JustinScott
Founder
Rear Admiral (RADM)
Posts:2176
 | | 18 Jun 2008 08:21 AM | | quote:
Originally posted by admiraljkb
So I'm going to pay $10 or so per torp in material and probably and optimistically (after much process improvement) 1 hour of time per torp to build it. That makes them $60 torps at minimum with time costs included, although I'd venture to say $100 per torp.
OK, I have glossed over this because I really don't care... BUT it keeps coming up so I feel like I must challenge it. I can understand the $10 per torp; however I think if they are actually manufactured @ that price we've done something wrong. I also understand your time is worth something. However, assigning a monetary value to it is assuming you are missing out on some other income. ($50/hr? @ work, sure... @ pond, Really? ) Frankly, this is a hobby. The whole thing is a waste of time; that's the point. [8D] Additionally, If you are 'priming' torpedos & it takes you an hour each; again we've don't something wrong. | | Cheers,
jks
DKM Tirpitz | |
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admiraljkb
Ensign
Posts:154
| | 18 Jun 2008 08:31 AM | | Cool. As long as it's acknowledged as a consideration. :)
Keep in mind that in the modern furball that is Model Warship Combat in all it's forms, a spread of torps in that manner is quite likely to hit your friends as well as enemies. | | | |
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JohnmCA72
Commander
Posts:701
| | 18 Jun 2008 08:33 AM | | quote:
Originally posted by PreDread
My objective:
Extend average torpedo range to the maximum effective range of the average ship's secondary battery. Notice I said average, allowing builders to tweek torps to their own tastes. Faster and shorter range, or longer ranged and slower.
Large caliber weapons ( scale 10" or larger ) should have a maximum effective range exceeding that of torpedoes. In order for a torpedo equipped vessel to effectively launch torps, it must pass through a "kill zone" where large caliber guns have the ability to turn the smaller ship into toothpicks.
Torpedos should have the ability to sink or a cripple a BB with 1 or 2 hits. Non torp guys may scream that this is unfair, but it ignores that fact that longer ranged locomotive torps will be much more difficult to effectively use.
"Fair" or not, historically (even more so currently) torpedoes are a weapon that can sink or disable even a very large, well-protected ship with a small number of hits (even a number as small as 1). quote:
Look at historical hit rates, they are ridiculously low, something like 5%.
Which compares how with the historical hit rates for naval gunfire? quote:
Current torp setups are so short ranged that it is almost impossible to miss. How can you miss when your sub has to ram the target to fire the guns? Or when your torps hit 8" from the side of your hull?
Long range torps would decrease the number of torp sinks, not increase them.
Now that requires a leap of logic that needs some further explanation. How does increasing the range of a weapon decrease its effectiveness? Perhaps there's an assumption that all torpedo engagements will be conducted at longer ranges, where accuracy is more difficult? How does this affect accuracy at short or medium ranges? Suppose, for sake of argument, that a self-propelled torpedo is effective at up to 50 feet. Accuracy at maximum range may be 5%, but what about short or medium ranges? I'd expect accuracy to improve as distance decreases, approaching 100% at very short ranges, as you assert for gun-style torpedoes. One option might be to build in some sort of minimum range (time) before the torpedo arms, so that it can't be used as a short-range weapons. The trouble is that this puts you right, square into the situation again where your intended target has no effective weapon to counter you because you can launch from a point outside of his max. effective gun range. Just from a game-play perspective, you've got to have to place your ship in a position where it's vulnerable to defensive fire, not merely where the target is able to evade. quote:
Sure, you might have dramatic sinks where a ship eats a whole spread and sinks like a stone, but most of the time a ship will simply turn to avoid them.
Now what I have said above may force the rules of combat to completely change. I'm fine with that, I don't currently battle, I'm an independent with a dream. I'm not forcing anybody to think like me, build with me, or battle with me. I know what I want to achieve, a more realistic style of battling.
Should that realistic style of battling also include longer-ranged gun fire, with barrel elevation & damage from plunging shots? Not that something like that's "wrong" in any way, but you'll probably have to start a whole new format to get it to happen. That's going to require drastic changes to basic ship construction, to allow plunging-shot damage, presumably without explosions. Note that, in real life combat, actual sinkings of ships in action are/were pretty rare, statistically, which should/would probably be reflected in a more realistic style. Be sure to keep safety in the forefront. JM | | | |
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admiraljkb
Ensign
Posts:154
| | 18 Jun 2008 08:42 AM | | I admit I'm taking seriously rough swags based on my previous experience as an independent Computer Consultant doing contract work for 8 years along with having to submit time/cost estimates a lot at work now for different development projects. But based on what I've heard so far, materials costs are going to run around $10, and I may have underestimated there by $10 to $20 depending on how much material is bought in bulk and what materials are actually involved in the final product. It costs a certain amount of time, of which I allotted an hour for when production has been tweaked, and 3 hours per torp for prior to production being tweaked and process improvements implemented. Those are *my* best guesstimates based on data presented in the thread.
Proving me wrong wouldn't hurt my feelings in the least. Swags aren't hard facts. :) Submit a plan with newer estimates. Nearly anything realistic would be better than my swag above. :) If you are a machinist capable of building these intricate little critters, and you haven't allocated $100/hr there is a problem there. $50/hr is definitely too low and I wouldn't accept that as a valid estimate if I wanted my supplier to stay in business, or keep supplying me. These are contract hours, not "work" hours at the office. Challenge it? Please, be my guest, I'm not offended. I think the actual numbers in the end with a valid design will come *close* though.
Now if it were me, ala myself manufacturing my own, even 15 minutes is too much time when I can spend 15 seconds and just throw 1/4" ball bearings into the tubes. :) Keep in mind that it would be 15 minutes PER torp. Personally I'd rather spend the time doing something else. | | | |
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PreDread
Ensign
Posts:173
| | 18 Jun 2008 12:46 PM | | Without going too far into tech...
I think we are seriously over-estimating the cost. If they cost a $100 a torp, then something is wrong. Although things like clockwork engines and microcontrollers may work... they are well out of the price range of what a torp should be. All attempts to stick with as many off the shelf parts, surplus parts as possible should be made.
We should be concentrating on developing only the custom parts, like the tapered tail section and fins, the warhead, and the tiny little prop. A torp should perhaps be a kit without the off the shelf parts. Let the buyer assemble the torp with is own time, yes everyone's time is worth money. But in reality would you rather buy $20-25 worth of parts and assemble yourself, or pay $50+ for a pre-assembled piece?
JM,
I really believe that any increase in range will decrease the number of hits. My entire goal with locomotive torps is to eliminate the point blank torp kill. If a torp will be a 1-2 shot battleship killer, it must be ineffective at ranges where it is impossible to miss. I think this problem will solve itself. The torps are small enough that any kind of prop we create will be inefficient, requiring time and distance for the torpedo to accelerate up to a reasonable speed required to activate the warhead. Any attempt to launch at extreme short range would result in the torpedo behaving like a "dud".
When I speak of increasing battle ranges and overlapping cannon fire, it is not my intention to increase range to the point where plunging fire through the decks is an issue for all but the smallest low freeboard ships.
As said above, a current 1/4" cannon will still penetrate balsa at 30 feet. At 0 degrees elevation, it will range out to 20 feet. What is the current range of a cannon at 5 degree elevation? 5 degrees is not out of the realm of current ship rolling on the pond...
My idea for overlapping fire is this. Ships should have something like a two foot immuze zone around them where waterline hits aren't really possible, in larger scales, this is simply extra room to manuever. Light weapons should have an effective range of 2 to say 15 feet, medium sized weapons should have an effective range of 10 to 25 feet, and battleship caliber guns should range from 20 feet to 35-40 feet. The minimum ranges are for waterline hits at maximum depression. Not a huge increase, but needed IMO, especially with the larger scales. A torpedo should have a range of 10 to 20 feet.
Now I do understand that what I have listed above is not everyone's cup of tea, thats fine with me, I wouldn't force any change upon existing clubs. | | | |
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JohnmCA72
Commander
Posts:701
| | 18 Jun 2008 02:02 PM | | quote:
Originally posted by PreDread
Without going too far into tech...
I think we are seriously over-estimating the cost. If they cost a $100 a torp, then something is wrong. Although things like clockwork engines and microcontrollers may work... they are well out of the price range of what a torp should be. All attempts to stick with as many off the shelf parts, surplus parts as possible should be made.
We should be concentrating on developing only the custom parts, like the tapered tail section and fins, the warhead, and the tiny little prop. A torp should perhaps be a kit without the off the shelf parts. Let the buyer assemble the torp with is own time, yes everyone's time is worth money. But in reality would you rather buy $20-25 worth of parts and assemble yourself, or pay $50+ for a pre-assembled piece?
JM,
I really believe that any increase in range will decrease the number of hits.
Why would you believe that? What element of increased range leads naturally to a decreased overall hit rate? I know that if I had a handgun, it would be fairly accurate at close range, considerably less so as range increases. The same round, chambered in a carbine, would probably have greater range, & accuracy at long range, but I would expect it to be exactly as accurate & lethal close in as the same round would in a pistol. The notion that extending the range automatically decreases the accuracy close-in isn't intuitive, at least not to me.
quote:
My entire goal with locomotive torps is to eliminate the point blank torp kill. If a torp will be a 1-2 shot battleship killer, it must be ineffective at ranges where it is impossible to miss. I think this problem will solve itself. The torps are small enough that any kind of prop we create will be inefficient, requiring time and distance for the torpedo to accelerate up to a reasonable speed required to activate the warhead. Any attempt to launch at extreme short range would result in the torpedo behaving like a "dud".
OK, but you've added a requirement to the mix that hasn't been listed before. Namely, that it should have a MINIMUM effective range. That's all I'm trying to do with my questions, is to get people to state what it is that they want to do. Without a clear & precise definition of what you want, it's just pure luck if anything actually gets built successfully.
The minimum range requirement brings up other issues, though. You've got to disable (or not enable) the warhead for some amount of time/distance after launch. Technically, it's going to be complex & worthy of a subsystem design in its own right. Administratively, whatever club(s) allow their use are going to want to test them to be sure they don't arm too early or stay armed too long.
quote:
When I speak of increasing battle ranges and overlapping cannon fire, it is not my intention to increase range to the point where plunging fire through the decks is an issue for all but the smallest low freeboard ships.
As said above, a current 1/4" cannon will still penetrate balsa at 30 feet. At 0 degrees elevation, it will range out to 20 feet. What is the current range of a cannon at 5 degree elevation? 5 degrees is not out of the realm of current ship rolling on the pond...
My idea for overlapping fire is this. Ships should have something like a two foot immuze zone around them where waterline hits aren't really possible, in larger scales, this is simply extra room to manuever. Light weapons should have an effective range of 2 to say 15 feet, medium sized weapons should have an effective range of 10 to 25 feet, and battleship caliber guns should range from 20 feet to 35-40 feet. The minimum ranges are for waterline hits at maximum depression. Not a huge increase, but needed IMO, especially with the larger scales. A torpedo should have a range of 10 to 20 feet.
That's an interesting idea. I'm no fan of ultra-close-quarters shipfighting either. It's going to be a challenge to administer, though, & ensure compliance. Just like it's hard to prevent a rolling ship from raising barrels 5 degrees (or more) above horizontal, it's going to be just as hard to prevent the same thing on the downward roll, enabling below-waterline hits at under 2 feet.
quote:
Now I do understand that what I have listed above is not everyone's cup of tea, thats fine with me, I wouldn't force any change upon existing clubs.
Nobody's going to force anything onto anybody. If it's a good idea, & you (or whomever) can demonstrate it as such, people will probably vote to allow it, but in the end it will be their choice. Most likely, you'll have to start a whole new "Realistic Warship Combat" format from scratch.
JM
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admiraljkb
Ensign
Posts:154
| | 18 Jun 2008 02:32 PM | | I really don't *think* I'm overestimating based on current data presented, combined with some educated guesswork, some dart board tossing and a little bit of Ouija board action. :) Keep in mind I've done this kind of estimating before based on customer's rough data and trying to turn it into something reasonably resembling their "back of napkin" requirements, which is where we are at here currently. But it's early on, nothings gelled yet, just a bunch of napkins and pens out around the table brainstorming. Life's good. I'm more concerned that I'm underestimating since I'm much more known for that. To put it in perspective, my Automatic Pump Circuit MkIII design costs around $5 in parts. The solid state, microcontroller driven APC MKIV is going to end up being $5-10 of parts. Both take an hour to assemble/debug when done onesy twosie every once in a while, and neither is very complicated. If I'm mass producing them, the amount of time goes down drastically of course, and soldering can be shoved off onto lower paid folks. Certainly neither of those have the technological sophistication/complexity that this torp is going to need. But hey, if I'm wrong, so be it. I can live with it. I'd much rather estimate too high and be happily surprised, than estimate way too low and be in the bottom of the large Texas sized margarita glass.
For the question of $25 worth of parts, or $50 assembled? I'll pay the $50. My time's worth a lot more than that. $5 versus $50? I'll take the $5 worth of parts, in fact $5 versus $20, I'll go the $5 route. All a matter of perception obviously, which is what the sales guys go after all the time. For this, we're talking about $10 worth of parts minimum and at least a 100 torps though. Now we are on a much bigger scale, and different economics. A ship only needs a max of $10 of parts to get an APC above, but she'll need a bunch of comparably priced torps for an enjoyable outing. The cost goes up really fast for maybe 3 hours worth of fun with it. The last commercial price on the "~$5 worth of parts" APC similar to my MKIII was around $20 from Battler's. Like I said, finalize the design, grab the parts list, figure out what it's going to take, make the cost projections for the phase 1 production run where everything goes wrong and Murphy has his way with you, then on to he phase 2 run where things are a little better, and then the successive phases where real process improvements start to kick in making the mfg cost go down. | | | |
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PreDread
Ensign
Posts:173
| | 18 Jun 2008 02:38 PM | | I think that hits will decrease for these reasons:
Increased run time at distance gives your opponent time to dodge the attack. I'm not going to say that we would be able to perfectly regulate torp speed, but the torpedo should run at a reasonable scale speed (say 30 knots in scale). The easiest way to defeat a torp is to turn away.
By turning away at full speed, say your ship is some kind of dreadnought with a top speed of 20 knots, the torpedo chasing you is only doing 10 knots relative to your speed, making it much easier to dodge than a flying ball bearing.
With a long ranged torp, there are many other factors outside your manuevering that lower the chance of a hit. The torp may fail to track straight for a number of reasons. Our little scale torps won't have gyros to keep the straight and level, the best we can hope to do is counteract prop torque with bent fins and hope they stay pretty straight over distance. The wake of another ship may throw it off course, it may hit a submerged object. Another ship might stray into its path. The battery may run out. Anything but a straight shot may cause the torp to glance off. Steady depth keeping may prove troublesome... the torp might pass straight under you... I would estimate at best are scale torps may achieve a 25% success rate...
There are so many more variable firing a moving torp, from a moving ship, to another moving ship at distance, than there is using torpedo spurt guns at point blank range.
I'm working on committing my shredder warhead design to paper for posting. To function correctly it must penetrate the hull of the ship slightly. It requires some forward speed to do this, anything less than the optimum speed will cause it to bounce off, or pop open harmlessly next to the ship (not enough speed=dud on both extremes of range). To activate the warhead, it must hit a release on the nose of the torp, vibration won't do it, glancing blows won't do it. The only way to put your eye out with it is jab it in your eye on purpose. If it were to pop open against your leg you'd come off with no more than a scratch... the only way I can possibly imagine my design seriously injury somebody is if they swallowed one armed. | | | |
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Kotori87
Rear Admiral (RADM)
Posts:2279
| | 18 Jun 2008 08:17 PM | | I have a few qualifiers to add to Gascan's range experiment, because I helped him perform it. First, the test was conducted with the shots impacting the balsa perpendicularly, with effectively no angle whatsoever. Sure, we were able to penetrate at 30 feet. The trouble is, once you add an angle to the shot, it doesn't penetrate so well. I have seen lots of dents and dings from shots fired at point-blank range that hit at an angle. Once you start adding an angle to the impact, it doesn't go through. And it's not very common to get a good perpendicular shot on your opponent when you're more than 6 feet away.
Second, during the tests, we missed. a lot. I'm talking less than a quarter of the shots we took were hits. And that was even after we got a laser pointer to help make our shots more consistent. The reason Gascan stated that maximum range was 30 feet was because that was the maximum range we HIT the target at. I have no doubt that the shots could go through at longer ranges, probably 50 feet or more. And most of that inaccuracy was minute changes in elevation, of the sort that you encounter with simple wind and waves on the pond. In 1/72 scale, the rocking will be less noticeable, but it only takes half a degree to miss completely at 20 feet range or more.
I do think that you will notice an increase in engagement ranges if you go up to 1/72 scale. However, it will be because your guns cannot depress as much for close-range engagements, and because your maneuverability will be less. Your accuracy will also drop significantly. The only way to get accuracy up high enough to actually consistently damage a ship at long range is to install onboard cameras, and that opens up a whole 'nother can of worms.
I can understand extending torpedo range out to 3 feet. But beyond that? it's too much. And when I hear 1- or 2-hit sinks? That's WAY overdoing it. Forget about historical reality, a 1-hit sink can ruin a person's day, and that's not fun at all. | | | There are 101 different types of people: those who understand binary, those who don't, and those who just can't count... | |
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Gascan
Veteran
Commander
Posts:777
| | 18 Jun 2008 11:52 PM | | Not to get off topic, but while searching for video of RC submarine torpedoes I found a thread about some depth charges. Don't get any funny ideas, these were made with pyrotechnics, which are illegal in most clubs. http://s181686668.onlinehome.us/phpBB2/messageboards.php5
Does anyone know of a video of torpedoes being fired from a model, so I can get a better idea how they behave? | | | |
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PreDread
Ensign
Posts:173
| | 19 Jun 2008 12:29 PM | | Kotori87,
What sort of cannon were you using for the tests? Thickness of target? Was the gun fixed or was it on a (floating?) ship?
Another thing to keep in mind with 1/72 scale in the increase in barrel length if realistic scale barrels are enforced. 12"/50 in 1/72 would have a barrel around 8" long. A machined, tight tolerance barrel, and an accumulator big enough to take advantage of it, may increase the range and accuracy of guns. You would also likely have noticable difference in the performance of a 12"/50 vs. something like a 12"/35... but thats a different discussion.
If a rolling ship is contributing to inaccuracy of the guns, some kind of roll sensor could be used with a director fire control (again this is simply hypothetical) to fire the guns when the ship is level.
The battleship Texas is fitted with a similar device because her torpedo bulges made the ship too stable... ruining her steadiness as a gun platform. | | | |
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Gascan
Veteran
Commander
Posts:777
| | 19 Jun 2008 02:12 PM | | I look back and realized that the link didn't work right. Heres the videos:
http://www.youtube.com/watch?v=ExA69prggRg
http://www.youtube.com/watch?v=JsR8kkvUZno
http://www.youtube.com/watch?v=AFOFBqXIGUg
You'll also find a couple frame captures in the thread, which can be found in the RC Submarine Videos section, under the thread "U861 under depth charge attack in minefield" | | | |
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Gascan
Veteran
Commander
Posts:777
| | 19 Jun 2008 03:21 PM | | The tests were performed using the two barrel torpedo cannons on my old Cadorna, whose barrels are three inches long after the bend and have an ID of 5/16 inches. At the time I was allowed to load two 1/4" balls per tube, but I only loaded one for the tests. I also did a safety penetration test and found that one ball required less pressure to penetrate the foam. The target was simulating three panels of a battleship, which the WWCC required to have 3/8" ribs with 3 inch inside-to-inside spacing. The 1/8" balsa had silkspan on two sides but no paint. The tests were performed in my backyard and were entirely above water. I started at five feet and worked my way back in five foot increments, firing directly perpendicular to the armor. The cannons were mounted in the boat, but that was braced against a bench so I could adjust the elevation. I had a bed sheet behind the target to catch missed shots and that also allowed me to see the laser pointer I used for aiming. At 20 feet I could hit the target pretty well, but after that it was more luck than anything else. I don't know how much a tighter tolerance barrel will help accuracy. These are smooth bore guns, not rifled, and they are firing round shot. If you extend the effective range to thirty feet instead of twenty, you will still have to deal with the wind and waves interfering with the shot, the rocking of the boat, and the problems of aiming when you're not on the ship yourself, which get worse the further away you get. It'll be very interesting to see, though I think it will be more expensive that I am willing to pay for the benefits it will provide. | | | |
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Mike Horne
Ensign
Posts:234
| | 30 Jun 2008 10:36 PM | | Moved from other thread:
It's something that generates a lot of initial interest in people freshly exposed to the hobby... and lots of people want to build a sub. Technology is getting to the point where it is more and more likely to see subs appearing. Like sales, the only way to discover and counter objections is to talk them out. Lots of talk :) So, a lot of theories will be tried and discarded... and a lot of designs will sound promising and fizz out... but for the people who enjoy challenges... It's a lot of fun to consider. When there is a working design, to 1/96 or 144 scale... there are going to be some significant game play and balance issues to hash out.
For fast gun, from the outside looking in, I don't think they will go this route. I think it is too fundamentally different, and incompatible with the units as they are allocated today. The ship lists would have to be revised, and I believe that there would be massive resistance to that. But there is probably a lag of at least year or more in my opinion right now anyway. So no worries there Boomerboy.
Mike | | | |
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Mike Horne
Ensign
Posts:234
| | 30 Jun 2008 10:59 PM | | Oh heck, I've lost where I've seen it, but I think Kotori ( I think it was Kotori) had a wonderful idea in a torpedo that vented it's propulsion and or firing gas if sailing out of the water. Dud rates being what they were... this would be a good simulation if the venting is enough to render said torpedo ineffective. Doesn't run true... doesn't work. Firing could be slow bleed to propulsion, ending one of John's concerns, and the range might be limited due to the nature of the corrections (venting gas) working on another issue
some food for thought.
Mike | | | |
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PreDread
Ensign
Posts:173
| | 01 Jul 2008 01:01 PM | | Mike,
That was Kotori's idea, and the idea is sound in theory. However, it massively adds the complication (and weight) of the torp. Every gram will count in these things, and an elaborate venting system wastes weight for a problem that has yet to proved as existing.
I have yet to find a story where a propel torp rockets out of the water. Most of those torps are held on their firing pins by friction. Propel gas was chosen for its ability to provide a slow, steady thrust over a period of time.
I've become a real supporter of pager motor powered torps, there is no way they can rocket out of the water, and they wont "cook off" at the wrong time.
As far as torps running erradically, its one of those things that happened in real life, and it will happen in scale. Ships have been sunk by their own torpedoes. I think the chance of torps failing to operate correctly, run straight, failing to "detonate" at anything but near perpendicular angles to the ship will all self regulate the use of locomotive torpedoes.
Even if 1-2 will sink a medium sized ship, that doesn't create an unfair advantage provided that the torps have high failure rates (and they will be small enough that they will have high failure rates). Torps will be a weapon that demands respect, but they won't cause an unfair shift. | | | |
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Mike Horne
Ensign
Posts:234
| | 01 Jul 2008 05:34 PM | | Perhaps there are two designs electro and compressed air. I favor compressed air. If I'm thinking right, the ball could be done with intersecting holes of differing diameters, figuring the ball and how to get it in there aside :)
What is Propel? if it is flamable, then there will be problems (ugh!) but I have not looked it up yet.
A side note, if the body of the torp is made with white polypro... then an embedded led will be easy to see for recovery in the evening.
That said, if the electro motor torp has this provision, with a slow bleed on firing air supply... there are some possiblilities.
If the slow bleed is timed to expire the torpedo at the end of it's range :) You may also get the streak.
luck!
mike | | | |
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BoomerBoy17
Rear Admiral (RADM)
Posts:2099
| | 01 Jul 2008 08:28 PM | | I think that compressed air would be safer and more reliable, both in attaining and using the torpedos. good luck, remember, no explosives! | | | Even though I walk
through the valley of the shadow of death,
I will fear no evil,
-Psalm 23. | |
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PreDread
Ensign
Posts:173
| | 02 Jul 2008 10:36 AM | | Propel is a low pressure, liquified gas.
Its similar to the "air duster" cans used for blowing dust out of computers. As far as I know it is not flammable.
While I do think it is perfectly safe to use to power torps, I still think pager motors are just as safe and far easier to use and re-use, since it is just a question of changing a battery or recharging a capacitor. | | | |
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Mike Horne
Ensign
Posts:234
| | 02 Jul 2008 12:04 PM | | The msds data bases have many propel(s)... searching for the word propel only yields only a few. I posted what I found on it on the technical thread, but if the msds I found is the correct one, then it is bad news.
Mike | | | |
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