torpedo system

[toppack]

It would be best to make both ends from somthing that floats (one that prop-shaft goes thru & one nose).
Yes, a good way to attach those end pieces correctly, to center tube, is a Critical and maybe difficult part of the assembly.
I've not thought about that part of it much yet.

Want to find some tube that is thin walled, not magnetic, but easy to attach.
Since it needs to be thin-walled, I doubt it could have Threads?
Maybe just a press fit with a O-ring seal, and a locking pin if necessary (if there's a small internal spring to keep a battery stack tightly together, pushing against nose piece)?
Remember we're talking about something about the size of a fountain-pen! :)

[deepseadiver]

this looks like an ideal motor for the torpedos, im looking for some tubing that i may be able to find with threaded ends i know some one that works with plastics that may be able to help out. this way the torpedo, can be un screwed into two pieces. But i like the one thats on youtube were he has made his from scratch displaying it in the bathtub, running it for the first time. I have written him for were he has gotten his supplies but no responce so far.

[toppack]

Micro Motor:
Purchased from eBay.
Click Pic:

[toppack]

Another problem is that since the very small motors (without gearing) have High RPM but not much Torque, so the motor has trouble overcoming the drag of the shaft seal along with the force needed to turn the prop. Need a shaft seal that is water-tight but allows shaft to turn freely at high RPM.
I think some kinda tubing would make best seal, maybe teflon tubing, if I can find shaft rods and tubing the correct size to make a watertight fit.

I got some more small motors, (direct from HongKong), that are only .24" diameter, but problem with them is that motor's shaft is only .030" dia. and about .1" long, which is not much for a tubing type shaft-coupling to grab onto.
They operate well at 1.2 volts and really scream at 2.4 volts. :)

I found that motors I removed from servos don't operate well at 1.2 volts.
They like at least 3. volts, which may be okay if I have to use and stack button type batteries, since I'll have enough length space to stack a bunch of them (probably 4). (Button type like used in hearing-aids)

[toppack]

Yes, I know I have some small reed-switches (the type sealed in glass tube), if I can find them.
My stack of Goody-boxes is Very Large, after about 50 years of scrounging and collecting, and those switches are Very Small! :D LOL :D

[deepseadiver]

ok i will think of ideas also. the magnet part to swtich off and on im sure is they way to go . But i will think of some other ideas also.
Jim

[toppack]

All I've seen so far in the Micro Li-pos is a flat card shaped pack. Too Large :(

[He Who Shall Not Be Named]

Hey, Jim, start designing and building!
Maybe we can come with a Better design if we're All working on it??
I'm still searching for a rechargable battery, the correct size, but No Joy so far. :(

Look at the tiny Lithium-polymer batteries used in those cheap, RTF helicopter toys.

David,

[toppack]

I will be watching this thread. you have my complete attention.

Jim:)

Hey, Jim, start designing and building!
Maybe we can come with a Better design if we're All working on it??
I'm still searching for a rechargable battery, the correct size, but No Joy so far. :(

[deepseadiver]

I will be watching this thread. you have my complete attention.

Jim:)

[He Who Shall Not Be Named]

Hey, Great Idea!
I could mount one of the magnets, I now have ordered, in wall of launch tube, and no need for switch hole in torpedo.
A simple contact-arm switch should be fairly easy to make, if I can't find sealed reed-switches that will fit, and mount inside torpedo.
I can use a tray, with magnets built in, to deactivate and hold the torpedos when on shore.
I may have to Order More Magnets! :)
Thanks,

Good move. Keep it simple.

David,

[toppack]

think: magnetic reed-switch.

David,

Hey, Great Idea!
I could mount one of the magnets, I now have ordered, in wall of launch tube, and no need for switch hole in torpedo.
A simple contact-arm switch should be fairly easy to make, if I can't find sealed reed-switches that will fit, and mount inside torpedo.
I can use a tray, with magnets built in, to deactivate and hold the torpedos when on shore.
I may have to Order More Magnets! :)
Thanks,

[He Who Shall Not Be Named]

David,
I may have come up with another design that combines the cocking and reset into 1 spring. By putting the cocking groove into the torpedo itself, not in the trigger-arm. So the ball sits in a depression in torpedo case.
The torpedo's power switch could be down in that depression also, with a membrane seal, so it would have double function, with no switch protruding thru side of torpedo.

Maybe that's what you were talking about?

think: magnetic reed-switch.

David,

[toppack]

I also determined that I'll also need to build a torpedo Holding fixture, to have on shore, to keep batteries from discharging thur motor, until I can reinstall them in sub.
Unless I put in a 2nd power Switch or added some kind of slide inside torpedo to deactivate the Momentary switch, which again could get too complicated.

[toppack]

I've about desided to go with a battery for power instead of a charged capacitor, since it would be very difficult to load the torpedo without accidently discharging the cap and the Run time is Very Short with a cap. (2 seconds or less, even with current limiting resistor)
It would not get to shore with that run time.

I may not be able to find at least 3.volts worth of Rechargable battery-pack that small tho, may have to go with non-rechargables.