After a lot of tests and trials, I've finally finished the WTC for my SCALE SHIPS AKULA II. First of all, forgive me for one thing: Although there's plenty of job to do so far, I've applied a coat of color (after one of coachbuilder primer) to the sub because she looks very much better tha in grey. The ballast system is with a 750 cc ENGEL piston tank. And of course is clearly insiperd in the thread by Ramesh. By the way thank you for your answers to my questiosn about.
After dry checks, made one complete test in water. Everything right at the begining, but leaks detected through the shaft seal and one of the rear plate nuts when started a cycle of ballasting and deballasting. Perhaps one of my mistakes was that to avoid the build up of pressure inside the WTC, closed it with the piston tank in the "ballasted" position.
Here you have some images of the WTC, the linkages of the rear planes, rudders and propeller and how the WTC sits inside the hull. Also a pic of the fore planes fittings, which are operated by the servo and manget mounted on the fore closing plate of the WTC. ALso in the fore plate is the "trigger" for switching on and off.
The WTC is closed with nuts, washers and o rings; o rings are also mounted between the tube and the closure plates. It's fitted with ADC (linked to the fore planes) and APC (with the rear planes). ENGEL piston tank has a safety system which blows the tank in case of signal lost.
I have no lathe, and the plates for the WTC were made from a plank of PVC, rounded using a drill and tested for fitting inside the tube. The "quality" of the results are clearly visible so, please be indulgent.
Regards from Madrid