12" scratch built cat

[Dr. Jet]

Plastruct L section come in many sizes and works well for stakes.

I have some 3/16" styrene angle (equal length legs). If I used that it would look like the attached screenshot. Strakes should actually be parallel to the water surface (although as shown, might actually increase lift by deflecting the moving water downward). Any "L"-shaped pieces would probably have to be trimmed to get them parallel, and the question then would be how to do that accurately for for several pieces up to 16" long?

[Jesse J]

Hmm.. my gut tells me that angles might increase drag. I suspect with that convex shape, not only is there a little more surface area, the deflection (lift) would cause also greater pressure and increase friction. I suspect a little more squirrelly handling too.

But empirical evidence is always welcome. Give it a try.

[Dr. Jet]

........But empirical evidence is always welcome. Give it a try.

Nah.... I think I'll go with table saw cut strips like I alluded to above. Gotta finish the Casper and the Atlas first.

Oh, since you thought the motor mount was a nice touch, I added a servo tray as well.


Hmmm.... Should I make mounts for twin motors??



EDIT:

OK, it was easy enough to make twin motor mounts and lips for access hatches in the sponsons.

[NativePaul]

You can halve the height of the styrene L section pretty easily by scoring down one side with a scalpel against a steel ruler, once scored you can snap it off pretty cleanly.

I would ditch the inner lifting strakes, and just fit the outer spray rails.

[Dr. Jet]

You can halve the height of the styrene L section pretty easily by scoring down one side with a scalpel against a steel ruler, once scored you can snap it off pretty cleanly.

That's not nearly accurate and repeatable enough for my preferences, but it could work in a pinch.

I would ditch the inner lifting strakes, and just fit the outer spray rails.

The spray rails really just reduce spray; they don't do much for speed or handling. My BBY Micro Scat cat has no strakes, no spray rails, and nearly vertical gunwales. It handles like a dream and goes like stink. I may just leave them all off and see what happens. I can always add them later if I get the urge.

[Jesse J]

I may just leave them all off and see what happens. I can always add them later if I get the urge.

[Dr. Jet]

I'm compiling balsa and ply to take to the laser guy for the Atlas Prototype #2. I may have enough 1/16" ply to cut a prototype for this one too.

[Dr. Jet]

Well, I have enough ply and balsa to make Atlas Prototype #2 and #3....... AND....... I have enough to cut three prototypes of this 16" cat. I'll be contacting the laser guy in a day or two.

[Jesse J]

[Dr. Jet]

Gotta wait for me to finish the Atlas and the Casper projects. I may frame one up right away, just to make sure everything fits; but skinning and outfitting will be later.

[Dr. Jet]

Well, I sent all the pertinent files to the laser guy. I have enough plywood to cut three of these, and each one has the option of being either a single or a twin or even a triple! (Where would the batteries go??)

I've been looking for stingers that are small enough to make a twin and I can't find any off-the-shelf ones that will work. I made the ones for the Micro Scat Cat (see: https://forums.offshoreelectrics.com...-Scat-Cat-Twin), but they are fixed. I would like the ability to adjust the angle on them. I could make something on the lathe and the mill, but it would be cool if I could do something that anybody could build with simple hand tools. I'm going to have to think about that one for a while.

[Dr. Jet]

Strut Problem for Twin Motor Solved

Sometimes the best solution is the easiest. I decided to make an option of having a squared-off transom. That solves the tricky "wrapping the sheeting around the corner" with the rounded transom. It also gives enough room to install a pair of the micro struts that Steve sells (https://www.offshoreelectrics.com/pr...prod=ose-80046)

So stay tuned. I'll frame up one single and one twin, and have one extra "kit" for further experimentation.

[Jesse J]

I hear ya, that rear end may look nice but it sucks your time away... then you have another compartment to fuss about. And for the bigger ones, would accommodate twin outboards

[Dr. Jet]

Update on the 16" Laser-Cut Cat....

I haven't posted in a while because of conflicting projects. I'm building a voltage regulator for the variometer in one of my gliders (I'm running 4S drone LiPos and the vario doesn't like 16V ~ I'm stepping it down to 12V). Additionally, I'm doing a refinish/relic job on a Fender Jaguar for a customer and fitting it out with Jazzmaster pickups (a Jagumaster?? ). Lastly, I was making a power feed for the cross slide and compound on my lathe and when I was parting the rather substantial piece, something moved resulting in the tool digging in and stripping the plastic spindle gears. I now have upgraded steel gears and I'm replacing the spindle ball bearings with tapered roller bearings. That should be a whole lot more stable. Additionally, I've installed a carriage lock and modified the compound rest to lock it as well. The result should be a whole lot more solid machine with less chance of things moving around when doing the admittedly demanding process of parting the work piece.

The laser guy has the wood and while he thought it would be done today, he asked if some other projects could go in front of it. I gave him the OK, so the laser cutting should be done by this time next week. My voltage regulator and lathe improvements should be done by then and the lacquer on the guitar needs a good three weeks or more to fully cure.

So stay tuned for another week or so for an update.

[Dr. Jet]

While I'm waiting for the laser-cutting, I've been thinking about power options. I have a handful of 450-sized helicopter outrunners in the 3000~4000 rpm/V range, but I found something interesting in my long-neglected parts box. It was the power system that was in my old 17" MHZ Micro Iceberg. It hauled a$$ on a 6-cell 800mah zapped NiCad pack, but due to the narrow scale hull width, it didn't corner for crap. I sold the hull more than a decade ago, but I apparently kept the power system for some reason.... This hull will be an inch shorter and a couple inches wider than the Iceberg. It might be a good fit.

What is it you ask? Well, it goes to show what an old-timer I really am. It is an Aveox 1005/2Y (3900 rpm/V) with a custom-fitted aluminum water jacket and an Aveox SL-18 ESC with water cooling added. We're talking OLD SCHOOL baby!! Old school or not, these motors were powerhouses and it should be perfect for the 16" cat.

Stay tuned for top-secret construction details.......

Now what should I use to power the twin version??