Akula 1/144 Scratch built

[bwi 971]

I’m working on the yokes.

Challenges

• Pushrod movement rear planes 7mm
• Pushrod movement rudders 10mm
• Need about 35° deflection on the rudders and planes.

Yokes fabrication

• Collars made out of brass, outer diameter 8mm (5/16), rod bore 2mm (3/32), screw 2mm (3/32).
• Bridge 2mm (1/16) brass rod

Work in progress, testfitting the yokes








Bell crank Arm.

In order to get the deflection of 35°, a very short arm was necessary. The pitch could not exceed 6mm. It was impossible to use the usual Z-bent pushrods the rod would hit the collar restricting the deflection to 10°.

I came up with the following construction to make it work.
A brass bushing with outer diameter 4mm (???) and inner diameter 3mm (1/8) was fabricated and soldered to the brass pushrod of 1.5mm (1/16).
An arm was fabricated out of 1mm (1/32) brass sheet. Two holes were drilled in the arm, pitch 5mm.
An pin was made out of 3mm (1/8) brass rod and provided with a hole to take a 2mm (3/32) screw.
The pin was soldered to the arm, and the arm was soldered to the yoke.
The bushing of the pushrod pivots over the pin the screw holds the assembly together, preventing the bushing to slide of the pin.

Ready to solder



All parts



Pushrod connected to pin



Assembled together.





Grtz,
Bart

[bwi 971]

Ok well understood David, Thks.

Design and fabrication progress of the bow planes linkages. Two days’ work…….......need one more day to finish it.......………but work is calling tomorrow DAMN.

Grtz,
Bart


Bushings:
Bushings dia 3mm, bore dia 2mm length 5mm





Supports:
Everything starts with making the required materials, 4 pc of 3mm styrene glued together to the required thickness of 12mm. Sanded everything square/perpendicular so I had a good base to start with. Strange shape? No I have to give room to the Fwd index lip of the lower hull, see below for the assembly.
Cut out the desired shape, provided with 3mm bores to take the bushings.






Bell-cranks:
made out styrene sheet, provided with a 2mm bore in the center piece and the arms are provided with a 1.5mm bore. Pitch is 10mm except the one with the longer arm pitch of that one is 15mm, will see which one I will use (probably the one with the 10mm pitch. That will give me app 30° deflection as per David’s instructions.




Assembly
Test fitting the assembly (parts are not yet completed).

[He Who Shall Not Be Named]

Thanks David, I'm almost back to flank speed.

I need advice regarding the bow planes from you guy's.
is a 50° degrees up en 50° degrees down movement sufficient?
I'm designing on the bellcranks for the moment.

Grtz,
bart

Good. Very good. Keep with the therapy and follow Doctor's orders, pal.

No, 50-degree deflection is way, way too much. Waterborne control surfaces typically stall out over 35-degrees. Anything more is only useful as drag-brakes (one of the maneuvers used for 'depth excursion' casualties, AKA 'fishtailing').

M

[bwi 971]

Thanks David, I'm almost back to flank speed.

I need advice regarding the bow planes from you guy's.
is a 50° degrees up en 50° degrees down movement sufficient?
I'm designing on the bellcranks for the moment.

Grtz,
bart

[He Who Shall Not Be Named]

I so enjoy watching a well done job coming together. You got the hands, my friend! And you're putting out this quality work with only one-and-a-half-arms. Once you're back up to speed, you'll be a first-class threat.

M

[HardRock]

Outstanding Bart. I love the pod.

[bwi 971]

I promised some foto's of the towed array pot, with the wax core.

Grtz,
Bart

Weight with wax 20g


Melting the wax in hot water


Weight without wax 7g


Hollow inside


Wall thickness of shell (showing a pencil point of 0.5mm)


I could not resist to dry-fit the rudders and scoops....she is beginning to look like a sub.

[trout]

That’ said Tom we have to stop praising him for a time now, or he will make sure that we regret we have said all those kind words.

Grtz,
Bart

Your right, but sometimes it just needs to be said. Oh look there is a short pier, I guess we better go jump.

[He Who Shall Not Be Named]

Thanks guy's.

As I see from where I started with making tooling’s (reusable boxes, etc....... see my post #24) and what I'm doing now it is getting pretty damn close to what David is doing.

I adapted things so they match my way of working and to the means I have available, but at the end why reinventing the wheel, you will end in an almost exact copy of what he is trying to teach us here because it took hem years to fine-tune things so they are simple to use, practical and fast.

And I agree that we are to be thankful he wants to share all this with us.

That’ said Tom we have to stop praising him for a time now, or he will make sure that we regret we have said all those kind words.

Grtz,
Bart

Too late. From this point forward soak all packages from Virginia Beach in water at least twelve-hours before opening.

M

[bwi 971]

Thanks guy's.

As I see from where I started with making tooling’s (reusable boxes, etc....... see my post #24) and what I'm doing now it is getting pretty damn close to what David is doing.

I adapted things so they match my way of working and to the means I have available, but at the end why reinventing the wheel, you will end in an almost exact copy of what he is trying to teach us here because it took hem years to fine-tune things so they are simple to use, practical and fast.

And I agree that we are to be thankful he wants to share all this with us.

That’ said Tom we have to stop praising him for a time now, or he will make sure that we regret we have said all those kind words.

Grtz,
Bart

[trout]

Came out excellent!
Well worth the wait and Kudos for following David's advice. It gets to me when someone begs for David's advice, he shares his recommendation, and the person will say I am going to try a different way. I guess it is good for someone to try something new, but for success, just follow his guidance. You did and wow the results are spectacular!

[HardRock]

Well done Mate. You're doing fine job. Hope you are back to full speed soon.

[bwi 971]

Thks David.

Just to let you guy's know that the towed array pot (lost wax method) also worked, weight before melting the wax 20g (0,7oz), weight empty 7g (0,25oz).
Pictures will follow soon, need to clear the living room from sub parts before I get into trouble.

Grtz,
Bart

[He Who Shall Not Be Named]

Well done ... well done, sir! (just passing on what others taught me).

M

[bwi 971]

Today after 6 days of curing I could open the pressure pot and see the result.

I was very happy everything worked out very well.....It's all in the prep gents.
The overkill bushings were encapsulated perfectly and the vacuum casted tiny pieces are incredible, no air bubble what so ever.

Lets not forget that I could not have accomplished this result without the help/guidance/instructions of HWSNBN, THANK YOU DAVID (I think this is worth a big step up the buttshark ladder?).

Grtz,
Bart

Opening the pressure pot


All stuff removed from the toolings


The result


Some details




These pictures were taken in macro focus.