SSN21 - 1/72 Seawolf

[ManOwaR]

Hi John,
Looks very good, man! I'm particularly pleased at the amount of ballast tank required (or lack thereof). That means success in my book! As for the shaft issue that you have addressed I actually designed the solid stainless shaft to end just forward of the bearing bulkhead leaving enough metal for a universal socket to attach to. The length that spans between this socket and the Sub driver drive socket is to be taken up by the 'cut-to-size' hollow 7/32" tube. The supplied nylon dog bone is cut in half, inserted on both ends of the shaft, drilled through and pinned in place with wire. This gives the Wolf and easy to remove and re-install intermediate drive shaft. To bolster the hollow tube further if required, a solid 3/16 rod can be cut to size and placed in between the dog bone ends.









Joel

[Slats]

Nice Joel.
Darn - I wished I twigged to that feature before. Anyhow I'll know for next time.

Have you done any in water tests Joel with running the boat up to high speed? I am just wondering about any vibration caused by in effect creating a 9" dogbone. I had prior to sourcing a long shaft an intermediate shaft with two universals either end. Admittedly that has more flex in the universals than the dogbone but high speed static test saw the whole thing let go quite dramatically.

Best
J

[ADDINGTON]

Regarding driveshafts and dogbones, my 1/96 Seawolf used the David Merriman design of a short steel shaft passing only thru the pumpjet portion with bearings on either end of the pumpjet, the forward end of the shaft extending far enough for a U-joint accepting a hollow aluminum dogbone longer than the 9" inches seen in Joel's photo. I relate this because this setup produced no significant vibration. Throttle commands were instantly translated and the jet was very thrusty. My guess is that Joel's setup will be similar.
Great stuff here-thanks again for sharing,
Kerry

[Slats]

Excellent information Kerry. And an easy fix too should I decide to remove that extra bearing / support across the hull.
Thanks
J

[Slats]

First order of business was to set up the drive shaft as Joel intended. Here you see the long dog bone.
In water tests reveal she works a treat.



Note also in the photo the quick release system I have to to the snort snorkel line using a piece of fuel line tubing.

[Slats]

I always keep the odd sprue from aircraft kits as they often come in handy. Here I have cut up a clear sprue that once held an aircraft canopy. Applying Tamiya clear Red on this the port side and clear green on starboard these sprues are glued into the sail.



Starboard side






Flooding the dry dock / test tank

[Slats]

Test thoroughly your SD. I also strive to try and get a 50/50 weight distribution of the SD. This one when the tank is full is perfectly distributed. Given that the SD's ballast tank sits on the COG / COR point a SD that is well balanced itself contributes to overall ballasting effort.




The 3.5" SD employed on my Seawolf - opened up after some testing

[Slats]

In the tank - a little above the Surfaced WL at this stage


The setup dived and with full gas charge is a little positive which is just the way I like it.



With the gas tank running low:


In the tank and a little positive - and a full inch clear under the hull. The Seawolf is the most voluminous hull I have ever submerged in my tank, and the only time I have ever need to have the test tank full to the brim.

[Slats]

We have thrust gentleman and lots of concentrated thrust. TIP : order the carbon fibre prop from Joel, in water tests on full battery indicate a lot more thrust than the white metal prop. I am sure the white metal one provides more than adequate thrust, but you also get a significant weight saving which is quite a distance from the COG / COR.

Full ahead


Half ahead


bad photo of close up swirl at Ahead one third

[Slats]

Conclusion to the build.
You get an awful lot of bang for your buck with a kit from Joel Stadnick. This is my third sub from his stable of hand crafted masterpieces and I have made no secret that Jim Russell and I have pre-ordered the 1/72 Astute. The kit is pretty much complete. If you wish you can even fit Joel's pre supplied rotating deck cleats. The periscopes and every conceivable scale detail is supplied.

The completeness and quality of how well the parts come together mean that Joel's kits can be built by just about anybody (beginner through advanced), providing you have some street smarts around hand tools.

The first opportunity I will get to run this boat will be the Australian Sub Regatta, in two weekends time. I provide a full report as to how the boat performs soon after.

Now Joel get onto that Astute mate. :wink:

[He Who Shall Not Be Named]

John,

When you slammed the throttle around in the test tank, did you observe any torque roll? If so what direction was the roll going ahead, and directon of the roll going astern?

Excellent work. What a beast! You've done Joel proud.

David

[Slats]

John,

When you slammed the throttle around in the test tank, did you observe any torque roll? If so what direction was the roll going ahead, and directon of the roll going astern?

Excellent work. What a beast! You've done Joel proud.

David

Very little torque roll David, but a big reservation is that the boat was being held forward by two large foam blocks to protect the boat from slamming into the tank sides. An unrestricted test is required. Happy to add that aspect to my report.
Thanks
J

[alad61]

G'day John,

I've been sitting on the side watching this thread and I have to say simply... STRUTH thats impressive. To see the finished boat & build up is certainly an insperation to a newbie like me. Envy also rears it's head a bit too LOL.... I would have liked to go to the regatta but with easter falling on the wedding aniversary & me spending many week night hours on the Seaview my lovely wifes good will to Alec clause is nearing expirery :P

I'm looking forward to your regatta report.

[Slats]

Thanks Alec, shame you can't be there. Have a great anniversary.
Best
J

[Slats]

Well the Australian Sub Regatta is always and awesome event, and having Seawolf hit the water for the very first time was very special.

Turning circle submerged was better than I expected. About 3m radius which for a boat this size I consider good. Surfaced turning like all nukes was poor. But you can improve this a lot by pulsing the throttle between a little burst of power and then letting the boat drift.

Lots of video onboard was taken via that great little Casewell video unit. I'll post that shortly.

Here are some great photos - taken by Craig Talyor-









Skirting through the Pat Drake Mine Field








Tomahawk Launch - Dr David Batagol at it again :biggrin: