Neptune mod, or late to the party.

[bigdave]

Re: Neptune mod, or late to the party.

Wow!
The sub ran great. The new motor and prop really powered the Neptune through the water.
It was so much fun!!
For about 1 minute.
Then I popped the fuse.
So what does this dummy do?
Put in a bigger fuse.
Well I popped the bigger fuse.
So not satisfied with that I put in another bigger fuse and may have damaged the ESC.
O well, I kind of figured the stock ESC was the weak link.
But it was fun while it lasted. BD.

[bigdave]

Re: Neptune mod, or late to the party.

Well as an update it turns out the motor was bad.
I had rebuilt it but I guess the timing was off or something.
The ESC is fine.
If not for the fuse it may have been a different story.
And not the one with the happy ending. BD.

[bigdave]

Re: Neptune mod, or late to the party.

Well I have decided to give a small brushless motor a try.
I had the parts in the dockyard so it's worth a try.
I am going with a Turnigy 450 outrunner motor. It has 250 watt output but is about 1/2 the size of the brushed motor.
The 890 KV rating should get me to almost the prop speed of the Viper motor.
The motor has a 4 mm shaft so it was to big for the stock 1/8" coupler.
So I made a 4mm coupler on my lathe.
I was able to modifi a airplane type motor mount I had in my parts bin to mate the outrunner to the Neptune motor mount assembly.
The outrunner motors cool through the stator so the Neptunes mount being in the water on the outside will add some water cooling.
I should be able to do some current and temp tests next week. BD.

[Guest]

Re: Neptune mod, or late to the party.

Should pull the prop round well enough. Can't help thinking you're shoving a small block in a Fiat 500 though. Something in the range of 400-500kv would still give lively performance I'd have thought, bearing in mind a modest 20 watts gets the Engel 212 moving pretty swiftly at around 5000RPM shaft speed.

[bigdave]

Re: Neptune mod, or late to the party.

I would rather have used less A less KV motor but the 890 was the only one I had that was close.
BTW A small block in a 500 sounds cool! BD.

[Guest]

Re: Neptune mod, or late to the party.

Not a 500 but its more angular successor the Fiat 126. Crazy stuff!

http://www.youtube.com/watch?v=sxNTcVlaJBM

[salmon]

Re: Neptune mod, or late to the party.

What grease do you put in the drive shaft?

[Guest]

Re: Neptune mod, or late to the party.

I would think a bit of silicone grease will work well enough.

The shaft seal is basically a small oil seal, most likely moulded in nitrile rubber, which is compatible with pretty much all lubricants. I think from memory it also has a small spring around the sealing component, which may rust if left ungreased, unless it's been made from stainless steel.

[bigdave]

Re: Neptune mod, or late to the party.

I used Racers Edge marine grease. It is made for lubing the shafts on model the race boats.

[bigdave]

Re: Neptune mod, or late to the party.

Not a 500 but its more angular successor the Fiat 126. Crazy stuff!

http://www.youtube.com/watch?v=sxNTcVlaJBM

How about a Fiat X19.
Now that would be cool.

[Guest]

Re: Neptune mod, or late to the party.

Think they all dissolved into rust.

[salmon]

Re: Neptune mod, or late to the party.

Thank you for your help. Tonight or tomorrow I will be water testing the sub.

[salmon]

Re: Neptune mod, or late to the party.

And it turned out to be tonight. Not sure if Sam or I was more excited.



It ran perfectly with no leaks. Tomorrow full hull installed and trimming if necessary. I think I need to open the vent and drain on the tail cone. Any reason not to? Any other areas that might need opening up?

[bigdave]

Re: Neptune mod, or late to the party.

Excellent!
The front section drains very poorly too.
I noticed that with mine a few weeks ago.
Larger openings in both ends would help.
I like the black planes.
Were you able to switch out the prop?
She is great fun when you can get some thrust behind her. BD.

[salmon]

Re: Neptune mod, or late to the party.

Thanks Big Dave! Larger drainage, duly noted. The prop on this sub came with the purchase and I am not sure if it is a performance prop or not. It is a black plastic three bladed prop that the front and back are cut to make it fit. Still considering ordering a new one, but that will be after we get it running in the lake or pool so we can judge whether it is already "fast".