Trumpeter Seawolf Start

[danl]

Maybe old stuff, but I'm new to subs and thought I'd jump in with some notes and pics on the build.
Dave W's WTC kit is great for someone getting started. The actual size CAD drawings he includes (done by "holy mackerel what detail!" Ed Szczepanski) make it a very easy build. I'd be scratchin my head for a long time figuring out what Ed documents so well.
Biggest issue for me is getting all the necessary components. I'm writing this to kill time while waiting for backordered parts from Mike's, etc.
Some notes, pics and questions:
1. As noted in other posts, the Trumpeter SeaWolf (TSW) lower hull is too short. I found the easiest fix to be adding a thin styrene strip with a backer strip to the front edge. You loose the lip for registering the hull into the nose, so I added three heavy duty alignment pins. Pic 1.
2. After front edge mods and cutting out all those square holes, I thought some reinforcement was necessary. Roughened surface and coated inside hull with JB Weld, my current favorite stuff. Waterproof, tough, sands/carves very well, esp w/some microballoons added. Drawback - long set time. Pic2.
3. Saw a strobe sitting proud atop the rudder fin in a SW pic, so added a flashing strobe. Its a 3mm superbrite white LED, wired in series with a flashing LED to add the flash. Pos wire runs down thru 1/16th tube used instead of rod for rudder pivot pin. Neg. conductor is the brass tube itself. Wires attached to rear tube cap with mini gold-pin connctrs from surplus place. Pic and prototype pic.
4. Didn't like idea of permanent attachment of propulsor shroud as in other build posts. Added 2 small mounting blocks hidden inside shroud and two ABS strips as screw brackets. Two screws allow removal of shroud and of prop and shaft.
5. A lot of switch options, but this seemed simple and waterproof, but we'll see how it works.
Less than a half inch twist of end cap on tube moves microswitch up small brass strip "ramp" on tube inner wall for power on. Endcap and tube outside wall will have protrusions JB'd to allow thumb and forefinger to rotate the cap on the tube.
6. The air tubing routing looked messy as diagramed. Dave includes a very good quality bag in the newer kits, but the tubing inlet point seems at first to interfere with bag placement. Running just an elbow out with just one tube following the edge of the bag back to a brass "Y" fitting that splits to the two cap fittings makes it neat and easy. Heat the brass tube to soften, cool, bend, file a saddle, solder saddle over a hole in a short straight section and you have the fitting. I covered the solder joint with JB Weld cuz I had some spare made up...
Hope this helps a future builder. I could use any feedback you might have. Thanks much,
Dan

[slugejudge]

Hi DanL,

There are still a

Hi DanL,

There are still a lot of people building and / or planning to build the Seawolf. I am almost finished preparing the hull, built the WTC sometime back. But I have modified the WTC twice since I thought it was finished, once for an adjustable APC ala Dave Merriman, and now the power on switch ala DanL. Also like the reinforcement of swiss-cheesed bow vent area and plan to incorporate the removable prop shroud.

Thanks I will be watching for progress, Rick

[himszy]

Dan,

Why have you got a

Dan,

Why have you got a 5A rated switch inline with a 10A fuse?

Michael

[danl]

Rick,
The rotating cap approach doesn't

Rick,
The rotating cap approach doesn't work. Tried it after the cap was on overnight and it was VERY hard to budge. Not practical for a switch. Instead, installed a through shaft/seal to activate the microswitch.
I'm waiting for delivery of an APC now- what's an adjustable APC?

Michael,
I've always assumed, but don't really know, that a 5A switch at 120V will take much more than 5A at a lower voltage (lower total watts?)
And I'm just guessing on the 10A fuse for now - have no idea what the rating should be other than I don't want it to fail during normal operation.
So - do I need a higher rated switch and/or a lower rated fuse?

Thanks much.

[bigdave]

Very nice Dan!
Looking foreword

Very nice Dan!
Looking foreword to seeing the build.
I just wanted to say there are reasons I have the propulsor sealed. It is only made out of very thin plastic and is not designed to be doing what we are asking it do. Operiate! By glueing the assembly together I was making it a stronger unit. I am not saying your way will not work, as I am anixous to see how your way pans out. The tabs you added will also cause turbulence and decrease the efficancy. I can say that after many hours of use I have not had one driveline failure. One reason is the Rulon bearing that will never need replacement. I hope this approach works out for you. BD.

[slugejudge]

DanL,

I saw the idea in

DanL,

I saw the idea in a thread by Dave Merriman on an Alfa and a Seawolf. To quote Dave," the inclusion of an APC (automatic pitch controller) linkage to set the angular displacement of the unit, for adjustment of the models 'zero bubble' set-point.. The Basic idea is to mount the APC on plate that can pivot with a control outside the wtc to control the attitude of the board without removing the APC or disassembling the WTC. Sorry I do not seem to be able to find photo.

Straight and Level, Rick

[JWLaRue]

Here's the original that "inspired"

Here's the original that "inspired" Merriman to start using the externally adjustable APC. This was something that a friend and I came up with around 7-8 years ago when first building our 1/72nd scale Skipjacks.

This first photo shows how a spare BHS seal was used for the adjusting dial. The dial (knob) is connected to a brass rod, which goes through the bulkhead of the dive module. The far end of the rod is threaded and screwed through a threaded hole in the internal bulkhead.



In this second shot, you can see where the threaded end of the adjusting rod comes through the internal bulkhead and then touches the vertical brass wall of the adjustable shelf. This is attached at it's lower end to the same internal bulkhead using a spacer to offset it away from the bulkhead. The shelf for the APC is approximately halfway between the top and the bottom of the vertical brass piece. The natural spring of the brass means that there is constant pressure against the threaded rod and that there is no "bounce" to the shelf.



With this in place, I have never had any problems doing minor in-field adjustments to the APC...and it means that I do not need to remove the dive module and open it up.

-hope this helps,

Jeff

[crazy ivan]

I've always assumed, but don't

I've always assumed, but don't really know, that a 5A switch at 120V will take much more than 5A at a lower voltage (lower total watts?)

Dan,

That is a relatively safe assumption. Consider too that a switch rating allows for it to be opened and closed while passing the rated current load, which results in destructive arcing across the contacts. This is not how you will likely operate a switch in an R/C model, unless you are prone to slam on the power with the throttles pegged to the max.

[danl]

Dave,
Good thought on the weak

Dave,
Good thought on the weak plastic propulsor shroud needing all the integrity. I bought a spare Seawolf kit on sale. Figured my first sub, I now have spares of all the parts. May have to do the propulsor shroud like you say.
As for efficiency, I already may have blown that. As a first sub, I'm playing around. I reshaped your propulsor, changed pitch and added "belly" to the blades - we'll see what happens.
Also, cut and individually mounted the dive planes. Is that enough control surface area to have with an APC, or is it betetr to leave the plane one piece?

Jeff,
On the external adjustable APC - mechanical trimming? When is an electronic self-trim unit coming out? You know - manually level the boat, power on/off twice and the unit electronically zeros itself.

Thanks

[tmsmalley]

Until a self adjusting APC

Until a self adjusting APC becomes available, a lot of us drill and tap a hole in the WTC right above the adjustment screw on the APC. Install a nylon pan head screw (with a faucet washer between the lexan of the tube and the head of the screw to form the watertight seal.)

To use - Level the sub, then remove the nylon screw, adjust the APC with a long skinny screwdriver so the planes are perfectly level, seal it back up and you're good to go! (don't forget to put the screw back in

I saw Skip Asay install one of these things in Jeff Jones' WTC with an Xacto knife at the pond a few years ago - no other tools!

[bigdave]

I have a servo attached

I have a servo attached to mine in my Nautilus. I can rock the APC back and forth to center it from the transmitter. It may sound extreme but the Nautilus was tricky to trim and it was much easier to do it from the transmitter. I had the capability with my Multiplex radio. BD.

[danl]

Uh-oh....That APC 3 looks soooo

Uh-oh....That APC 3 looks soooo big. Thanks for the picture, Tim. I ordered an APC for the Seawolf, but now I'm wondering if it will fit. Is the board behind it in the picture part of the APC, or did you mount the APC on that board?

Also, what happened to the pics in the firts post? Just the litttle symbol shows up.

Thanks,
Dan

[stark]

Free photo posting, they should

Free photo posting, they should come back later?

Get the APC 4 if you buy one, the old ones work well I still use mine. I liked the APC 1, the box's you can discard, just take them out and shrink wrap them.

I have used RTV to secure the unit in place, or two sided tape them where you want. Adjusting them while inside the WTC is easy to do by drilling a hole over the addjusting pot, and a peice of electrical tape over the hole, works well.

Brian

[slugejudge]

DanL,

I second the APC-4, they

DanL,

I second the APC-4, they are small and work better than the other one I bought. Fact of it I have bought 3 APC-4.

Enjoy, Rick

[danl]

Questions, please...

I did order an APC 4.

Questions:
Should I use a Subtech S10 ESC? Has no BEC as far as I can tell. I have an MTroniks Viper Marine 15 that will fit just fine. Has a 1.2A BEC.

Ordered a Subsafe 2. Don't see it mentioned in other Seawolf builds. Needed?

Plan to use 6 NiMh AA's w/2500 mAH capacity. They fit, but is weight too much?

Have the whole tail section complete, and the rear cyl. (except for the ESC), the front cylinder (except for Rx) and center. Need to string all the wires between them, solder up the battery pack, install alignment/locking rails in hull and install Rx and APC when they arrive.
Made up a working foam float periscope system, but prefer a controlled system. Any simple ideas for this small a boat?

Thanks,
Dan