M1 Submarine

[Paul TParticipant @pault84577]

Hi to the model submarine builders.

I have a technical question regarding the flooding and pumping out of the ballast tanks.

How do you pump out the ballast tanks when the model sub is under water and how do you compress and store the air? and how do you blow the tanks and still maintain trim?

Paul

[Mike DavidsonParticipant @mikedavidson22772]

I have seen photographs of the M1 in the Royal Naval Submarine School where I used to work, and it was some big gun. The hull seemed pretty much the same as her contemporaries,and according to the Wikepedia site, she was lost after a collision with a Swedish merchant vessel, if you key into your search engine the words HM Submarine M1, quite a few interestingsites spring to life, and as the London newsboys shout, you can "Read all abaht it", it is wonderful just how much you can dig out, I have learnt that my house is built on top of an amazing wartime tunnel complex, just browzing my local areain wikepedia, but that’s enough of this, I must go and nail some more guardrails onto my Tamar class lifeboat model. photo’s available on request

[Penny LeeParticipant @pennylee76979]

Mike………

Paul, That’s one for Alan Poole.

I have the same system he had in his Ocelot,though.(see his Gallery)

Fire away on that method (but there is a new system each week….I can guess but I’m no expert)

Regards

Penny Lee

[Penny LeeParticipant @pennylee76979]

On the Craycraft produced system,the water tight modules included the basic equipment less the receiver,pitch control .

The compressor sucked air from the middle of the three compartments and stored in the forward one up to a pressure of 1 bar.That would mean ,so long as the sub wasn’t taken to silly depths ,the stored air could be released by a servo hitting a release/safety valve.

The pictured compressor was a specially manufactured for Craycraft and had a non return function so air was stored when power to the compressor was cut by its controller.(see image)

Compression stopped when ballast water reached two metal probes at the top of the centre chamber.

All power was supplied by a battery stored in a flooded area of the hull.The anode of the battery was sealed against water ingress and hooked up using a waterproof connector.

In this system the ballast air is at the centre of gravity so the models are quite stabledue to weight distributed at nose/tail.

Under sail Craycraft, maintaned trim by an aft servo controller which contained a pendulum sensor and electronic control.Although a pendulum type I found it was much improved when the brass disc was replaced by aluminium and braking magnets.

The maker of Craycraft’s ballast control & pitch control electronics later made an improved ballast control called a dive manager and the first commercial solid state electronic pitch control called an AST.

Regards

Penny Lee

[ashley needhamParticipant @ashleyneedham69188]

Paul, I have hankered after a sub for ages, but after reading and seeing that lot would stick to dynamic diving !! Ashley

[Penny LeeParticipant @pennylee76979]

Eh?

[ashley needhamParticipant @ashleyneedham69188]

You know, have the diving planes set at a down angle so that upon reaching a certain speed the sub dives, when it slows down the action of water pressure caused by the aforesaid foreward speed on said planes lessens and the sub rises. Easy, well, I never managed it on the sub I made from an article in "boys own" annual 40 years ago, but the theory is sound! Ashley

[Penny LeeParticipant @pennylee76979]

Ashley,

You have scored an unintentional bullseye!   I may scrub the post and replace with two or three line diagrams…..Don’t clap!

Last week I read yet another of those big forum postings "one who build everything bar r/c set" to make a static diver of their own design. I only persevered through because of the "novice tries something " aspect .Line diagram,photo and caption sprang to mind.

What a short memory I have.

Seriously,Ashley,youve got it the wrong way round. Those folk who finish a Robbie U-boat deserve all the praise they get. Ones like me who got an assembed module are checkbook modellers in comparison. That’s a mere paint job then install running gear and join pushrods.

Go hunt out Nick Burge’s old article He managed it in a week,from Eden Model’s casting the hull.

You have to be really anal-retentive to stretch it out two years.

Penny Lee

[ashley needhamParticipant @ashleyneedham69188]

Penny, I may be a bit dense here, are you saying the method I quoted will not work ?? I am quite willing to accept that, I have never actually tried it, but it seems like a good idea! I will have a surf later on to see what other methods are out there, if any. I am not man enough to get technical with all those bits in a sub to get it to dive and surface properly . Cheers Ashley

[Paul TParticipant @pault84577]

Hello Penny

Thanks for the information: I understand the principals involved with the removal of the air from the centre compartment but the storage in the forward compartment has me slightly bemused. I presume that some kind of pressure vessel is employed as the storage pressure is 1 bar, could you please clarify what kind of storage system is used.

A further question would be what about the free air that is in the forward and rear compartments? has this bouyancy any affect the dive or is the flooding of the single compartment sufficient to achieve this?

Hi Ashley

I appreciate and understand your comments on dynamic diving but I am trying to atchieve a dive system that will work in the stationary position.

Hello Mike

Thanks for the message, you must have had a great time working at the sub school.

Paul

[Penny LeeParticipant @pennylee76979]

ashley needham wrote (see)

Penny, I may be a bit dense here, are you saying the method I quoted will not work ?? I am quite willing to accept that, I have never actually tried it, but it seems like a good idea! I will have a surf later on to see what other methods are out there, if any. I am not man enough to get technical with all those bits in a sub to get it to dive and surface properly . Cheers Ashley

Hi Ashley,

Indeed it will ! There is a trade off that it’s easier for a dynamic to dive if trimmed, decks awash,less so if trimmed showing all its glory.The point I alluded too was it was easy to muck that kit up and the modular approach requires less fit and & fiddle…….ever wondered why the ratio of kits sold/sailed is so high.

I usually make a point of not telling fellow modellers what to do but others will agree. Don’t go looking on the internet. You’ll never get that time back! Go see them in action in Barrow-in-Furness on Sunday.The only other simple system that works at a budget is like Otwdesigns and Sheerline module pump in-pump back.

I was lucky in that ,when I decided to have a go,I saw who were managing to sail their models and who were forever pulling them apart. I had an education in physics and engineering so I could see the Craycraft module,with Nick Burge’s expert input, had cleverly cut out redundant plumbing and electrics but would work reliably and safely.Apologies to Greg Engel but I’ll use his "tuppenyha’penny" stuff and that’s all.

I am right with you on the non-techno approach. I expressed a desire to do rc planes again and I had to halt a guy from telling me about a C.A.D. wing-loading calc. program.

Paul’s turn NEXT

Regards

Penny Lee

[Penny LeeParticipant @pennylee76979]

The Fat Controller wrote (see)

Hello Penny

Thanks for the information: I understand the principals involved with the removal of the air from the centre compartment but the storage in the forward compartment has me slightly bemused. I presume that some kind of pressure vessel is employed as the storage pressure is 1 bar, could you please clarify what kind of storage system is used.

A further question would be what about the free air that is in the forward and rear compartments? has this bouyancy any affect the dive or is the flooding of the single compartment sufficient to achieve this?

Hi Ashley

I appreciate and understand your comments on dynamic diving but I am trying to atchieve a dive system that will work in the stationary position.

Hello Mike

Thanks for the message, you must have had a great time working at the sub school.

Paul

Hi Paul
You see what I meant when I replied to Ashley? “You have scored an unintentional bullseye! I may scrub the post and replace with two or three line diagrams…..”

Yes and Yes. You can see that forward and rear compartments are held together by brass tie rods. Central ballast chamber has enough volume to displace considerable superstructure weight. The forward compartment air pressure rises.Pressure rise limited by the servo op. release valve which leaks air if pressure differential exceeds 1 bar.

Forward compartment pressure does not reach a dive pressure of 1 bar and dive pressure can be reduced further to 0.4 bar by removing the FWD-REAR seal so air sucked from middle goes to fwd/rear compartments .You have to get a calculator out (adiabatic pressure equation) because the elevated pressure is reached when you dive to the inversion depth…..if your compartment ratios are such that you get 0.4 bar then you don’t want to release or else water comes in throgh comressor and you sink.

……..That is the achilles heel but fortunately there are all-singing all-dancing failsafes that monitor pressure,voltage,radio,overtilt. ….If you get 4 metres before “dive manager” kicks in then you have drinkable water. The images attached includes a depth control with output for ballast control/dive manager

1. Servo depth control (forward planes)
2. Engel SPC Pro pitch control (aft planes)
3. servo depth control with failsafe outputs

• Engel SPC Pro on its own

The grey box servo/compressor ballast control was replaced by a “dive manager” for Craycraft system and a digital servo failsafe for bidirectional pump system (works with sheerline/Otw pumps) -………google modelcontrollers + nautilus for those bits but I have instructions here somewhere as well as the AST which was the basis of Engel’s SPC Pro. I attach a picture here.

I fear the above reply will mean much less than diagrams and photos. I’ll try tomorrow eve.

Penny Lee

[Penny LeeParticipant @pennylee76979]

Hi Paul, there’s a typo but the message is too big to Edit.

If you store ballast tank air in both fore/aft then the reduced prssure say 0.4 bar means you don’t want to lose radio signal below 4 metres.

http://www.rc-sub.com/WTC3.html  Bob Shaw has smaller later version of the grey box in a yellow enclosure.

http://www.rc-sub.com/resources/modelpics/3WTC/wtcfinished2.jpg you can see the blue pitch control.

http://www.rc-sub.com/resources/modelpics/3WTC/wtcfinished1.jpg Yellow ESC by Modelcontrollers ( Craycraft electronics dude)

http://www.rc-sub.com Bob Shaws Nautilus build

[Penny LeeParticipant @pennylee76979]

Hi Paul, I missed a bit of your post. You asked….

"A further question would be what about the free air that is in the forward and rear compartments? has this bouyancy any affect the dive or is the flooding of the single compartment sufficient to achieve this?"

You want to get that air to escape through holes.It  would cancel out the equivalent volume in the ballast tank but that’s not a problem,though even a small amount upsets trim if you just do a stationary dive.

Have a look at Robbie VII and you will see holes all over the place.

Penny Lee

[SubcultureParticipant @subculture]

That’s Bob Martin’s build, not Bob Shaw.

 I supplied Bob with those electronics in trade for a Nautilus hull. I used to buy them in direct and sell them to fellow modellers, as they were so good. Unfortunately no longer available.

[Paul TParticipant @pault84577]

Hi Penny

Thank you very much for all of this information.

I shall spend the next few wet days going carefully through it all and checking out all the links.

A very big THANK YOU once again.

Paul 

[Penny LeeParticipant @pennylee76979]

Paul ,there are more inented dive systems posted on the internet faster than you can read them.

As said by me 31 Aug 17:36…

"I usually make a point of not telling fellow modellers what to do but others will agree. Don’t go looking on the internet. You’ll never get that time back! "

Don’t get tied up in gadgetry.You could sail it dynamically and add plumbing later.I’d advise you spend some face time with members of the "sub school" at some show. Half of them ,these days, buy 4 foot of perspex tube,brass rod,waterproof pushrod boots to make 3 chamber water tight compartments.They are a friendly lot so if you can’t machine some plastic tube and plate,someone who’s done it before will do it for you.Seek out owners of models with drips on them. You have a skill to barter with.

The guy two posts up has lots of pretty models,has an encyclopedic knowledge of all model sub things down to o-ring seals.Give him a p.m. ,exchange numbers and find a show in your county.

Penny Lee

[Mike DavidsonParticipant @mikedavidson22772]

Hi Paul the Sub School was very good, but surpassed by working on the actual boats, my particular favourite is the Vanguard class SSBN’sfollowed closely by the Trafalgar class ,the bit I worked on was pretty much the same in both. The engineering side of things is fascinating, you should see the size of the hydraulic ram that operates the hydroplanes, and the torpedo handling gear in the bombshop. there’s no comparison between those and my farty little futaba servo’s,but they do work,and that’s what I like about modelling
Enjoy your hobby all. mike D

[Paul TParticipant @pault84577]

Hello Penny

Thanks again for your reply, I am afraid that for the time being I am restricted to research so the internet is my only window onto the world.

I did talk to some very helpful submarine modellers at Birchwood and had a good look at their excellent models, many of which contained the aforesaid plastic tubes with pushrods.

I have also had some very helpful information from the Royal Naval submarine school, the Submarine Museum, Vickers and (of course) Grumpy. I have amassed a full set of working drawings and reams of information relating to the M1 so I am ready to produce my own construction drawings but I still need to understand how model submarines work, hence all these questions.

Thanks again for your help.

Paul

[Paul TParticipant @pault84577]

Hi Mike

The world of submarines had been a closed book to me until 2 years ago but now I find the subject fasinating. 

Paul

[Mike DavidsonParticipant @mikedavidson22772]

Hi Penny, That’s interesting, I was on board HMS Ocelot the other day in Chatham dockyard. She is open unconditionally to visitors where you can go on board at one end and walk through the vessel and see most of her workings. That brings me to something else. Chatham dockyard houses a lifeboat museum which is absolutely fascinating, and well worth a trip if only to visit the ropery to make your own piece of authentic rope as a souvenir. I cannot recommend Chatham highly enough. Sorry all, I’m not selling tickets. Mike D

[Mike CaswellParticipant @mikecaswell26782]

I have prepared an article on submarine ballast systems that might help one understand the processes available.

The Pro’s & Con’s of Ballast Systems

[Mike DavidsonParticipant @mikedavidson22772]

Hi Paul Good luck indeed with your M1 project. I did indeed have a great time working in the Sub school, submariners are a great bunch, most gregarious, and highly professional. Without breaching the official secret s act, I can tell you that in the Atrium of the school is a giant picture of an aircraft carrier and a submarine with the legend above and below saying " There are two types of ship ",       Submarines and Targets, which I thought was hilarious. I have been thinking about diving systems, and my best idea is to have a servo operating a wafer switch applying positive and negative supply to either one or the other sets of contacts of a motor driving a lead screw operating a bicycle pump type piston up and down a cylinder at each end of the model which is vented below to allow water in or the other end through the periscope to allow air in to replace the waterpushed out the other way. the lead srew idea is quite good I think because good old Newton and his screw had a point. but I have just seen a big negativewhich is that if the periscope tip submerges, it will allow water in at both ends, and the Lutine bell will toll for you. You need one of those ping pong ball valves you see on snorkels, I don’t see why that cannot be done in miniature………..Good luck !……. Mike D

[Paul TParticipant @pault84577]

Thanks to the two Mikes for their input:

Mike Caswell has produced an invaluable piece of information that has clearly explained the solution to my problem and has confirmed a few half baked ideas of my own.

Mike Davidson has given me food for thought regarding operating a pumping system and another cheerful insight into his very active life.

All contributions are very gratefully received as every piece of information helps me formulate my building plan.

Thanks again

Paul

[ashley needhamParticipant @ashleyneedham69188]

Paul. Check out the latest MMI offering… a submarine special !!   i am not sure that theres too much in the way of technicalities in there, but its nice to see someone elses efforts. The issue includes a free simple sub plan, and I am going to have a go at that (sometime in the future) but with an Oberon top,,,or even an M1 top !!    Ashley

[Author]

Posts