Moebius (Revell) Skipjack Build

[trout]

Those motors have internal spark suppression capacitors, Tom. You're good.

And the word, Squish, has not officially been added to the lexicon!

M

Who told me that you never start a sentence with the word "And"?
Thanks David for the information. To say I am WOWed by the work you have in this Sub-Driver is an understatement. There is a light that emanates from the cylinder and I hear music when it is taken out in the open. On a serious note, You and Mike have really done a fantastic job on this.
Peace,
Tom

[He Who Shall Not Be Named]

Those motors have internal spark suppression capacitors, Tom. You're good.

Mike found a source in China that would install them at the factory -- it's great to have the clout of the Caswell Company working for us. I could never arrange for that kind of consideration when I was buying them ten at a time, not by the hundreds.

Spring for the mini's -- lots of force coming off those bigger control surfaces, Tom.

Yeah, hit those forward bulkhead O-ring grooves with some Teflon tape. Or, send me your address and I'll send you a replacement forward bulkhead (but no guarantee it will be tighter -- each bulkhead has to be custom fit owing to sloppy industry cylinder tolerance adherence).

And the word, Squish, has not officially been added to the lexicon!

You got enough reserve buoyancy in that tank to lift just about any 'modern' 1/72 submarine model representing a single shaft nuclear powered submarine. The SKIPJACK 3.5 SD is suitable in a wide range of subjects.

M

[He Who Shall Not Be Named]

(Sorry, Mark, I hit the 'edit' button instead of 'reply to thread' on you -- that's how I accidently stepped all over your above thread. Sorry)

David

[trout]

Thank you Mark and David. That helps.
Looking over the Sub-Driver (the name specifically for David's WTC) you will quickly see she is a beauty. Opening the wtc was a little tough, but David built notches into the edge for a flat head screw driver to enter. I did not see any bubbles or weak castings looking it over. Once I got it opened the safety float valve plopped out. That surprised me, but once in the cylinder it does not appear to move that much. There were some areas that I have questions about.

I noticed there are no capacitors attached to the leads on the motor. Perhaps they are built inside, if not I think they should be added especially since the antenna runs under it. I will read over the cabal reports and postings again to see if I missed something.


My micro 9 gram are too small for the current distance, but would they work? If not, I will buy some mini. The space between the brackets is 1 3/32" or 28mm.


This concerns me, the o-rings on the bow end of the etc look to have light contact or no contact. I will need to add a wrap or two, three of plumbers teflon tape, like I did on the Gato.


Another area of no contact with the cylinder. I did not have a switch in my parts, so I will need to order one.


Great squish in the center bulkheads.


Aft end has one o-ring with great squish and one with so-so (but ample to seal)


This baby has lift!

If, and that is a big IF, I did my math correctly, it looks like this ballast tank has about 1.6 pounds of lift. In Tim the Toolman Taylor grunt "arr,arr,arr"

[greenman407]

My two cents is that I have heard others say that, that is what they are running on,7.4 volts. 25C is a good rating for your pack, the higher the better. As far as MAH rating, I would recommend at least 4000, but the more the longer run times. In my opinion , too much is better than not enough.

Sure, it will run at the lower voltage. Just not as fast as a 11.1-volt pack (same as playing major-league baseball with Whiffle bats). The charge/discharge rate is of no matter -- you're never going to pull that many Ampere's with that motor, unless you stall it on some weeds. Capacity is the big player here: I can run my SKIPJACK for three hours with 6 Ampere's of 11.1-volt battery on board -- two 3000mAh, 11.1-volt, two-cell batteries wired in parallel.

M

[trout]

Can the sub-driver for the Skipjack run on 7.4v? or must it be 11.1v? What would be a reasonable mah rating? Is a 25c discharge rating adequate?

[trout]

Yes, Manfred, I do remember you doing that on the 212! You and others inspired me to try it out. My goal in this hobby is to try a little of everything to learn as much as possible. Maybe next time it will be hydraulic lifts. Anyways, thank you for the kind words! I really appreciate it and I appreciate learning from you, David, and others here and other forums.

[MFR1964]

Tom,

Nice job on the floating peroscope, as you know, i did the same with the 212 to get things up, as for the bobbing, i didn't build such a construction inside, once the water inside the tower is high enough it will stay ferm, i encountered the bobbing by making the foamfloat thicker, so it's less responsive to any slight waterlevel change, as long it's a few centimeters nothing happens.

Manfred.

[trout]

Made a hinge and snap latch. Painted the top most surface black. The entire contraption is 7.5 grams which if I did my math to about .46 cubic inch of ballast. Please correct me if I got this wrong. Trying to understand the technical aspect better.

Put down the darker grey.

Using the advice of Alec, put tape on either side before laying down a coat of glaze.

Yup I made a mess.

Peeled the tape off before it completely solidified. Made it so much easier for sanding.

Quickly put some paint on it. will finish painting after it is trimmed out. Now it is time to go to the sub-driver.
As a side note, looking at the photos of the other subs done by David and others, I hope I can do a decent job on my sub.

[trout]

Thanks for keeping me straight on the E. My memory seems to keep getting worse. No more contraptions, I promise. I wanted to do something new, not just out of the box build. I held off lighting it with opening running lights in the sail and playing with torpedoes. Worse case scenario, I will remove the box and foam gizmo.

[He Who Shall Not Be Named]

The 'E' is for Efficiency, Tom. Can be red, white, or green. Outstanding performance in the areas of Engineering, Operations, or Aviation. Spooky boats get lots of white E's.

Take care, you have some reserve volume in the ballast tank, but not much -- you add too much stuff atop the waterline (your foam gizmo for example) and you wont have enough ballast tank volume to counter all that displaced water your scope floats and box will add to the boat. I think you're good, but don't cram in any more goodies for now. Get it wet and see if you can achieve the designed waterline in surface trim.

M

[trout]

LOL Thanks guys for the help. Mark, I think I am leaning to that three shade paint job. The one with the E over the number. I found out the E stood for excellence, a rating given for performance or inspection, I think. Maybe someone can expand on that.

David, your advice is duly noted. This all brings back memories of the Gato and your advice there was 1. this is not rocket science 2. get her done then go back and add the details - usually followed with a kick in the pants. So before that happens let us move on......

More on the periscope. Made a rectangle tube from styrene, 18mm x 20mm x 87mm. Taking the foam that the propellor came on, cut a block out and shaved to fit.

The periscope I mounted on a brass tube to strengthen the end so it could be mounted in the foam block. I am skipping some steps, like how do I know where it goes on the block, but will cover that in a little bit.
The periscope is adhered to the block of foam with RTV silicon.

I added the brass plate (Yeah RTV silicon) after playing with different configurations.

The foam and periscope was a little too light without the brass plate and would not retract or it would get stuck from the slightest friction. Adding the small amount of weight helped. It might need a little more.

The rectangle tub was capped off. Placing the styrene unit in the sail and using a mechanical pencil (with the lead extended a lot), marked where the scope should be. Drilled out the hole to allow the scope to rise. The other squares are holes sealed off after experimenting (larger, smaller than no hole) and found that they were not necessary. The hole the periscope rises in was filed to allow smooth motion doing so made it slightly oval.

Testing to make sure the foam slid easily. At this point testing was done with the bottom open. My son assisted in creating waves to see the bobbing factor. The scope showed a lot in the first 1/3 of it rising, bobbing mid way, but as the scope became fully extended it reduced. So some reduction did occur just as it was.

To help reduce it further, I made a baffle for the bottom. The thinking is slowing down the water coming in will reduce the wave action. Sam created more waves. The baffle worked. The bobbing was minimal and the sail rose just smoothly. Upon rising, the sail would not always respond by going down. My guess is the small holes are the cause of that (failure rate about 25% of the time). I might seal the 4 holes and use just one larger hole.

The as I look at it, I can imagine debris and moisture getting trapped in here. So I will need to make the bottom open up. Off to the hobby store for some styrene to build a hinge.


Slapping on paint as I type.

[He Who Shall Not Be Named]

The two bottom shots are mine. One shows pre-commissioning (red from waterline down), the other is patrol ready (red from centerline down). One for Mike, the other for me.

Don't get anal on us now, Tom. Slap paint on that sucker and be done with it!

M

[greenman407]

This picture definitely shows a color difference between the sail side and the manifold cover or whateveryawancalit?

[greenman407]

I found these the otherday on one of these threads but I dont remember right off which one it was.