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Author Topic: Raising periscopes????  (Read 3331 times)

TomP

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Raising periscopes????
« on: August 06, 2013, 09:27:22 PM »

It's been bugging me for a while on how to do this using a cylindrical WTC? I thought about using pneumatics but not sure if the cylinders will be ok in the drink? Wanted to know how others have done it or any ideas to help? Cheers
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Capt Podge

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Re: Raising periscopes????
« Reply #1 on: August 06, 2013, 09:46:18 PM »

Not sure how you would tackle this but, one idea that came immediately to mind - something along the lines of those automatic car aerials ? Used to see quite a lot of them. Some used to operate at the turn of the auxiliary setting on the ignition switch - might be worth investigating anyway...
 
 
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Martin [Admin]

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Re: Raising periscopes????
« Reply #2 on: August 06, 2013, 10:38:05 PM »


How much room do you have above the WTC and the top of the conning tower?
 That's maximum height your scopes etc. can be.
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gingyer

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Re: Raising periscopes????
« Reply #3 on: August 06, 2013, 11:19:53 PM »

I saw this done somewhere using the compressed air
From the WTC and a syringe
It was connected to the outlet of the syringe
As the air from the WTC compresses it pushes the push rod part of the syringe out then raises the periscopes, then as the water leaves the WTC  and the air goes back to normal the periscopes are lowered
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Re: Raising periscopes????
« Reply #4 on: August 07, 2013, 01:22:03 AM »

A linear servo ?
or linear actuator ?
flange nut with screw?
Theres a few different options, all requiring atleast one servo, and/or servo hacks.
http://www.servocity.com/html/servos___accessories.html
 
 
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tsenecal

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Re: Raising periscopes????
« Reply #5 on: August 07, 2013, 03:38:46 AM »

a piece of cork or foam at the bottom of the periscope?
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TomP

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Re: Raising periscopes????
« Reply #6 on: August 07, 2013, 08:18:17 AM »


How much room do you have above the WTC and the top of the conning tower?
 That's maximum height your scopes etc. can be.


Well I have 3 at different stages of being built so for all of these, needs to travel about 100mm so a servo I don't think will give enough movement?? A linear actuator might be something to look into or modify a servo to do the same with some limit switches

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Circlip

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Re: Raising periscopes????
« Reply #7 on: August 07, 2013, 09:16:27 AM »

Working on the car aerial principle, a plastic core laying parallel to the top of the WTC and turned vertically upwards by powered "Rollers". The periscope array would have to be mounted on a bar which would need to be guided vertically on a pair of tubular guide rails. Stripping the core out of a defunct aerial would help.
 
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Subculture

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Re: Raising periscopes????
« Reply #8 on: August 07, 2013, 04:12:14 PM »

Using pneumatics will work, but does tend to look unrealistic in operation as it tends to be rather rapid in operation. In addition you will require a double acting cylinder, fiddly to make. Motorized operation is also possible but can be difficult to seal, puts weight in the wrong place etc. A better alternative is to use hydraulics. Use a master and slave cylinder arrangement. The master cylinder can be located inside the wtc and the slave built into or actuating the scope in the free flood area. The master cylinder can be actuated by a servo.

Sub driver

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Re: Raising periscopes????
« Reply #9 on: August 07, 2013, 06:34:34 PM »


 Hi,
Check out Engel subs web site.
I have an engel akula with powered scopes, basically an electric motor with a gear drive on a threaded shaft , captive nut on the scopes frame work. electric motor runs turns the threaded shaft ..shaft cannot move up or down so turns this forces captive nut to run up and down the thread..and hey presto scopes go up and down.
relays and microswitches at end stops...
simples.. :-))
Engel can sell you the electronics and frame / kit
regards. 
Sub.
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Davy1

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Re: Raising periscopes????
« Reply #10 on: August 08, 2013, 09:24:47 AM »

I have used (and written article on it in the AMS mag. Copy on request.) the hydraulic system (based on syringes and water) It works quite well but takes up space in the WTC.
One thing to watch out for in all systems is avoid top weight - your sub then falls over!
The latest Model Boats mag (Sept 2013) has a nice article by John Parker on the Engel 212A sub. It seems that  Engel now have a pneumatic system using the over pressure from the piston tank.
Looks a very good idea but I bet it will cost you.
David
 
 
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Re: Raising periscopes????
« Reply #11 on: August 11, 2013, 04:34:38 AM »

100mm..
Ok a continuous servo, with a small threaded rod attached, a nut in the bottom of the periscope tube, raise lower.. wouldn't take much ..just a 9gram servo.#6 or #4 threaded rod....
As far as limiting the rotations..A guy might be better served using a stepper motor and a microprocessor, like picaxe, or even Arduino..
Don't discount the pneumatic suggestions..
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Subculture

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Re: Raising periscopes????
« Reply #12 on: August 11, 2013, 12:09:16 PM »

If you want to go the motorized route, a good way would be to use a very small motor, say a pager motor, but instead of using a servo which will give you too much torque and will be far too slow, use some pulleys. These can be found from old tape decks, or you can purchase them online from places like ebay or technobots.

With a pulley driving a threaded shaft, you don't require limit switches, when it hits the end stops, the belt will just slip. A further enchancement would be to use a current sensing chip. These will stop the motor when it pulls above a certain preset current, and prevent it from damage.

If you want an example of this in action, open the draw of the DVD/CDROM drive on your metal mickey, when it's half way open, stall it with your hand, and observe what happens. For a short moment it will continue to drive, but then will stop, after a short pause it will retract back. It's an inexpensive and simple way of doing away with the need for feedback and/or limit switches. It only works for low torque applications, but rasing and lowering scopes is in that category.

I've looked at Engel's methods. The system on the Typhoon in particular is a source of amusement to me, as they have taken a sledgehammer to crack a walnut.

Personally I would go for the hydraulic master/slave arrangement, as it's simple, offers the bets control, and is dirt cheap. Plus you have stacks of room inside your dive module(s).

U-33

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Re: Raising periscopes????
« Reply #13 on: August 11, 2013, 12:12:16 PM »

What about a piece of cork on the inner end of the 'scope?
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sub john

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Re: Raising periscopes????
« Reply #14 on: August 11, 2013, 11:05:09 PM »

HI Tom
     After reading peoples thoughts on raising periscopes it got me thinking, about making a realistic raising periscope that would work slowly up and down the same as the real thing. Took a trip down to Halfords and a couple of other places to get the bits and pieces to make it work, got it all working this afternoon the pump that i needed was on of the 12 volt geared water pump that they use for wind screen wipers, all so needed  two one way valves and all so needed three variable air control valves the type they use on fish tanks but would be OK for water going through as they are made of plastic, i all so needed to use a small water tank so i used a small fuel tank that they use on model planes. The geared pump can go forward or reverse for making periscopes going up or down 2  control valves are used  1 to  set how fast the periscope goes up and the other to set how fast you wont it to go down third control valve is to set how much pressure is allowed to go to syringe working periscope up and down. This way no need for cut out at end of syringe as pressure is fed back in to water tank it seems to be working very well this afternoon.
   
     The way system works will be-able to use it for torpedo doors for opening and closing should work realistic in manner
                                           Sub John
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TomP

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Re: Raising periscopes????
« Reply #15 on: August 12, 2013, 03:31:44 PM »

 Hi, thank you for all the replies. The Robart air retract system has a 2 way valve which you can adjust the rate each cylinder operates, but I wasnít sure if I can put the valve in the water? When you lower the cylinders the air is released from the valve so it could go in the WTC put then I need an air pump for it. Also this all works very nicely but only drawback only has 50mm of travel not enough.
I looked into the Engel motorised system for the Typhoon then saw the price and how complex it was so thatís out of the question. Cork would be a nice easy and cheap option but it would be nice to raise them when surfaced.
It looks as the syringe option is the way to go, John would love to see a picture of your idea?
 
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Re: Raising periscopes????
« Reply #16 on: August 12, 2013, 04:41:51 PM »

Just keep in mind that if the volume of your periscope tube must be equal to the syringe volume.
If your periscope tube has a volume of 10 cubic centimeters fully extended ,the syringe would have to be at least equal
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sub john

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Re: Raising periscopes????
« Reply #17 on: August 14, 2013, 09:35:06 PM »

HI TOMP
       You said you would like to see a picture of the idea of using a syringe going to try and fit it in to my sub only trouble is i have to take the top of the periscope shears off the top of the cigarette deck on the conning tower every time i take the deck off  and would have to keep taking the silicone tube off the syringe, which will induce air in to the silicone tube which is going to be a pain in the neck. So what needs to be done to get around the problem the syringe has to be fixed to the main deck facing upwards with a magnet on it so it mates up with a magnet on the periscope which will stop me having to take the tube off the syringe. When i get it done i will put a video link to youtube up on hear so you can watch it working on the sub.
       All the best Sub John
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