different type of switch that allows you to switch to any of the other two positions without passing through?
The 3PK has a dedicated 3 position option for the 3rd channel. You just go to FUNC-DIAL. Then you choose the dial that you set your 3rd channel to and change the option to 3PS. This way the 3rd channel will go from 100% left, to center, to 100% right in just to clicks of the dial, one click for each position. If you wanted to change the channel to a switch you could do that too (which is what I would do).
The way I'm undestanding this tranny dig thing is that it's basically a mechanical mechanism where a servo simply moves something in the dig mechanism a certain distance to engage either the front only, both, or rear only. Is that right? If that's the case then you're 3PK should work just fine. you'd just need to make the mechanical adjustments to your linkage so the servo movements provide the correct amount of movement to the tranny dig thing.
Now as far as mixing goes and esc blah blah blah. That's a bit over my head. I know the 3Pk allows channel mixing but I've never used it and really don't even get it since I've never looked into it.
The 3PK has a dedicated 3 position option for the 3rd channel. You just go to FUNC-DIAL. Then you choose the dial that you set your 3rd channel to and change the option to 3PS. This way the 3rd channel will go from 100% left, to center, to 100% right in just to clicks of the dial, one click for each position. If you wanted to change the channel to a switch you could do that too (which is what I would do).
The way I'm undestanding this tranny dig thing is that it's basically a mechanical mechanism where a servo simply moves something in the dig mechanism a certain distance to engage either the front only, both, or rear only. Is that right? If that's the case then you're 3PK should work just fine. you'd just need to make the mechanical adjustments to your linkage so the servo movements provide the correct amount of movement to the tranny dig thing.
Now as far as mixing goes and esc blah blah blah. That's a bit over my head. I know the 3Pk allows channel mixing but I've never used it and really don't even get it since I've never looked into it.
sweetdiesel
aka SouRGassssssss
Supporter
- Thread starter
- #12
After studying the diagram I think I understand the concept of how the rear gets locked. The switch essentially shorts the motor causing it to lock up the axle. It's all starting to become clear now.
chip cross
Hardcore RCTalk User
Yes you are correct, a radio such as a MX3,DX 3.0 or STOCK TQ3 only has a 2 position 3 channel. Guys you WILL need to be able to adjust the E.P.A or you will fry your dig servo.
CharliesTheMan
Gone - bye bye.
Yeah if you can set the 3PK to have a switch or dial and switch to left, right,and center, as well as adjust the endpoints of each, then it should work. I had a really hard time finding any information on using this radio for dig, and I finally bought a Spektrum because of the way that the switch is set up along with the screen indicator for the position of the dig.
I'm going to be setting up my dig in the next few days and doing a tutorial. If the 3PK will indeed work for dig, then I can sell it in a heartbeat. The reason that it hasn't sold is because I haven't been able to tell anyone if it would work for dig.
you are exactly right
I'm going to be setting up my dig in the next few days and doing a tutorial. If the 3PK will indeed work for dig, then I can sell it in a heartbeat. The reason that it hasn't sold is because I haven't been able to tell anyone if it would work for dig.
you are exactly right
chip cross
Hardcore RCTalk User
You are correct, doing a dig setup like this there is NO mechanical parts(VF dig,R2 Dig,or homemade dig to bind or break). It can be made for less than 25.00
sweetdiesel
aka SouRGassssssss
Supporter
- Thread starter
- #16
I'm going to play around with the mixing functions on my 3PK to see if this can be done.
CharliesTheMan
Gone - bye bye.
Thanks let me know what you come up with. I'm taking care of my Mom who just got home from surgery, so working on the crawlers has taken a back seat.
sweetdiesel
aka SouRGassssssss
Supporter
- Thread starter
- #18
After reading the 3PK manual for about an hour I think this is how the TX can be programmed for front dig rear lockout with freewheel option with two separate ESCs.
ESC1 (front axle) plugs into normal channel 2 position on RX.
ESC2 (rear axle) plugs into channel 3 position on RX. BEC wire is disabled on ESC2.
Program Mix 1
Master as throttle
Slave as channel 3.
Forward set to +100%
Backward set to +100%
Offset 0%
MXMD set to MIX
Trim ON
MODE Active
Program Mix 2
Master as throttle
Slave as channel 3
Forward set to -5% (may have to experiment with this value)
Backward set to -5% (may have to experiment with this value)
Offset 0%
MXMD set to MIX
Trim ON
MODE Active
Reassign PS1 to toggle Mix 1 off and on. PS1 is reachable with the left thumb.
Reassign PS2 to toggle Mix 2 off and on. PS2 is reachable with the left middle or ring finger.
Keep Dial 3 to default setting of trim adjustment of channel 3, then center Dial 3.
For front DIG rear freewheel keep both mixes off. Only the front axle will have power. Dial 3 is centered so ESC2/rear axle should not have power and is able to freewheel (not 100% freewheel since the motor's magnets will provide some resistance)
For normal 4WD, click PS1 to toggle Mix 1 on. Both axles should run in unison for forward and reverse.
To activate DIG rear lockout, click PS1 to toggle Mix 1 off. Click PS2 to toggle Mix 2 on. With Mix 2 having -5% mix on channel 3 the rear axle should lock out by the ESC applying brake or slight reverse.
I think this should work, I'm going to try it this weekend.
ESC1 (front axle) plugs into normal channel 2 position on RX.
ESC2 (rear axle) plugs into channel 3 position on RX. BEC wire is disabled on ESC2.
Program Mix 1
Master as throttle
Slave as channel 3.
Forward set to +100%
Backward set to +100%
Offset 0%
MXMD set to MIX
Trim ON
MODE Active
Program Mix 2
Master as throttle
Slave as channel 3
Forward set to -5% (may have to experiment with this value)
Backward set to -5% (may have to experiment with this value)
Offset 0%
MXMD set to MIX
Trim ON
MODE Active
Reassign PS1 to toggle Mix 1 off and on. PS1 is reachable with the left thumb.
Reassign PS2 to toggle Mix 2 off and on. PS2 is reachable with the left middle or ring finger.
Keep Dial 3 to default setting of trim adjustment of channel 3, then center Dial 3.
For front DIG rear freewheel keep both mixes off. Only the front axle will have power. Dial 3 is centered so ESC2/rear axle should not have power and is able to freewheel (not 100% freewheel since the motor's magnets will provide some resistance)
For normal 4WD, click PS1 to toggle Mix 1 on. Both axles should run in unison for forward and reverse.
To activate DIG rear lockout, click PS1 to toggle Mix 1 off. Click PS2 to toggle Mix 2 on. With Mix 2 having -5% mix on channel 3 the rear axle should lock out by the ESC applying brake or slight reverse.
I think this should work, I'm going to try it this weekend.
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Timmahh
RCTalk Addict
ok, so now the ? is what DIg unit. I see the RC4WD is a dig/complete tranny setup at 80.00 new. i see TCS has their TF dig avail at 40.00 plus there is the DNA (not sure on price). I would be interested in seeing a diagram of a DYI dig unit if anyone has one.
CharliesTheMan
Gone - bye bye.
When I got ready to purchase my dig, I talked to a lot of people with the dig units. I didn't talk to one person that bought an FT dig unit that liked it, and almost everyone ended up going to the other units. The R2D has a better reputation than the FT by far. RC4WD has a lot of problems with their parts in general, usually resulting from poor machining. However, the R2D must be one of their better parts because so many run it with no problem after the initial setup and midifications, adjustments, etc.
The DNA dig is by far the best product on the market, however I feel strongly against their customer service. It's a huge conflict for me, because generally I will not buy a product when I know that the manufacturer chooses to offer poor customer service. I purchased 3 DNA digs about a month ago on back order. On Monday about 4 to 5 weeks ago, Don, the manufacturer, now with DNA, promised me that the digs were shipping to the retailer where I bought my digs from. Now the last run of digs he had sold a bunch via pre order and promised that they had already been shipped out, when in fact they didn't ship for a month or two after that. After apologies and excuses and all that he switched to DNA from Visionary Fabrication. So I figured that it must have been problems with the company and he would not lie to the customers again. 4 to 5 weeks ago, he promised me that my digs were being shipped to the retailer the first thing the next morning. I ordered three of these dig units, so it was a rather large purchase for me. I then told the members that I been able to preorder some DNA Digs (they're almost impossible to get because they're the only dig unit that actually works worth a dam in many people's opinions) and so a few people told me they wanted some. I told them that I had ordered them, and then later that they were being shipped the next day, and here I am with no dig units. I bought a second hand unit that a guy had rebuilt, and paid almost twice as much for as the new ones because of the demand, just to have a dig for my comp rig.
So, I say that the DNA dig is by far the best unit, but if I had another option I would buy from someone else just because of poor customer service, I just don't like being intentionally lied to. The problem is, RC4WD keeps selling people products that don't fit, don't work properly, kits with missing parts, etc... just because they're in a hurry to make a dollar, which also pisses me off to great extent. I'm sitting on $800 right now that is for my scaler project. I had planned to buy the RC4WD kit. They were late to market with it, so they rushed it into production, and many pieces were machined completely wrong, they shipped tons of kits with major parts missing, etc... This is a $600 scaler chassis kit that we're talking about, and it shouldn't be messed up just because the manufacturer is greedy for the next dollar. So when I look at the R2D tranny, I wouldn't switch to it from the DNA because the customer service isn't much better, and in general the companies parts have a lot of problems.
The DNA dig is by far the best product on the market, however I feel strongly against their customer service. It's a huge conflict for me, because generally I will not buy a product when I know that the manufacturer chooses to offer poor customer service. I purchased 3 DNA digs about a month ago on back order. On Monday about 4 to 5 weeks ago, Don, the manufacturer, now with DNA, promised me that the digs were shipping to the retailer where I bought my digs from. Now the last run of digs he had sold a bunch via pre order and promised that they had already been shipped out, when in fact they didn't ship for a month or two after that. After apologies and excuses and all that he switched to DNA from Visionary Fabrication. So I figured that it must have been problems with the company and he would not lie to the customers again. 4 to 5 weeks ago, he promised me that my digs were being shipped to the retailer the first thing the next morning. I ordered three of these dig units, so it was a rather large purchase for me. I then told the members that I been able to preorder some DNA Digs (they're almost impossible to get because they're the only dig unit that actually works worth a dam in many people's opinions) and so a few people told me they wanted some. I told them that I had ordered them, and then later that they were being shipped the next day, and here I am with no dig units. I bought a second hand unit that a guy had rebuilt, and paid almost twice as much for as the new ones because of the demand, just to have a dig for my comp rig.
So, I say that the DNA dig is by far the best unit, but if I had another option I would buy from someone else just because of poor customer service, I just don't like being intentionally lied to. The problem is, RC4WD keeps selling people products that don't fit, don't work properly, kits with missing parts, etc... just because they're in a hurry to make a dollar, which also pisses me off to great extent. I'm sitting on $800 right now that is for my scaler project. I had planned to buy the RC4WD kit. They were late to market with it, so they rushed it into production, and many pieces were machined completely wrong, they shipped tons of kits with major parts missing, etc... This is a $600 scaler chassis kit that we're talking about, and it shouldn't be messed up just because the manufacturer is greedy for the next dollar. So when I look at the R2D tranny, I wouldn't switch to it from the DNA because the customer service isn't much better, and in general the companies parts have a lot of problems.
