Thunder Tiger Yellow submarine seen on Norimberk - Page 5 - RC Groups
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Nov 19, 2007, 02:18 PM
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Ok when the motor is running the servos at the rear have a mind of there own?

Ihave disconnected the motor and run the speed controlto full speed and the servos operate correctly, so it is the motor itself which is causing the interference?
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Nov 19, 2007, 02:52 PM
Man from Atlantis
Sub culture's Avatar
Sounds like it.

Have you got three capacitors fitted to the motor. One across the terminals and one from each terminal to the can of the motor?

Also make sure your power leads are well separated from the radio/signal wires.

Other things to try are small toroid rings for each motor lead.

It could well be that the interference is caused via the ESC's BEC. If the glitching and interference persists, then try removing the red wire from the ESC's receiver plug, and either use an external BEC or plug in a 4 cell battery pack for the receiver and servos. If this cracks it, then you may need to consider a different ESC.

Last edited by Sub culture; Nov 19, 2007 at 03:04 PM.
Nov 19, 2007, 03:17 PM
Registered User
I think the problem lies with the main pcb at the front of the sub, there seems to be more problems, there is power coming into the board but nothing coming out now, i think this one will be taken back or i will ask if the main board can be replaced.
Nov 19, 2007, 03:31 PM
Registered User
No the problem was not the main board, i found a switch that was trapped and it switched it off!

Back to the drawing board!
Nov 19, 2007, 03:41 PM
Registered User
Russ, another little suggestion.

If you are afraid of the motor position close to the servos, you may remove the motor, apply longer wires, place the motor somewhere else (far from the servos) and run again.
If the problem still exists, the position of the motor has no influence: the cause is another one.



By the way, are the two motors of the same model and voltage? They should be.
If so, what about replacing the propulsion motor with the pump one (*), just for a test, and see what happens? If there's something wrong with the propulsion motor, the problem should disappear.
Otherwise, you'll have to check the other electricals, as Andy suggested.

(*) disconnect the hose to the bag, of course!
Last edited by Ocean's One; Nov 19, 2007 at 03:48 PM.
Nov 20, 2007, 04:11 PM
Registered User

...or anyone else who might know: I'm following this thread with interest, since my dad and myself are considering buying one of those little (?) beauties for Christmas.

However, it seems that dealers in Germany (where we plan to purchase it) sell only an ready-to-run version, which would spoil half the fun. You however seem to have gotten a kit with assembly plan and all...?

Was that a special order? Or how else can one get a DIY-Neptune like you did?

Thanks in advance for the help!
Nov 20, 2007, 04:54 PM
Registered User
In the UK the Neptune is only available in kit form, the rtr version i tnink is not available until 2008, a few model shops now have these in but they seem to be scarce and hard to come by at the minute, i should imagine they will be better availability towards christmas.
Nov 20, 2007, 06:39 PM
Registered User
Great, thanks! I now found a shop in the UK (wonderlandmodels) where I can order the kit.

Sorry to bother you again, but...
- What radio set did you buy for it? Any tips on what I should think of when looking for my own?
- Did you also buy the Polyphemus camera and cable? Any tips on where to get that one?
Nov 21, 2007, 03:27 AM
Registered User
Hi there,

Radio set should be 40 mhz 4 channel mimimum, be sure not to go for the 2.4 ghz wireless as the signal will not transmit through water, as for the camera i am installing my own, i think the one that ThunderTiger produce doesnt have any infa-red lighting so i think it will only be any use in a clear swimming pool and the monitor is very small, i have gone for a 8 inch lcd monitor which can be powered off battery and a 2.4 ghz wireless camera powered off the Neptunes battery, again with the transmision problem the cameras transmitter aerial has to be lengthened so that it sits on the top of the water with some kind of buoy(ping pong ball maybe).

Nov 21, 2007, 07:17 AM
Man from Atlantis
Sub culture's Avatar
If you can spare the extra cash, a 6-channel TX is worth the investment. Most people usually want to add a function or two above the 4 channels usually used, and the cost of a 6-channel set isn't significantly greater.

For a receiver I would strongly recommend one of the newer generation microprocessor PPM receivers.

Jeti MPD, Schulze range and Hyperion receivers all feature these advances. The microcontroller filters out spurious information and stops servo jitter, improves weak signals etc.

They offer the benefits of PCM with out the disadvantages. They cost a tad more than standard receivers, but it's a small price to pay for the benefits they offer.

Nov 21, 2007, 07:29 AM
Registered User
Ross and Andy,

Thanks a lot! I’ll see what I can find on the net…

How’s the work with your sub progressing, Ross?

…and another thing, concerning the camera. Here’s an interesting site giving some food for thought on the issue:
Assuming that you don’t speak German, and considering your plan to put the aerial on a ping-pong ball, here’s one key idea I picked up from it:

What he suggests is to have a larger buoy. As it seems, if you use an aerial all the way up from the sub to the buoy, the signal would become too weak to be effective. He therefore suggests to take one with at least 1 litre (could even be a duck decoy), in which you can put both the sender for the camera and the energy supply for the sender.

Another thing he describes is the difficulty to steer the sub with a camera. Even 2mph seem very fast from the viewpoint of a tiny camera, one doesn’t have any references to steer by, and it’s difficult to guess whether one is going up or down or which way the sub his heading. One tip he has concerning the latter is to build in a little compass that you can see from the camera (he doesn’t specify exactly how, though). As for a depth meter he has no idea (yet) how to solve that one.

Concerning b/w cameras: don't you think it would be possible to add projectors to the Neptune, either inside the sub or outside? It’d be fun to see the bottom in all its colourful (ehm…) glory, after all… Plus that it might attract some fish.

Do you have any tips on where to buy cameras and monitors, by the way?

And one last question: I vaguely recall having read that it’s not possible to have an RC sub in saltwater, as the salt absorbs the radio waves. Is that true? If yes, does any of you have an idea on the modifications that would need to be made in order to place the sender in the buoy rather than the boat?


Nov 21, 2007, 08:37 AM
Registered User
Hi there, the Neptune is now fully built and ready for water trials, i have tested the WTC in the bath and will try it next in the swimming pool before i take the plunge into the lake. As with the camera install i am trialing a few methods using homemade water containers first with various methods of lighting.
Nov 21, 2007, 09:13 AM
Registered User

please accept my compliments: four days from delivery to finished model is a very good performance indeed!
Now keep us informed about your swimming pool test, tks.

Regarding buoys, I agree that the most functional solution is a buoy having inside the sender and its battery, even if it becomes larger. I've built such a buoy and I will post some pics. Eventually, I'll check how it performs during my next test with the Neptune.


I'm happy you wish to be a Neptuner!
Regarding salt water, the problem exists but there's also some solution. You may look at the thread "Titanic wreck" in the submarine section.

Ocean's One
Nov 21, 2007, 11:19 AM
Registered User
Oceans, i think i misunderstand, the camera i am using as the transmitter built into it so does not require a seperate sender?
Nov 21, 2007, 11:40 AM
Registered User
Ok, sorry, I didn't get it.
I supposed your camera needed an external sender, and therefore I suggested to place the latter inside the buoy.
If there is a built-in transmitter, you have just to let its antenna reach the surface.
(By the way, have you already decided how the antenna will pass through the Neptune's hull? You'll need a long antenna as well...)


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