Scaleships Akula II

[Peter W]

Mr M, thank you for the answers. So the Skipjack one and not the 30" long generic 3.5" SD. I assume that the bigger one is just too big?


Peter

[He Who Shall Not Be Named]

Starting to seriously think about an SD for the Akula now. For those of you in the know I assume that the 3.5" SAS is the way to go with the single motor bulkhead kit?

I also have very daft question to ask, but how does the vent valve work exactly?

Peter

It works great. Thanks.

It's a rubber element pushed onto the valve vent seat by the round-head of a 2-56 machine screw. That screw pushed up and down by a servo operated linkage-arm

[He Who Shall Not Be Named]

Starting to seriously think about an SD for the Akula now. For those of you in the know I assume that the 3.5" SAS is the way to go with the single motor bulkhead kit?

I also have very daft question to ask, but how does the vent valve work exactly?

Peter

This beast demands the 3.5" SAS type SD: http://www.sub-driver.com/sub-driver...ub-driver.html As this thing is already assembled all you need is outfit it with the devices, drop it in the hull, and go make the lake safe for Communism.

It's got about 30 ounces of floodable volume in the ballast tank. More than enough to float that thin-walled AKULA of yours (now that you've hollowed out that god-awful egg atop the rudder!). Give me your wallet, walk away, and no one gets hurt.

From those of us in the know.

M

[Peter W]

Starting to seriously think about an SD for the Akula now. For those of you in the know I assume that the 3.5" SAS is the way to go with the single motor bulkhead kit?

I also have very daft question to ask, but how does the vent valve work exactly?

Peter

[HardRock]

Akula holes! I see what you mean peter about the scribed lines on the sail not matching up with the plans. I'm glad that I read that on your post before going ahead like a maniac.

[Subculture]

The hollowing out looks fine. You would need to keep a bit of thickness in the pod, as the plastic is unreinforced, so I think you've gone as far as you can.

33 grams probably doesn't sound much, but right at the end of the boat , it seriously throws things out of whack. Also it's almost 7% of the boats ballast tank displacement, assuming you use a 500ml tank. That probably sounds a bit more impressive.

[Peter W]

Scott, on reflection it wasn't too differcult doing the brass this way just time consuming and it has worked a treat. This hobby will throw up different ways of doing things. I do have to CA them from the back yet using baking soda to cure the glue as directed by Mr. M.

I have to also say that scooping out the pod wasn't as hard as I had feared. As we communicate now I am starting to plan and do the vents to make it free flooding.

Peter

[HardRock]

Scott, I think I went for the harder 3rd option. I cut the holes smaller than the vent and then used a diamond burr to rebate the hull. I , rightly or wrongly, felt this would give more strength to the bond between brass and CA.
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Slow and steady work but good results IMHO. The tricky bits using this method are the rear access hatch part no. 10 ( that one was heart in mouth stuff because of the aggressive nature of the tool I used) and the front and rear round things part no. 5. Any minor over runs with the burrs just got filled with Red Acryl Filler ( my favourite product recommended to me of 2014)

[ATTACH=CONFIG]29434[/ATTACH]



Andy, does my effort on the pod pass muster then ?

Peter

The third option! It must have been a bugger getting the gratings flush with the deck. At this stage I might have to leave the gratings for a time whilst I bone up on pulling a mould of the towed array "egg".

[HardRock]

You'd be better off using old school methods. 3D printers are good for some things, but producing low displacement thin wall components isn't one of them from what I've observed.

If you want a really low displacement piece, pull a two part tool off the original solid item you have, and lay up a super lightweight epoxy glass laminate. This will be very strong but should only displace a few grams at the most.

Sounds like a better plan. Have to bone up on mould making.

[Peter W]

Scott, I think I went for the harder 3rd option. I cut the holes smaller than the vent and then used a diamond burr to rebate the hull. I , rightly or wrongly, felt this would give more strength to the bond between brass and CA.

Slow and steady work but good results IMHO. The tricky bits using this method are the rear access hatch part no. 10 ( that one was heart in mouth stuff because of the aggressive nature of the tool I used) and the front and rear round things part no. 5. Any minor over runs with the burrs just got filled with Red Acryl Filler ( my favourite product recommended to me of 2014)





Andy, does my effort on the pod pass muster then ?

Peter

[Subculture]

You'd be better off using old school methods. 3D printers are good for some things, but producing low displacement thin wall components isn't one of them from what I've observed.

If you want a really low displacement piece, pull a two part tool off the original solid item you have, and lay up a super lightweight epoxy glass laminate. This will be very strong but should only displace a few grams at the most.

[HardRock]

Hey Pete,

I feel your pain. Not that I'm afraid of hard work etc etc, BUT, I'm planning to break out the 3D printer and run up a new hollow egg. Meanwhile, I have been venting. Wondering if you made use of the indented edges of the vent holes as a mounting flange for the brass inserts or cut the whole thing out to get a completely flush fit with the hull. I've done both and the latter seems to require less work. Thoughts?

[He Who Shall Not Be Named]

If you butten it up, you have not reduced the displacement of the thing one bit, and the exercise was for naught. It's gotta flood when submerged.

Put your drain-flood hole under the rudder where it won't be seen, and put one 1/8" diameter vent hole at the extreme high point on the egg. Done.

Good work, pal.

M

[Peter W]

Ok, took a grip again and have done the hollowing out thing.


The planned cut

The cut, new xacto extra fine blade required now it is well and truly blunt now.

Started the material removal with this 22mm (3/4") scotia 1/4" drive router cutter

The result

After using a variety of drill bits, a mini drum sander and a few diamond burr bits I have done it. Now do I have it free flooding or sealed ? Free flooding does mean lots of unsightly holes. I have managed to get the weight down from 52 grams ( 1.8342 oz) to 29 grams ( 1.0229 oz ) and loss of 44%.


Peter

[HardRock]

Jeezus H. Christ on a crutch!!! .... what is it with you complexity worshipers anyway!!!!!

Do as I say. At the very least, do what Andy says.

Don't make me come over there!

M

Yes Sir. Right away Sir. Three bags full Sir!