Hi guys,

Several issues (mainly my health and other projects that have also stalled due to that) are severely delaying my first submarine build, all I have is a box of parts and a list of things to make yet...

I came accross this and ordered me one to see if it'll work (slightly) better than the smaller "subs" I purchased in the past, which all either sank, or stopped working due to water ingress:

https://www.ebay.com/itm/6-Channels-....c100227.m3827

Major benefit for me is the larger size compared to the revell and happycow minisubs, which were only operable in a tank or small basin.

I may even try to replace the Tx-Rx with a 40 MHz FM, to get a better range.

First it has to arrive...

Getting a "wallmart' Dallas sub, which works in a similar way was also an option, but not at the prices I have to pay for those here in Europe.

Regards, Jan.

After a surprisingly short shipping time (order date April 28), the package arrived today.

It is indeed a sort of educational assembly packet, with the three motors, the receiver and the battery tray already factory assembled.
I have to assemble the 27mHz transmitter and the rest of the sub.
Unfortunaly all (elaborate) instructions are in Chinese, the pictures will have to do, but there's also a section on physics, and how to balance the sub on its waterline bij adding floatation, provided in the form of a piece of styrofoam, which you'll have to cut to fit.

As I suspected all controls are on/off, I'll see how that works, before I attempt to make the controls proportional, depending on the space in the electronic box I'd swap out the receiver for a 40 MHz FM one and at least a small ESC for the propulsion motor.

At first glance, not a bad product for the €33,00 I paid for it.

To be continued.

Regards, Jan.

Can you extend the propeller shaft so the prop is outside the stern?

Originally Posted by redboat219

Can you extend the propeller shaft so the prop is outside the stern?

That would mean reducing the prop diameter as it sits inside the tunnel (Kortdüse), see picture, prop not visible from the side.
But why would I want that? This way the prop is shielded.

Assembling the transmitter and the sub is a matter of hours if you take your time, I tested the Tx/Rx function last night once I put batteries in them (3 x AAA for the Tx and 4 AA for the sub).

Regards, Jan.

Just did a short test in a small basin.

Forward speed is good, the steering at speed not so; it looks like the flow at the steering tunnel breaks off, just like the bowthrusters on 1:1 boats, at slow speed it works kind of OK.
Too bad it's full forward or nothing.

Once put in the water, the sub fills until just the tip of the tower just peeks out, it floats a bit nose up, so when going forward, I suspect it'll come towards the surface instead of dive.
A little extra boyancy at the rear should remedy that.

Activating the pump was a bit of a surprise to me: it empties the hull so it breaks the surface, once you've reached a certain level the pump stops and the hull starts to fill up again, activating the pump again keeps it surfaced.

I haven't tried it out in deeper water yet, I don't trust the range very much so I'll bring a rescue tug in case I run the sub out of reach.

Sofar I'm not disappointed bij my first attempt at running a toy sub.

I think the next step will be to make the (motor) controls proportional.

Regards, Jan.

Today I've done a major investment, just under a third of the price of the sub; an inflatable testfacility, see picture.

Once filled, I ran the sub and had to be creative to be able to run in circles without permanently hugging the sides...

As mentioned previously, the steering doesn't work when the sub moves forward (or in reverse for that matter), so I have to apply full right rudder while giving intermittened short burst of throttle, to allow the steering to bring the rear round.

It's a complete new experience for me to have a steering that only works when there's no forward movement.

Most likely as a result of propwalk, left hand turns are even harder to acheive.

In terms of a toy, it's a nice plaything, as a working submarine, it's a complete failure.
When I've gotten tired of puttering around with it in stock form, I'll disassemble it and see how much room there is for my small receiver, a small ESC and a servo for the rudder, replacing the rear 'rudder' thruster.

Depending on how that works out, I'll either keep the pump, or replace it for a second servo to operate the diving planes, making effectively a dynamic diving sub.

As there are small watertight servo's on the market, I may (have to) go that route due to space restrictions in the watertight electronics compartment.

Any suggestions which servo's to get?

Regards, Jan.

Tiny update:
The box, holding the electronixs is screwed on, like all parts of this sub. Unfortunately the box itself is glued shut...

I'll disassemble the sub in all it's parts and weight all components, to see if building a new RC box with my own receiver, ESC and servo is an option, weight wise.

Another option would be to cut out the bottom of the battery compartment, construct a box on top of that and use the battery hatch as access, as it is screwed down onto a rubber seal with six bolts in brass inserts.
While I'm at it, the four AA's would be replaced with a Lipo.

Downside to the latter would be the size of the acces opening, which is just four AA's, this makes working inside the 'wtc' a challenge for my large hands.

A new box replacing the old one would have a bolt on lid.

Regards, Jan.

I bit the bullet and dissassembled the entire sub, which is quite easy as everything is screwed together.
Exeption is the radiobox, which I sawed open to find just one small circuitboard with a couple of IC's and some SMD components, no relay for the pump, everything is switches electronically.

I'm starting with a piece of 2 mm thick ABS which fits onto the mounting studs of the steering motor and the pump and will mount a receiver, an ESC and two servo's on if, wire everything and make the connecting rods to the rudder and diving planes.

The rudder (or a tube) will sit behind the tunnel, aft of the prop to have sufficient steering in small spaces, the rod will pass under the motor into the interior to the new radiobox.

I'm not sure if I'm going to make the rear dive planes movable, as it's shaft would pass through the prop, next to that it would be extremely fiddly and I have big hands...
I know there are ways around that (litterally), but it's my first venture into this and I don't want to overcomplecate things for now.

In stead I would add forward dive planes and leave the rear vanes alone.

Are there severe objections to going this route? Please let me know.

Once everything is set-up, I'll add sides to the ABS bottom and a rim with a bolt-on lid.
As I only need little servo movement, I'll try the Dumas way of sealing the rods with a piece of tight(ish) fitting silicone tubing over the rods with a grease filling.
(I don't have rubber boots that small lying around and no hobbyshop nearby that carries them).

I'll add pictures as soon as there's something to show.

Regards, Jan.

Originally Posted by pompebled

Are there severe objections to going this route? Please let me know.

Well you could have just gotten a length of pvc pipe and put your electronics inside instead of going through the trouble of converting a basic looking toy sub.

Hi Redboat,

Yeah, I know; I have the PVC pipe and innards to go in that at hand, but not enough time and energy to go from scratch completely, that's for the future.

What I meant is the difference between operating the diveplanes at the front (with the rear ones stationary), or at the rear(with no front dive planes).
I've never run a sub, so I can't say if I have to expect handling issues between the two.

Regards, Jan.

Small update.
I started with the making the bottom of the new WTC from 2 mm ABS sheet, but before I could fit the rear attachment to the hull, I had to remove the steering motor and it's tunnel and close up the hole.

I heated up a piece of ABS sheet and bent is over a Ø70 mm pipe to get the same shape as the sub.
This was then cut to fit and glued in place with a few drops of MEK.

Once this had evaporated, the inside was given a layer of ABS solved in MEK goo, this welded everything solid.

A few layers of tape on the outside to avoid the goo spilling and making future sanding easier.
A couple of clamps were added in case the ABS should develop a memory of it previous flat state, before the goo has set...

I still want to know if having only RC front diving planes will give me grief running the sub?

Regards, Jan.

Forward Dive Planes vs Stern Planes.

Originally Posted by pompebled

In terms of a toy, it's a nice plaything, as a working submarine, it's a complete failure.

RC Submarine dives Under Water - Did it come out? (7 min 49 sec)

That's a very poor video, too much chatter, but it gives a good impression of the performance, or better, lack of it...

Regards, Jan.