Trumpeter Seawolf Start

[danl]

Steve, Tim,
Thanks for the nice

Steve, Tim,
Thanks for the nice words. Hope I can add something new to the hobby as I learn more from all of you.
Tim, you'll have to come over for the first sea tests...

[tmsmalley]

Let me know when you

Let me know when you have the hot tub/test tank ready to go, and I'll be there!

[landlubber]

Sorry Big Dave didn"t mean

Sorry Big Dave didn"t mean to check you up. Your likely suffering from a case of sub-basementittis ,only cure I've found it to float your boat somewhere sunny and warm for 6 months.

[bigdave]

Not a problem Kent! Please

Not a problem Kent! Please knock some sense into me. Anytime
I need all I can get.
And Tim, no Speedo's You don't want to frighten the submarine.

[crazy ivan]

For example, Dan took an

For example, Dan took an inexpensive ($70) beginners Vac-U-Tug kit and turned it into a thing of beauty including his own design of high-output smoke generator!

You see that, Larry K.? Better find out how he did that!

[bigdave]

Don't give Larry anything more

Don't give Larry anything more to think about CI!!!!!!!!!!!
He need to be working on a certain Akula!!!!!!!!!

[danl]

Dave, how big is your cheater?

You mention a cheater rudder that clips on the Seawolf. Could you post a pic, please?
I took a shot at one, attached by pins at the bottom and a rubber band (drawn in) to hold it in place. Better ideas?

[danl]

WTC alignment - lesson learned, I think...

With a WTC that has different dia tubes, rotational positioning of the double endcaps is crucial to alignment.
The pics show it if you look at the edges of the 4ft level that I palced the tube on. Look at the edges of the center tube relative to the edges of the level.

I'm trying to line it all up now after install of all the components (the blue tape subs for the o-rings during alignment). Better advice, I think, assemble the tubes and endcaps before any holes drilled, components mounted and carefully align the tubes on a level or other device that will evenly cradle the tubes for alignment. Then mark top center marks on all pieces for later reference. All machining, drilling, etc then needs to be indexed to those centerlines.

I can align everything, but it was a sloppy and inconvenient way to get there.

Ah, you ask, how did I notice? I was assembling the WTC on a flat countertop, and the sucker would roll. Got me to thinking that's what it would do to the boat, and not only front-to-back weight distribution, but rotational weight distribution and alignment wre critical too. As I figured out things were a bit cockeyed, I realized that teh WTC would have to be reassembled in EXACTLY the same rotational orientation or the balance would be different every time.
Wouldn't that drive you crazy at the pond...

[bigdave]

Hi Dan,
You should always

Hi Dan,
You should always try and have your heavier components in the bottom of the WTC if you can. But this is usually not the case in the real world. Things have to fit first before balancing comes into play. This is where your keel weight comes in. You try to design the cylinder with some reserve bouncy so it will need more weight to ballast out. This weight is placed (usually lead shot) in the bottom of the hull in the keel area. This will keep the sub from healing over and compensate for any out of place weight in the WTC. I also put marks on the end caps to show the orientation of the caps when assembling. Your cheater looks like it will work fine. I will take a photo of mine and post it. BD.

[danl]

Almost done with the Seawolf!
A

Almost done with the Seawolf!
A few questions please:
1. For the SubSafe, I hooked that into the servo that both pumps air and vents air (pump and Schrader valve). How do you set which way it goes when activated? Wrong direction would send sub deeper rather than surface it.
2. I have a port for adjusting teh APC4 - how often does it usually need adjustment? Just seems a PITA.
3. How do you set up channels for speed, rudder, planes and dive? (left stick, right stick, etc) Saw a post on this, but can't find anything on it now.
4. Any pre and post-dive set-up/maintenannce procedures recommended?
5. Reco's for a carrier/stand?
6. Bought some $1 bellows at bike shop (for brake cables)- very small size is great, but seem very stiff. Are the control link bellows you use very soft and flexy, or pretty "stiff".
7. Antenna inside WTC or out? Can go either way - pros/cons of external antenna?

Status:

WTC:
Everything is in place in the WTC and its all together except for the receiver and battery pack. Bought a Polk Seeker and Tracker -waiting for delivery.
With an APC and Subsafe, this small WTC is pretty chock-full. Already thinking of a rebuild with shorter mid-tube and slightly longer rear tube for more battery space (your thoughts, Dave???) As it is, I don't think I'll get the 6AA Nihms in with the receiver. Will probably go AAA's and maybe make the tube mods later. Also, ordered the S10 ESC, thinking it was pretty small. Had already installed a Mtroniks Viper Marine 15, thinking I'd change to the S10 when it was delivered. But the S10 was as big as the Mtroniks, and the Mtroniks has a BEC - the S10 doesn't, so I left the Mtroniks in place. Darn, now need to build another sub to use the S10.

Hull:
Pretty much done, except for sail and periscope mechanism. Control surfaces look good and mechanically work well. Each of the fins was filled with JB Weld/microballoons - they are nice and solid. Spent ALOT of time cutting and placing hull alignment tabs and locking tabs, but have a very smooth latch down now, and very tight hull seams.
Next steps is dumping the full WTC in the tub for a leak check, then an electronics check, in-water run and then paint.

Many thanks to Dave for the great WTC kit (the CAD drawings are essential!) and help, to Mike and his wife (sorry - name again?) for the shopping trip by phone, to all who gave me feedback, and to Dave M. (for the painting article) who I am going to try to copy in the finishing/detailing.

Now this sucker better float...

I'll post pics later. Thanks.

[tmsmalley]

A lot of guys use

A lot of guys use the Subtech seals for pushrods Dan. I use them with my RCABS with no leaks.

The people that use bellows (in North America anyway) tend to use Dubro bellows - (Hub Hobby usually has them in stock in the TC area - otherwise Tower has them too.) They are much more flexible than bike brake cable bellows.


SubTech seals




Dubro 3108mWatertight Seals at Tower

[danl]

All electronics tested and operating.

All electronics tested and operating. Weight added and into the tub - took awhile but got her trimmed well. The heavier 6 x AA batts were no problem - ended up making a 5/8" longer battery tube for extra room and shortening the center tube. Had to add more lead than I thought - 8.5oz.
Surprised at the very very small amt of air that causes dive or float - just a "burst" not even a second long. Is that normal?
The boats not moving in the tub, and only maybe 10" water. Hope bouyancy control easier when moving.
After open water testing this weekend - if the weather holds here - paint and periscope details will be addedto finish it off.
Any advice for the first time out to the pond?

[tmsmalley]

Keep her close to the

Keep her close to the pond's edge so if she won't come back/up you won't have to swim in 34 degree water

[Guest]

Robbe bellows are jolly nice

Robbe bellows are jolly nice too-



Andy

[danl]

Bouyancy control improvement

The RCABS approach in a small boat like the Trumpeter Seawolf doesn't give very pecise or repeatable control of bouyancy.
After a lot of playing around with trim weights, bag shapes and configurations, etc, it seemed to me that two things were causing most of the problem - 1. Residual air in the bag/variable bag geometry due to air shifting, etc and 2. Way too much air volume from just a touch of a burst from the air pump.
So...I filled the air tube right at the point it enters the bag with epoxy and then drilled a #80 hole thru the plug. I'd make it even smaller if I could. Result is that the air flow both into and out of the bag is somewhat slowed, making the control of bouyancy a LOT less touchy. I run 7.2V to the airpump - lower voltage and a smaller pump would also help.
To make the bag deflate more uniformly and to give it a more unvarying geometry, I completely covered the bag with rubber bands. The bands go around the acrylic tube and hold the bag flat against the tube. The air pump has plenty of power to still inflate the bag. The bag empties more evenly too. The problem of more air in the front or back of the bag as the sub points up or down is also minimized, as the rubber bands have more effect on bag compression than the small depth induced water pressure difference from back to front. Seems to be less effect too on the bag compression/expansion as overall depth changes. Another big deal was that with a rubber band compressed bag, my lead ballast weight came down appreciably.
These are two pretty easy mods and seem to have made a big difference in controllong depth/attitude.
A prob Istill need to run down - at a hover in the bathtub - total water depth 11", hover about midwater - the sub will start to slowly sink after about 45 seconds. No bag leaks. Is air flowing back thru the air pump? Is there a small check valve that can be used?