Submarine Torpedo Launcher for Battlestations!

RE: Spring Torpedo Launcher for Battlestations! Ok, time to try this again, with some new ideas this time. Instead of the scale rod, I'm going to use 1/4" ball bearings. The tube will be made out of 1/4" i.d. pipe. It should be sturdier than the copper and easier to cut. I think I'm going to drop the cocking rod to save space and weight, and also make it simpler. I'm also going back to the original Idea of putting the firing pin in front of the ball bearings to hold them and the spring in place before firing. I shouldn't have too much of a leak as long as I grease it good. I do have a few questions for you all. First off, what spring do you all think I should use? I'm hoping to make it small enough to fit in a 1/96 Gato submarine for Battlestations. If I can get it to be just a bit over 1/4" dia., then I might be able to fully arm it with 6 tubes in the front and possibly 4 in the rear if I can figure out the spacing issue. Secondly, how should I fire it? Should it be fired by a servo controlled by the transmitter, or should it be "bump fired" like the ones in the WWCC. Right now I'm leaning toward using micro servos to pull the firing pin, provided it has enough power. Any ideas are appreciated.

 

RE: Spring Torpedo Launcher for Battlestations! Pretty sure that a micro servo, or even a standard servo, will not have enough power to pull back the spring you will need to get half decent penetration results from the ball bearing.

The manual cocked launcher sounded like the best bet considering that to reload, the sub has to come back to shore anyway, right?

Of course, just going with a compressed gas fired system would be the easiest solution IMO.

 

RE: Spring Torpedo Launcher for Battlestations!
You're right that it wouldnc't have enough power to compress the spring, that'll be done on shore manually.The servo would just pull the pin that keeps the spring compressed an the bearings in place. Regular CO2 guns would be easier I agree, but I like the weight and space savings, plus it's cheap, which helps alot. It's also fun to make little launchers you can supprise people with the next time you have a paper war

 

RE: Spring Torpedo Launcher for Battlestations! Now thinking about it, I may end up going the pneumatic route. But how?

 

RE: Spring Torpedo Launcher for Battlestations! I'm trying to figure out a way to save weight, so I'm thinking of possibly going around using a CO2 tank and using 1" by 3" accumulator tanks for each set of tubes. Turned sideways, they should just fit inside the hull. I do need some help though to figure it out. First, would that sized tank work to propel four 1/4" Ball Bearings fast enough to pearce 1/8" balsa? These would just be one shot weapons, so I'm hopping it won't take much gas. Also, what firing valve should I use, a Mav-2 seems to be too small to allow enough airflow to get the bearings moving fast enough. Any help would be appreciated.

 

Below is what I am using for single shot underwater torpedoes in my 96 scale Henri IV. Ball bearings are loaded muzzle loader style and held in place by a magnet glued to the end of the barrel. Accumulators are 1 cuin, the valve is a Clippard JEV - 58 scfm or about 8 times a MAV-2 flow. I've fired them a couple of times but they are not fully tested.

 

I see how the red line fills the accumulator tanks, is the blue line used to fire the gun? If so, how did that work? I haven't messed with valves to much, so I'm not sure how all this stuff works.

 

Would it work charging the tanks as stand alone tanks, and using a 12 oz Co2 cartridge attatched to a Mav-3 which splits to reach three cannons, firing three of them at once?

 

Close, guys, but not quite. The JEV is a quick-exhaust valve, meaning it vents (fires) when pressure is REMOVED from the blue line. To charge the cannons, gas is applied to the blue lines, charging the accumulators. To fire the cannons, gas is removed from the blue lines, probably by a SMAV-3 or a slightly different type of MAV-3. The red lines are only to allow safe de-pressurization of the system, without triggering the firing mechanism. I have thought about using JEV's in my destroyer Z-25, in place of the current MJV-2 valves. But since I do not have foam to re-test the guns afterward, I don't want to upgrade and lose their current foam-tested performance.

 

The valve is a quick exhaust valve (QEV), so it is filled through the blue line and also fired by the blue line. As long as the blue line is pressurized, the valve is closed. When I vent the blue line, the valve fires. The red line is the accumulator vent. Since I can't vent the accumulator through the blue line without firing the valve, I have to use a separate line to vent the accumulator to safe the system.
If you have filled the accumulators on shore, there is no need to have a 12g cartridge on board. You could vent the input lines for all the QEV valves at once through a MAVO-3 or even a SMAV-3 (configured for N.O.). If you want to close the valves after firing and keep the water out, a smaller accumulator on the input side of the control valve should suffice.
I have some more details in another thread: http://www.rcnavalcombat.com/Forum/...fault.aspx

 

Would it be less weight to connect the tank to a MJV-2, which in turn connects to the guns? I'm believe I need 6 cuin of Co2 to fire all six guns, but would it be better to have three tanks set up to fire two barrels each, or have one or two tanks connected togethether to fire all of them at once? If I catch a half sunk ship, I would prefer not to shoot her with all the tubes, and have none left to go ater anyone else.

 

I don't think it matters if there is one accumulator for three barrels or an accumulator for each barrel.
My experiments have made me believe that for reliable firing, each barrel needs its own valve. When running tests, I also found that the higher the valve flowrate, the smaller the accumulator needed. So if you use one MJV-2 for three tubes, you only have about 8 scfm flow for each tube. Also, one tube might get 8 scfm, while another gets 12, leaving 4 scfm for the last tube. That is a significant difference from each barrel having 58 scfm.
I would suggest setting up experiments with the different configurations you are considering, that's the only way you are going know for sure if it will work.

 

I could see how you would be able to fire multiple QEV valves all at once, but how do you do that with a MJV-2 without using a servo per valve?

 

You screw a MPA-3 on the MJV to turn it into a pilot actuated valve. Then all you need is a small 3-way valve to control the pilot pressure. Since the control valve is only providing a pressure signal, not flowing a large volume of CO2, it can control several actuators at once.

 

Sorry for all the questions, I didn't have a very good grasp of how all this works. I may go with the QEV setup since it seems like it's simpler and more compact.

 

The QEV is lighter and more compact, but not simpler. Since removing inlet pressure is what fires the QEV cannon, it requires extra configuring and parts to safe the cannon without discharging it. MJV valves are most commonly used because of how simple they are.

I have also run some experiments comparing QEV and MJV valve, along with two different lengths of barrel and two different accumulator sizes. I'll do a more extensive writeup on the experiment once I get back from leave, but basically in order to take full advantage of the QEV, you need a larger accumulator and a longer barrel to benefit from its higher flow rate. With either a shorter barrel or a smaller accumulator, the result is not much different from a totally stock MJV cannon.

 

Since space and weight are an issue, I'll probably end up with a QEV setup. Since I'll probably use just one tank, would connecting the tank to multiple valves using hose work without having uneven flow rate?

 

I recommend keeping the hose from the accumulator to the valves of roughly the same length and with the same fittings to minimize flow variations. There will be some variation, but hopefully it won't be too much.