Lil Scharnie winter of 2012 refit

Like 9 pounds or so.

 

Got a lot done today! Mostly working on cannons and firing circuits, some pump work, and random small things. Below is the bottom of the stern deck. The Kip is mounted upside-down to the deck on one side, has to be there to clear the drive motor. Very glad that one can loosen the nut on top of the valve and rotate the coil so that the wires point away from the outrunner drive motor. The positive wire curves back to the leftand under the hold-down, and will get a powerpole connector. It is a straight line from the positive main power bus. The negative line goes to two places: the NO (normally open) connection of the relay card, and to the SPST momentary button above and to the right of the gun in this pic. This is the test button, used for tweaking the guns without having to use the RC stuff. The negative line from the negative main power bus goes to the Common connector of the relay card. The last wire goes from the NC (normally closed) connection of the relay card, over to the test button. What this does is allow either the RC system or the test button to control the flow of power through the solenoid. The relay card is capable of very fast action, certainly faster than 10 cycles/second, which is faster than I can do. So I'm not concerned about a relay vice electronics like a TD card. The relay card is by Basic Micro and costs like $16.95 each (half the cost of a TD card), and one of these did nicely firing a bank of 4 cannons in POW, at 12 volts. Should do fine firing one cannon at 7.2V in Scharnie. Linky: http://www.basicmicro.com/Power-Swi..._p_44.html

Key thing there is that everything is attached to the stern deck, which comes out easily, just the Powerpoles, the servo lead, and a single 1/4" hose to disconnect (and that from a push-quick fitting). Any single part can be disconnected in fairly short order for a replacement if necessary.
Below is the same stern deck secion, from topside. The cannon is not mounted yet, just there waiting to be solidly attached. The little dot inside the barbette is the test button. Fully protected from the evils of enemy fire. The whole setup got tested today and it is fabulous. I was quite gleeful, excited even.

I also got a little done on my Othar-pump. Tiny tiny tiny. The gold cylindrical object between the CA glue and a standard Futaba servo. Half an inch in diameter and an inch and a half tall. Lightweight and brushless. Still have to solder on the brass nuts for the setcrews that hold the pump body on the motor (it fits over the motor case like a sleeve), and the discharge tube. One very sweet looking 1/4-unit pump. I'm hoping for 1/8 gal/min, anything more is gravy. The rotor was a pain, little fiddly bits. But hey, what price can you put on art? Hiding in there somewhere is part of the Tug-pump Mk III.

 

I contemplated dual sterns, but I have more fun with a gun on either end, so that's what I'm building More fun, ja?

 

I haven't posted in a while, but rest assured that Scharnie is progressing. I've got everything in and tested satisfactorily, apart from the pump, which I'm wrestling with in an effort to wring a little more performance out of with tighter tolerances. Easy to get okay performance with a little looser tolerances. But I think that the improvement versus effort to get there curve is an exponentially increasing curve. I'll take some pics tonight of the water channeling and other stuff I've done (rudder, rudder linkage, plumbing, electrical system, ballast, battery bracket, etc). Hoping to get good weather next weekend to allow sheeting so that I can do the final ballasting. She weighed 9.5 pounds last Nats after I added weight on Sunday so my windows would be legally deep enough. Embarrassing! But that's why we check these things, to catch honest errors and fix them. My theory was that I ballasted Scharnie (during the first build) for the windows where they were cut, and in a later rebuild I took some out for some reason and didn't think about it. I share this so that newer people 1) know that people who've done this for a while make mistakes and 2) that they may profit by the example and check their boats prior to big events In my case, the ship was 8.5 pounds when we found the windows 'too shallow'. Returning it to normal scale weight (9.6#) brought it in spec. Another lesson: build light and you'll have room to play if you need it). I expect Scharnie will be a hair over 10.5# in this incarnation, giving me deeper windows than I legally need. Not going to change the windows over it, and the extra weight will help stability. A good chunk of it will be amidships way way low, as well, helping turning and stability at the same time.

Pics tonight!

 

Progress has been slow because I got tired of my old workbench. Hence, a new one has been built. Super-solid, longer, wider, and a much higher standard of craftsmanship than the old one. Pics will be posted shortly (taken but I'm in a rush this morning). Scharnie is almost done apart from sheeting and the pump. I've been wrestling with the pump, I think I'm getting too picky. The impellers work fine slightly out of round, but I've been getting very persnickety about the roundness and I think it's getting sill but I've been unable to let it alone. Maybe an intervention is needed. In any case, I discovered yesterday that the POW pump fits nicely in Scharnie. *Evil grin* The motor is a little bigger in diameter than the drive motor, but quite a bit shorter, too. I can only imagine how much damage Scharnie could take with the POW pump...

 

Heh. I would 1) fix the restrictor issue, in POW's case, it was a quick kludge and didn't work out (lucky BB hit a zip-tie) and 2) It might, it might not, but I'd likely dial back the endpoint adjust on the pump channel. But since I've got 2 duplicates of last year's Scharnie pump (made for the Edgar Quinet lesson to be posted shortly)... I'd rather run one of those and be happy. Last year's pump was pretty awesome for a 1/2 unit pump, so not really a loss. Also, a nice fellow with a lathe made me some sweet tapered restrictors to use

 

Uploading some pics tonight. Got the pump done, hull sheeted, float testing done, pump tested, guns tested, armor in, etc etc. Only thing I have a lot left to do on is superstructure. So get THIS. I found that the old center deck section (the part that lifts off for rearming) fits perfectly (total coincidence, actually) and so I am running the old center deck with old SS while I get the new one all pretty for Nats(x2). Quite happy with the pump. Got tired of messing about with plastic and fumes, wound up doing the exact same basic pump as previous incarnation, PVC body with wood improved several things on it but it looks remarkably similar except for the outlet, which goes vertical.