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08-10-2007, 07:26 AM
| #1 |
| Rock Crawler Join Date: Feb 2007 Location: Ramstein Air Base Germany ...ya Ive been Ramshafted
Posts: 567
|  Hydro steer made easy
Ok so for months Ive been working on a comp tuber and in the very begining I told a good buddy of mine "dude wouldnt it be cool to have hydro steer just like the real Crawlers". Well He said it would be cool but that It wouldnt work, and that you probably couldnt build it small enough to mount it on a R/C crawler and have it be reliable on the rocks. Little did he know all he did at that point was light a fire under me to make it happen but at the same time he was probably telling me this because he knows me and knows that I will spend months on something and it will be forever before we crawl together. He was right!! Its been 8 months since I got back from my deployment and Ive spent countless hours at work on my Custom TLT based Comp 2.2, to say the least my good friend isnt happy with me and I recieved a text msg from him the other day saying "HTFU" he he On a good note........I am almost done and will post pics of everything I have done once I figure out what I am going to copyright and what I am not. However because there are things in this world that are of no mystery to some and totaly forien to others I have decided that I am going to post something that I think could be the next best thing to the R/C crawling industry and encourage anyone to improve upon my design, have fun with it and lets see some of the awsome tallent out there! Hydraulic Steering made simple! Basicaly it started with "what the hell am I going to use?" Aluminum, Brass, steel,? How was I going to seal it all up, how will I bleed the system? How am I going to make it look scale and will it have enough force for crawling? It has to be rebuildable on the trail! I am no stranger to hydraulics or mechanics so Ideas started to form very quickly, I took a look at the years of stuff I have acumulated in my shop and was still scratchin my head. But then I decided to start with the simple things.........seals! I took a look at the shocks that come with the tlt kit and decided to start cutting them down on my lathe and parted the sealed end from the rest of the shock thus making a (seal end pack). Once I figured that out it was a piece of cake! So because I am long winded and just realized that most of you probably dont want to read all this I will let the pics and video explain itself! One more thing remember if your going to do this keep it simple!! Also all this is is a simple closed loop static system (Master and slave) setup just like the hydraulic clutch system on some cars/trucks/heavy equipment. No pumps, no valves just a servo to actuate it! Enjoy!!! And remember to click on the link to the video and turn you speakers up!             for oil I use airtool oil sold at Lowes seems to work well! __________________ If you cant play with the big dogs, Stay on the porch! |
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08-10-2007, 07:40 AM
| #2 |
| I wanna be Dave Join Date: May 2005 Location: CITY of CHAMPIONS!!
Posts: 2,086
|  again holy **** thats awsome! you should sell these!
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08-10-2007, 07:45 AM
| #3 | ||
| I wanna be Dave  Join Date: Oct 2006 Location: Martinsburg WV
Posts: 2,781
| Quote:
I had the same idea a few months back, it never got past the paper stage though. My main goal was something that looked more appropriately scale instead of a servo mounted on top of the axle. I don't have a lathe and some other things that are nessecary for a project like this so I never took it any further than an idea on paper, but I'm a little stoked that what I drew up looked very much like what you've built. Makes me feel like I was on the right track! I was also worried about bleeding/adding fluid w/o some kind of reservior built in to the system, but you seem to be getting good results without one. Do you just syringe fluid into the system through either bleeder valve? The problem is that you really don't create any kind of real mechanical advantage, it just looks more "appropriate" for the application. You still need a strong servo to get good torque. I may be wrong, please correct me if I am - you seem to have a lot more experience with hydraulic systems than I do. Quote:
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08-10-2007, 07:51 AM
| #4 |
| Rock Stacker Join Date: Apr 2007 Location: Longmont
Posts: 74
| ....holy **** bro, thats one of the coolest things I've seen. How'd you secure the hoses to the tubing? I'll have to try something like that now!
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08-10-2007, 07:59 AM
| #5 |
| I wanna be Dave Join Date: Oct 2006 Location: Martinsburg WV
Posts: 2,781
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I did this computer drawing from my first "napkin sketch" late last winter - never took it past this:  My hydraulic experience is limited to on-the-fly repairs of heavy equipment. I was just working off what I knew - that you can't compress fluid and it will transfer rotational energy to linear energy. Once it was done I looked at it and said to myself "you can't machine all those seal seats and stuff" and shelved it. I never thought to adapt existing off-the-shelf parts into it, what an obvious easy solution! Good job with that, the video looks great. I'd love to see this setup in action on the rocks... |
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08-10-2007, 08:10 AM
| #6 |
| I wanna be Dave Join Date: Oct 2005 Location: Columbia TN
Posts: 6,154
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Very nice, I like it.
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08-10-2007, 08:22 AM
| #7 |
| RCC Addict Join Date: Mar 2007 Location: St. Louis (High Ridge)
Posts: 1,279
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actually, watching the video, it looks like the slave cylinder has about an inch of stroke, while the masters do about 1.25-1.5" there would be mechanical advantage there to the tune of 25-50% I think the bigger trick will be getting that much throw out of a servo without putting extra long arms on it and losign the mechanical advantage. also, I know it works without a load, but if in a bind, or under impact, if fluid makes it past a seal in the slave cylinder, your steering ends up off center, there is only so much you can do with trim on the t/x before the master cylinders start moving at different rates which screws up internal pressures. Maybe. On the other hand, you could use one servo per master cylinder, with a reverser, so you would have one in pressure pushing, and one in vacuum pulling without trying to fit them both on the axle. Imagine mixing chanels so you have two 5995's each running one master cylinder. 300 oz.in. of pull, and 300 oz.in. of push, plus 50% mechanical adventage, minus 30% mechanical disadvantage for 1.25" servo horns and pressure losses (friction in the fittings etc.) you could still get 7-800 oz.in. of steering force. Yikes. |
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08-10-2007, 08:24 AM
| #8 |
| Rock Crawler Join Date: Feb 2007 Location: Ramstein Air Base Germany ...ya Ive been Ramshafted
Posts: 567
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Hey Big Mike Thanks for the comments man I appreciate them! Ya its not all that complex of a system pretty simple infact and it doesnt suprise me that you came up with the same idea, there seems to be allot of talent on this forum and Id like to see more people post things like this! I understand the fact that some dont have the machinery to do some of this kind of stuff. Ive spent alot of time and money on that kind of stuff and im just fortunate to have a wife that alows me to buy what I say I need. She actualy worked a second job to help build the shop that I have now! Now as far as correcting you on the mechanical advantage thing, I wont correct you because I am a jack of all trades and a master of only some ha ha and I havent mastered hydraulics yet I just understand a great deal about them and deal with them in my work. So here goes with the tech stuff strait from the book k! "Applying a force of 2 lbs on the piston in the smaller cyclender would lift a wieght of 100 lbs supported on a piston in the larger cylinder." "applying a force of 2 lbs on the piston (refering to a picture) in the smaller cylinder produces a circuit pressure of 2 psi because the force is applied to a sectional area of 1 sq in." "the circuit potential is 2 psi and because this acts on a sectional area of 50 sq in it can raise 100 lbs" "accordingly, if a force of 10 lbs was to be applied to the smaller piston, the resulting circuit pressure would be 10 psi and the circuit would have the potential to raise a wieght of 500 lbs" " So if we wanted to calculate the force exerted by a cylindrical ram (steering actuator) we would use the following formula: Force exerted (servo ) = hydraulic pressure (psi) x cylindrical area ( diameter squared x 0.7854) even simply put: 100 pounds of force on a 1 in piston produces 100 psi acting on a 2 in piston is 200 pounds of force applied to what you are trying to move ( like a steering knuckle) there for mechanical or hydraulic advantage! its exactly like a hydraulic clutch setup in a car, if you look at the master cyl its smaller than the slave pushing on the clutch to make it easier on your leg if not you leg would get tired real fast. Hope that helps man! |
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08-10-2007, 08:28 AM
| #9 |
| Rock Crawler Join Date: Feb 2007 Location: Ramstein Air Base Germany ...ya Ive been Ramshafted
Posts: 567
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Nice!!! See you got it!!! So are you a heavy equip mechanic or what? I went to school for that but Im still in the AF and I have been a crew chief on KC135's for about 10 years. I may be getting out though and going back to school to finnish HVY EQPMNT.
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08-10-2007, 08:35 AM
| #10 |
| Rock Crawler Join Date: Feb 2007 Location: Ramstein Air Base Germany ...ya Ive been Ramshafted
Posts: 567
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you are very correct! Im not bashing you at all when saying this but as far as the force goes we are talking an (R/C) crawler we dont realy need that much if you think about it carnage sucks you know! But again you are very correct! As far as blowing a seal or seal blow by, I machined the pistons with extream close tolerance (unlike my spelling) he he but ya very close fit and durring my testing of this I applied blunt force quick shock loads to each master and had no probs with it but you never know what will happen on the rocks but niether do the big guys. I also machined everything so I could remouve and replace, repair anything in the system quickly! Hope I thought of everything!! Thanks for your comments I love the imput!!!!
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08-10-2007, 08:41 AM
| #11 |
| Rock Crawler Join Date: Feb 2007 Location: Ramstein Air Base Germany ...ya Ive been Ramshafted
Posts: 567
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Thanks man!!! for the moment the hoses on the master cyls are just on barbed fittings and the others are on some press in hydraulic hose fittings 1/8" those allow me to quickly take a hose out if I blow one or need to work on the system at a comp! I got those at House of Hose here in Spokane. You know obviously there is the potential for more than neccasary maint on the rocks at a comp but I thought it would be cool to take the extra step forward in this hobby and make it that much cooler and I dont have to worry about servo's getting wet when Im playing!!! I invite anyone to improve this do it!!!! lets have fun with it!!!!! Thanks again for your imput!!! |
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08-10-2007, 09:47 AM
| #12 |
| I wanna be Dave Join Date: Oct 2006 Location: Martinsburg WV
Posts: 2,781
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I did'nt even factor in the effect of different size surface areas of the pistons (I drew a bigger actuator piston and smaller slave piston just from what I've seen on heavy equipment) seems a mechanical advantage addition to a cheap low-torque servo could be a reality here if it's dialed in right. You could do a crude test by sitting the rig on thick shag carpet - if it still turns the wheels easily you should have at least adequate torque, depending on the overall weight... Last edited by Big Mike; 08-10-2007 at 09:50 AM. |
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08-10-2007, 10:05 AM
| #13 |
| 06 Super National Champ   Join Date: Jun 2004 Location: Stark Industries Bar and Grill
Posts: 11,361
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Nice work. My hydraulics use a pump but when they need to turn they turn.  On carpet against a wall you can turn the tires and push away from the wall - with micro servos on a 13lb truck. |
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08-10-2007, 10:06 AM
| #14 | |
| I wanna be Dave Join Date: May 2006 Location: Arlington, VA
Posts: 3,377
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08-10-2007, 10:09 AM
| #15 | |
| 06 Super National Champ Join Date: Jun 2004 Location: Stark Industries Bar and Grill
Posts: 11,361
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08-10-2007, 10:19 AM
| #16 |
| RCC Addict Join Date: May 2006 Location: In England, looking for the threadlock...
Posts: 1,150
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Nice idea, I've thought about trying it before, but space is an issue on a Comp Clod tuber. Nice job on making it work, keep us updated on how it bears up to crawling in the real (1:10) world!  |
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08-10-2007, 10:30 AM
| #17 |
| ΜΟΛΩΝ ΛΑΒΕ  Join Date: Dec 2006 Location: In tha Bush of Louisiana
Posts: 4,343
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GOOD JOB |
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08-10-2007, 10:50 AM
| #18 |
| I wanna be Dave Join Date: Dec 2005 Location: Orlando
Posts: 7,420
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So is force of the steering determined by the strength of the Servo? I.E. If I had a Traxxas 2205 VS a HiTec 5995.
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08-10-2007, 11:09 AM
| #19 | |
| RCC Addict Join Date: Sep 2005 Location: Behind the torch!
Posts: 1,360
| Quote:
This is a very good idea. How much does it cost to make? Any plans of selling in the future? Or... | |
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08-10-2007, 11:37 AM
| #20 |
| Quarry Creeper Join Date: Jun 2007 Location: Torrance, CA.
Posts: 282
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Nice work. I noticed that you have not attached the ram to the knuckles. You don't have much space for links so it may be tricky to get the extra link in there. |
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Linear Mode
