RCCrawler Forums

C-MURDER · 09-05-2007, 12:00 AM

Hey all,

This is my first Crawler and I'm fairly excited about it so far. In case the thread title looks familiar, well, bRIBEGuy, myself, and one other good friend have embarked on a mission to create three very different crawlers, but all using the same chassis. We will have a bit of competition when were done building.

Needless to say, I've never built one of these things before so it's been an interesting thing to learn about. I'm happy to join such a fanatic group.

So about my crawler…,well working within some very strict guidelines for our machines such as tire size, body format and wheel base, we all had free range to build the suspension, steering, etc in whatever way we wanted. I really didn't know much about the "best or most common" setup for suspension, so I just looked at the thing for an hour and came up with my Six-Shock idea. My point was to get a set ride height (with some amount of sag), yet have almost no resistance when articulating. So I decided to mount a central shock front and rear with no oil ( to keep the ride height), and four oil filled shocks on all four sides with no springs (for dampened articulation, but not bound by springs). Interestingly, what I found was that the central shock pivots in a slightly off center manner, always putting the chassis back into alignment after articulating in any way. So here are some pics and a quick vid of my first ride just showing the setup. (the vid is poor quality sorry, I only have a camera that takes small vids)

Its not done by any means and still needs some finishing touches.... and a body.... and paint.. and better tires/rims for sure!

Cheers.

http://www.rcthingsandstuff.com/medi...rock_crawling/

some_guy · 09-05-2007, 12:19 AM

interesting

run2jeepn · 09-05-2007, 12:29 AM

Different... But having a shock at each corner gives more traction on the Tires. That resistance you speak of is what gives you traction. If plan on keeping that set up. Something that would help would be to weight the Tires as much as you can. Something like 13-16oz per tire. This will help provide more weight for Traction since there aren't any shocks providing pressure down on the tires.

C-MURDER · 09-05-2007, 10:08 AM

Thanks for the comments. Yesterday I took it out for a quick trip on some bigger rocks. It seems, as with most things in life, there is a compromise that needs to be made here.

The crawler seems to work really well over some fairly horizontal rocks and flows over the terrain really well. Where I have noticed an issue is indeed with the initial bite into the more vertical movements. Its seems to lack "bite". And I now understand the need to put pressure on those tires to offer more traction and balance the weight distribution through the addition of shocks. I did think about adding more weight to the tires, and although I know that would help, I think that the physics behind the addition of springs is what is going to put the weight of the truck over the tires that are doing the actual grabbing.

I know this will be a balancing act of sorts to get all the variables just right where you have as many tires on the ground as you can while appropriately maximizing Articulation, spring compression/resistance and traction.

So, I'll add the four springs to each corner and see what that does. There may actually be no need for the middle shocks at all. Too bad. I will experiment with it to see if will add any real performance benefits.

One thing I know for sure is that the truck needs more weight. I just want to find a way to do that without actually putting the weights in the tires. I've never been a fan of rotating mass. Maybe Ill find a way to mount some weight around the axles (not batteries). Sorry for the rambling. I’m just thinking out loud here as I venture into this first crawler.

Cheers.

4stAir · 09-05-2007, 01:50 PM

i cant imagine that it sidehills very well at all...

bRIBEGuy · 09-06-2007, 01:44 PM

Nice pics, the beast is lookin' good!

run2jeepn: While your point on springs = traction does have some merit, it is important to remember that there are alot of successfull crawlers out there that do not use a spring or torsion set-up. Any of the new breed of "droop" crawlers such as the Hustler are good examples of this.

I think the 6-shock 2-spring set up definately has merit, but tuning and testing will be the key. My suggestion, C-Murder, is to try a thicker shock oil if the suspension is too supple. A lacking of "initial bite" will more likely be a result of the tire/wheel/foam set-up you're running at the moment.

One way or another, I think it's nice to see people thinking outside the box for new designs. It looks like a great first crawler.

Big Mike · 09-06-2007, 02:45 PM

For a first build that looks great. And unconventional thinking going on too. That I admire for sure.

Quote:

I've never been a fan of rotating mass.

I hear ya there, neither have I. It's not such a factor in the low wheel-speed world of crawling, though. Unless you go totally overboard.

Keep tuning her up man!

C-MURDER · 09-06-2007, 06:17 PM

Ok, I’ve decided its time to add some weight to each corner of the truck. The Steering knuckles seemed to have a bit of available real-estate so I thought I’d work with that. Again, I don’t like putting weight inside tires if I don’t have too. I know we’re not going fast, but maybe there is something better anyway.

I found a cool thread where Kamikaze had fashioned some neat axel weights and thought that would be a good way to go about it. Here’s that thread.
http://www.rccrawler.com/forum/showpost.php?p=788701&postcount=112

Unfortunately, I don’t have a great way to cut steal or have a CNC machine at my disposal. What I do have is a band saw, standing drill press and a belt sander.
So, like Fred Flintstone I went about “hacking, drilling and grinding” some 3/8 thick aluminium plate into shape. Pics below.

From here, I plan to add some 3.0 oz bolts horizontally to the face of this plate. That way I can add or remove the weight as needed. I should be able to add/remove 13-16 oz per wheel with this setup. So far the side mount plates I have made fit well with no wobble despite how they look. Actually they fit really well and don’t move easily because of the inherent teeth formed from the drill holes that make up the sleeve for the steering knuckle.

I’m sure someone is selling a better solution but I will try this first. It should work… I think…. I hope… I have no idea.

bRIBEGuy · 09-06-2007, 09:16 PM

Uh............wow.

That's alot of work with a drill and belt sander!

Guess it balances out with the amount of work it took to mount the on-off switch with that piece of tape. ;)

bRIBEGuy · 09-06-2007, 09:27 PM

Since this build thread could use some tech & spec, here's what C-Murder is running under the hood:

Chassis: Reign K2-3S
Axles: Duh.......what sub forum are you in? ;)
Motors: Tamiya 27t silver cans
Pinions: 9T with CPE motor mounts
ESC: Tekin Rebel 2
Radio: Spektrum DX3
Wheels: T-Maxx rims & tires (for now...) mounted with CPE 12-14mm adaptors
Servos are some bluebird high torque ones (200oz/inch + each).

Yup.

I think wheelbase is sitting at 14 1/8" and ground clearance is about 5" at center.

Hope you don't mind me posting this buddy!

C-MURDER · 09-08-2007, 11:07 AM

Man.... What did I get myself into? These things are mega time consuming to make. I hope it's worth it in the end. Perhaps this is a bit ambitious for a first crawler...

Progress in these photos:

*addition of metal epoxy to smooth out the contact surface between main weight plate and steering knuckle ( the black fill between the teeth on the plates...nice smooth inner finish.)

*Drilled out three holes in the test plate to mount three .5" X1.5" bolts.

The first (test) plate is a total of 10 oz. The second plate that has no bolts in it yet will hold 13-16 0z of weight. The nice thing about these is that it makes it easy to add/remove weight as needed, its not rotating mass, and you can bias the distribution of the weight.

more soon.

lunchbox · 09-08-2007, 11:31 AM

Wow. I like the idea of a semi-fixed (sprung) center point that the ends are free to flex around. Did you do the weights one by one, or screw 4 hunks together and drill, cut, sand then as 1 unit? Could you have just used the stick on weights inside the hub flange?

C-MURDER · 09-08-2007, 11:43 AM

The stick on weights were one idea, but I wanted something a bit more industrious.

As for your point about cutting and drilling all at once... I WISH!!
Unfortunately each one of these things is cut, drilled, filled and sanded one at a time. That’s all I can get away with considering the tools I’m using. Way more trouble then its worth I am sure.

But at the end of the day I can move the weights, add more, take some away.. Who knows. This could be a great experiment in pain and suffering and nothing more. lol. Oh well, all that time in the work shop keeps me from pimping on the streets.

jagg · 09-08-2007, 06:04 PM

Quote:

Originally Posted by C-MURDER

The stick on weights were one idea, but I wanted something a bit more industrious.

As for your point about cutting and drilling all at once... I WISH!!
Unfortunately each one of these things is cut, drilled, filled and sanded one at a time. That’s all I can get away with considering the tools I’m using. Way more trouble then its worth I am sure.

But at the end of the day I can move the weights, add more, take some away.. Who knows. This could be a great experiment in pain and suffering and nothing more. lol. Oh well, all that time in the work shop keeps me from pimping on the streets.

I do most of my work with a drill press and a band saw also, so I know that there is a %#$& load of time involved in those. Honestly though, I would have gone with the stick on weights. Originality is one thing, I wouldn't have had the patience.

bRIBEGuy · 09-08-2007, 07:19 PM

That's freakin' hardcore man........................

bRIBEGuy · 09-10-2007, 10:20 PM

Well, the 6 shocker lives!

I got to see this thing in action over the weekend and it is quite the sight to behold. It needs some tuning, and some new meats (who'da thought stock T-Maxx tires with full foams would suck for crawling...lol), but I think this rig has some real potential.

Got those pimp wheel weights finished yet man?

kaetwo · 09-11-2007, 09:53 AM

Thats an amazing looking rig. I really dig the unconventional setup and your method of adding weight to the 4 corners.

Well done!

If you could get ahold of some older Pro-Line Giant Tracs that would be a perfect match for this rig.

C-MURDER · 09-11-2007, 10:16 AM

Thanks guys.

A quick trip out to our local mountains made for a spectacular day and wicked crawling.

bRIBEGuy also took his rig out and, from an armature’s perspective, his Droopy K2-S3 was amazing to watch. I love how looks more like a standard RC until you see it crawl and then it seems to just hug every nook and cranny. Its a smooth operating rig for sure..

About mine, I still have some tuning to do. Some of which may include
* lowering the truck a bit by sliding the suspension down.
*Adding the wheel weights.
*limiting my articulation by 10 degrees or more.
*Adding thicker oil to the shocks.
*Better tires. !!
*4500mah six cell battery

Overall, the truck performed beyond my expectations and really fun to drive.

bRIBEGuy · 09-11-2007, 04:00 PM

I think your list of mods will completely open your eyes as to the potential of your rig.

Time to get started tweaking!

bRIBEGuy · 10-12-2007, 05:42 PM

Any updates on this rig?

;)

I think you need an Escalade body man.................

09-05-2007, 12:00 AM	#1
C-MURDER Newbie Join Date: Sep 2007 Location: Calgary Posts: 12	Six-Shock the K2-3S Hey all, This is my first Crawler and I'm fairly excited about it so far. In case the thread title looks familiar, well, bRIBEGuy, myself, and one other good friend have embarked on a mission to create three very different crawlers, but all using the same chassis. We will have a bit of competition when were done building. Needless to say, I've never built one of these things before so it's been an interesting thing to learn about. I'm happy to join such a fanatic group. So about my crawler…,well working within some very strict guidelines for our machines such as tire size, body format and wheel base, we all had free range to build the suspension, steering, etc in whatever way we wanted. I really didn't know much about the "best or most common" setup for suspension, so I just looked at the thing for an hour and came up with my Six-Shock idea. My point was to get a set ride height (with some amount of sag), yet have almost no resistance when articulating. So I decided to mount a central shock front and rear with no oil ( to keep the ride height), and four oil filled shocks on all four sides with no springs (for dampened articulation, but not bound by springs). Interestingly, what I found was that the central shock pivots in a slightly off center manner, always putting the chassis back into alignment after articulating in any way. So here are some pics and a quick vid of my first ride just showing the setup. (the vid is poor quality sorry, I only have a camera that takes small vids) Its not done by any means and still needs some finishing touches.... and a body.... and paint.. and better tires/rims for sure! Cheers. http://www.rcthingsandstuff.com/medi...rock_crawling/ Last edited by C-MURDER; 09-05-2007 at 12:27 AM. Reason: trying to get the embeded video to work

09-05-2007, 10:08 AM	#4
C-MURDER Newbie Join Date: Sep 2007 Location: Calgary Posts: 12	six-shock experiments continue Thanks for the comments. Yesterday I took it out for a quick trip on some bigger rocks. It seems, as with most things in life, there is a compromise that needs to be made here. The crawler seems to work really well over some fairly horizontal rocks and flows over the terrain really well. Where I have noticed an issue is indeed with the initial bite into the more vertical movements. Its seems to lack "bite". And I now understand the need to put pressure on those tires to offer more traction and balance the weight distribution through the addition of shocks. I did think about adding more weight to the tires, and although I know that would help, I think that the physics behind the addition of springs is what is going to put the weight of the truck over the tires that are doing the actual grabbing. I know this will be a balancing act of sorts to get all the variables just right where you have as many tires on the ground as you can while appropriately maximizing Articulation, spring compression/resistance and traction. So, I'll add the four springs to each corner and see what that does. There may actually be no need for the middle shocks at all. Too bad. I will experiment with it to see if will add any real performance benefits. One thing I know for sure is that the truck needs more weight. I just want to find a way to do that without actually putting the weights in the tires. I've never been a fan of rotating mass. Maybe Ill find a way to mount some weight around the axles (not batteries). Sorry for the rambling. I’m just thinking out loud here as I venture into this first crawler. Cheers.

09-06-2007, 06:17 PM	#8
C-MURDER Newbie Join Date: Sep 2007 Location: Calgary Posts: 12	Wheel Weights in progress Ok, I’ve decided its time to add some weight to each corner of the truck. The Steering knuckles seemed to have a bit of available real-estate so I thought I’d work with that. Again, I don’t like putting weight inside tires if I don’t have too. I know we’re not going fast, but maybe there is something better anyway. I found a cool thread where Kamikaze had fashioned some neat axel weights and thought that would be a good way to go about it. Here’s that thread. http://www.rccrawler.com/forum/showpost.php?p=788701&postcount=112 Unfortunately, I don’t have a great way to cut steal or have a CNC machine at my disposal. What I do have is a band saw, standing drill press and a belt sander. So, like Fred Flintstone I went about “hacking, drilling and grinding” some 3/8 thick aluminium plate into shape. Pics below. From here, I plan to add some 3.0 oz bolts horizontally to the face of this plate. That way I can add or remove the weight as needed. I should be able to add/remove 13-16 oz per wheel with this setup. So far the side mount plates I have made fit well with no wobble despite how they look. Actually they fit really well and don’t move easily because of the inherent teeth formed from the drill holes that make up the sleeve for the steering knuckle. I’m sure someone is selling a better solution but I will try this first. It should work… I think…. I hope… I have no idea.

09-08-2007, 11:07 AM	#11
C-MURDER Newbie Join Date: Sep 2007 Location: Calgary Posts: 12	Wheel Weights continued Man.... What did I get myself into? These things are mega time consuming to make. I hope it's worth it in the end. Perhaps this is a bit ambitious for a first crawler... Progress in these photos: addition of metal epoxy to smooth out the contact surface between main weight plate and steering knuckle ( the black fill between the teeth on the plates...nice smooth inner finish.) Drilled out three holes in the test plate to mount three .5" X1.5" bolts. The first (test) plate is a total of 10 oz. The second plate that has no bolts in it yet will hold 13-16 0z of weight. The nice thing about these is that it makes it easy to add/remove weight as needed, its not rotating mass, and you can bias the distribution of the weight. more soon.

09-05-2007, 12:19 AM	#2
some_guy Quarry Creeper Join Date: May 2007 Location: melbourne, australia Posts: 274	interesting

09-05-2007, 12:29 AM	#3
run2jeepn I wanna be Dave Join Date: Sep 2005 Location: USA Posts: 11,196	Different... But having a shock at each corner gives more traction on the Tires. That resistance you speak of is what gives you traction. If plan on keeping that set up. Something that would help would be to weight the Tires as much as you can. Something like 13-16oz per tire. This will help provide more weight for Traction since there aren't any shocks providing pressure down on the tires.

09-05-2007, 01:50 PM	#5
4stAir RCC Addict Join Date: Jan 2006 Location: The Amish Ghetto Posts: 1,932	i cant imagine that it sidehills very well at all...

09-06-2007, 01:44 PM	#6
bRIBEGuy Rock Crawler Join Date: May 2004 Location: Calgary Posts: 807	Nice pics, the beast is lookin' good! run2jeepn: While your point on springs = traction does have some merit, it is important to remember that there are alot of successfull crawlers out there that do not use a spring or torsion set-up. Any of the new breed of "droop" crawlers such as the Hustler are good examples of this. I think the 6-shock 2-spring set up definately has merit, but tuning and testing will be the key. My suggestion, C-Murder, is to try a thicker shock oil if the suspension is too supple. A lacking of "initial bite" will more likely be a result of the tire/wheel/foam set-up you're running at the moment. One way or another, I think it's nice to see people thinking outside the box for new designs. It looks like a great first crawler.

09-06-2007, 09:16 PM	#9
bRIBEGuy Rock Crawler Join Date: May 2004 Location: Calgary Posts: 807	Uh............wow. That's alot of work with a drill and belt sander! Guess it balances out with the amount of work it took to mount the on-off switch with that piece of tape. ;)

09-06-2007, 09:27 PM	#10
bRIBEGuy Rock Crawler Join Date: May 2004 Location: Calgary Posts: 807	Since this build thread could use some tech & spec, here's what C-Murder is running under the hood: Chassis: Reign K2-3S Axles: Duh.......what sub forum are you in? ;) Motors: Tamiya 27t silver cans Pinions: 9T with CPE motor mounts ESC: Tekin Rebel 2 Radio: Spektrum DX3 Wheels: T-Maxx rims & tires (for now...) mounted with CPE 12-14mm adaptors Servos are some bluebird high torque ones (200oz/inch + each). Yup. I think wheelbase is sitting at 14 1/8" and ground clearance is about 5" at center. Hope you don't mind me posting this buddy!

09-08-2007, 11:31 AM	#12
lunchbox Quarry Creeper Join Date: Feb 2007 Location: Fresno Posts: 472	Wow. I like the idea of a semi-fixed (sprung) center point that the ends are free to flex around. Did you do the weights one by one, or screw 4 hunks together and drill, cut, sand then as 1 unit? Could you have just used the stick on weights inside the hub flange?

09-08-2007, 11:43 AM	#13
C-MURDER Newbie Join Date: Sep 2007 Location: Calgary Posts: 12	The stick on weights were one idea, but I wanted something a bit more industrious. As for your point about cutting and drilling all at once... I WISH!! Unfortunately each one of these things is cut, drilled, filled and sanded one at a time. That’s all I can get away with considering the tools I’m using. Way more trouble then its worth I am sure. But at the end of the day I can move the weights, add more, take some away.. Who knows. This could be a great experiment in pain and suffering and nothing more. lol. Oh well, all that time in the work shop keeps me from pimping on the streets.

09-08-2007, 07:19 PM	#15
bRIBEGuy Rock Crawler Join Date: May 2004 Location: Calgary Posts: 807	That's freakin' hardcore man........................

09-10-2007, 10:20 PM	#16
bRIBEGuy Rock Crawler Join Date: May 2004 Location: Calgary Posts: 807	Well, the 6 shocker lives! I got to see this thing in action over the weekend and it is quite the sight to behold. It needs some tuning, and some new meats (who'da thought stock T-Maxx tires with full foams would suck for crawling...lol), but I think this rig has some real potential. Got those pimp wheel weights finished yet man?

Sponsored Links

09-11-2007, 09:53 AM	#17
kaetwo I wanna be Dave Join Date: Jun 2004 Location: Whales Posts: 2,939	Thats an amazing looking rig. I really dig the unconventional setup and your method of adding weight to the 4 corners. Well done! If you could get ahold of some older Pro-Line Giant Tracs that would be a perfect match for this rig.

09-11-2007, 10:16 AM	#18
C-MURDER Newbie Join Date: Sep 2007 Location: Calgary Posts: 12	Thanks guys. A quick trip out to our local mountains made for a spectacular day and wicked crawling. bRIBEGuy also took his rig out and, from an armature’s perspective, his Droopy K2-S3 was amazing to watch. I love how looks more like a standard RC until you see it crawl and then it seems to just hug every nook and cranny. Its a smooth operating rig for sure.. About mine, I still have some tuning to do. Some of which may include * lowering the truck a bit by sliding the suspension down. Adding the wheel weights. limiting my articulation by 10 degrees or more. Adding thicker oil to the shocks. Better tires. !! *4500mah six cell battery Overall, the truck performed beyond my expectations and really fun to drive.

09-11-2007, 04:00 PM	#19
bRIBEGuy Rock Crawler Join Date: May 2004 Location: Calgary Posts: 807	I think your list of mods will completely open your eyes as to the potential of your rig. Time to get started tweaking!

10-12-2007, 05:42 PM	#20
bRIBEGuy Rock Crawler Join Date: May 2004 Location: Calgary Posts: 807	Any updates on this rig? ;) I think you need an Escalade body man.................

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Thread: Six-Shock the K2-3S