Inherited 688i - Page 3 - RC Groups
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Feb 10, 2014, 10:11 PM
Ah, so its THIS again. . .
Ronin055's Avatar
Hey guys Thanks again for the intel.

Im going slow. The switch that you guys commented on is infact a push rod and not a toggle switch. And it is indeed water tight and did not have rubber to begin with I believe.

After inspecting all seals visually, I gave the WTC a submersion test this evening.

All the seals in the water tight areas held.

There were small intermittent bubbles from one of the screws in the ballast chamber that came about every two seconds or so. And then a very small bubble from around the air release valve on the ballast chamber that came at about every three to four seconds.

There were no bubbles from around the rudder, dive plane, or primary drive controls. There were no bubbles around the forward seal either. SOoooo looks good so far.

So all in all I call that a successful test.

One thing I seem to be having trouble locating is a adapter to put gas in my ballast system. I realize that withtout a radio that its not going to be that big of a deal. But I figure that if I can locate it online, that I can get it ordered while we try to locate the radio at the shop.

Any ideas guys?
Last edited by Ronin055; Feb 10, 2014 at 10:38 PM.
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Feb 10, 2014, 10:28 PM
CG Bob's Avatar
Originally Posted by Ronin055
I have to go sideways from that and ask if anyone runs Lipo in subs. My friend at the hobby shop seems to think its a bad idea. And I want to keep it original.

And where do I acquire an adapter to put the duster air into the copper cylinder?

Thanks guys.
We do run Lipo's, just keep the battery inside the WTC. We also use NiMh's and SLA's (Sealed Lead Acid or gel cell) in subs.

You can get a Propel can adaptor from Mike's Subworks. Use a good air brush propellant like Badger Propel or Pasche N-12. Don't use the Testor's air brush propellant to charge the gas tank; it has mustard oil added that acts like tear gas; and it will craze or discolor the Lexan cylinder.
Feb 10, 2014, 11:22 PM
Ah, so its THIS again. . .
Ronin055's Avatar

I found the adapter and I will order that this week.

Badger Propel is sold at Michaels craft store and we have two of those here in town, so thats all good too. No worries.

I think just for the sake of run time, I may end up converting this sub to run on Lipo power in the future. Im sure that a nice ESC and lipo set up will increase my run time at least two fold. And hey, more run time makes everyone happy!
Feb 12, 2014, 12:05 AM
Ah, so its THIS again. . .
Ronin055's Avatar
More good news. I plugged in a 2.4 system that I have laying around, and went through all the controls. Everything seems to work just fine.

I've got to put it all together and check dive controls. But first I will have to pick up the propel adapter.

So everything looks good.

Question though. I did find a small amount of water in the WTC today. I'm not sure what seal it came through. So I'm going to disassemble and grease all the fittings.

What kind of grease should I use?
Feb 12, 2014, 12:17 AM
Registered User
One way to help you locate a leak is to submerge the wtc and slightly overpressurize it and look where the bubbles are coming from. Remove the valve stem from the schraeder valve and attach a length of rubber tubing. Blow into the tube gently and observe.
Feb 12, 2014, 02:09 AM
Man from Atlantis
Sub culture's Avatar
Silicone grease is best for use on nitrile seals. It doesn't emulsify with water. You can get this at plumbers merchants or electronic supply stores, also used for distributers on cars, although not many cars have them these days!

For very small water tight housings I find any potential leaks by submerging it in hot water. Leaks quickly show themselves by a stream of bubbles as the hot water heats up the air inside.

The use of lipos in model submarines is a little controversial. Many modellers use them successfully, but some won't owing to the more volatile nature of this battery technology.

I think most of the horror stories of lipos are down to misuse/abuse or good old fashioned short circuits, which in fairness can happen with any battery technology. Shorts in a lipo are pretty scary, as the batteries tend to have very low resistance, so things get hot very quickly. However provided you take care with charging and fuse your boat well, things should be uneventful.

Clearly if a battery combusts inside a sealed pipe it can have somewhat more serious consequences (pipe bomb anyone?). Having said that with the design of WTC you have the end cap would just pop off with any large expansion of air, so that would alleviate the issue of creating an expensive grenade.

The other issue with lipos is running them below 3 volts per cell which tends to ruin them. On a modestly powered sub it can be difficult to spot when you're getting low on power, and underwater noone can hear your lipo monitor going beep-beep. Therefore it's a good idea to run one of the gadgets specially designed for lipo use in subs which do things like blow the ballast tank or set the dive planes to up when it's time to come in.
Last edited by Sub culture; Feb 12, 2014 at 02:25 AM.
Feb 12, 2014, 10:54 AM
Ah, so its THIS again. . .
Ronin055's Avatar
Thank you for the answer on the grease.

And Thank you for the heads up on the battery.

I run Lipo in my planes and I just picked up one for my sailboat.

So I was thinking of changing out the ESC for a lipo speed controller with a Low Battery Cut Off.

The theory here is that when the battery gets low, the ESC cuts off the motor but allows you to still work control surfaces. So I should be able to blow ballast and get her to the surface anyway.

And as to the volatile nature of the batterys, that's exactly what my friend said. Where as my Nicad will short in water, the Lipo has a chance of blowing up. So at this point the idea is to run the Nicad for a while and make sure everything is going as it should. Address all the problems as they arise and get to a safe and secure point in the subs capabilities. Then Ill see about switching over to Lipo to extend run time. However it may be a mute point, because of the gas chamber, I may be having to come to shore every so often to recharge anyway. So I may end up keeping everything original to the first build. And honestly that dosnt bother me. I love the classic feel to things, and I love keeping stuff original. So only time will tell how I feel about this.

Thank you again. This is a very exciting endevor as well as a pretty scary thing. I feel the responsibility is a bit more, because I didnt start this build. But Im having to honor the person who did. So Im going to do my best to minimilize the error part of trial and error.

OH YA! I almost forgot. One more question. There is a foam float in the ballast chamber. I understand that that is rigged to the pressure release and the gas release valve. But what does it do functionally? (float, I know)
Feb 12, 2014, 11:25 AM
Man from Atlantis
Sub culture's Avatar
I think it's unlikely the lipos will explode if they come into contact with water. Lithium is reactive with fresh water, but it's more likely they would just fizz a bit and that is assuming the casing was damaged in some way.

The foam float is called a gas saver, what it does is shut off the gas once the tank has emptied, much in the way a ballcock works to shut off the water flow in a cistern. This saves you wasting gas by blowing bubbles through the tank vents.
Feb 12, 2014, 02:31 PM
Doing things differently
Subsonic Mike's Avatar
I can confirm that lipos dont blow up in water,
I know someone who flys a float plane with a 4 cell lipo. After every landing he would open the hatch and the lipo would be sitting in 5-10mm of water.

Should be safe unless punctured, no guarantees though!

Feb 12, 2014, 03:41 PM
Registered User
tchalfant's Avatar
Did you get my email?
You should have a basic troubleshooting manual for the sub-driver you have.
You are going from 0 to 60 in 4.2 seconds, so there is a lot to throw at you.

I use LiPo batteries on my subs and no ill effect from it.
You have the subtek SubSafe, do you also have the leveler in there too? When you put in your receiver, when the wtc was tilted did any servos move like it was trying to compensate?

The fact that you can use your receiver means the servos are not as old as dirt and have the newer (it is all relative) J or S connectors rather than the G connector.

So far things are looking good.

Another source for silicon (it is a paste) is scuba diving centers. I use both the liquid silicon and the paste on my subs. Usually the end caps get a coat of the paste the inside bulkheads get liquid run into them. Pushrod seals get liquid, but sometimes I might push a little paste in there too.

Visually you can see what contact you are getting with the o-rings.
Here you can see a nice even line where the o-ring gets squished to the tube wall.
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What you do not want to see is gaps or damage to the o-ring:
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If the o-rings are not making contact (a lot of resins shrink with time), you can use wrappings of teflon tape under the o-ring to tighten up the gaps.

A little water in is not good. Because you are holding it under a few inches and for a few moments - the leak will amplify at a few feet or more time. So take the time to hunt it down.
Last edited by tchalfant; Feb 12, 2014 at 08:20 PM.
Feb 13, 2014, 05:14 AM
Man from Atlantis
Sub culture's Avatar
I went further with a lipo cell and sliced an old one open and dumped it in a bucket of water. The result was a few tiny bubbles coming off the cell, but no pyrotechnics, bit boring really.

From what I've seen with lipo accidents, they're almost always caused by extreme use or direct short circuits.
Feb 13, 2014, 11:21 AM
Ah, so its THIS again. . .
Ronin055's Avatar
Alright, after a day of getting hammered here at the shop, and then occupied at home, I have a moment to pay attention.

Thats all really great news on the Lipos. I think that that possible upgrade just went up a notch on the consideration list. Again the only reason it wouldn't be a 100% mod, is that I'm strongly leaning towards keeping the sub as original as possible. However run time = fun time, right?

The silicone paste sounds like a good idea. Oil question, I used to play paintball a few years ago. And we used silicone air tool oil for our O-rings. Is that the kind of oil your talking about, or close enough.

Ok and along the line of potentially bone headed questions. Has anyone tried CO2 in the ballast chamber? I say bone headed because potentially that is to much pressure for the little chamber, and or due to the density of CO2 it wont help the sub rise the same as O2 would.

And to answer the question above, no I do not see a leveling device at this time. When I hooked up the sub, I used my 4.2 reciever and had the WTC pulled apart. So I couldn't really tell what was all doing anything except when I used the controls. I guess I could power it all up and then turn off my controller and see if the ballast servo does anything. I didn't think of that.

Oh and on the subject of controls. My left stick is throttle ofcourse, on the forward and reverse position of the stick. Then the Left and Right function of the LEFT stick seems to operate the ballast chamber valve. While the RIGHT stick does dive plane on the Forward and Backward position of the stick while Rudder seems to be on the Left and Right position. Does this sound about right? Or is everyone just doing it how ever they are comfortable? Because I was thinking of putting the ballast on a 3 position toggle, if I have the option. So that its neutral, dive and rise in relative positions.

Well thanks again for all the help.
Feb 13, 2014, 11:58 AM
Man from Atlantis
Sub culture's Avatar
On no account should you use Co2 in that boat. The pressures with C02 gas are far greater than airbrush propellent type gases, and the unit just isn't built to take it. There are other issues with using Co2 as well. Co2 boats have been built, but it requires a great deal of care, and personally I've never liked the idea, because of the high pressures involved (several hundred psi).

One thing you could do at a later stage is convert the boat to a snort system, which uses a simple inexpensive low pressure air pump to blow the tank out.

Regarding controls, use the scheme you prefer. Personally I like rudder control and hydroplanes on the right stick, throttle on the left, and ballast control on a separate switch or pot away from the sticks altogether.

Some sets won't allow that final luxury, but I find it's best to separate ballast tank control from the main sticks as it's all too easy to nudge the stick the wrong way and put the boat out of trim.
Feb 13, 2014, 04:22 PM
Ah, so its THIS again. . .
Ronin055's Avatar
Ya I didnt think the CO2 was a good idea with the current build. I have plenty of experience with it and it just didnt seem like a good fit.

Good News. I ordered the Propel Can Adapter from Mikes sub works today. Great guy, lots of fun to talk to. Hes a very helpful and friendly man. So thats in the bag and I made another great contact in the Model Submarine community.

Good News #2, My buddy at the hobby shop came up with a radio system for me today. So total Score !!

Ill be heading out for some Silicone lube today on the way home from work, along with some clear silicone caulking to reseal the WTC after I put the new RX in it.

So all is well, and we are moving ahead at about 1/4 speed. Perfect learning pace at this point.

Thank you all again for all you've done for me so far. I really appreciate it.
Feb 13, 2014, 04:24 PM
Registered User
tchalfant's Avatar
Propel is like 50psi were CO2 is 800psi (give or take a few psi, but you get the idea)
Here are some instructional videos for your education:

Sub-Driver Ballast Adjustment part 1 (6 min 26 sec)

Sub-Driver Ballast Adjustment part 2 (7 min 24 sec)

Seawolf Sub-driver Instructions Part 1 (9 min 3 sec)

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