Toy conversion to 1/230 ALFA

[JHapprich]

Greetings!

This is the continuation of my presentation of making an semiscale ALFA from an old Revell 1/230 SKIPJACK kit.

I started posting about it here:

https://forum.rc-sub.com/forum/build...to-1-350-akula

I doubled the wall thickness of the sail by weld-glueing another layer of 1mm ABS sheet on it. I kept the wooden master inside and applied pressure from the outside so the shape of the sail wouldn't collapse during the process. This was necessary as there still was not enough space inside the sail to accomodate the toy submarine hull inside.

This evening, i made an upper and lower rudder from surplus planes, a new stern cone and i installed the forward diveplanes. The bow was ground a bit rounder. The coolant intakes were made from an unused external fuel tank of an airplane kit.

The last picture with the NOVEMBER's stern to the left showing the tiny dimensions of the model of about 30cm!



Jörg

[JHapprich]

Hi there! I continued completing the sternplanes that will only need sanding and sealing with resin. The auxilliary thrusters were added, the planes tips will come last. The sterncone with the shaft bushing was glued down. The hull was split using a z-cut. I made a small 4-blade prop from brass tubing. A 2mm tube for the core, 2 peices of 3mm tube were split halfways and the halves were bent to the sides and shaped. Put the 3 parts together forming a "+" and soldered it. Original prop had 5 blades.

[JHapprich]

Update. Since my last post i completed most of the model, with some scribing left and of course painting it. I made a holding fixture for the toy sub's stern. A bayonet-lock creates a socket and the assembly is screwed down onto a spacer nut glued to the hull. I left the "keel" portion at the stern of the toy that locks indo a cross-shaped cut-out of the hull in front of the lower rudder.This keeps the section aligned. With the upper hull in place, it is fixed:



For weight reduction, i made some cut-outs:

[JHapprich]

The hull-halves are joined by indexing lips, a stainless locking bolt screws through two corresponding blocks into a M2.5 brass nut:


The forward planes are glued onto their axis, which rons through a brass tube.their angle can be adjustes with a set screw that can be accessed from the outside with the hull closed:

[JHapprich]

The cable wires of the toy were extended and the hull perforations sealed with RTV. Due to leaking caising damage to the receiver board, i had to buy a new toy sub. Sealing the ENTIRE stern solvey the problem.

[JHapprich]

I skipped the brass propeller as it was inefficient. I figured the small motor could handle a much larger prop and used an 3-bladed (and VERY old) plastic spare that received a brass tube as a core and a plastic hub. Not scale, hardly paintable as its NYLON. The good old 80's stuff that will last forever. I had issues with a rattling driveshaft because the fitted stern tube gave too much tolerance, so i made a tiny brass bushing and replaced the 1,2mm brass shaft with 1mm stainless steel. The bushing was CA'd into a recess at the stern and filled over. A piece of cable insulation creates the coupling with the engine. For positioning and coupling on and off, there is a small opening in the lower stern. However, the prop is press-fitted onto the shaft with a piece of heat-shrink tube and can be removed with some force as well.

[JHapprich]

The two white tubes in the stern end are the "wave-tunnels" for the stern thrusters. They were made grom 1mm ABS sheet, wound around a round core and pressed into the round openings left/right besides the thruster. Weld-glued and filled with CA and plastic powder.

[JHapprich]

I used a lot of "plastic soldering" on that model, e.g. load bearing parts were drilled through and pinned together using plastic rods. With the soldering station set to the proper melting temperature, i then used styrene sprue as a "solder" to melt the parts together. The stern still needs some attention/ grinding/shaping.

I ground the bow rounder and filled it with CA filler from th inside to achieve a more blunt look. I am undecided yet if i should scribe in the tubedoors. This project has already grown bigger than scheduled...

I also made several floodholes at the upper hull. I presume ill add some more and see where i can reduce weight above water level to achieve a nice waterline. I still have lots of reserves in the balast tank volume.

In the picture in the pool, almost no foam was in the boat and it would sink with only three "clicks" on the dive control (RCENGR will know).



HAPPY HALLOWEEN (yes, that's actually me) !



Jörg

[RCENGR]

Nice! I'm interested to know if the bigger prop will impact the motor life. The way you did the thruster tunnel makes me wonder if I should have made the openings bigger on my sub.

This project has already grown bigger than scheduled...

It's mazing how these toys can eat up the shop time, I sure put more time into mine than I ever anticipated.