Thor Seawolf build - 1/96th scale with working fish

[RCSubGuy]

I just finished up a buildup of a nice little Thor Seawolf for a customer of mine.

The build featured one of Mr. Grumpy-pant's awesome cylinders and a pair of Caswell torpedo launchers. Bench and trim testing went really well and I hope to have a maiden voyage under my belt by this weekend, weather permitting (it's supposed to rain for the next while down here in sunny Florida!).

This video is more of a technical overview, but some of you might find it of interest. I also have a few seconds of video showing the torpedo testing in my pool. It was tricky getting the footage and firing the fish, so don't complain about the cameraman!

I hope you enjoy!

https://www.youtube.com/watch?v=nIOJ6jBQyXU

[He Who Shall Not Be Named]

Bob,

Wow! What a job. Beautiful work, as always. Excellent production values -- the hat-cam permitted spot-on focus on the topic at hand and gave you the flexibility to handle the model and associated stuff without dodging around tripods or having to put down a hand-held camera.

However, you so-and-so, as I watched, I saw that rubber bag within MY SD and went ballistic; I felt violated ... violated, I tell you!!! But, before instinctively stomping the cat and breaking any thing within reach I heard your narrative. Thank goodness!

Now, I see: you're using the bag as a means of displacing a fixed amount of water to tune the SD's tank volume to suit the boat. Very crafty, Bob. You had me going, for a few seconds there. I thought you had converted the thing to RCABS. Yikes! Careful with that flexible air-filled bag, as you go deep it will compress, letting more water into the ballast tank; the boat will loose displacement and will go negative on your. But, you already knew that. And that death-spiral is only an issue with significant depth excursions as you know.

I recommend a more positive acting closure to the upper hull; magnets may not be enough if you blow a flexible hose on the up-stream side of the on-board bottles gas restricter. It'll happen like this: You're in a warm lake, the hose blows, the over-pressure within the hull pops the upper hull clear of the lower hull, the upper hull floats to the surface (all that foam), the lower hull sinks (lost all that foam). Hope some of that gas found its way into the ballast tank to discharge enough water to float the lower hull. If not it's mask and fins time. I recommend a screw fastener somewhere up forward. The capture lip back aft is good enough.

You and Alec and others here are convincing me, through your good works, to try my hand at pastel chalks again. The results you guys demonstrate on your models all but sells the technique.

The underwater shots of the weapon launches shows the continued instability problem the 1/72 torpedoes have: broaching, diving, slewing around -- anything but a straight run. You were kind enough not to state the obvious with the narrative, Bob. But, know that I'm still working on it. Currently I've made a 'super buoyant' lot of these weapons: I've reduced the wall thickness so they will make the surface immediately after launch, once in surface-capture they should run hot, straight, and normal. I'll be testing the first batch next week. And a very nice job you did installing the launchers and working out the linkage -- your usual well thought out and executed engineering on display there, Bob.

And don't sweat the larger than scale weapons -- the SEAWOLF class is supposed to have 30-inch bore torpedo tubes, so the 1/72 weapons your using have a viable excuse for being aboard this 1/96 scale model. Funny how things work out sometimes, huh?

You have inspired me to complete my almost done Thor 1/96 SEAWOLF kit (guess who did the scribing work on that master back in the day?) that has been languishing on the pegs for nearly ten years.

And there was so much information crammed into the collage of in-work photos at the end of your presentation. Most informative. Looking forward to the in-water video, Bob. Well done, sir!

M

[crazygary]

Beautiful model and a most interesting and instructional video!
Many thanks for your post!!

CG

[RCSubGuy]

Dave,


Thanks for the kind words. The proof of execution will come in the maiden voyage this weekend. It's one thing to have it working in the pool in a static situation, completely another to put some speed to it and see what it does.

In regard to the torpedoes, you really need to stop beating yourself up. The system that you designed is stunning and works right out of the box. It's simple, elegant, and functional. Can't ask for anything more. My only gripe is that the stock brass springs are weak for pulling the breech back. I had to add additional springs to give it a very positive movement.

In regard to the torpedoes themselves, I think you've got good capacity in the existing design. I would suggest that perhaps we can look into a way to reduce the throat even more. You've got a hairline opening there right now, but even with that the torps escape the tubes like rockets and can easily propel themselves several feet once they breach surface. If we could get that throttled down a bit more, I think we'd get a bit better scale speed and a more controlled path.

In my (admittedly limited) experience, I would guess that we have a couple of issues at play:

1. The discharge air creates a void upon launch which allows the weapon to skew in a random direction as one end or the other "falls" through the bubble until it catches water. It would be awesome to have a super slow motion camera that could catch the whole launch in detail. My limited video arsenal doesn't allow for it, unfortunately.

2. I really think that straight fins are the way to go. When I was experimenting with my 32nd scale fish for my Type XX1 build, I found that canted fins were detrimental to performance, especially once the torp was on the surface. What happens is that the lower fins bite water while the upper ones are in air. What you end up with is a rudder that steers the torpedo in a constant arc. My torps with straight fins did much better for straight, long range shots. This seems counter-intuitive as rifled bullets fly straight and true in air, however with a semi-surfaced torpedo, I think straight is the way to go.

My next build is a 32nd scale OTW Type VII with twin tubes fore and one aft. I'm going to steal your design in a bigger scale for these and hope that the experiments will prove out my theories.

[RCSubGuy]

This is the video of my 32nd scale torps. You can see that the fish run at a really nice speed, but steer constantly left as this fish has twisted fins. In later testing I found that straight fins gave (near) perfectly straight shots. The throat of these torpedoes were made from 1/16" brass tubing that was crimped nearly completely shut.

https://www.youtube.com/watch?v=eJSDxh2n3fc

[trout]

Bob,
Really enjoyed your overview of the sub. Well done. May I ask, should you do that again or even just get some PVC and create a short video on how I did this painting, weathering techniques, it would be helpful (Like you have done for the Nautilus).
When I read your posting on another site and I saw Mr. Grumpy-Pants I could not stop chuckling over that statement. All politics aside, these sub-driver units are well built and very flexible for different subs. I like seeing modifications that you made and others like Mark are doing. Thank you for the quality of videos you do and the innovation you demonstrate!
Peace,
tom