Hydraulic Cylinders

[tarmo120]

I'm almost ready to start on 2 hydraulic cylinders.
The only issue is that I have limited access to a milling machine, and fairly little to no access to a milling machine.
So I was wondering, if it's possible to use shocks for hydraulic steering. I know that this is done before, just not using shocks.
I have looked at shocks, and can't decide which to try out.

First is the Pro-Line Powerstroke shocks. I think they would be better than the others.
http://www.rpphobby.com/product_p/pro6060-00.htm

G-Made shocks. I just picked those out because these and the Pro-Line have double O-rings on the lower part where the shaft exits the shock body.
http://www.rpphobby.com/product_p/jungm20604.htm

All I am asking, is which one would you get, and why.
Really the last thing would be to make them myself, but I rather would modify already existing cylinders.

[troublecat]

here are some

http://www.gardentrucking.com/

[jamesdicken]

I think most shocks have two o rings on the shaft. I would go with older non threaded losi shocks. I think mainly because they dont have a cap and they are smooth

[tarmo120]

Originally Posted by jamesdicken

I think most shocks have two o rings on the shaft. I would go with older non threaded losi shocks. I think mainly because they dont have a cap and they are smooth

Are these still available to buy? If so, could you please shoot me a link.

Well I can always use the threaded shocks and lathe them smooth.

[SMR 510RR]

Figure out how much travel you are going to need then pick a shock that will fit those requirements. Just about any shock should work but who knows how much pressure it will take or how much you will actually need to get the authority you need.

It would be very cool for a scale rig though. What are you planning on using for a pump?

[Tryker46]

Well said SMR, I have been thinking about how to go about this for some time. Are you thinking of using one double acting cylinder or opposed single acting cylinders? One thing I was thinking was using a cartridge type shock with a bleeder hole in the cap. Just tap the hole for a fitting and plug the holes in the piston and you have a single acting cylinder.

[SMR 510RR]

You could just use one single action cylinder, double action would be much harder to achieve, you would have to have the flow all proportioned out perfectly otherwise you would run into problems. Single action would be much easier, you need to make a piston with probably 2 o-rings to seal the two chambers and find o-rings that would fit the I.D. of the shock body (not sure if they would be perfect you may need to bore them out to get a good seal). Then just drill and tap for two connectors to connect up some lines. The cylinder is the easy part sourcing a orbital valve and all that would be more challenging, I guess you could use a servo to control it but I dont know if a servo would give you enough rotation to go lock to lock. You could use a servo modified into a winch to control it but then it wont return to center...

Maybe you already have all that figured out, share it with us if you do...I may want to do it on my scx-10 if it would be inexpensive enough.

[Big Mike]

Originally Posted by SMR 510RR

What are you planning on using for a pump?

That was my question as well. You have to force the fluid to do the job somehow. The actual ram seems to be the easy part. Then there's the what are you powering the pump with question?

gardentrucking.com is a one-stop source for a scale hydraulic system, but the pump itself is 6" long and powered by a 540 can. You're not using this stuff on any build under 1:6th scale, not easily anyway.

A couple years ago a guy on here got pretty deep into a hydro steer project. Something about a linear servo pushing a remote piston back and forth and transferring the force thru tubes to an axle mounted ram. I don't think it worked out for him, I don't remember seeing a finished product.

Whatever you do it's gonna involve moving fluid to and from an axle mounted ram. You have to connect the ram to whatever is moving the fluid with tubing, and there's just not much room for extra stuff in 1:10th scale. 1:6th scale would be another matter. Whatever tubing you use has to be soft and flexible or it will add resistance to the suspension and affect it's performance.

[ToyTundra]

Originally Posted by Big Mike

That was my question as well. You have to force the fluid to do the job somehow. The actual ram seems to be the easy part. Then there's the what are you powering the pump with question?

gardentrucking.com is a one-stop source for a scale hydraulic system, but the pump itself is 6" long and powered by a 540 can. You're not using this stuff on any build under 1:6th scale, not easily anyway.

...

One-stop if you have a thick wallet. It's cool stuff though.

It's easy to modify the pump to be a little smaller. I ran a Crawlmaster outrunner on mine and cut down the reservoir to reduce the length. I'm currently using a much smaller outrunner for a total length of under 3.5 inches. There is also a "mini" pump available. It's even more expensive and fairly long as well.

A few guys have used Robart or Clippard pneumatic cylinders for hydraulic applications. Even in a true pump driven system. They are much cheaper than the Leimbach cylinders. If you are going to use a master/slave cylinder arangement like a guy on here did in the past, the air cylinders may be a good option. They are a little large in diameter though.

[Tryker46]

The plan I had for my ax-10 was to use two opposed cylinders with the shaft end screwed to each steering arm and the cylinder end mounted to a bracket on the "center section" then make a pump that resembled the oil pump in a small block chevy that was driven by a motor and speed control out of my rc18t. My thinking was the pump would just be moving fluid from one cylinder to the other to steer so ther would not be a need for a reservoir or valving. But then again I might be over simplifying things. At the time I wasn't thinking of needing to return to center, but in theory it would work.

[SMR 510RR]

Originally Posted by Tryker46

The plan I had for my ax-10 was to use two opposed cylinders with the shaft end screwed to each steering arm and the cylinder end mounted to a bracket on the "center section" then make a pump that resembled the oil pump in a small block chevy that was driven by a motor and speed control out of my rc18t. My thinking was the pump would just be moving fluid from one cylinder to the other to steer so ther would not be a need for a reservoir or valving. But then again I might be over simplifying things. At the time I wasn't thinking of needing to return to center, but in theory it would work.

I cant figure out how it would return to center. There would have to be a control board in the rig or some custom mixing on the radio to make it return. Lets say "fwd" was left and "rev" was right (Rotation of the motor mounted to the "Exchange pump") you turn the wheel left and the motor keeps spinning "Fwd" until you stop turning...When you stop everything stops and nothing happens leaving you at wherever you were when you let off the wheel. Same goes for right.

For that type of setup to return to center there would probably need to be some type of linear encoder to monitor the length of the ram. Then there would need to be some sort of processor to control the pump to modify the steering angle vs. your radio input.

Much more complex than it is worth.

[Tryker46]

I had just figured it was a trade off of using a hydraulic setup. There are numerous designs you could try, it just takes some tinkering

[tarmo120]

Originally Posted by Big Mike

That was my question as well. You have to force the fluid to do the job somehow. The actual ram seems to be the easy part. Then there's the what are you powering the pump with question?

gardentrucking.com is a one-stop source for a scale hydraulic system, but the pump itself is 6" long and powered by a 540 can. You're not using this stuff on any build under 1:6th scale, not easily anyway.

A couple years ago a guy on here got pretty deep into a hydro steer project. Something about a linear servo pushing a remote piston back and forth and transferring the force thru tubes to an axle mounted ram. I don't think it worked out for him, I don't remember seeing a finished product.

Whatever you do it's gonna involve moving fluid to and from an axle mounted ram. You have to connect the ram to whatever is moving the fluid with tubing, and there's just not much room for extra stuff in 1:10th scale. 1:6th scale would be another matter. Whatever tubing you use has to be soft and flexible or it will add resistance to the suspension and affect it's performance.

I'm going to try a servo as the pump. 2 cylinders, one on the axle of my scaler and one somewhere hidden and connected to a servo. I have a link for the thread somewhere...wait...oh here it is. The idea there is that the servo moves the shaft of the 2nd cylinder and that forces the fluid to move thru the lines. Looks at the thread and I hope you get the idea.

http://www.rccrawler.com/forum/showt...32#post2060432

Since that guy made it work, I'm sure i can too.
I'm not saying it would be perfect, but noone can stop me from trying. I say it's worth to try.
About the scaler I have in parts. It's going to be a ''Nacho'' Ramcharger with Fracture V8 and leafs with links and 4 link. I know it's crazy but that's how the 1:1 is built. I'm not in a hurry so there is no build thread...yet.

[Tryker46]

That's the spirit! Throw up some pics when you can!

[tarmo120]

Of course. But now there's still the question, which shocks to use. Because I am not going for the gardentrucking pistons. Just too expensive.
What do you guys think, would the Pro-Line shocks be better than the G-Made

[Tryker46]

IMO the gmade look more like hyd. cylinders. But the fact that the prolines have a removable top cap which makes it easier to drill and thread or a fitting. Just depends on what u want.

[tarmo120]

I really don't care about the thread on the outside of the body. I can always ask someone to lathe them smooth or do it myself. Not a problem. Let's rephrase. Which one would be better for hydro cylinders on the pefrormance side?

[SMR 510RR]

Originally Posted by tarmo120

I really don't care about the thread on the outside of the body. I can always ask someone to lathe them smooth or do it myself. Not a problem. Let's rephrase. Which one would be better for hydro cylinders on the pefrormance side?

Any shock should work fine...Try to find something that will fit a standard sized o-ring down the piston bore.

[tarmo120]

Originally Posted by SMR 510RR

Any shock should work fine...Try to find something that will fit a standard sized o-ring down the piston bore.

Will try. But here's another issue.
How big is the standard o-ring in metric mm?
And since English isn't my native language, would someone kindly explain to me what is the piston bore.

[Tryker46]

No, I meant the amount of material in the cap to put threads in for a fitting. The gmade's have that rounded top that might be too thin to hold a fitting.
The piston bore is the inside of the shock body or I.D.
Sorry if I was confusing.

Performance wise, that's trial and error...