1st gen Durango IFS TRUE SCALE (you're going to want to see this)

[jonnywachter]

Basically at this point its an entirely new truck minus chassis rails.

[MAC FAB]

Take a bellcrank setup and have it 90 degrees off axis, horizontal so they swing down. Have the tie bar on the opposite side of the tie rods (normal location), servo drive rod could hook there as well. Not scale, but you can prove your theory and would allow for infinite theoretical tie rod mounting locations to minimize or even eliminate any bump steer. Plan B makes me think of Traxxas Summit suspension, done with prop rods. That may be the better option as I invent your build in my head.

[jonnywachter]

I didn't really like the idea of the 90* bell cranks because of the inherent issues with bump steer, the ball height changes as the bell crank moves so basically the bump steer is always changing as the wheels are turning. I went ahead and designed it anyway and fought with it for the last couple of hours with no prevail. I'm going to work on a sliding type of mechanism next. This will be a lot more consistent, my only worry is dirt getting into it and binding up.

[lonleycreeper]

Dirt binding the sliding bar is a very valid concern. Twin hammers has that arrangement and it is a constant issue.

[CODYBOY]

Originally Posted by lonleycreeper

Dirt binding the sliding bar is a very valid concern. Twin hammers has that arrangement and it is a constant issue.

You beat me to it. It would be hard to make that set up trouble free.

[jonnywachter]

Originally Posted by CODYBOY

You beat me to it. It would be hard to make that set up trouble free.

I completely agree, there's really no other option unless I want crazy amount of bump steer.

[Brake Weight]

Twin chassis mounted servos with a link between the arms? Same idea, more torque, and...something else...

I would personally move the moving bits to face the back to hide it some. Would any of the Twin Hammers aftermarket steering ‘fixes’ be use?

[jonnywachter]

Originally Posted by Brake Weight

Twin chassis mounted servos with a link between the arms? Same idea, more torque, and...something else...

I would personally move the moving bits to face the back to hide it some. Would any of the Twin Hammers aftermarket steering ‘fixes’ be use?

LOL, adding two servos would probably complicate things more than it will help. I considered moving everything to the back but that takes away from the scale appearance IMO

[CODYBOY]

Originally Posted by lonleycreeper

Dirt binding the sliding bar is a very valid concern. Twin hammers has that arrangement and it is a constant issue.

Originally Posted by jonnywachter

I completely agree, there's really no other option unless I want crazy amount of bump steer.

Ok, I don't have a math/geometry back ground but have been building custom trucks on here for a number of years. I don't know if any of it will help you but here is a thread that has a whole new IFS I put together for my Hammer. It has a bell crank system and next to no bump steer. No big deal if you poo poo it, but hoping it will give you a little insight for your design. What you're doing is very cool and I envy your drawing skills.

Codyboy" TwinHammer rebuild V2

Ernie

[jonnywachter]

Originally Posted by CODYBOY

Ok, I don't have a math/geometry back ground but have been building custom trucks on here for a number of years. I don't know if any of it will help you but here is a thread that has a whole new IFS I put together for my Hammer. It has a bell crank system and next to no bump steer. No big deal if you poo poo it, but hoping it will give you a little insight for your design. What you're doing is very cool and I envy your drawing skills.

Codyboy" TwinHammer rebuild V2

Ernie

Hey man any help is great. I have been working on the steering all day and I've made no progress. LOL

[MAC FAB]

Seeing that you will 3d print everything, print a shock body that has a thru shaft, mini rack. Pull off one side to the servo. Shock shaft length to match the appropriate pivot points. Problem solved. Big servo will drive that all day long.

[jonnywachter]

After 12hrs of designing 10 different possibilities this is the best I've got so far. The steering angle is less than desirable but there is virtually no bumpsteer. I'm on the right track!

[Brake Weight]

Granted this is a Yoder, I just saw this ad and thought it could be of some use to this project.

http://board.marlincrawler.com/index.php?topic=103556.0

[MAC FAB]

Not hydraulic, but a mini rack. No piston, just o rings on either side, like the bottom of a shock body on each side. Use one of the sides as a common end and use some flat bar to connect to the servo, making it a cms. Print mounting tabs on the "rack" body. Keeps dirt out of the rack that way. Doesn't need to be very long either. A linear guide if you will. Found now???

[jonnywachter]

Originally Posted by Brake Weight

Granted this is a Yoder, I just saw this ad and thought it could be of some use to this project.

Marlin Crawler's New Rock Crawling Long Travel IFS Suspension System (#RCLT)

It would be so nice to be able to design parts so tightly tucked together like that. Unfortunately as parts get smaller tolerances don't. We are still both working with the same 0.01"-0.05" tolerances in both situations. The only difference is 0.05" over 3ft is nothing but when the parts only 1 inch long, that's a huge difference.

Originally Posted by MAC FAB

Not hydraulic, but a mini rack. No piston, just o rings on either side, like the bottom of a shock body on each side. Use one of the sides as a common end and use some flat bar to connect to the servo, making it a cms. Print mounting tabs on the "rack" body. Keeps dirt out of the rack that way. Doesn't need to be very long either. A linear guide if you will. Found now???

I can see a better idea of how that works now, great idea for keeping a slide mechanism clean. I may look into it further, it would be hard sourcing a "shaft" that was long enough and had the same threading on both sides. then there's the actual attachment to the tie-rod I don't know how to accomplish.

Anyway I woke up with an epiphany and got right to work. Last night I kept making the spindle arms longer to change the geometry and in turn I was just making a longer lever that had to move further to accomplish the angle I wanted. So I went back the opposite direction and kept shortening it. Ended up with a setup that gets more steering angle than the CVD will allow which is what I ultimately wanted. This angle is over 90* of total movement now. Now I just need to figure out where the servo will fit.

[MAC FAB]

Cvds only get about 35 degrees of angularity. Steer shaft woes, tap and die set, or singularly, and cut your own threads on the length desired. I just hope 3d printed parts will handle the abuse for your sake.

[jonnywachter]

Originally Posted by MAC FAB

Cvds only get about 35 degrees of angularity. Steer shaft woes, tap and die set, or singularly, and cut your own threads on the length desired. I just hope 3d printed parts will handle the abuse for your sake.

Not all CVDs are created equal.... I’m very familiar with the SLS nylon I want to use. I’m confident it will hold up to the task.

[jonnywachter]

Drew up the wheels and tires and "brake" hubs to get a better idea of the clearance of things and im lucky I did because its very close. Check it out! Also I wanted to show how compact the steering ended up turning out, nothing hanging out in the way at all. What do you guys think of the servo position? Will it be in the way there? I cant really find a better place for it.

[RadioFlyer]

Nice.

Looks like you could spin the servo 180 degrees so the output shaft is facing backwards. Then instead of a servo arm you can run a printed gear and make it rack and pinon.

[jonnywachter]

Originally Posted by RadioFlyer

Nice.

Looks like you could spin the servo 180 degrees so the output shaft is facing backwards. Then instead of a servo arm you can run a printed gear and make it rack and pinon.

OH I definitely thought about it, I don't think the 3D printed gear could hold up to any sort of torque though.