I notice that my first ever post on this forum (16th Nov 2009) was about scratch building an Akula Class Submarine. That project has been cooling its heels thanks to all the bright people on this forum who completely corrupted me from being an innocent newbie  into a hard core RC addict.   

(I shamefully note that I have committed the sacrilegious typo of "4 chennels")

The Akula may be sleeping but the Submarine dream lives on. First I picked up the 1/125 scale U Boat, U 99,  from Lucky Hobbies. I was impressed with its size (about 21 inches) as it offered some scope for motorisation and RC for a Static Diver.

Just a fortnight ago, I happened to be surfing Ebay and came across a seller from Turkey who was offering the Trumpeter 1/144 scale Gato 1941 model. What's more, for a brand new unpacked model, the price was a steal @ $20 inclusive of postage to India. It normally retails for $47 + postage. I snapped it up and was prepared for the worst as it was being shipped through EMS. However, it arrived at my doorstep within 12 days of shipping! It is an awesome piece more than 26 inches in length. This particular model has been successfully converted to RC by many modelers all over the world. I plan to convert her into a static diver. That is going to be tough on a budget. Tough but not impossible. Can be done.

These 3 Subs shall comprise my next project after the Hovercraft's are completed.

you are the man VC, Neutral Buoyancy will be a challenge along with static trim, all the best

Hello VC,
I had built a non-r/c Academy models U-boat. It uses a very simple principle to control the rear hydroplane to dive and surface. Its powered by 2 old torch light batteries that give it the extra weight to dive.
Regards
Nilanjan

WingCo, I recall our conversation. I am going to drive you in reverse figures of eight when the time approaches for help, help and more help. Beware, I have warned you. (Cavete praemonui RAF 66 Squadron). Thanks Sir.

Nilanjan, I know that particular model. Would you be having any photographs around? Would be of invaluable help to me.

Thanks and regards.

Hello sir, I have no knowledge of subs. Can you please tell what is a static diver and what all modifications are you planning to do in the sub for the same?

A Static Diver Submarine model, dives just like the real thing. It can remain static in the water, and then dive slowly to the required depth and operate and then surface. For this, we need to create a contraption to pull in water to increase the weight of the sub, thus causing it to dive. For it to surface, we need to expel the water so that it becomes light and rises to the surface. Just like the real thing.

A Dynamic Diver is easier to build. You need to be able to control the angle of attack of the forward/ rear dive planes. As the model moves forward in the water at a high speed, the angle of attack causes the model to submerge. (Just like an RC Aircraft with Wing Ailerons and Tail flaps reversed) The nose goes down and the sub dives. As you lower the speed and neutralise / reverse the angle of attack of the dive planes, the sub rises to the surface. Thumb rule for a Dynamic Diver is : High speed + Sharp angle of Attack of Forward Bow planes (In this case Leading Edge down and Trailing Edge up) = Dive // Low Speed + Wide Angle of Attack (LE up sand TE down) = Rise to the Surface.

When travelling in a car on a highway at a good speed, put your hand outside with your fingers close to each other and pointing up (Like the Congress I Symbol) , the force of the air will force your palm to rise. If you reverse the position of your palm and your fingers point down towards the highway, your palm will will be forced downwards by the force of the wind.

Hope this explains as bit. I am not answering your questions about the required modifications as I am still working on them. I need to create a Water Tight Chamber or WTC to house my electronics for a Static Diver, that's for sure.

You and VK get ready to supply the parts required!

So doesnt the radio waves get noise underwater? Till what range a 2.4GHz radio can work underwater? What kind of radio do you plan to use? How will you pump in and pump out the water??? Will you be using a one way valve concept? How do you figure out the exact position of a sub in water from ground, keeping in mind the phenomenon of apparnent position of an object in water due to refraction??

2.4GHz Radio won't do the trick here. I need my good old trusted FM radios for this. I will be using the one way (non returning) valve concept in conjunction with automobile windows fluid cleaner dispenser submersible motors (with necessary modifications so that it fits within the hull). That's all I can tell you now.

Hi VC,

How are you planning to empty the ballast tanks. I hope you are using compressed air or something similar. Just pumping water out will not work as equal volume of air needs to get in the ballast tank.

-Ismail

Try a bottle with holes and and a ballon with holes

Izmile, if I knew the perfect answer to your question, all the subs would have been sailing by now! However, I am experimenting with blood transfusion bags. They are connected to the ballast chamber. When water is pumped into the chamber, the displaced air moves into the bag which will inflate to accommodate it. As the water from th ballast chamber is pumped out, the air rushes back in from the bag to fill up the space. Should work.

Quote from: VC on February 16, 2011, 12:58:29 AM
2.4GHz Radio won't do the trick here. I need my good old trusted FM radios for this. I will be using the one way (non returning) valve concept in conjunction with automobile windows fluid cleaner dispenser submersible motors (with necessary modifications so that it fits within the hull). That's all I can tell you now.

The motor for this, in my car,is external. Was also so in my earlier one.

Posting pics of something similar to what I have. Tested it. Works fine. Probably belongs to a Maruti 800. Inbuilt motor.

srry it was a bottle with holes and a balloon without holes

but still u can replace it with a airpump

Thanks for the rectification Joy, I was a bit confused! 

Having researched RC Submarines for almost 3 years now and gathering / storing bytes and bytes of data and photographs, I've realised just one thing about this project ; 'If you think you can, you can. If you think you can't, then you can't."

There are major experts, internationally renowned, who somehow project this as a very difficult challenge that can be overcome only by purchasing expensive (for us middle class Indians,  prohibitively expensive) components from specialised manufacturers. A decent sized sub kit is anywhere around $ 500 upwards + Radio + Props + Fail Safe etc. etc. etc.

And then I come across something like this and it defies all the logic put forth by the experts.



This is not the first time I faced this dilemma. Be it Hovercrafts or Rockets, every other field of RC modelling,  apart from Aircraft, Ships and Cars,  has been placed upon an 'exalted and reserved for the few' altar by worthy members internationally.

So my advice to everyone out there is don't research too much and be brave enough to experiment and above all get your hands dirty. To hell with theory!

I understand that a team of expert shipbuilders had built the Titanic and a novice had built Noah's Ark! 

Cheers!

VC you should try bellows (inkjet cartridge refilling bellows) filled and emptied inside the balast tank with help of small compressed liquefied gas bottles of lighters/ gas torches or even refillable CO2 bottles of air guns.

What is the material of the sub model which you are going to convert?. If it is foam or any other less buoyant material it is going to be that much more difficult to get it inside water.

All the best for your project.

i think a electric air pump normally used in fish tanks should suffice!!

And how do you draw air underwater to pump inside sub

@reply 10 by VC When the ballast is filled the emptied air has to be either compressed or vented. if it is going to be any where inside the sub then the buoyancy remains. further due to the volume of air still present inside the volume of the sub, it is impossible to fill the ballast.

by long really long plastic small dia. tubes!

Then we can call it a Snorkeling Tank instead of a Submarine 

 

   

atleast you need to sometimes compromse on some aspects though

would you mind if i give you a proper idea
??

Put in a standard electrolysis equipment in there
hydrogen and oxygen offcourse are lighter than water

hope you have a good power supply

but in case hydrogen spills water (fire literally)   on your project  lets hope water helps it atleast the skeleton of that project

checkout specs of fools gold event  technovanza
i won it with my team

   

Now there you have got some thing to ponder about. It is a sure possibility in large scale and is actually a fact in actual subs. The air generated by electrolysis needs to be compressed and stored to be used at the time of need to surface. else it is uneconomical in-terms of time required to surface.

I Think we should not Hijack VC's Thread. What Target VC has set for himself is a tall order in terms of achieving it in the miniature scale he desires. Achieving Neutral Buoyancy at this small scale is a herculean task of precision.

I remember way back in the early eighties, Rishi Kumar of IHC Kolkata had constructed a rubber band powered U Boat. It was around 24 inches in length. He had achieved a perfect neutral buoyancy (decks awash) by gluing simple lead weights and iron rods to the bottom of the sub. The model was carved out of a solid block of hard wood and performed beautifully. Beginners luck, I guess!