Hi again Peter,
Here you can find the very latest rules and regs!
Cheers, Doug
https://www.ofcom.org.uk/spectrum/radio-spectrum-and-the-law/licence-exempt-radio-use/licence-exempt-devices/Radio-controlled-models

Hi Doug - not sure what frequency - not used that radio in some time - boat busted in transit . Will dig it out and check - need to get it going again - still have 2 spare receivers for the ones in progress - hopefully all finished this year.

Hi peter,
Attached a pdf of the allowed frequencies here.
You'll notice that the UHF 433MHz frequencies mentioned somewhere amongst this sub stuff haven't been available for RC here since 2008!
Lower French frequencies? Puzzles me.
Attached is also the UK and European 40Meg chart and channel numbers.
Both bands start at 40.665 !?
Possibly some rogue channels in France.
The French ALWAYS do their own thing😉
Surprises me that you can run a 35Meg set on a 40Meg crystal!
Wouldn't have thought that the rest of the circuit would resonate properly.
(Psst! Don't tell anyone but when I first came here all I had was a 35Meg Sanwa set.
I used it for my destroyer cos I didn't 'ave nowt else, until I could afford to buy my first Graupner MC-10 'computer' set.) Quantum leap😉
Cheers, Doug 😎

Hi Doug,
Bought some 40Mhz crystals in France - much lower frequency than you could get in UK . I run a 3 channel Hitec single stick with them - meant to be a 35Mhz radio.What frequencies are available in Germany ? Apologies for going off topic again.........

I believe that there is a 'reversing mechanism' Martin 😉
But then you can't read the labels, so if you are colour blind - you're in trouble😮
😎

You're right Pete,
Oh! Phttttt! 😮😔

I am not sure Doug,
But do they have reversing switches.

Martin.

Sounds like a load of CO2 to me Doug.😮

One each of course Martin, for both ends 😂🤣
Apropos 'Motor reversing' where do we get the motorised socks from!? 😜

The old sock, is it port or starboard ?

Martin.

Sorry Pete🤔
NASA / JPL secret!
Suffice it to say It's analogous to instructions about how to get a square peg into a round hole!😁

Have you got the plan for that Doug. I have the cardboard, an old sock and some duct tape.👍

Houston - 13. "I have a problem. I think my WTC tube is not good."
"Thirteen - Houston. Aha! What you need is a filter adaptor made from cardboard, sticky tape and an old sock!"😂🤣

Hi Fred,
2.4 on the surface is fine of course.
433Megs also, slightly better than 2.4G but still severely restricted under water.

"as the old 40Mhz has more or less gone for good"
Almost but not quite😊
There are still some model sub specialists who still do 40Meg stuff, and some of it tailored to 'Pig Boat' driving👍 This is the one I use most.
https://engel-modellbau.eu/shop/en/home/
As you can see on the Home page even xtal-less 40Meg RXs are no problem.
Lots of Futaba stuff still available as well.
https://engel-modellbau.eu/shop/en/R-C/
Cheers, Doug 😎

"Sorry to hear about your grill, but looking at your avatar you will need to get a BIG grill. LOL!!"
What you see in my Avatar is only the half of it Martin😋😊
Gisela was struggling through the other half with a big grin on her face😁
Shucks, can't find the pics now, was several years ago at a Santana concert in the Olympia Halle here in Munich, 27th May 2006. 😮 Tempus fugit!!
Probably have to connect up an old external back up drive to find them.
Just ordered replacement grill/oven. Slightly bigger than the old one but not THAT BIG!!!
Cheers 😎

Hi Pete,
Definitely a different edition! See pics.
ID page only says Reprinted 2005 though, nothing about 'Revised'.
Foreword from Norman is also still the 1991 version!
Some of the tech components may have changed (shrunk?) in the meantime but the principles haven't👍 Scan or photo a page or two anyway for comparison.
Cheers, Doug😎

"Sub guys recommend 3mm as standard. Oooopss!!😀 "
Must admit that was my first thought!
I actually first wrote 3 to 5mm, then changed it to be on the safe side🤔
Didn't want you contacting a compensation lawyer😉
😎

".....In one of my sub's I have a WTC made out of a rainwater down pipe, with very tight push in end cap's and I have taken her down to 8ft with no problems, before WTC a lot of the Sub's used the old Darnell system and we also used to take them down to 8ft....."

So long as the external pressure is greater than the internal, an end cap with a ledge will stay in place.

The problem here is that venting spare air into the WTC increases pressure inside, and can blow the ends off if they are not positively secured. And, as I think RNinMunich mentioned, pre-pressurising the WTC to suppress leakage would also require positive securing...

".........When I finish it will be read not blue.😀......."

When I am dead, I hope it will be said,
"His sins were scarlet, but his books were read..."

Hillaire Belloc: Epitaph.

Hi All
Well this is starting to get interesting,
Some of us model submariners have now gone over to open LRS 433Mhz👍 as the old 40Mhz has more or less gone for good☹️, some also fill that you could use 2,4 in a Sub if you keep the ariel above the water line meaning you can only submerge to periscope depth, we have a member in our club that only runs his sub on the surface and that has 2,4.

In one of my sub's I have a WTC made out of a rainwater down pipe, with very tight push in end cap's and I have taken her down to 8ft with no problems, before WTC a lot of the Sub's used the old Darnell system and we also used to take them down to 8ft,

As for the pressure I would think Boyles law will come into play?

As we all live in one bar (14,5psi) and the water pressure doe's not increase to much until we get down to 33ft then it doubles ie 29psi😴😴

Time to get my coat
Fred

Hi Doug.
If your book is 2005, I would like first chance as I think the technology might be more up to date perhaps. Might be the same. I will find a page that seems dated, take a picture and send to you for comparison if you don`t mind. I would send as PM.
Thanks.

Sub guys recommend 3mm as standard. Oooopss!!😀

Hi Doug.
The book appears to be 1996 vintage.
When I finish it will be read not blue.😀
Pete.

I agree Doug.
Sorry to hear about your grill, but looking at your avatar you will need to get a BIG grill. LOL!!

Martin.

Just looks like two servos glued together to me🤔
Just specially made to slot into the particular heli as a spare part I guess.
Two mini or micro servos would probably do the same job at half the price!
Gotta go now, to buy a new mini grill/oven - the old one went bang💥 (and took out the mains circuit breaker😮) while grilling the sausages for Sunday breakfast😭
Ciao, Doug 😎

Doug,
I have just seen this.
2.4g.
Expensive!

Martin.

Thank you for the offer it is much appreciated but I am not really a sub guy.
I just tinker to see if I can do things.
Thanks again.

Martin.

My tube is exactly the same as yours Peter.

Martin.

"The book I bought is light blue ..."
He He😁
What was it the big guy in Porridge said-
"I read a book once ......... It was green!"😂🤣
Great Ronnie Barker series👍

Not sure of the date until it arrives. I will let you know.😃

"The book I bought is light blue and was published in 1996."
Same as mine Pete, with four pics of model subs on the front.
Reprinted in 2005?

Would you like the book Martin?

"I have a problem. I think my WTC tube is not good. It is 70mm od and 66mm id. 2mm wall section.😀"
Hmm! Might work, especially if you don't go deeper than 1m.
Water pressure there is only about 16.15 psi, or 1.1 bar.
What's the tube made of?

"if you use the 9g small servos ..."
There are even 4 and 5gm servos these days.
Primarily intended for small Park Flyer aircraft, drones and the like I suppose, but I find them ideal for small Plastic Magic projects, e.g rudder servos in cramped spaces, and other jobs where a large force is not needed; e.g. to operate tiny micro switches, gun or crane rotation etc😉
😎

I have a problem. I think my WTC tube is not good. It is 70mm od and 66mm id. 2mm wall section.😀

Hi Doug.
Thanks for the offer of the book but I bought it on Amazon last week. It is due tomorrow. The book I bought is light blue and was published in 1996. Thanks very much for the offer though.👍

Hi Pete (again😉)
"It surprises me that the small dive tank overcomes the two air filled chambers."
Remember: if the boat is correctly trimmed to the waterline on the surface ANY small increase in mass, i.e. a little bit of wet stuff in the tank will start to give it negative buoyancy. I.e. it will start to sink! DON'T PANIC ...
Until the increased water pressure, and hence density and upward resistance force, counteracts the increase in mass and the sub reaches neutral buoyancy. Put more 'mass' in and the boat sinks further until again reaching equilibrium.
Blow some 'mass' out and the boat has positive buoyancy and starts to rise.
A somewhat simplified description perhaps but that's the basic mechanism. How much of the boat is above and how much below the water at any time alters the equation slightly! Displacement vs mass!!😁
Brüggen's book explains the dynamics in greater detail than I can.
The dive tank for my Akula has a volume of about 700ml, i.e. mass of 700gm. Which is about 20% of the total expected mass of ca 3.5kg so should be fine for diving to 2m max. Not that I expect to be that adventurous😮
Anyone still awake, need an aspirin!? 😁
Happy diving folks, ONCE ALWAYS 🤔WORKS!
Cheers, Doug 😎

Hi Pete,
"If the water compresses the air within the chamber, would the cylinder swell and the seals be compromised."
Not if everything is properly dimensioned; pressure hull and bulkhead thickness, sometimes even a separate chamber to take up the air expelled from the tank or bladder (😮)
The pressures involved at the depths our subs will (hopefully!) operate are not that great.
For every 10m you go down the pressure increases by about 14.6psi, i.e. 1 x normal atmospheric pressure at sea level, 1 bar or atm. So at 2m maximum, more is not recommended or indeed particularly useful for models, the pressure is about 17.6psi. Not a too dramatic increase (ca 20%) which pressure hull walls and bulkheads of ca 5mm perspex or similar should cope with with ease.
Of course the bulkheads need to be secured with more than just friction on the O rings!!
I'll dig out my dive-tank and check the wall thickness.
Cheers, Doug😎
PS As I wrote below, somehow I have acquired two copies of Brüggen's book on model sub technology. I think an Aunt sent me a copy for my birthday, about a month after I already bought it 🤔 If you want my spare copy PM or e-mail me!

Absolutely DG 👍
One false move and the boat could get into a deadly death spiral!😭
Was surprised to read Martin's system description and learn that he vented the air!😮
Cheers, Doug 😎

Hi Peter,
When the Gato submarine is ballasted correctly you will be surprised just how little water is required to start to submerge it.
I used standard servos as that was all I had,but if you use the 9g small servos you will end up with a lot more room and it will be lighter so you will require more ballast.

Martin.

Hi Martin.
It surprises me that the small dive tank overcomes the two air filled chambers. I thought this might have been bigger. At that length, there should be more room available for the other things like an attitude sensor.
I am mainly concentrating on the Gato build at the moment but busy researching the WTC at the same time.

Thanks Fred. The model submariners site looks to be very helpful.
Thanks again.
Peter.

Thanks guys. I now see exactly what I have taken on.
I will sort through all the information posted by you all and see what is what. I really am looking forward to getting further into the dive system. I see that you can buy them complete but I think I would like to have a go.
I have seen a commercially available WTC where the end caps have been screwed in using four screws behind the last seal.
I have a question Doug. If the water compresses the air within the chamber, would the cylinder swell and the seals be compromised. It is hard to understand the pressures involved. Martin`s idea does mean that there is no additional stress on the seals but limits the dive depth. I would like to go deeper so will have to review my methods and see how this can be achieved. I have some reading to do looking at all the suggestions.
Thanks again all.😊

Commercial dive sets, like my Akula II (and DIY ones from guys with a fantastic machine shop🙄) use bayonet end caps.
I've also seen DIY articles from guys who have used longitudinal studs to hold things tightly together.
Trimming (pitch control) is done in my kit using an attitude sensor and hall effect sensor for controlling the dive tank. The hall effect sensor detects the position of the tank piston.
The attitude sensor detects deviations from neutral and adjusts planes and / or piston accordingly.
https://engel-modellbau.eu/shop/en/Submarine-Kits/AKULA-II/Hall-Sensor-for-Compact-Tank-Switch-CTS2-2-upgrade-set.html

https://engel-modellbau.eu/shop/en/Sub-Components/Pitch-Control/Pitch-Controller-SPC2.html

In Norbert Brüggen's Model Submarine Technology book (see below) there are instructions on how to build these devices (and more) with circuits, parts lists and layout drawings.

Doug 😎

Eventually when I am completely happy with the way it all works I will fit a few small retaining screws in the end caps.
She is trimmed both in surface trim and submerged trim using lead weights and close cell foam.
At the moment when I flood the tank she submerges fairly evenly.
But it is all experiments at the moment.

Martin.

"....On my WTC it is only the O rings that hold it all together tightly, I have not fitted additional screws...."

Ah. I think that if/when I play around with pressurised tubes I will want to have everything positively secured. Not tried to build a WTC yet, but have stored up a perspex tube and nice Futaba f14 for the radio for when I do.

How do you do fore-aft trim?

Thanks Admiral bro,
My style/form of model making has changed over the years and due to lack of finances now I use what ever I can to achieve the final outcome, it seems to work out ok as you can see on some of my models but I would love to be able to purchase some of these fantastic model kits that are now available.
I now tend to look at something then think to myself how could I make that, luckily I normally come up with some sort of answer.
Then if that didn't work I try something else.

Martin.

"but then as I had spare bits and pieces i thought I would just have a go. "
Way to go Martin👍
That's how great discoveries and inventions are made!
Keep on tinkering Bro.

Hi DG & Doug,
I had originally tried it so that the air went into the rest of the tube but with only half a cup of water It popped off the end caps.
On my WTC it is only the O rings that hold it all together tightly, I have not fitted additional screws.
I have ballasted the submarine so that when she has a full tank of water she will still have about half an inch of the conning tower above the water and will then need a bit of forward motion and a slight tilt of the dive planes to pull her under.
As this was the first WTC that I have made I was totally unsure if it would work.
But after a lot of testing it seems to be working fine.
I am not really a submarine type of guy, I just like tinkering.
As I only planned on running at periscope depth, the idea behind my thinking was that should I lose sight of it or have a signal/power problem then she would surface.
I may be totally wrong.
If I did take her deeper then had a signal/battery problem then I think that I would have problems.
My first plan was just to have her as a surface runner, but then as I had spare bits and pieces i thought I would just have a go.

"........I pump the water in the air is then forced up through a small tube to the periscope and out.
Now as I do not have a solenoid valve fitted the water inside the ballast balloon wants to slowly force it way back through the pump and as the submarine has slight positive buoyancy it will rise to the surface on it own after about three or four minutes........"

Why do you need to lose the air through the periscope tube? I would have thought that you could pump it to the rest of the tube. That would pressurise the tube a bit - and balance out the external water pressure. You would need non-return valves of course, to make it failsafe, and that makes it less simple...

I presume that the water leaks back out through the pump because of the pressure caused by the elasticity of the balloon? At what depth does the outside pressure overcome this elasticity? Because if that depth is reached the sub will start to take water in, and become negatively buoyant...

Thanks for the link Fred👍
First thread I looked at 'Submarines and 2.4GHz' is a timely warning!
Read it and you will understand why I have a stock of 40MHz RXs from Standard to Pico versions. And why I bought all the 40Meg crystals I could find locally a few years ago.
I also have two MC-10 40Meg transmitters plus the 40Meg job that came with my Southampton tug. Southampton is being converted to 2.4Gig leaving that TX free for my subs😊
Cheers, Doug 😎
http://www.theassociationofmodelsubmariners.com/t83-openlrs-and-2-4-ghz-and-submarines
BTW: I think this should be a good source of 40Meg sets, tailored to submarine use😊, for some time to come. This guy is a specialist who does ONLY sub stuff.
https://engel-modellbau.eu/shop/en/home/