R/C Naval Combat

does anyone have any torpedo ideas?

We've been beating this back and forth in the Battlestations section. We're in 1/96 scale, so we have a little more room to play with, so we're looking at powered torpedoes (as well as using 1/4" ball bearings to simulate torps). The first torps to get used will probably be Propel-powered, and there is a posssibility of electrically-driven torps. At this point, we're not sure if they'll even penetrate balsa at range, but it'll look cool, and with some R&D who knows. :)

To read the whole thread, go to the Battlestations forum and read the threads that have Torpedoes in the titles.

I have been trying to come up with someways to build an electric torp, but problems with electric torps costing over 2O dollars and the chance of losing it. What are Propel-powered torps? do you have any links for them?

I think PreDread has been looking at them, perhaps he'll jump in.

As far as losing them, well, them's the breaks. I didn't say torps would be cheap :) Also might want to check the rules for the club you want to battle with to see what they say about torps. Some clubs don't do them at all.

quote:

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Originally posted by Tugboat



As far as losing them, well, them's the breaks. I didn't say torps would be cheap :) Also might want to check the rules for the club you want to battle with to see what they say about torps. Some clubs don't do them at all.

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The way I look at the cost is that it becomes incentive for those who use them to not overuse them (should they become highly effective weapons) and it'll provide a motivating reason to do more development on them to further bring down the cost not to mention offer a means to more proportionally arm the smaller ships (instead of having broadsides of torpedo guns).

Yep its me who is trying work out propel powered torps,

Propel is a liquified gas, its the air duster in a can stuff. RC Sub guys have been using it for quite some time to build scale, although inert, torpedoes. It does work, and works pretty well.

The problem is turning them into safe weapons. Things that go boom are a no no for many reasons. I'm trying to work out a spring powered warhead that flys open and shreds the side of the ship. Its a difficult concept to work out, but it is do-able.

I'm currently saving for a lathe, but it will be a while. The torps will never be cheap, $20 a torp isn't bad if your buying them from somebody. I think I can make mine cheaper... but the time involved would be high. I'm hoping to make my torps float when they run out of gas... so they can be recovered.

I still think 1/144 is too small for torps... at least from an R&D standpoint. Its easier to build a working prototype in a larger scale and then try and make it smaller.

You probly could work that out, let me know how it goes.

For the would-be powered torpedo developers to consider:

* Mass of a 0.25" steel ball bearing is about 1.05 g, or 1.05 *
10^-3 Kg (0.00105 Kg).
* Muzzle velocity of a 0.25" cannon is about 50 m/sec. at near
max. penetration (2" foam).
* That works out to E(k) = 1/2 * m * v^2, or 1/2 * 0.00105 * 2500,
or 1.3 Joules.

That's what it takes to reliably penetrate a combat warship's 1/8" balsa skin. Your torpedo must do the same.

Work out the math to calculate what speed you need to achieve for a given mass of torpedo (or, if you know what speed you can get, work out the mass you'll need).

v = sqrt((2 * E(k)) / m).

So, if you have a torpedo with a mass of 3g (0.003 Kg), you're going to have to move it at about 29.5 m/sec (97 ft/sec; 66 mph) at the time of impact. You've got to accelerate it in whatever is to be your minimum attack range, & maintain that speed until you reach whatever is to be your maximum range. So, if you want to have an effective combat range of 1' to 20', you're going to need to accelerate your electric torpedo from 0 to 60 mph in a foot, then maintain that speed for another 19', or about 0.3 sec. of runtime.

Your challenge is to manage the power draw, size, weight, power capacity (power draw over time) to deliver your payload mass at necessary penetration speed, over some range of target-lethal distances that you determine based on your combat experience, within whatever cost you also determine is reasonable.

So, when you say that you believe you can do it, that's the "it" that you must do.

JM

Electric & Propel powered torps
are going to be complicated,
so for now I'll go CO2 powered or spring powered.
Thanks for the info.

John, your first half of that calculation is wrong. you have 4.25 joules, not 4253 joules. Keep in mind that 4253 Joules is more energy than a 30-06 bullet impacting at close range. If anyone creates a 1/4" Bearing cannon that can give me that kind of energy, I will go looking for an Elk with it.

the energy being correct is imperative for folks trying to create a spring powered warhead at the end of the torpedo, as it allows you to consider sizing the spring based on stored potential energy.

the impact needed to penetrate balsa is why folks are looking at warheads, not a super high speed torpedo. Hence the references to spring powered warheads.

Who erased my post?

You can erase a post?

Only a moderator for that forum, or the person who orignally made a post can do that.

that one was a different thread

quote:

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Originally posted by archer183

John, your first half of that calculation is wrong. you have 4.25 joules, not 4253 joules.

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WHOOPS! Should have been Kilograms! Corrected in the original.

Thanks!

JM

JohnmCA72 is totally right concerning the difficulty in making a torpedo that can penetrate balsa.

A "warhead" is, IMO, the only way to make them work and have them act somewhat like the real thing. I plan to have, for lack of a better word, a small "teet" on the nose of the torpedo, this is the only part that has to penetrate the ships side. The impact releases the spring powered warhead and only the very end of the torp (flying open) does the damage.

Trying to drive the whole torp through the side of a ship is an exercise in futility. Conditions would have to be perfect, you'd have to hit a moving ship, from a moving ship, dead on perfect to even have a chance of it working. But I do agree that torpedos should start off slow and build speed, then hold a fairly consistent "attack speed" for reasonable distance. A low speed start acts like a safety that helps keep you from torping yourself should the torpedo fail to track straight.

In some countries, a "," is used in place of a "." and a space is used where us Americans use a "," so 4,253 J could be considered correct by some.

We should really get all the torpedo warhead discussion posts in one thread... or at least start putting new ones in one thread :)