Piston Ballast Systems

4,now place the piston on a bench face up,if you look at it you will notice four triangular web',they meet in the centre of the piston crown,these web's need to be cut away to allow insertion of a 2mm nut in the centre of them,I use a modelling knife to do this,insure that the nut is a good fit an is on centre,
SEE PHOTO.
5,when you have done that find a drill that will fit nicely through the nut you have inserted in the piston crown and drill strait through the nut and the piston,this is best done on a drill stand,but with a bit of care can be done with a hand drill.
6,now remove nut from the piston and open the hole in the piston up too 2mm,then install a new nut in the piston crown,brass or stainless is best.

7,you now need a length of 2mm brass threaded rod,6inches should be fine for most tanks,this can be made from stock brass rod or bought.
8,screw a 2mm nut an inch down the brass rod followed by a 2mm washer then screw the rod through the piston until the rod end is flush with the top of the nut installed in the piston web earlier,put a small amount of blue loctite on the threaded rod at the bottom of the piston and bring the second nut with its washer up to it and just nip it up gentle,then leave it to set,
8,re-install the seal pust the piston and rod back into the outer cylinder,and there you have it a cheapskate cylinder.
I will sort out the gearbox details tomorow.
YES I KNOW THE ROD I HAVE USED IS NOT THREADED,I COULD NOT FIND ANY SO THAT'S JUST AN OLD PROP SHAFT

Nigel, Thank you for the beginning instructions! You are a man of your word!
This is excellent. I can't wait until part 2.
Peace and Cheers,
Tom

Thanks for all the information .. Time to hit the drawing board ....

Do I unpack my Gato now ............. !!!! Or wait until I have some time to myself !!!!!

Hamster tired or the wheel broke?

Wow, sorry to hear that he is without power! Certainly waiting for the rest of the instructions builds anticipation. I just pray all is well with Nigel during this time.
Peace,
Tom

Can't blame him. I would probably be the same.

I'm SORRY to hear that.I really hope he and his family are OK.I hope the problem wheel be solved most quickly as possible.
All the best
MARIUS.

Well at least it needs a hurricane remnant to keep our Chairman quiet!

Nigel phoned me the other night to apologise about his lack of a reply - his power is still off!

I always thought of Essex being an urban county but he is right out in the country. He has a generator and apparently the electricity company is dropping off fuel to him!

He mentioned that Salmon is looking for a very small piston tank. By way of a fill in, have you seen the photo on page 49 of Norbert Bruggens book, Model Submarine Technology? (Worth getting if you haven't got it.)

This shows a "20 ml tank for the Red October plastic model" It is directly driven from a powerful servo using a rack and pinion arrangement. Very small and simple and, of course, proportional.

I just saw his book on ebay and amazon. Thank you for the tip! I will look it up. Please, let Nigele know there is no pressure and I do not want him to give it a thought at this moment. When he can, I am sure he will. I am sure he has more important things to worry about.
Peace,
Tom

I ordered the book by Norbert Bruggen and hopefully in the next week I will get it. I went to the hardware store and picked up some threaded rod to build a piston with. The only type they had is zinc plated....will that work? Stainless steel or brass are probably better, but have not seen it yet.

That shouldn't be a problem as long as it doesn't rust. I've used SS. The only other advice I've heard is to make the easily replaceable bit of softer material - brass, say, for the middle threaded section.

BTW I have got my original single syringe setup now working as a double syringe setup with a capacity of about 70ml. I will put some photos up soon.

http://puremtc.com/info_faq/ballast_system/index.htm

This was an interesting link which I spotted on Model Boat Mayhem.

An interesting way of doing things but I see that it is no longer commercially available.

I wonder what the mysterious slime sealant was?

How is Nigel doing?
Peace,
Tom

david f wrote:http://puremtc.com/info_faq/ballast_system/index.htm

This was an interesting link which I spotted on Model Boat Mayhem.

An interesting way of doing things but I see that it is no longer commercially available.

I wonder what the mysterious slime sealant was?

as you say an interesting system, especially if space is of a premium, to my mind if the ` sealant ` needs replacing it cant harden in any form, so it begs the question is it a silicone grease
my worry would be if the piston ` cocked over` as the pull from both sides is offset, if it did/does then it will be adding a wear mark into the tube over time, this could allow water under pressure to enter the air side or lose compressed air into the free flood side which only has the depth pressure

Good point Treeboa. I look at the string or pulley as a weak point, but since I have not seen one of these it is just conjecture on my part.
Peace, Tom

Hello everyone,

last week I had the opportunity to make some photographs of another selfmade piston ballast system. That modeller (his name is Wilhelm Bauer) has used some brass tubes and has installed three pistons in his model for trimming/ leveling. Maybe they look a little old fashioned but they work.

Kind regards
Hermann




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Hello Richard,

Wilhelm (William) would have been very pleased by your comment - but sadly he died more than hundred years ago (in 1875). But that model submarine (his 3rd, built 1852) has been preserved in the technical museum at Munich (where I took these photographs). You can see that the piston ballast system is a really old method. As I can remember even David Bushnell had a piston a system installed in his "Turtle" much earlier (but that was a big one and not a model)...

Best regards

Hermann








p.s.: I think Wilhelm would have been happy if he had got a radio control for his model in those times...

I pause in awe. That is really amazing and a testimony to the skills of the creator. Than you for sharing!