Arkmodel Red Shark

[steveuk]

That does not sound good. These things are not set up to work very well. But with some small modifications (hopefully) they could be made operate like they should.

[Sonnich]

Absolutly, this is a very simple contraption, I will get it working brilliantly :-)

[Sonnich]

New shark arrived in the mail today. Just without batteries, ESC, and radio.

Mailman also dropped off a Revell Skipjack 1/72 as a future project :-)
It is larger than I had expected.....so that is cool :-)


My unfinished Robbe U-47 next to them just for comparison

[steveuk]

Yep, Skippys are a good size, and they sail very well. Good luck with your sub projects.

[Sonnich]

Motors arrrived today. Ordered one, but they sent 2....

Since these motors dont have caps on them, I soldered 2 on.
The stock motor has them on the inside.

The shaft coupling is not drilled true, so it is really out when you turn it.
I drilled the coupling from 5mm, to 6mm, and installed a bushing, and got it way better than it was before. A flexible jount or rubber couppling would be much better than a ridgit one.... But I dont have any in stock :-)

Installed it all again, and tested it. This motor has quite a lower RPM, and Im not sure it will be enough.

The prop was glued on before. Now I installed a thin brass nut to tighten it up against the prop.

[Sonnich]

last pics......

[steveuk]

Does the shaft spin centrally right now, fixed to the motor spindle this way?

[Sonnich]

It is not perfect. The stock fixed coupling sucks. But U have reduced it so much so I feel its ok. We will see :-)

At least the motor is dampened in the o-rings that is holding it.

[Sonnich]

I have ordered a waterpump, solinoide, and ESC for them. Where can I get the bladder bags that poeple use in subs ?

I would like to make my second Red Shark a static diving boat.

[gantu]

Build this in the boat is nuch better then the stuff from Arkmodel.

http://www.modelluboot.de/Zubehoer/Wellen_Motore.html

[Sonnich]

Thanks for the link......going right into my favorites :-)

Got it in the pond today, and it went fine.

This new motor is half the power of the, so at first, it needed 100% throttle to dive, and it was a little difficult, because if you try dive too fast, the prop will come out of the water, and loose power, and the sub will loose its speed, and never go under.

But, I added a stick of zink ballast, and weighed it down to the line on the sail, and now it is awesome :-)
Much easier to control pitch, as it does not want to surface like a cork. Allthough, the manual says to lower it even more, so the waterline is just bellow the sail dive planes.....but that just looks stupid in my opinion......but it would probably be great under the water with so little positive boyancy........ I want a static diver !! :-)

The motor is very hot......finger burning hot. but not so hot that water will boil off of it :-)
But it seemd to work fine for the 2 1/2 hours I was running it today. ESC is pretty cool.

Im running 3S 5000 lipos x 2 10 10A of run time :-)
The Original 6V lead acid battery is also installed, just for ballast.

I cant believe how well my JR 40Mhz SPCM radio system works. I rolled the RX antenn around 3 fingers, and just placed it up front so it looks like a birds nest, and it has great range...both far away, and under water...amaizing.


I believe the shaft seal is grabbing very tight on the shaft, and causing quite alot of drag.
I did not fasten the new motor....just sits in the o-rings teh sub came with.

I bet a 2 bladed prop would be way more efficiant than the multiblade scale thing of a prop that is included......but it does look cool :-)
But a new prop would save the motor....thats my guess. A true running shaft would also help a great deal.

Now it needs a repaint :-)

I like black :-)



Here is a video of it before I added ballast......very hard to dive, and its running at full throttle.
With the extra ballast, it will dive at 80% throttle...
Im filming, and my buddy that only flys drones and helicopters is running it......it was his very first time running a submarine, so bear over with how it is operated

[Sonnich]

The insides.....

[Sonnich]

This is where the final waterline ended up today.....

[steveuk]

Wow, you have it working now!

[Sonnich]

It works quite well. Will try it with a heading lock gyro in the elevator tomorrow :-)

It sails much better now, than in the video. I was doing figure 8`s infront of myself at periscope depth.

Gaining the correct boyancy is really a night and day experiance.


Will add a periscope on the sail, to see it easier when submerged.
Our pond is not very clear, and it disapears very fast even with a shallow dive.