small proportional ballast/trim tank

[raalst]

I built a small ballast tank for my Trumpeter Kilo.
I use an (expensive) lineair servo and a 140 Ml syringe.

here a film of the thing :

http://www.vimeo.com/moogaloop.swf?clip_id=1331216

and a picture of the servo


after all is said and done the tank can contain 60 ml (2 oz) of water.
That is twice as much as my old Kilo setup. and it fills up a lot faster too.

The total volume of my wtc is about 600 ml, I expect it to contain 300 ml of air after putting all the stuff in. that means the tank will pressure the wtc with 300/240 = 0.25 bar.
Now if only my end caps will stay in place and my seals will hold....

[Guest]

Hello Realst

Try my simple inexpensive

Hello Realst

Try my simple inexpensive system of 2 syringes of your choice in size and a small gear pump as seen in my posts.
2 or more mini counter ballancing proportional tanks can be made for under 30.00$

Even if your WTC is small or large there is no vacume or pressue produced,just the transfer of water from one tank to the other ,and no need for limit switches or extra electronics just a reversing switch or 2 microswitches on a micro servo, since the syringes operate from bottom lock to bottom lock and the pump will not lock up nor overheat if its a gear pump,they are not 100% positive displacement.

I use this setup in my U-32 and fine adjustment of trim can be done at all times and realy can be seen at a hover.
Just adjust the amount of water you need to transfer in the syringes ,it can be verry small to quite a bit,also a few drops of anti freez lubes the pump.
I use large glow fuel tubbing ,3/16 aluminum tubbing and non twist lock syringes since the needle atachment end is longer and holds the fuel line on better.

If you can fit this pump I have found it to be the best or the one from OTW desighns or Cassle creations work good to but cost more.

If you need more info just let me know

Dave Amur Ship Yard

[raalst]

that's smart !
as far

that's smart !
as far as I understand you pump water from the one syringe
(in the front) to the other (in the back of the boat) ?

can you tell/show me the pump you use ?
I'll have a look at OTW...

Unfortunately, I need this thing as a ballast tank, so your system would not help me, I guess. serves me right for calling it a trimtank

But I need a small bi-directional water pump anyway..

[Guest]

This is the one I

This is the one I have found to do it all,can be run in the wet,radio surpressed,high quality gears and motor,draws very litle power can draw dry a fluid from about 7 feet,is cheap on Ebay used or new.Would work great as your main ballast pump.
Yes the water is pumped as needed from forward to aft or at any point that you need to trim the sub.At enitial set up all the air is bled out of the system by useing the syringes and then operate the pump.
Cut to any lenth the syringes you feel is enough water needed .Then cut the plunger handle to about a half inch with the seal in place ,that way the alighnment is kept in tact.You can instal a screw or wire stop for the other end but is not neccesary since they work from stop to stop at the bottom of the stroke.The pump is always primed and emediate operation is efective.
In the pics is where I used 6 syriges in the U-32 trim system.
Lecma Rc has them or your Autoparts store for Volvo 95 to 98 models 850 s.

This is also the pump I use for the ballast system ubove ,it will fill or emty a leter and a half in about 90 secounds ! For any size sub it will do the job,and even used in my hydraulic systems such as retracting ect of the dive planes on both the Alfa 5ft and the Robbe XXI,very scale like smoth operation even down to the sound.
If the pressure or speed is too high just use a ESC such as the Aquacraft 7037 or other inexpensive units and that will give you the ability to reduce the pressure and direction on comand,this simple set up is so realistic and reliable that I am sure that more submariners as well as robotic,Aircraft ect folks will be using it in the future.
If the pump is to large for your WTC just run it in the wet it runs even cooler and simply seal up the several posible vents in the geare side,then cut with a dremel wheel the scert at the terminal end off so that you can sualder on the wires for operation and seal them with Goop or epoxy.

Also makes a decent thruster in the bow without having to make a large hole as in a standard propthruster.

As you will find out this pump has many aplications.
I get mine from EbayMotors.

Dave Amur Ship Yard












In this pic the pump runs in the wet area,WTC too small,no problem.

[raalst]

Thanks !

scavenge mode on

Thanks !

scavenge mode on !

[ricknelson]

Mfg/Part Number for pump

Hi aquadeep,

I'm intrigued with your trim system. Do you have a manufacturer and a part number for the gear pump?

TIA
Rick Nelson

[Guest]

The pump is made by

The pump is made by VDO. Just do an ebay search for Volvo windscreen pump.

[chuck chesney]

Hi Aquadeep, and anybody else

Hi Aquadeep, and anybody else who has first hand knowledge of the ballast pumps that you mentioned. I searched ebay, and there are a bunch of them for sale, at about $15 each...a real bargain. My question is: are these pumps gear pumps or centrifugal ? If they are gear pumps, that would go a long way toward eliminating the need for a check valve when the pump is turned off, making them truly a bargain. They would also be able to effectively pump in both directions equally well, to both fill and empty a ballast tank.
Thanks for any additional info that you have on these pumps.

[Guest]

Yes these pumps are gear

Yes these pumps are gear pumps that work in both directions and in my system there is no need for a check valve on the pumpping circuit as seen in the above diagram the only are 2 check valves on the vent circuit.


These pumps come from varios makers one is VDO and the other are sub liscenced to Asiain and U.S. makers ,and have sutle difrences mostly in the gears,VDO use brass gears while the others use a different material.

Both types work very well and have proven to last,and at 15$ bucks or so what bargain!

Let me know if you need any ferther assistance with these pumps and related sysytems.


Dave Amur Ship Yard

[JWLaRue]

Anyone know what their stall

Anyone know what their stall pressure is?

-tnx,

Jeff

[Guest]

I dont know but they

I dont know but they don't lock up drawing or under pressure and that is good for keeping the system simple,no need for pressure switches.
If one forgets to turn it off it will simply strain a bit ,draw some more amps but nothing to worry about.
There is another VDO /Volvo ect. pump that I use for watercoolling and is the main ballast pump in one sub the Akula II. It also has great characteristics but draws a bit more amps,but the neat thing about it is that it can be taken apart and just the pump head used for the coolling system as seen in the Type XXI build.It has a 2 mm or so input shaft that the Legos can connect to without any mods!Or another 2.3mm motor ect. with adapters.Used on the 240 series Volvos.
As you can imagine I have searched the web for hours trying to find suitable pumps and there are only a handfull since they must have small inlets and outlets,not draw much ,stay cool,gear pumps that can reverse with equal psi and be small and inexpensive.Land Rovers also have a pump in there early years and apear to be the one OTW uses but I havent tried them, and cost more.
The main thing is not to let it run dry too long,which in our aplications it usualy wont happen.
There is one general perpose pump that I dont recomend ,though small ,cheap and geared but draws way too much amps ,overheats too fast and has plastic gears,I will post a pic soon.

Well I hope more Captains will try this great system and see how fun and easy it is to make your sub both dive and serface with ease,hover to perfection and operate all those neat hydraulic mechanisms that have been eludding us for there complexity or cost .
Now it all can be done.

Dave Amur Ship Yard

Dave

[anonymous]

Worth putting this pump on

Worth putting this pump on the list. Gear pump develops about 1.5 bar and is widely used here in the UK (Also Sheerline models , I think.)

Easily available from model shops as a glow fuel pump for the flyboys.

Davy

[Guest]

Yes, it is the Fiat

Yes, it is the Fiat pump but it cost more and one did lock up.

However it is smaller and can run in the wet.
I dont know about the current draw or gear type.

[raalst]

A long time ago I

A long time ago I took one of these apart,and it is a geared pump :
two gears rotate, taking the water with them on their outside.

this type of pump does not close off very well under pressure.

I also found it to be a large lump. But then again, I like my subs small
(generally..)

as I just took it to pieces, I don't know the voltage/amperage.
as it is a car pump, voltage should be expected to be 12 volts.

[anonymous]

Hi,

Yes it's a gear pump.

Hi,

Yes it's a gear pump. It draws just over an amp at 12v , as I recall.

I'm only mentioning it because here in the UK its probably been one of the most widely used pumps for many years in pressurised and unpressurised tank systems. Its very reliable and widely available in model shops.

It needs some form of shut off valve but I don't think you could rely on any gear pump to not allow flow when it is not running.

The Volvo pumps look very interesting too and a few people here have had good results with pumps intended for caravan (trailer) water systems.

Davy