Miniature Hydraulics - How and why!

[AQUASUB]

In this thread I will demonstrate how I make and operate the miniature hydraulics system I employ on my subs.
Its lots of fun to build and design and especially to operate!
Please ask all the questions you like.

Dave:biggrin:

[Scott T]

Is your pump a windshield washer pump? Never mind info is on other post.

Scott

[AQUASUB]

In case it was not posted with more details, this is the range of Volvos it will fit and you need to look for on Ebay or at Napa Auto Parts.
You will have to ask for the less expensive one that is around 8.00$. I haven't tried their other one for $25.00 or so, but probably not too much difference.
You can also get a VDO brand one, but they cost much more and have brass gears and same motor. I like them a lot and get them second hand on Ebay.
The 8.00$ ones are good also. They feature a Derlin or Nylon gears and they wear well, but try to run them as wet as possible which is not a problem in this hydraulic system.

I thought I might mention that there are several small gear pumps out there used for washer pumps, but this one stood up the best, no overheating or radio interference and they can be easily sealed for wet submerged running, keeping them even cooler and out of the casing.

As one sees my approach to engineering a sub, especially the larger ones, you will see that I like to keep it simple and rugged so that the systems and components will endure and function properly in the hostile environment of the pond. Even the wire I use is marine grade 10 or 16 gauge soldered hard wiring, which is sealed with Goop. I have found over the years this holds up exceptionally well to seal out the moisture that is very pervasive. Some like to use Silicone sealers and adhesives,I did also until I found Goop, the fantastic sealer adhesive that stays flexible yet hard, dries in a short time, is clear, cheap and will stick to just about anything. Some say it is hard to remove, not as bad as Epoxy by far and it "peals" very cleanly. No need to grind it off or like Silicone rub it off. Silicone does not keep out moisture 100% over time it will come unstuck and let in moisture or worse.
I have seen on many casings where silicone was employed on main electrical leads that pass into the casing that over a short period of time leaks developed and electrolysis was occurring, not so with Goop.
Goop is very similar to what is used in the Navy and ROVs electrical cannon plug connectors, where the wiring is sealed with a clear Goop like substance, probably the same stuff.

So in my opinion get rid of the silicone and reseal it with Goop it also comes in a Marine form that has UV protection though I have never seen any difference. They are all great products and I would be at a great loss without it!

Dave

[AQUASUB]

A video of the finished systems ,sorry for the poor video.

http://www.youtube.com/watch?v=UdkzTfXt5-o

[AQUASUB]

Captains I have a rather interesting and funny announcement to make and kind of fitting for this time of year.
Remember I was experimenting with different fluids for the hydraulic systems, one that would not bind the syringes or harm the silicone tubing or pump and was not toxic, expensive or hard to get.
Well the other day I had a deep fried turkey served up by my wife and friends and while I was enjoying it I had a thought, what about the oil this bird is in, could it possibly do the trick, would it have all of those properties I am seeking?

So I made a test run of several days so far and to my delight it works like a charm,no ill effects so far,the pump works even smother and stronger than before as it is super lubed and will post more findings.
The oil is Peanut Oil and turkey fat, I will try without the turkey fat later.
So my hydraulics smell like oil roasted turkey and that's funny!
If any of you guys are setting up or are using my system you might want to save that oil from Thanks giving:wink:

I will post another video of just how strong and fully proportional this system is you will be amazed as I am.
At slow speed the large syringe can not be held from extending by hand! It can easily lift a 5 amp lead acid battery.

Think about the possibilities, hear is the ultimate linear servo,wet ready or dry,can be made to virtually any dimension with simple syringes and silicon tubing or equivalent and a ESC or not, amazing does it no justice with no special electronics anyone can make it happen!

On the drawing boards hear at the Yard I have a sub that will have hydraulic arms that actually work by hydraulics and possibly the dive planes and rudder, now that I have found the right fluid things are really looking up.:biggrin:

Dave Amur Sub Yard

[AQUASUB]

This video shows the basic operation of the mini hydraulics ,notice how proportional the control is, no jerking and its very strong in both directions, so much that a 8 amph battery can be easily lifted.


The syringes bottom out stopping the other from moving any more, that is the simplicity of it, no pressure switches or electronics needed.

http://www.youtube.com/watch?v=2F3FSeamf1c

[He Who Shall Not Be Named]

Slick! I assume that's a gear-pump that will permit blow-by when the pistons bottom out? Lots of applications here.

David,

[AQUASUB]

Yes that is the gear pump mentioned above, it will pump quite fast and strong at 12v and at 6v a nice scale-like operation. I developed it about 2 years ago.

The best performance is with an ESC that has equal range in both directions,very smooth and extremely slow operation can be obtained or fast as needed.
The pistons bottom out preventing any further movement can be adjusted by just how much throw one needs. It can be just 1 cm to a full syringe, just add or subtract the fluid with one bottomed out, it will always return to exactly the same point no matter how long the stick is commanding it to go on.The pump just allows for blow by and no harm to the pump or lines since the pressure is in the negative on the bottom side, so silicone lines can be used with barbs. I add a small ring barb made with a dremel on each tip, this adds a grip for the tube.

For long runs of tubing I use Versa tubing. It is aluminum aircraft grade tubing that is very flexible, light and easy to handle and cheap.

You bet the possibilities are endless here, even air cylinders or Lego air cylinders. Try it do as I did with an ESC and you will see just how nice this system works.

A note - the smallest one cm syringes do not work, only the next larger ones, and peanut oil and animal fat works the smoothest, tried just Peanut Oil and was not as smooth.

From doors, masts, hydraulic arms, folding wings, control planes, the possibilities are now obtainable with this - the ultimate linear servo.

Dave

[Kazzer]

................. and peanut oil and animal fat works the smoothest, tried just Peanut Oil and was not as smooth.

Dave

I wonder if something like Cod Liver Oil and peanut oil would work? I somehow don't fancy the drippings from the turkey inside the boat. I noticed in my convertible car that the roof catch above the windshield has a hydraulic pump working it. Perhaps the fluid in there would work too?

[AQUASUB]

I have not used Cod Liver Oil mainly because it smells nasty,Peanut Oil has virtually no oder.The fat is mostly at the top of the container so probably a small amount is emulsified in the oil and it does make a difference in slickness,the molecule is different some how.For centuries animal fats lubricated everything where needed and without being toxic.

If there is any trace of mineral oils the silicone tubbing and the syringes will swell and cause them to jam.Same goes for silicone based fluids.
The fluid must be completely inert to silicone and the plastic and rubber plungers.I do not know if the fuid in the roof system would work ,find out what it is?

Those pneumatics cylinders can be used as well but are not as flexable in that they can not be cut to any size and cost much more, and are much heavier,plus I do not know what fluids would be compatible.

So far this is the best non toxic fluid that after long periods of not being used does not cause the swelling.It also cleans up with just soapy water.
I might try air compressor oil next.
Dave

[AQUASUB]

I have an update ,the oils are out and just water is in ,the water does the job just fine,I will try with some detergent like Ivory liquid soap ,it might make it even more slick.


Dave

[Scott T]

What do you think about putting some liquid soap between the two wiping seals on the plunger?
The soap would lubricate the walls of the syringe but not be washed away or diluted in the hydraulic fluid (water).
Drill a filling hole on a portion of unused syringe wall. Locate the plunger so it allows you to fill between the seals
through the hole. Now when you push past the fill hole the soap will be ready to lubricate the walls.

Scott

[AQUASUB]

I will try that ,so far the water soap mix also causes binding.

[kanoni]

Thank you very much for the info on the pump . I am working on a similar project for opening misseles doors on a typhoon that i am building now . My goal is to run one pump back and forth to open and close 10 sets of 2 doors 1 set at the time . Will that pump work both directions if i chance the polarity of the motor ? Did you used Goop to seal the terminals ? or the back plate of the motor ? Thanks again

[AQUASUB]

You are welcome!
First yes the pump will pump the same PSI in both directions and can be connected to either a ESC to regulate the flow or speed very precisely along with stop and reverse,or directly to a reversing servo switch.I use allot of both depending on the application in your case you want to use 10 doors or actuators individually,I did it with just 2 and works very well,also on the Engel Typhoon along with masts.
I would suggest for the doors that 2 pumps be used that way it will work with more psi ,you can make two separate hydraulic systems activated by one Chanel and then you will see how scalelike the operation is the doors will not all close at once but will slowly close individually just like the full size sub does!
You can use for the counter syringes the larger ones so that you have like a 5 to one ratio for example ,that way less space is used and the pump does not have to work so hard to move a large number of syringes.
Also look into the Lego air actuator shown ,by adding a larger bottom nipple it is converted to hydraulics use,and they work very niclly and are a quality item,get them at Bricklink.com ,they are set up the same as syringes,the nice thing about them is that they have the pivot points on both ends just like a hydraulic ram.With the vast range of Lego parts a super realistic operating hydraulic system can be built with a very little cash.

The pump has to be sealed with Goop if it is going into the wet,by simply cutting off the terminal shield then sealing the terminals after soldering and the pump head and rear case by the terminals also must be sealed.
Use 12 volts to get maximum psi.

A simple reversing switch can be made with any servo,it also isolates the power systems from the radio system and will even work for quite some time if flooded!Just glue 2 micro servos to a servo clamped in place,be sure that they are positioned so that the double arm of the servo comes into good positive contact with the micro switch.

ESC use is the best and a cheap one like the Pro Boat blue ones work very well.But if you have allot of rams to operate than a servo reversing switch will do the job just as well without costing more.If your operating say a few masts then a ESC must be used as they will move too fast.

Have fun for you are entering the world of mini hydraulics and the possibilities are endless!

Dave