Use of pneumatics

[helderluiss]

Pneumatics, does any one here use them to rise the periscope or open torpedo doors?

I see a lot of this been used especially from some modelers in Europe but all the process is strange for me.

In my Type XXIII I made the periscope rise by the action off one altered servo, this works but is not fail safe and takes a lot of space to watertight the servo and all the mechanics.

I have seen some pneumatics parts in a few German sites from Lego but I would like some advice on this.

Does they consume the air inside the WTC or is a closed circuit, which type to chose and here to buy,...

http://www.stahl-modellbau.com/53544198 ... 88e01.html

http://www.modellhydraulik.net/html/modellbau.html

[raalst]

I have these systems not

I have these systems not in my boat(s), but
my impression is that hydraulics are a better
choice : you have a very large supply of it and
it packs a bigger punch.
pneumatics are an option if you have a source
of pressurized air already on board. Chances are,
you need that pressurized air more urgently
to surface the boat.

I made a prototype of a pericope on a piston,
where the piston was intentionally
leaky and heavy.

the water pumped the piston up, excess
pressure was leaked. when pumping stopped,
the weight (and leakyness) pulled the piston
down again.

unfortunately, you do not want top-heavy
submarines, and this rig had to sit on top of a
skipjack.

nevertheless, it worked nicely in the lab.

[Guest]

Go hydraulic !

I have developed a very simple and easy to make not to mention very inexpensive hydraulic system that can be instaled in any sub and will do so much more than just raise or open doors .
Due to a simple law of fluid or in this case water will flow in a path of least resitance and equal force input gives equal output or a double piston from one pump or more pistons!,or what I call rams.These rams are syringes ,cheap and last forever and come in many sizes ,imperviuse to water and thermal efects.No special valves!
I see you know about Legos ,use the Technics parts to engineer the mechanical suport ,by useing RTV 100 % adhisive on the syringes because the plastic is not able to use CA ,GOOP works good also.
Also pnuematics leak offen and will cause the sub to go out of balance and the rams could corrode.I use pnuematics only in the dive system with an onboard compressor just like the real thing.
The pump is small fuel transfer pump and has brass gears and is very efficient ,available from Hobby Lobby for 20.00$.12 Volt but even 6 volts work just slower or change the motor or use a nomber of other pumps but gear pumps always work the best.

The lines are the large 1/8th silicone tubbing for glow fuel engines and if long distances are needed than aluminum air craft 3/16th dia. or plastic tubbing can be used and looks better since its rigid and bent in place then glued to the hull for a neat instalation. See my posts in builder threads Hydraulic Masts and doors for the Typhoon ! I am DEEPDIVER.

Water is used since its safer and lubricates well along with a small amont of antyfreez.Be sure to use syringes that have the long needle fitting that way the tubbing wont blow off.

Another option is to make your own rams from K and S tubbing,for extra long masts as in my Alfa the mast is as tall as the sub is ,just like the real one,so a special system had to be made and it works like a charm completly to scale not to fast nor too slow,and verry stong.
But there was a problem from an open system not sealed by having 2 or more rams one on each side of the pump.
Air would enter and cavitate the pump,well a simple air seperator is used to get the air out,a aircraft fuel tank with 3 lines one is the in the other is the out and the third is the vent or fill .
2 lines of aluminum of the same lenth go almost to the bottom of the tank and the third is the vent though caped off normaly ,the tank is presurized during operation and then the bubbles are seperated as they rise to the top and only water is entering the other tube,simple.
Vertualy no maintence just ocationaly fill the tank.
When the rams finish there stroke the pump works harder but no damage just turn off the pump.Reversing the pump retracts the rams and just turn off the pump.Presur switches could be used but not neccesary.

A simple motor reversing circuit is used iether electronicly or 2 micro switches on one servo is what I use and all sub micro for space saving.

Believe me this works great and is so cool and reliable that I see all subs and everthing RC from Tanks to Battleships to aircraft landing gear using this basic hydraulic system and the aplications are endless.
Let me know if you have any questions.

Thanks Dave Have a great day.

[Guest]

Also the syringes are very

Also the syringes are very light and K and S tubbing is as well.

If alot of water is needed the pump can use filtered water from the pond and the filter self cleans when the pump reverses,the filter is a fuel filter also used on model air craft .

Even a compound hydrualic system is used on my Alfa to make an open mast ram not extend to far .I will explain next time.

Dave

[helderluiss]

Dave, looks simple enough but,

Dave, looks simple enough but, for each action you need one pump, is this right.


For example I will need to open five doors an raise the periscope all controlled individually, does this means that I will need six pumps?

Probably not, what kind of mechanism do you use to control several operations with one pump?

[Guest]

No you can open 5

No you can open 5 doors or more with one pump one servo,then the mast is on its own servo and pump,also if you use a sealed system or 2 rams or more on both sides of the pump you will have the option of lets say retracting cleats as I did on my alfa,the planes retract and the cleats emerge from beneath the hull,just like the real thing,that way not just one thing is happenning at once on one chanell but two seperatly un related or related operations as do the real subs do.

Find other interesting things your sub did in real life and with this system it can be done at a verry inexpensive cost and corrotion,waight nor lack of flexability is an issue.
The syringes come in many sizes and can be cut down to fit your stroke lenght as well as epoxy used to modify the piston rod for any mast or size,or actuating ends.
The actuation is smoth and reliable with just water! Try it frst with 2 syringes one per side of the pump or a sealed system,and also no air enters the lines iliminating the need for a air seperator thats on open systems that are much larger for like 4 masts and large syringes and use the pond water.
Ballance is not an issue when the rams are in the free flood area.Bleeding is done with ease just pump it out or use another syringe with the rams all the way in and the last line joint open.Use the lines and syringes as explined in the post,there are other ways but it cost more and does the same or not as good as results.No special valves no limit switches just one pump ,some syringes ,lines and a way to reverse the pump and water.

The pump I like is the one from Hobby Lobby 20.00$ brass gears and is a fuel tranfer pump,and is very efecient ,just use 2 100 pf capasitors to iliminate radio interferance,and wont overheat nieither.

The circuit a simple 2 micro switches on a servo of any size smaller the better 12 or 6 volt the later is slower and will do fewer rams.Or go electronic switching.I use 4 pumps on my 5 ft Alfa one per chanell on a 10 chanel radio.

Have fun ! Dave

[helderluiss]

Here is one very interesting

Here is one very interesting valve that I am employing in my Subs.
Its made by Beswick Engineering Co. Inc. and the price is 149.00$ plus shipping.
Although a bit steap it is well wort it.Very small,the one pictured is the 3 port vertion.
By adapting a servo to the input shaft of the valve and once all conected with the hydraulic lines and gear pump a single Rc chanel can do the work of 6 individuual hydraulic functions,actuly 12 since no reversing valve is needed in my sytem as are in most sytems the push then pull is done by a 3 position valve.

This probably would be the solution, with this valve that you post I would be capable of controlling all the six (or more) functions with one channel,right?

But is not designed for use with liquids, only air. Do you know any capable to be used with your hydraulic system?

[Guest]

Yes that valve could be

Yes that valve could be used to operate several doors individualy from one chanell,and that is why I use it in a particular instance where most of the chanels are being used for other funtions and a means to multyply the functions was needed.
It can be used for fluids its made of brass and plastic and neopreem seals it just leaks around the input stem so I have made a revevoir that surounds it with water that way only water enters the valve /lines.

Naturaly it is positioned outside of the pressure hull with a sealed shaft conected to a servo rotating the valve stem.

But if you dont mind having all the doors open at once ,then its alot cheaper to do it the other way and you could combine that function with lets say the raising of the mast,all from one chanell.

Also alot simpler if you open the wrong door and fire ,ouch!
Just thougt.

Dave