As far as big gun goes, I have seen mentions to JC White cannons, Indiana cannons, Canister cannons, Stomper cannons, and negative pressure cannons. What are the basic differences between them? What are the pros and cons of each? Disregarding ease of manufacture, which is best (air usage, firepower, reliablility, ease of maintenance and repair, space requirements)and why? Does anyone have any links to the basic workings of any of the above?
Carl started a thread on different cannon designs but never finished it. It talks a lot about big gun cannons, including the breech and valve types and stuff. Because he never finished it, it doesn't cover all the different types of cannons. http://www.rcnavalcombat.com/rcnavalcombat/forum/topic.asp?TOPIC_ID=181 Some of the terms you mentioned refer to general design aspects (negative pressure, cannister), while others refer to specific designs (JC White, Indiana, Arizona). I'll start with some of the general aspects, then cover specific cannon designs. Negative pressure cannons have a different actuator, which causes them to fire when pressure is drained, instead of the more common actuation when pressure is applied. Cannister cannons refer to the use of a large diameter, short accumulator underneath the cannon, rather than the more common version which uses a longer, thinner accumulator that runs off to the side of the cannon. Closed breech has a piston of some sort to prevent air leaking out of the breech. Tandem cannons refer to a cannon that has two separate rotating magazines fed from a single accumulator. The JC White cannon is the same as the Indiana Cannon. One name refers to the inventor, the other to the first ship it was installed in. It may also be called a BDE cannon, since that is the type that BDE makes. This is the standard big gun cannon. It fires on positive pressure, as an accumulator off to the side, has a rotating magazine, and can fire multiple barrels from a single valve. There are a few minor variations, such as low-profile designs and fixed cannons. Torpedo cannons are similar to Indiana Cannons, except they lack the separate, rotating magazine. The barrels come directly out of the valve. Some have a small magazine and breech for each barrel, but most are non-reloading. The Arizona cannon (also called the MJV-2 cannon) is similar in basic operation to the Indiana cannon, but uses a clippard MJV-2 valve instead of a home-made valve. It can be open or closed breech. Only a single barrel can be fired from each valve, so multi-barrel turrets consist of several Arizona cannons chained together. These cannons do not rotate. The Stomper cannon is a closed breech, negative pressure, cannister style cannon. It is especially unique in that the whole magazine drops down to close the breech when the cannon is fired. Until recently, the only working samples were four-barrel 1/4" caliber cannons intended for the French boats. Sliding breech cannons are wholly unique and separate from other big gun cannons. As far as I have heard, no one has installed a sample in a boat yet, though they show great promise. O-ring or restrictor tube cannons are not very common in big gun. Some examples include the piston-selector cannon (also called the Swampy cannon and BC cannon by some big gunners), spurt guns, the Jam-Elbow Gun, the Trombone Gun (I still need to find out more about this cannon) and the two-barrel "hybrid" or "cannister cannon" being developed by Greg (archer183). I am still trying to find photos of some of the cannister cannons I have seen. The open breech used by most big gun cannons. The two balls overlap, so when one is fired out the barrel, it pushes the other ball back up the magazine, and prevents it from firing multiple balls per shot. An Indiana cannon made by BDE. You can see the accumulator off to the side and the rotating magazine on top of the valve, though the actuator is not visible because it has been built into the valve. A tandem Indiana cannon made for a Montana. Note that there are two magazines, but only one actuator, valve, and accumulator. A single Arizona cannon. You can see the accumulator, MJV-2 valve, MPA-3 actuator, and the breech. A multi-barrel Arizona cannon. You can see how it consists of three single cannons chained together. A pair of fixed torpedo cannons. They are the same as Indiana cannons, but they don't have the separate rotating magazine. A pair of unassembled fixed Indiana cannons. The valve, actuator, and accumulator assembly is exactly the same as a standard Indiana cannon, but the magazine lacks the rotation mechanism and has a square shape.
Thanks, That clears up a lot. Now that you mention it, I think I've seen either a picture or conceptual drawing of one of the stomper cannons, but I don't remember where. The pictures are awesome, The one of the cannon for the Montana shows some big time shock and awe!!! That thing could scare other boats into sinking!!![}]
You may find it interesting that our ruleset only gives Montana 8 guns. This particular Montana was intended to be a two-person boat. One person would drive and operate a single triple turret in the bow. The second person would be a dedicated gunner operating the other five barrels off the stern. Because of the difference in the number of barrels for the two magazines, one held about 900 rounds while the other had 600, as I recall. The ship carried two 20oz bottles and would have lasted for more than 30 minutes of continuous firing. It was intended as an area denial weapon: park outside the opposing port and totally deny the opponent access to their port. With one person focused entirely on gunnery, there would always be steel flying at any threat. Having two people would also make handling the massive ship easier, especially since the builder has a bad back. You're right: every aspect of that boat was meant to be serious shock and awe power. I have seen conceptual drawings of the negative pressure cannons, but not one that contains all the elements of the stomper cannon. Last time I saw one, I was operating an unarmed transport after joining the club. All I knew was that it sent four large balls at me. Recently one member has begun working on reproducing the design, so we may see the stomper make a return.
That explains it, I was wondering why there was only 3 barrels per turrent. More questions, When both turrents are fed off of the same accumulator, is there any difficulty getting all barrels to fire with reasonably equal force? Seems like it would be difficult to dial in. Also, it looks like those particular magazines hold multiple layers of balls.... Do they feed ok??
Yes, tandem cannons often have problems with imbalance. One is usually more powerful than the other. In this cannon, the builder test fired it without the magazines, and felt the pulse of air from each outlet with his hand. He then sized down the more powerful hole until the pulse was about the same. The ship has not been completed, and I don't believe the cannon has been fired with live ammo, much less a full combat loadout. I don't know if it will feed properly with two layers or not.
