RCCrawler Forums

insanerc · 04-09-2006, 12:33 PM

Hey all, I call this my ugly stick. It's a torsion design (shockless) with a few things done to it that you may or may have not seen. First of all when I decided to build this thing I was concerned about how floppy it would be as well as backbone loading causing it to flip off the rocks at critical angles where a very soft touch is required. My first build up (regular) certainly proved these things to be of real concern during both bench test and out on the rocks. After that I knew I needed to try and come up with some ideas to control the flex, it's unloading and floppy characteristic.

My next step would be to arch the channel to improve ground clearance and make it possible for me to run another channel (straight) along side the torsion channel with springless shocks to be used for dampening only. This worked to some degree but still left a lot to be desired. One thing I want to point out is on the backbone bend it is not just a single bend through the center section but three bends that bring it back level to keep the caster where it needs to be which is fairly important. Center ground clearance with this design came out to a nice 7" even with the stock Clod tires.

After doing the backbone bend I was surprised that it actually had an effect on both articulation and loading in a positive way. I was on the right track but needed to take it a bit further. To help ease loading and improve articulation a little I decided to try and drill a series of hole through the sides of the backbone. I started with these holes small and far apart as I check articulation and unloading after ever change I made. Here are the final results. This ugly stick is as predictable as any chassis design that I have used and crawls extremely well. The only true place that it lacks now is adjustability of spring rate for different types of courses. Just to describe how predictable this design is you can grab either the front or back axle, let the other rest on a level surface, suddenly twist the axle you are holding to 90 degrees and watch the other axle rise up on one side until it is about 2? off the level surface and stay there with no bounce at all and only a nice smooth movement and rest. This seems to be about 70 degrees of articulation which is great for most purposes. I went ahead and did BTA front steering for this test so the steering links would not be in the way.

Overall I would highly recommend this design so am passing along what I learned. Now this stick is torn down as it was for experiment purposes only and I am currently working on another design based on the stick with shocks and swivel rod ends.

I just noticed and wanted to add the date on the one photo is wrong. I forgot to set it when I took the pic........

DUKEMURMUR · 04-09-2006, 12:44 PM

I have a freind that is trying to figure out a kind of center pivit stick chassi that flexs in the center using shocks...i called him stupid...but at least someone else is trying the pivit idea...

Duke

insanerc · 04-09-2006, 01:06 PM

Hey Duke, I wouldn't be so quick to call him stupid as he may come up with a sick design that works like a dream. I'm sure a lot of famous inventors in our past were called stupid. As far as this chassis it does not incorporate any PIVOT whatsoever but rather a torsion design.

clodbrett · 04-09-2006, 02:01 PM

Galileo was thrown in prison for saying that the earth was not flat .. ;)

_bR3T7

rockcrawler_101 · 04-09-2006, 03:25 PM

what do you mean its not flat? I want on it every day and it looks flat to me

HaPtOAD · 04-13-2006, 03:55 PM

you mean walk. Cool idea I'm wanting to build a stick for my little girl to drive. Might have to borrow your idea.

04-09-2006, 12:33 PM	#1
insanerc RCC Addict Join Date: Mar 2006 Location: Bedias, Texas Posts: 1,083	Ugly Stick Experiment Hey all, I call this my ugly stick. It's a torsion design (shockless) with a few things done to it that you may or may have not seen. First of all when I decided to build this thing I was concerned about how floppy it would be as well as backbone loading causing it to flip off the rocks at critical angles where a very soft touch is required. My first build up (regular) certainly proved these things to be of real concern during both bench test and out on the rocks. After that I knew I needed to try and come up with some ideas to control the flex, it's unloading and floppy characteristic. My next step would be to arch the channel to improve ground clearance and make it possible for me to run another channel (straight) along side the torsion channel with springless shocks to be used for dampening only. This worked to some degree but still left a lot to be desired. One thing I want to point out is on the backbone bend it is not just a single bend through the center section but three bends that bring it back level to keep the caster where it needs to be which is fairly important. Center ground clearance with this design came out to a nice 7" even with the stock Clod tires. After doing the backbone bend I was surprised that it actually had an effect on both articulation and loading in a positive way. I was on the right track but needed to take it a bit further. To help ease loading and improve articulation a little I decided to try and drill a series of hole through the sides of the backbone. I started with these holes small and far apart as I check articulation and unloading after ever change I made. Here are the final results. This ugly stick is as predictable as any chassis design that I have used and crawls extremely well. The only true place that it lacks now is adjustability of spring rate for different types of courses. Just to describe how predictable this design is you can grab either the front or back axle, let the other rest on a level surface, suddenly twist the axle you are holding to 90 degrees and watch the other axle rise up on one side until it is about 2? off the level surface and stay there with no bounce at all and only a nice smooth movement and rest. This seems to be about 70 degrees of articulation which is great for most purposes. I went ahead and did BTA front steering for this test so the steering links would not be in the way. Overall I would highly recommend this design so am passing along what I learned. Now this stick is torn down as it was for experiment purposes only and I am currently working on another design based on the stick with shocks and swivel rod ends. I just noticed and wanted to add the date on the one photo is wrong. I forgot to set it when I took the pic........ Last edited by insanerc; 04-09-2006 at 12:53 PM. Reason: Explanation of date on photo

04-09-2006, 12:44 PM	#2
DUKEMURMUR Rock Stacker Join Date: Feb 2006 Location: USA Posts: 50	I have a freind that is trying to figure out a kind of center pivit stick chassi that flexs in the center using shocks...i called him stupid...but at least someone else is trying the pivit idea... Duke

04-09-2006, 01:06 PM	#3
insanerc RCC Addict Join Date: Mar 2006 Location: Bedias, Texas Posts: 1,083	Hey Duke, I wouldn't be so quick to call him stupid as he may come up with a sick design that works like a dream. I'm sure a lot of famous inventors in our past were called stupid. As far as this chassis it does not incorporate any PIVOT whatsoever but rather a torsion design.

04-09-2006, 02:01 PM	#4
clodbrett Join Date: Mar 2004 Location: Washington state Posts: 110	Galileo was thrown in prison for saying that the earth was not flat .. ;) _bR3T7

04-09-2006, 03:25 PM	#5
rockcrawler_101 Quarry Creeper Join Date: Aug 2005 Location: San Juan Bautista Posts: 268	what do you mean its not flat? I want on it every day and it looks flat to me

04-13-2006, 03:55 PM	#6
HaPtOAD Pebble Pounder Join Date: Jun 2005 Location: Rockwell, NC Posts: 131	you mean walk. Cool idea I'm wanting to build a stick for my little girl to drive. Might have to borrow your idea.

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