Hey guys, i thought some of you might have some suggestions here... i just got it this morning so i haven't had much time to sit down but i thought maybe you would know of something. My friend in Germany has asked for some help with his model of the SMS Derflinger. Note that this is not for combat. i've already told him how to get a smoke cloud by running a tube from the CO2 into a pillbottle of talcum powder, with another tube running to the gun.... (well i told him more details than that)...but this is the part i'm not positive of... My SMS Derfflinger will have four twin-turrets like usual two astern and two on the foredeck. I want them to turn and fire in groups fore and aft. But I also want them to fire half-salvos like they did in real battle. That means that e.g. the left barrels of Turret (A)nton and (B)erta elevate approx. 16° fire simutanously and go down. Then the right barrels come up and fire. Understood? And of course the same with (C)äsar and (D)ora Turrets.
Are we talking CO2 powered firing cannons? Does he have any embedded controller experience? How does he want to do it? electrically or pneumatically?
1 of 2 jobs in a combat warship that your standard R/C hobby servo is particularly well-suited for (the other being rudder actuation). JM
yes, there will be CO2 firing talcum powder, but not any projectiles. I dont think he has too much experience with radios... ..as for electrically or pneumatically it doesn't really matter as long as it works. But from what i understand, hopefully it goes automatically when he tells it to fire.
Servo would be the easiest way of creating a up/down motion. But he is talking about automation. He presses fire, the barrel elevates, blows dust everywhere, lowers... THEN it's casemate lifts, blows, and lowers. I can't think of a good way of doing that via standard hobby radios & mixers. He could pay an engineer to make it for him?
well to my disbelief, i actually figured out a system that only takes 2 servos to fire all 8 guns as he wants! I was sitting in class sketching out plans instead of paying attention (my forte') when i realized i had done it! i knew it was too good to be true (i'm not very clever when it comes to this stuff), and then it hit me... my system wont allow them to turn! so now i have to go back to the drawing boards or convince him not to have them turn...
A system of cams and pushrods with a servo modified to rotate thru 360? Lift-fire-depress, lift-fire-depress? One servo per turret?
not quite i understand, i'm terrible with electronics lingo... Would you mind doing up a quick sketch or explaining it in more simple terms for a moron like myself?
Well, it shouldn't be terribly difficult to elevate and fire each barrel in a turret separately. I'm curious if he also wants to fire full broadsides. Basically, I'm thinking he should start looking into microcontrollers. The picaxe would be a good place to start, and while he's at it he can work in a nifty gun director system as well.
he wants broadsides but not full... he wants gun 1 in A and B turrets to fire together, followed by gun 2 in A and B. Then with completely seperate controlling, the same thing only for C and D turrets.... he doesn't want all guns to fire simutaneously.
I think he has three options. 1.) kotori's... learn picaxe 2.) hire someone to do it 3.) a fully mechanical solution using push rods & servos, like tuggy said. As the servo is at 0% nothing happens, it turns to 50% the servo horn lifts the barrel (using a push rod), it turns to 100% the push rod is still being lifted & a trigger is hit which fires the gun, then back to 50% the push rod is let go and falls back down.. then back to 0%.
Well... Wreno on the big gun list is working on a fire control computer and after I get my tirpitz on the water with fixed guns that is one of my next projects (based on wreno's work) as a tirpitz upgrade.
yes, what i designed is somewhat like Tuggy's .... but the problem with it is the turrets need to turn!
You know... the more I think about it, the more I realize john was right. (Unclear, but right) Set it up like normal big gun... But instead of having the lift & fire on two channels, have them on one. Set the onboard "trigger" to fire only at 100% of the servo turn. So what will happen is as you lift the radio stick, the barrels will lift & when they are at their maximum the guns will fire. Now this will work well for a full broad side... so put each turret's barrels on separate servos & each firing mech on different (overall two combined) CO2 valves. THEN use two radio channels. ---BEYOND THAT--- He could get even fancier if he uses one channel's 0%-50% for barrel1's lift/fire/depress & 50%-100% for barrel2's lift/fire/depress.
hmmmmm..... i'm not very technical so i dont quite understand. I dont know how big gun is setup, and in fact i've never setup fast gun guns either.... remember he isn't firing a salvo, he's firing talcum powder... If you wouldn't mind writing it up as if for a "setup for dummies" thing... that way i'd understand it and so would he, as he's german so complex english he may not understand (and i wont either! haha)
I think the "big gun setup" refers to the servo layout. A Big Gun battleship usually has several servos for operation. One controls firing, front and back. Others (linked with a Y-cable) are located in each of the turrets, to depress the barrels. What Justin is saying is to have the servos in the turrets do the firing as well. As you pull the trigger to fire the cannon, the servo starts to elevate the barrel. When the servo reaches its maximum range of motion, it both presses the trigger, and reaches maximum elevation. I will draw up a diagram tomorrow.
Well, You've seen my experimental tirpitz turret (or part of it)... Part of its design req. are ease of elevation and rotation control. I actually plan on (for rotation) bonding a section of MXL belt to the outside of the canister magazine to turn it with another MXL belt (far easier than making gears!) and using a flexible tube from the magazine to the barrel to allow for elevation. The magazine will have a cap that fits into machined sub deck turret bases with round openings.. a piece of plastic cap and some occasional greasing and poof: rotation. more pictures once it is completed.
I don't know if there's any "right" or "wrong", but let me clarify a little based on what I know about the problem. Hobby servos are great for barrel elevation. In this case, 1 could be used for each turret. Depending on the size (scale of the ship wasn't mentioned, that I saw) it's going to probably take something pretty small to fit inside the gunhouses. I use Hitech & Hobbico sub-micro metal-gear servos for most barrel elevations. The shock of firing can tear up plastic gears, but that may not be an issue here. One servo per turret could elevate both barrels, acting as a cam. In the "neutral" or centered position, neither barrel is elevated; moving the servo up to full one way or the other could elevate one barrel or the other. Y-harnesses could be used to ensure that A/B & C/D operate together; servo reversers on 1 of each pair of servos could make them operate opposite, if a mechanical solution isn't practical. I don't believe that any turrets need to rotate > 360 degrees, so wrapping of elevation servo leads shouldn't be a problem. Rotation can be done either with a pair of servos or motors & reversing speed controllers. It should be easy enough to mechanically couple pairs of turrets together, so that only 1 motor/ESC/servo is needed for each forward/aft pair. "Firing", I don't know what he has in mind. Guns could be fired automatically by tripping a switch or valve as they reach full elevation, IF he wants them to fire only/always at full elevation & never at anything less. Otherwise, some other method will be needed. Controlling all of this is going to be a challenge. As long as it's not going to be used in combat, with other ships shooting at him, it shouldn't be that big of a deal - nobody will really know when he's shooting in the wrong direct, at the wrong time, with the wrong guns if it's all just for show. Here's a minimal breakdown of individual devices that need to be controlled (each meaning 1 control channel, in standard R/C): - Rotate A/B turrets - Rotate C/D turrets - Elevate A/B turrets (include auto-fire?) - Elevate C/D turrets (include auto-fire?) - Fire A1/B2 or A2/B1 (R/C can fire 2 guns per channel) - Fire C1/D2 or C2/D1 Using a standard R/C set, that's going to take a fair number of channels & doesn't even cover propulsion, rudder, or anything else that he might want to control. Double the firing channels if you want/need anything other than half-salvos; eliminate them if auto-firing on full elevation. Using a microcontroller sounds sexy. Servicing all those servos isn't going to leave much time to "do" stuff, so I'd use a dedicated multi-servo controller, freeing up the micro to sequence them & ship servo commands over a 2-wire serial interface to the dedicated servo controller. The question then becomes, how do you get aiming & firing data to the microcontroller? You need to tell it where to shoot, & when. What form should this data take, how should it be transmitted from shore to the ship, & what sort of user inputs should be used to generate the aiming/firing commands? JM
Whoa John! I think you are over complicating. If I understand the problem correctly, it is just for show. He is going to put it on a shelf and fire the guns once a while for show. I think using the servo with the fire switch at maximum would be the best solution. However, john has another good idea in there... Use one servo / turret ---> 50% means no barrel is lifted, 100% mean barrel1 is fully lifted & fires, 0% means barrel2 is fully lifted an fires
