Thunder Tiger Neptune SB-1

[trout]

Mike sold me his Neptune a few weeks ago. Downloaded the manuals and began the assembly and repair. The owner before Mike got it added some planetary gears and a pvc extension. That all got removed and a new motor mount was added. A few nuts, washers, and bolts that were missing, I got at Ace Hardware store. What a great selection they have. For a brief while when Lowes and Home Depot did not have the metric sizes I needed, I thought I would be buying boxes of stuff from McMaster or some such online store, but around the corner from where I live, is this Ace Hardware store - it now will be my first stop.
The goal is to get it back to original (or as close as possible), get it running, then add on to it.
Tonight we water tested it.


Sam and I let it sit at the bottom of the tub (which was killing Sam). Finally let him play with it surfacing and diving. Everything checked out all systems worked and we were leak free.
Next we will put the full hull on and trim (sits slightly aft heavy)
The tail cone drains so slowly, might need to open the vent and drain hole up a bit.

[crazygary]

Cool little sub!!

Sam will have a blast with that one!!!

Good job, Dad!!!

[Subculture]

These are very hardy boats, over engineered in many respects. Early kits had a lot of issues with the electronics, but those wrinkles were ironed out within the first few months and seemed to mainly affect the kit versions, but these weren't made available in the U.S.A.

I read a story the other day that one in four Americans is unaware the Earth orbits the Sun, so perhaps that is why!

[crazygary]

Not what you might call "readily affordable"!!

Somewhere in the vicinity of $700.00!!?? Huh??

Good score there, Tom!! Way to go!!

[trout]

I can not speak to the performance yet, but the thinking is this will be a camera boat to film the other subs. It is pretty cool the features built into the sub including a pressure sensor that will shut off the water pump from over filling the ballast bag. Now I am thinking about adding lights to it (Sam wants some added). When Kevin came through Las Vegas, we talked about a lot of stuff, but one was keeping the LED inside the wtc and fiber optic to the various areas. I might just try that.

[trout]

It leveled off perfectly with the entire shell placed on. The tub was not deep enough for a complete submerge, so we will need to go to the pool.

[alad61]

There was one of these at the sub regatta I attended down here last October. I have to say they are a neat sub and they behave very nicely indeed. Their ability to maneuver and hover and just glide under water... Below is one of the videos I did from the meet but haven't got round to you-tubing yet

[trout]

Thanks Alec, I like the camera on top and the skids underneath.
This sub, if it works at the pool, would be cool as a photo platform.

[trout]

Got a small window to go and test the Neptune this evening.

I did the initial test, but then gave it to Sam to play.

He dove it in the deep end, made it turn tight circles, surface, dive, and got good at finding a semi neutral balance.

After about 40 minutes, the sub just shut down.
Fortunately it was on the surface when it happened. We figured that must be the run time on the lead battery.

Once it was home, checked to see if water leaked in, nope not a drop. Went to put it on the charger and it was 11.7 volts on it. That seems like a lot of juice still there. Pulled the fuse to check and it was blown.
Something made it blow, Do not know if it was the fact that it was running full bore most of it's run, but I will check things out to see.

[Subculture]

IIRC, it has a 10A fuse as standard, which should be ample for a boat that size and power. Perhaps it's just a bad fuse (unusual but not impossible). Recommend fitting a 10A slow blow fuse.

[Buellman1]

I eliminated the fused block first off. Reason being, I'd rather still have power to bring it to the surface and have burnt up the esc or motor for propulsion. I've not yet to burn up anything anyway. The best upgrade was going with the six blade prop which can be found at tower hobbies. I've also installed a 6000 mah lipo in place of the stock battery and use audible alarms to track low voltage. I don't run it out too far most times, so I can hear it. Another thing I installed was a piezo gyro to smooth out the dive plane action. Does not work exactly like the leveler in say the gato, but it does help.

[Subculture]

Looping out or not fitting fuses is not a good idea, especially with lipos which are capable of supply very high levels of current inside a sealed pipe.

I've seen the tech rack of an Engel Lafayette turned into what resembled melted cheese because of a short in the speed controller.

If you're worried about a stranded sub on the bottom, then use an independent BEC and fuse each power line separately e.g. an individual fuse for BEC, one for the ballast pump, and a third for the ESC. Should a short occur in any one, it gives you some back-up.

I work in an electrical engineering discipline where circuits are fused all the way through. Nuisance blowing is incredibly rare.

If your boat has blown a fuse, I would do a bit of checking on the electrics to ensure the sub is not pulling more current than it should, or you haven't got any bare cables anywhere that could induce a short.

[trout]

Thanks for the suggestions. As Andy suggested I will replace the fuse first. I do not think I will run without the fuse. Many do, but call me a wuss, a fuse is cheap, the other parts are not.
The prop on here is not the stock prop it is a plastic prop, that a prior owner put on, and was an upgrade. It pushes a lot of water (an area that makes me suspect it caused the fuse to blow). Sometimes more can be too much. That 6 bladed prop, Sam saw it and thought it would be a cool looking addition for his sub and I did too. That might be the next move, to replace the prop. I asked on another forum about props, many use a Raboesch prop and Andy suggested a ducted prop (which would be super powerful). Still that six bladed scimitar prop looks cool, so hearing you have seen a great improvement helps. Thank you!
I think the number two upgrade (right after the prop) is power source and lot of people have upgraded the lead battery to LiPo. I will consider it, but after I see how long this puppy will run without blowing a fuse. A assume you put in a 11.1 volt LiPo?

[Subculture]

You can get a very good idea of current draw by using a cheap ammeter to measure the current drawn by the motor when holding full throttle in the bath tub. It shouldn't be much anyway, primarily because gelcell Pb is not capable of providing huge amounts of current, generally they tend to be about 1c, e.g. a 4A cell can provide 4A of current.

[trout]

I have ordered a new prop, for now Sam has won and it is the 6 blade one. The current prop had its grub screw stripped and would slip off.

yep, hovering (mostly).
Fun sub. Need to work on the video portion, so this sub can be a camera sub.