My latest sub is the fourth RC dynamic diver I've built. The watertight compartment is a plywood box with a clear plastic lid screwed down onto some wood strips around the top edge. Provided the lid fits reasonably flush onto the wood, a bead of grease applied before screwing down has always produced a water tight seal.
The hull shape was made by gluing thin ply to the sides and bottom of the box. Access was via a removable deck again made from thin ply. This produced a very "boxy" hull but a touch of streamlining was created by using blocks of balsa at the extreme bow and stern.
Control is by stern surfaces alone. This has always worked for me and avoids any bow surfaces which would likely be damaged. Having the movable surfaces aft of the propeller give the model immediate response to any transmitter commands and offers the propeller some protection.
Trimmed with the deck almost awash, the rear hydroplanes are adjusted to make the bows slide under the surface when the model is given full ahead. The force of the water flowing around the hull plus the vertical component of the props thrust, drive the model downwards. As soon as the vertical radio aerial, a length of plastic coated wire, enters the water it creates a "bows upwards" force that counters the downwards forces. By adjusting the speed and/or hydroplane angle, these forces can come into balance. This is a stable condition as any increase in depth creates more upwards force on the aerial and vice-versa. So I can usually cruise around the lake with only the top section of the aerial visible.
Not perhaps as sophisticated as the static diving models but I figure it's 80% of the fun for 20% of the cost and effort?
The plans for Nixie were published in the Oct 2017 issue of the magazine Model Boats.

Originally Posted by wattechighland

Thank you.
Each degrees are case by case.
Basic way of thinking.
The bow plane has big angle and wide area.
The stern plane has little angle ,because screw slipstream strengthens the power.
Each plane doesn't work ,when dead slow ahead.

Have you taken into account the effect of your anti-roll keel device? They are dive planes themselves. Why not try removing them temporarily to see how your sub behave without them.

Originally Posted by redboat219

Have you taken into account the effect of your anti-roll keel device? They are dive planes themselves. Why not try removing them temporarily to see how your sub behave without them.

I wasn't installing keel device by the first test.I-401 couldn't submerge smoothly at the beginning.
Because water line was set lower than setting for good appearance, it was easy to roll due to motor torque.
The keel device is installed so as to assist downforce of each plane and to perform anti-roll, so to lower forward speed.Everything is balanced and a smooth dive becomes possible.
When a submarine floats on water, the keel device isn't seen any more.There is nothing to worry about.

German export sub type 209 Simpson with compressed air diving system.
200 cm, 20 cm diameter, 46 kilo

SIMPSON Typ 209 by Pressluftjunkies.net (3 min 14 sec)

Wow great driving! It's like you've done that before!....Kidding aside, awesome sub!

I modified the 1/150 scale U-boat of Doyusya into a submarine capable of static dive with a tube pump.

1/150 U-boat static dive RC submarine (5 min 9 sec)

Swap meet find of the decade. Complete D&E Skipjack with WTC. Pretty excited.

A bit off topic but I have to share-saw this on a local pickup truck...loved it..

A little something I made a few years ago, the TopGear Bond special Lotus car. This was an actual real car modified to go underwater (as opposed to the film Lotus which was a hollow fibreglass shell with divers in it). It dives Dynamically, and although there are wagglers at the rear they are useless as the thing is so heavy. Steering is by differential prop thrust, (Tank steering), and the downwards thrust comes from the slope of bonnet and windscreen rather than having dive vanes. It dives really easily and stays under incredibly well, even when turning (where it remains flat, no banking).

Simple two channel control. bank of LED`s under the front completely ineffective in lighting up the bottom of the pond.

Ashley

Originally Posted by wattechighland

I modified the 1/150 scale U-boat of Doyusya into a submarine capable of static dive with a tube pump.https://www.youtube.com/watch?v=vKiWTh7Osk4

Congrats on your diving system!

Could you, please, give and show further details on the pump driven by the servo?.

Thanks in advance for your attention.

Jesus Cardin

I second that... would love to get a better look at a servo driven 2 way pump. that's cool!

1/150 U-boat VIIc late afternoon cruise (4 min 13 sec)

I'm glad if you can use it as a reference

https://blogs.yahoo.co.jp/wat_rcair/41161970.html

Like a peristaltic pump? Very clever!

Did you make provisions to compensate for the increase in pressure inside the hull when the syringe is full?

The inside of the hull is kept under negative pressure so that cracks do not enter the bonded surface of the hull.
Before closing the hatch, fill the syringe with water or air, so leave it full.
Close the hatch and drain inside the syringe before operating.
Linkage and Stern tube are sealed to prevent leak.