Nikko Seawolf - blast from the past

[redboat219]

I think what David meant by "not scale" is the Nikko submarine is NOT a scale representation of a real life boat. Look at all the model subs being built here, you got your Skipjack, Seawolf, Akula, Alfa, Uniform, Kilo, Sierra, Type VII, XXI,XXIII etc. With the exception of Capt. Nemo's Nautitlus and USOS Seaview, most are based from real life boats.

How about using a vertical thruster in the docking collar of a scale DSRV?

[tifosi12]

Because it ain't scale.

David

You're saying just making everything bigger wouldn't work because the down suction is limited in its force? Just making that part bigger wouldn't pull down a bigger boat, is that the rationale?

[tifosi12]

There's a thread at RCG where the owner replaced the old seal with some silicon baking sheet and a lid from a food container. https://www.rcgroups.com/forums/show...-Submarine-mod

Whoa! That's a great thread and what an undertaking OldNeet did changing the electronics and servo. Wow! And figured out how to replace the seal, not bad. I have to find some Chef Boyardee stuff as a backup. :)

[He Who Shall Not Be Named]

I'm curious as to why hasn't anybody tried doing their own hobby grade RC sub based on the working principles of the Nikko sub. That vertical thrusther is simplicity itself. No ballast mechanism to fiddle and adjust. Just push the switch and down she goes. Stop and let bouyancy do the rest. David already showed how to make a gimballed prop for pitch control, it's just a matter of turning it 90° for yaw control. Or you could just go with a normal fixed prop and servo operated rudder.

Because it ain't scale.

David

[tifosi12]

I'm curious as to why hasn't anybody tried doing their own hobby grade RC sub based on the working principles of the Nikko sub. That vertical thrusther is simplicity itself. No ballast mechanism to fiddle and adjust. Just push the switch and down she goes. Stop and let bouyancy do the rest. David already showed how to make a gimballed prop for pitch control, it's just a matter of turning it 90° for yaw control. Or you could just go with a normal fixed prop and servo operated rudder.

It is simple and immensely effective. Goes down and up fast but not too fast, just right.

I suspect the reason it isn't popular because it looks odd and out of place. So it wouldn't work for any scale model of an existing boat. But it would be a good solution for a fantasy boat and/or a research boat, the ones that have all kinds of weird appendages. In my case I'll "dress" it as a Bond villain's boat pretending the vertical thruster is the connector to the underwater station of Spectre. :)

BTW: Nikko also did a nice job with the buoyancy: You add as many horizontal rings as needed to get the ride height correct and then in a second under the bow container you add little weights to get the forward vs rear balance right. Again, super simple and effective.

Somebody should reverse engineer this boat and 3d print it twice as big. :)

[redboat219]

I'm curious as to why hasn't anybody tried doing their own hobby grade RC sub based on the working principles of the Nikko sub. That vertical thrusther is simplicity itself. No ballast mechanism to fiddle and adjust. Just push the switch and down she goes. Stop and let bouyancy do the rest. David already showed how to make a gimballed prop for pitch control, it's just a matter of turning it 90° for yaw control. Or you could just go with a normal fixed prop and servo operated rudder.

[redboat219]

There's a thread at RCG where the owner replaced the old seal with some silicon baking sheet and a lid from a food container. https://www.rcgroups.com/forums/show...-Submarine-mod

[tifosi12]

Since we're talking so much about the perfect seal, here is what mine looks like:

[tifosi12]

The seller noted the sub was still fully operational but the seal wasn't good anymore.

It's possible that the sub is indeed working and that the seal deteriorated over time but in that period the sub wasn't used. Still I'd be super cautious once we are looking at a broken seal. There is a video on Youtube on how to fully disassemble a Nikko submarine. It's doable but I wouldn't know where to begin if a motor or the electronics had a problem.

And: you won't find a seal as a replacement by itself. If you find one, it is normally attached to a fully functional sub. :)

[redboat219]

Key thing is the rubber membrane; it needs to be in perfect condition.

The seller noted the sub was still fully operational but the seal wasn't good anymore.

[tifosi12]

Too bad I missed one being sold online locally for only $10.

There are several of them on ebay but a good one that has seen little if any action runs for about $ 200. Still dirt cheap compared to the regular building costs of a RC sub.

Key thing is the rubber membrane; it needs to be in perfect condition.

[redboat219]

Too bad I missed one being sold online locally for only $10.

[tifosi12]

Here is a brief video:

[SubDude]

Pretty cool!

[tifosi12]

Finally had a chance to take the boat out to the local fountain. Behaved even better than in the tank: Instant reaction to all directions, dives on a dime, surfaces nicely, not jerky while submerged. Even took her so low that the entire antenna was submerged at which point the downward motor stops and the boat starts slowly surfacing thanks to its slightly positive buoyancy. And after the dive, the interiors remained bone dry, the 40 year old rubber seal is still holding nicely.