subcaptian

could you convert this revell model?

CrunchyFrog

Man, that's nice...I think I had that kit, but under the name Growler SS-215.

How big is that? Overall length, diameter inside--how big of a cylinder could you fit in it holding electronic parts?

I haven't played with watertight cylinders, but I expect someone who has will want to know.

Captain Nemo12

I believe that is a Revell 1/125 USS Lionfish model that they made a couple of years back. Haven't tried converting one though, but fabricating a water-tight compartment out of styrene sheets should be fine. Alternatively, you could also make the sub a dryhull. That is, make every inch of the model waterproof to gain more space.

CrunchyFrog

Where does one find styrene? Would clear styrene be hard to find?

Captain Nemo12

They should be available in most hobbyshops. Look for Plastruct, Evergreen or Raboesch brand styrene, they are usually good quality. You can also use plain clear PVC sheets for clear plastic although they are hard to bond for glues.

CrunchyFrog

Thanks!

I'm getting curious about scratchbuilding, at least for a dynamic diver. Do you have a preferred method of mounting motors to the cylinder? Do you generally build more than one cylinder into a model...if not, how do you access stuff that's in the lengthwise middle of a long cylinder ? Are there readymade radio-control kits with just electronics and motors that work well for submarine projects ?

Captain Nemo12

I personally like to dismantle cheap RC cars for my conversions, even though sometimes they tend to break easily...

Also like to install my electronics+motors into separate cylinders, they kinda act like removable modules you can install into other RC-submarine hulls that fit the WTCs. This has an another added bonus in case of flooding as only one compartment could be flooded instead of the whole cylinder.

As for motor mounts, I usually make my own also (why spents $$ on something that you can scratchbuild straight from scrap styrene laying around at home?) as it lets me play around with gear arrangements in order for them to fit inside the cylinder.

CrunchyFrog

I can see how a cheap RC car would come apart so its receiver and main motor would go into a cylinder. But don't you typically get only one motor in a little RC car? What do you look for in an RC car for conversion?

If I were building a dynamic diver, I would think I'd have to dismantle three RC cars so I could get power for three dimensions: forward/reverse, left/right (as a thruster with a prop, or rudder servo), and up/down (again as thruster or plane servo). Then my command module would be three separate transmitters, one from each car, that I'd have to tie together and coordinate. Am I off the mark or what?

Captain Nemo12

The biggest drawback I guess with RC-cars would be the limited functions... This is why I use them mostly to test out conversions of plastic model kits (Trumpeter Kilo, Seawork, maybe a Revell VIIc, etc) without having to purchase expensive micro-sized RC-equipment. A dynamic diver could easily achieved by just using 2 RC-cars (of 2-channel each and different frequencies also) that way you'd have for example:

Car 1 (27mhz)

-Forward/Reverse
-Rudder

Car 2 (49 mhZ)

-Dive planes (I think they are easier to use than thrusters but it's your choice)
-Extra Channel

With the extra channel you can even command a pump for a ballast tank (makes it a static diver in this case)! Or even add functionnal torpedoes!

CrunchyFrog

Hey yeah! Static diver was my first thought when you mentioned an extra channel. Yay! Thanks for your input, Captain.

I guess when you're rigging your own dive planes, you can fix the travel for as steep an angle as you want. How much travel do you like to use, and for what kind of cruising (pool, pond, lake...) Do you spring-load yours so the plane will return to level position when you're not directing it?

Cool stuff ! Thanks again.

CrunchyFrog

And of course, I've got more questions. How do you penetrate these Styrene cylinders--for wiring, and for prop shafts ? I like what you say about getting parts on the cheap--could you enlighten me on through-hull parts ? What are your favorite sources, and methods?

Captain Nemo12

No problem Crunchy,

The diving angle can vary greatly depeding on the size of the servo arm, the length of the control rods, etc. I always get this weird nervous feeling when I dive deeper with diving planes, you never know if you're going too deep and whether if it'll be your sub's last dive... Artificial ponds with a clear bottom is your best bet, I primarily use pools for testing trials or when old man winter hits in. If the servos don't have self-centering features, then a spring-load is your best choice.

As for WTCs, PVC is usually pretty cheap. Resin or bondo end-caps with O-rings give easy access and make a good seal. However, I don't own a lathe so I'm currently experimenting with metal cans for a cheap WTC source. There are some that come with a resealable plastic cap. I believe that if you reinforce them and add an elastic band around the rim, you should get a pretty good seal!

CrunchyFrog

Hey Captain, thanks again...by the way, what do you like to use for prop shafts, since you favor cannibalizing cars? How do you connect them to the prop?

CrunchyFrog

I see what you mean about wishing for a lathe. Until I can find a good way to file things level for bolting
lids on, keeping sawn-off-and-siliconed PVC sections watertight will be a major part of maintenance.

On static divers, what kinds of ballast systems are available for a single on/off channel? Does it
have to be an always-pumping/always-blowing mechanism, or can it have an off position ?

"Blow negative to the mark !"

Captain Nemo12

Hi Crunchy,

To answer your question on prop-shafts, I usually go to my LHS and look for the correct diameter of shaft I want, since I don't always use the car's stock motor in my conversion.

For the ballast system, you can can have what's called a sealed ballast system, an on/off switch activated by a servos turns a pump which pumps in water to a sealed balast tank through a valve. As teh water enters the tank, the air inside is compressed. To vent the tank and surface, all you have to do is open up the valve to let the air through, the pressure of the compressed air inside the tank automatically blows all the water out.

CrunchyFrog

Your LHS...gotcha !

subcaptian

about how much would it cost to convert it?

CrunchyFrog

That's neat about the sealed ballast system.

Captain Nemo12

Let's see:

Electric motors X2 (dual prop system): $2.00 (if you buy from electronic surplus stores).

Battery: depends on motors' voltage rating.

Radio System: ~$100 (3-ch minimum)

Micro Servos: ~$30 (cheap GWS brand)

Micro ESC (used IF normal ESC are too big): ~$30-$50

Of course, it could go much higher... but for under $200, it's a pretty nice price!

P.S: Don't forget to include the cost of the sealing materials (styrene, PVC tubes, O-rings, grease, etc).

CrunchyFrog

Captain,

Watertight cylinders seem a snap to get together.

What do you do, though, to get weights to stay where you put them, and floats to stay put? Styrene bulkheads ?

Captain Nemo12

Yep, if you have the right sealing materials, it can be easy. To secure WTCs, I like using screws, a latch system is also neat... Or if you really would like to go cheap, use velcro!!

subcaptian

does anyone have anything the'd like to sell?you know, cheaper than in stores,...

CrunchyFrog

Trumpeter Seawolf RC Build--question

I've had my troubles getting my reappopriated RC car parts to turn a shaft through the nearly 1/2" WTC lid: Aside from the motor's shaft being smooth, it's short (1/2" ), no teeth on the end, and it's so narrow that drilling a pin hole for a gear to mount on the shaft and grab another wheel for gear reduction seems impossible. Maybe my inexperience talking.

No budget for a bigger motor yet. I think I'll salvage Wally-boat gears (4:1 I think?) to slip onto the shaft after I've fixed things in-position. Wish that shaft had teeth, though, so there wouldn't be as much slippage.

I know I could probably get a bigger motor--either with predrilled shaft holes, or wider so I could do the drilling and add a cleavis. I know sections of ink-pen tube are also handy in many places (thanks Nemo! ) especially when the shafts have teeth in opportune places.

I really have two questions:

1) what alternate ideas might I try for now, since I don't have a budget to upsize the motor yet?

2) What's available out there? Anybody want to tell me about the pretty-good motor they're using? How much did it cost? How do you get the power from the motor to your prop, if you started with a short-shaft motor?

Captain Nemo12

You can get really cheap motors from electronic surplus stores, they usually go for $2-$5 depending on the size. The best bet would be visit your LHS, they usually have a metal center with several shaft sizes in stock.

CrunchyFrog

The hobby shop staff recommend wheel collars for lots of things. I wouldn't doubt by the time I add the three wheel collars I see a place for, this small motor might steady at a slower speed and direct-drive might be a better solution.

I was thinking, I wonder how much of a chance I stand of burning up the board if I wire more batteries into motor stage. I've heard of Battery Eliminator Circuits along these lines, but anything I can do cheaper...well, my rig only has to outlast my interest in this particular configuration