My AKULA is my next project so thanks very much for that, most interesting!
Hello Martin, I spend all I have prepared for textoque magazine Subcommitte for you to work on his Akula.
IMPROVING THE MODEL TURNING RATIO
There’s no better satisfaction than, after having our rc submarine floating on the surface of a crystal clear pond, ordering immersion command until leaving it hovering at a desired depth, wait a few seconds to confirm even keel level and then follow command with the sub’s slow harmonious glide through the water depths.
A problem arises however, when trying to make a turn at such a slow speed. Our model doesn’t respond to our radio command, being forced to increase throttle to be able to make the turn, losing this way the charm of that harmonious glide through the water.
This problem gets particularly aggraviated in the nuke type models given the screw placement behind the rudders, even more so if the nuke model is of a long stern.
For this purpose, and to improve the turning ratio of our submarines, I offer you two very simple ways to improve the maneuvering of our models’ slow turning ratio, without having to increase throttle (speed). I’ve installed the two different systems in both the Akula and Trafalgar (by Sheerline) respectively, with amazing results. Now, I can navigate in any lake or pond no matter how small.
This, more than a system, is just a little trick for smaller models where internal room is rather crammed or tight to work in. The trick consists in prolonging the diving plane by using a piece of methacrylate anchored by small sheet metal screws. (photo 1)
This system, which is my friend Xavi Grau’s idea, consists in using a small thruster installed in the bow, for a more precise bow maneuvering. Although it appears complicated at first, is in fact rather simple and practical to do, as I will show you.
Utilized materials (photo 2)
• Two 12V water pumps, the type we can find in any store specialized in outdoor camping.
• Two stop switches
• A small servo
• Four pneumatic connectors, 4mm diameter
• Pneumatic tubing, 4mm diameter
• Tubings, with an inside diameter 6-8 and 10mm
I’ll use the example of my Akula by Sheerline models.
a) Water pumps. Strip off the plastic of the electric wires, separating them and encapsulating them over each of the two (4mm) pneumatic tubings and 4cm long. Sealing the connection by using vulcanizing tape. (Photo 3)
At the exit of the water pumps, insert the different hoses of 10-8 and 6mm diameter.
Note: the water pumps, although 12V can perfectly work under 6V. My Akula
Sheerline uses a 6V electric system.
b) WTC end cap. Drill four holes with the same outside diameter of the pneumatic connectors. Fit the pneumatic connectors into the drilled holes and seal them in place with CA. (Photos 4-5)
These pneumatic connectors could be substituted by pneumatic end cap drive-thrus. The reasoning behind this is to run the water pump wires through to easily place and organize all the components.
c) Switch board. We’ll construct a small switch board out of a plastic plate (lexan)to place the two stop switches and the small servo (photo 6).
These elements will give the “on-off” commands to the water pumps. Last, we’ll connect the water pump terminals to the stop switches, and to the positive and negative of our model’s battery. (Photo 5)
Thi system can be substituded by any other electronic system that feeds the water pumps.
d) Water pumps placement. Before installing the water pumps we need to dril two 9mm holes in the hull, one on each side of the bow to pass through the 8mm (ID) tubing by 3cm long (Photo 7-8). Place the two wáter pumps behind the WTC and connect the 6mm tubing through the 8mm tubing before mentioned, placing in between a little collar with a 10mm tubing to reinforce it. (Photo 9). Lastly, we’ll cut off whatever extra tubing of the 6 and 8mm. (Photo 10)
e) Trimming. Before putting our model in the water, we’ll need to trim the model positively to compensate for the extra water pump weight.
f) Radio equipment. Making the pumps work can be done in different ways. I use a dedicated channel for this purpose. And having a digital radio, I can mixed it with the rudder channel, enabling me to actívate the water pumps this way too.
Rushing to the pool for trials.
With the boat on the surface we command forward ahead while giving at the same time the command to turn using the pumps, the results are amazing, works perfectly: slowly and smoothly. We stop the boat on the surface, and give a static diving command, stopping the boat at mid depth. While activating the pumps, the boat turns around over its axis in full circle, just amazing. If a command is given to move forward and turn, the submarine will turn smoothly and majestically. If we increase spped and give command to turn using both the pumps and the rudders, the pumps overrides the rudders into the turn, simply perfect.
Finally, we can conclude that the proposed system is very economic, simple and easy to build. The pumps, placed in the wet area outside the WTC don’t take up needed space inside of it.
I’d like to extend my gratritute to Brian Bejarano, Subcommittee member, for translating this article from spanish to english. Thank you Brian.