small proportional ballast/trim tank

[anonymous]

I forgot to mention that

I forgot to mention that the red gear pump will not operate in the wet. (It does not have a sealed casing.)
That is where the Volvo pump is particulary interesting.

Davy

[Guest]

Here are some gear pumps

Here are some gear pumps only they are the only kind of pump that works well in hydraulics and in ballast systems as well as ballanceing systems,see other posts.
Roler or paristolic pump also work well but will lock up or hydrostatic lock will occur,diafram,bellows are not suitable since they pulse the fuid.
Vane types are also not suitable as they are not positive displacement and dont work in reverse. I have tried and can give some results.

This one is the general perpose replacement windshield washer pump.
This one overheats too easily but can be run in the wet,cost about 10.00$,has plastic gears and does not like to be run dry at all.
But if you remove the pump head it has a 1/8th shaft input drive and therefore can be directly driven by a standard can motor for cooling the motor or as a pump,makes a nice sealed marine drive cooling system.


This one I used to use alot but it also overheated but was smaller than the rest ,has brass gears but not radio surpressed so I had to make it so and it does not run dry well.
The gears can be adjusted with the 4 screws as they wear if run dry too much but they get noisy and lose pressure eventualy.I would not use it for a ballast system.From TowerHobbies see fuel dilivery electric.


This one is the Fiat pump its small and draws as mentioned above ,and is a good pump but watch the dry run time.I did make it run in the wet just seal it with GOOP.



This is the Land Rover /Jag pump it also can run in the wet but runs warm and is moderatly strong in volume pumped ,but is costly.



This one is highly recomended ,it is produced by several makers originaly from VDO.
Also this is the one I mentioned that it can be disasembled to use the head for cooling and makes a good hydraulic pump,comes in brass gears if a VDO or non brass if another make.Is cheap on EbayMotors and is used on older Volvos 240 models.
Its larger than most of the above pumps but is a good value ,and could be made to run in the wet.

This one I havent tried yet and will post results when I get One ,its a US aoto OEM part.
Car pumps are usualy a better product than general perpose pumps that are available at Hobbie outlets or even scientific fluid handling pumps ,the later being the cost is prohivative.
Automotive pumps have to be able to last in harsh enviroments and still perform at a reasonable cost and redily available.

After alot of bench time testing pumps I setled on the first Volvo pump for all the above reasons especialy since it produces plenty of pressure and volume of water and is a quality unit.

Dave amur Ship Yard

[Guest]

Here is the pump painted

Here is the pump painted red in the wet stern of the Type XXI ,and works very well.

And another used as the hydralic retracting system for the forward dive planes and is so cool to watch and hear the operation.

[chuck chesney]

This is just an FYI

This is just an FYI for all that may be interested. Two night ago I purchased the VDO pump on eBay...nineteen bucks, new, free U.S. shipping. Really good deal !

[anonymous]

Thanks for a really useful

Thanks for a really useful survey of pumps. It may seem unimportant to some but these pumps have actually revolutionized our hobby. I will put an ebay search in for the VDO pump and give it a whirl.

David

[Guest]

Great to here your interest

Great to here your interest in this important component to our hobby,as you can see it has super revolutionized my subs and made this fine hobby a hole lot funner!

Enjoy all the things it can do!

Dave

Amur Ship Yard

[tommydeen]

Ronald could post a link

Ronald could post a link were you got that linier servo? Thanks
Tom

[raalst]

Sigh,

I have been

Sigh,

I have been sitting on that servo, in the sense that I hoped some vendor
would be willing to buy it in volume. But nothing much is developing and
the only comment from the customer base (i.e. you lot ) was
"too expensive".

So I guess there is not much point is keeping it from you any longer.

http://www.firgelli.com

type L12, and be sure to read the product selector and the data sheet.
one of the versions is controlled by standard R/C signals. that's the one
you need. And you need as high a gearing as you can get.

Remember, you heard it on the SubCommittee Forum first.

[tommydeen]

Ronald..... that liner servo is

Ronald..... that liner servo is SWEET!!!! im ordering one!!! just the the thing i was looking for..

[raalst]

Glad you like it too

Glad you like it too !

I think it is very sub-friendly. but beware that the
moving arm is not of the smoothness you need should you want to
stick it outside. I *think* it is too coarse for an O-ring seal.

[ricknelson]

L12 NOT waterproof

Be advised that the Firgelli L12 Linear Actuator is NOT waterproof. If you want mount it outside of the WTC you will have to do two things:

1. Install a sealed boot or bellows over the entire actuating rod and part of the plastic housing to protect the shaft entry point. A possible candidate boot can be found at McMaster-Carr (http://www.mcmaster.com/) on page 3673. The "Molded Neoprene-Latex Bellows", P/N 5298K77 should fit.

2. You will have to apply a liberal amount of RTV on the plastic housing around the cable entry point to seal it.

Also, the R/C interface will cost an additional $20.

[Guest]

Syringes cost under 2.00$ and

Syringes cost under 2.00$ and make great linear actuators and if it breaks no bigy and the action is smoth and strong not to mention totaly waterproof.
Thats why I developed this simple system, to avoid the above complications.
Just my opinion.

[tommydeen]

Thats what i wanted to

Thats what i wanted to do was to use the syringe method. does look smooth in travel. BTW what is syringes lubed with? silicone oil /grease?
AAAHH the wheels are turning again

[raalst]

I never lubed it.
beware

I never lubed it.
beware that some oils attack rubber, so if you need to choose, I would say take the silicone.

@rick
I have not had the experience that the RC interface cost extra.

And the lineair servo is indeed not suitable for operation in the wet.
I was just referring to the possibility to stick it's arm thru a seal.
and even this, I think is not a good idea.

but with a bellows as a seal it probably works nicely, because it stays totally dry.

[Guest]

I found that water and

I found that water and a cm of antifreez works well ,does not harm anything and lubes the pump.
And the best pump is this one displayed before.

You can cut them to lenght iether the plunger or the cylinder use GOOP since it adhears well to the plastic.
Rods or lego components can then be glued onto the ram end and an actuator is made.

http://s82.photobucket.com/albums/j278/ ... 0001-2.flv