RC Sumo

Nemo! You HAVE been busy! I haven't looked in here in a bit....but my recent sialing of my Wally sub brought me back. Awesome input fom everyone. Capn.....I was going over the prevention of the torp spinning in the tube....when I came up with another fantastic super artistic multitalented paint drawing! I believe we could kill 2 birds with one stone on this one. How about mounting a single large fin along the bottom...perhaps weighted. This should help with torque and allowing the torp to run true. Now......the second benefit would be to combine this with a long slot cut out of the launching tube that is just wider than the fin. This should help hold it still in tube but still allow free movement for the torp to be PUSHED out of the tube. Thoughts? crackpot ramblings of a fool perhaps?

Captain Nemo12

The fin at the bottom of the torp would also help steering it in a straight direction, as for weight, a short and thin metal rod can be glued onto a piece of say, styrene or foam and be then fixed on the bottom of the torp. This is similar to the idea of the weighted keel but I like the "fin" idea, sorta reminds you of those fitted on the bottom of sailing boats to prevent capsizing!

holyfrijoles

He Folks,

I'm new and have been following the Walmart Sub post and now this torpedo
post.
You guys are very good at coming up with great ideas.

Heres something to consider for torpedo applications:

How about ZIP cars for parts. The Zip cars are as small as a Matchbox/Hotwheel car
but are actually RC cars. Anyone here remember these cars. Radio Shack usually
carries them. About 20 bucks.

The motors are small, well, everything is small, perfect for this Torpedo
application.

You might be able to use the Receiver/Motor and small battery and wa-la,
A remote cotrolled Torpedo, simply press forward and ...Torpedo away !

Hope this helps

Captain Nemo12

My newest aquisition:

Ok, this post might sound like something suited in the boats/warship warfare catergory but I think it fits nicely into this subject of torpedoes, I've just aquired a little nice looking PT boat from an ATR RC kit (CCLEE), I'm thinking about adding a few little extra mods on and inside the hull. Pictures below:


The boat in drydock, as you can see, the usual torpedo tubes visible on PT boats have not been included with the kit. These should be easily made from a scratch piece of PVC tube later on.


Profile view from the port side.


A stock set of props to provide propulsion, I haven't yet tested the boat so I don't really know of the speed of this baby....


Inside view of the electronics and running hardware: as you can see, the hull offers a nice amount of space for later mods, I plan to use a spring-like mechanism or air canisters to launch the torpedoes into the water.


A stock 2 channel radio is provided along with the kit for an easy and quick assembly.

Benthehen

oh man, i just typed up a big, huge, informative post- stupid thing didnt post it. so, condensed version.

nemo, i have an idea for a nice n' cheap launching system/electric torpedo. cant see it going above $30, although you may have some of the stuff lying around.

parts:
hs55
$10 electric freeflight plane and launcher from walmart
glue, scratch material, and so on

anyways, it would probly be mounted next to the cabin, and be able to charge and then launch the torpedo forwards off of the deck and into the water, then go for about 10-20 seconds.

it wouldbe controlled by one of those flip-switches on the tx- hit it one way for 10 seconds to charge the super capacitator in the sub, then hit it the other way for a second to launch it. unfortuanatly i dont have any small servos and ground rxs laying around, so i will have to use a real old airplane reciever and a HUGE servo(over an ounce, sheesh) to test it.

also, heres a little CHAPSTICK TUBE? torpedo i made. electric, slowish, but works ok. it has a weight on the bottom rather than fins.

benthehen

EDIT: oops- remembering to put the pic in helps.

Captain Nemo12

Thanks for the tip and input Benthehen, I ran the boat today on its maiden voyage in one of the ponds just outside of my apartment building, the other ponds were full of goldfish and I couldn't risk hurting the little guys . Anyways, I found one pond were the fishes seem to be settled on the bottom (don't worry, they are not dead!), the boat performed really well, making sharp turns and hitting the shore rocks a couple of times but she was ok. Although its inabilty to run in reverse limited its performance somewhat, I'm still impressed with its run! Here are some pictures to acompany along:


The boat sitting serenely in the water, just before I pressed on the throttle.


Makin' waves!!! There were two little kids around me watching and I gave them the helm for a few seconds. To tell you the truth, I was a bit afraid in letting them driving it though...


Sitting still...


....and off again! I couldn't get that much shots this time. You have to remember, I running the boat at the same time while taking the pictures!

Anyways, getting back to the subject of torpedoes, I think it'll be a great idea to use those launchers for the boat! I've seen those pistol shaped ones where you press a trigger to release the plane located on top, perhaps by a spring or elastic method, this will also allow the torpedoes to "fly" into the water before diving, gotta capture this one on film!

P.S.: By running this boat, I ended up with about 10 mosquito bites on my legs![:@][:@]

Oww, itch, itch, itch........

Benthehen

ok, these forums are really annoying... i posted a huge post last night, and i guess it didnt show up. well, now all you get is pictures of it.

benthehen

coast219

i got an idea on how to power small size torpedoes. Just fill up the torp body with some baking soda. To launch just squirt in some vinegar, the reaction would produce CO2 gas which would propel the torpedo. a little messy though...

Captain Nemo12

Somehow, the vinegar + baking soda method never seemed to work for me[&:], it could be that I used the black kind of vinegar versus the white kind, how would be able to insert the vinegar (or sodium bicarbonade) into the torpedo while the torpedo tube (under belly of the sub) is underwater? You could use a tube and connect it to the rear end of the torp, but then the substance inside the torp would have to be the baking soda since we don't want vinegar flowing everywhere, all that is needed to produce the reaction is the vinegar, to be poured into the tube. I think a simpler way would be to mix the ingredients together inside the torp before putting them into the sub, by sealing the torpedo shut just as the reactants are about to produce the reaction. Would be just like popping a balloon, only the air is CO2 and the balloon is a torpedo made from a pen...

--> Benthehen, I encountered that problem one or twice too, I think a better way is to copy your words before posting them, just for the sake of not writing them again!

FlyNRight

u can buy engines at radio shack 4 for $15

u69

hmmmm ....

I found 4mm diameter engines on a robotics site(see the "I heard a rumor" post). perfect for the revell sub (torpedoes are 9/32nds in diameter)

Still in the design phase, I have been struggling what to do about the torque myself.

Assuming the friction of such a small propeller will be almost null in the water:
Does anyone think that mounting a second engine inside the torpedo body tuning opposite to the main drive engine, perhaps with a small weight on the drive shaft, will counter the tourque effect of the main drive engine?

-sean

PS: BenTheHen - A good habit I have gotten into over the years... when posting ANYTHING, ctrl+A + ctrl+C all the text you have typed before hitting "submit". that way is your seesion times out because you typed too long, all you need to do is paste it back in.... has saved me many times.

Captain Nemo12

I think it will work, by putting another engine inside a tube that has one engine causing toque one way should reset the counterbalanace to zero, just look at it here:

http://www.pt-boat.com/torpedo/torpedo.html

I've always thought that the second motor was used to operate the counter-rotating props put on a closer look, it seems to be operating the counter-torque system instead.

u69

Yea - I read that one too.... I had assumed that it was driving the second propeller myself..

Best thing I can think of is to ask him.... I'll let you know.

-pkh-

My Feedback: (2)

If your talking about the twin motor setup he has 1/2 way down that page, those are driving counter rotating props... the motor on the right spins the tube that drives the inner prop (left-most prop), and the motor on the left drives the shaft (that goes through the tube) to spin the outer prop (right-most prop)... at least that's what the photos and text indicate.

kriegsmacht

My Feedback: (12)

Hey I like the idea of rubber band drive. Simple, reliable and inexpensive.

On the other hand, a tiny electric motor has the plus of going and going all the way to the other end of the pool or whatever. I was trying to think of the smallest electric motor possible and the vibrator motor in pagers or cellphones came to mind. I had a junky old pager so I took it apart, unsoldered the connections for the motor and it will fit real nice inside a pen body. Check out the photo. I think you could activate it by slipping a piece of stiff plastic between the battery contacts and out a slot on the side of the body and launch tube. A servo would pull the plastic out allowing the circuit to complete. The battery could either possibly be a AAAA (in the photo section at walmart) or the little button type stacked up.. like hearing aid batteries. I think those would be more expensive though.

Captain Nemo12

Looking good Kriegsmacht!

You know guys, this electric torpedo idea really got me thinking. Now to the idea, smaller pager motors should offer great promise, plus inside a 10mm diameter tube, a AAA cell battery should fit in nicely. As for the battery contact question, I thinking that using a plastic strip to block the contacts should work well, just like Kriegsmacht said, a thin piece of styrene strip should do the trick. You can insert the strip via a thin opening in the tube of the torpedo.

So nothing fancy this time, just a rough diagram of how it could work. Below you can see the copper contacts (orange) leading to the connections' end of the motor. A ring is attched to the top of the plastic strip (blue) so that a servo can probably pull it out using a hook of somesort. The battery contacts should be just flexible enough to flip and touch the battery end, launching the torpedo into action!!!

Turbulent

Recovery would be tricky, even in a swimming pool due to lack of bouyancy, would this weight also effect performance? I'm messing about with some kind of compressed air system for my OTW type VII

u69

You can get surplus pager motors from http://www.solarbotics.com/ ... rather than bashing apart an old pager.

OR

the micro RC boats and cars from http://www.raidentech.com/ also have engines that are small enough - too bad the nicad batteries inside them are too large...

-sean

coast219

-about mounting a second motor inside the torp. Instead of using it to turn a counterweight, why not use it to turn a second prop located in the front of the torp turning in the opposite direction there by cancelling the torque?

Captain Nemo12

Yes, I've thought about that too, but what I'm concerned about is that a second prop located in front of the prop might not be able to draw enough thrust to propel the torp with the torp body behind blocking the thrust. A much simplier way would be to use dieFluggeister's method suggested on the second page of this thread, one motor propelling two sets of props located at the rear of the torpedo.

mad redgy

i was thinking about how u could make a torp fire but every thing i came up with was to complecated and thid was the simplest i could think of. and i dout this one would work either.
its all in the image if its there lol.

Cobalt Saber

where did you get that boat?

Captain Nemo12

I bought the little guy last summer while I was visiting my father in Shanghai, China. It was sitting on the shelf at the hobby section and I couldn't resist buying one! Easy kit to put together, took me about an hour to prepare it for sea, most of the electronics and lower hull were already installed, so no fuss there, all you had to do was to pretty much assemble the deck and superstructure. But I doubt the kit will ever make it to North-America.

Cobalt Saber

YOUR DAD LIVE's IN CHINA!!!

DUDE COOL

are you chineas?

Captain Nemo12

Yep, you're correct (what? You've never seen a Chinese Captain Nemo?), been at the hobby for a number of years now and still fascinated with every single sub I see. I wished that RC-subs existed back then when I was a kid, I would've had a really big advance in hobby by now!