I am trying to pick up as much info as I can. I have a full USS South Dakota class kit from BC - awesome to begin with, and great instructions. I know its a big one to start with, but she's my home state's namesake and she got a really bad rap from historical records, though her sisters did well, and I'd like to do her proud. I had a few initial questions that I hope some of you experienced vets could help with, and sorry if they sound naïve, but I have found it is always better to ask questions first from those who know. I have pretty good building skills, but some of the electronics stuff I have questions on. BC and Strike have been very helpful in some of my questions, but I had a few others that have come up. First one is one pumps and motors. I have taken advice and am planning on using a pair of Powerizer 3.2v 20 Ah LiFE batteries for drive motors and a Mtronics Viper 40 for ESC. Do I need to use separate battery for the pump motor (same 550 as BC for drive motors) or will it work okay if they all run off the same batteries? I know the ESC controls the drive motors speed, but does it affect the pump speed too? Also - based on some of the threads - would it be better to use a pair of Viper ESCs (one for each motor)? Thanks for any input I can get! There are a few of us up in northeast SD and southeast ND that are just getting into this amazing-looking and fun hobby, and we could use any help we can get!
You can use the same batteries for pump and drive. You should probably plan to put more batteries in than just the 2, you'll need the ballast anyways. Your selected ESC would drive only the drive motors (though you could wire it to your pump as well, it would be bothersome to have it reverse every time your ship did, and to not pump when you sat still). You will need a electronic switch/relay/servo driven switch/ aircraft ESC to control your pump. The viper 40 is quite capable of driving both motors under non-stalled conditions. Some folk prefer to have a redundant arrangement and run one ESC per brushed motor. I personally don't view the viper 40 as a likely failure point but I do like to have a fuse between the ESC and each motor to forestall any potential problems, some people prefer to fuse between the batteries and ESC, and others simply don't fuse and rely on the ESC to protect itself.
Batteries: You will want to put 4 in, they only weigh slightly more than 6 lbs total and a SD has a ton of weight and room. I personally prefer to run the ship at 13 volts (batteries in series) which gives a higher available torque and theoretically a slightly better efficiency. If there is power at the lake it is possible to charge LiFePO4 batteries in the ship between battles if you set it up right. ESC: I prefer chinese brushless, they have a ton more available torque than similarly sized brushed motors, which translates to improved turning ability, better acceleration, and higher pump capacity. In my case they have been cheaper than a brushed setup using Titan marine motors and Vipers, in two weeks of battling 2010-2011 I lost 6 vipers (mainly because the battery eliminator circuit can't take even the slightest abuse, has no protection and cannot be removed, also plugged in a servo connector on one shifted over one pin and fried it), 7 Titan marines due to brush spring failure (they don't like to run under water for even a couple seconds). Also had a problem with cross-talk between multiple vipers through the signal wires that would cause them to stutter, which I do not know if the manufacturer has corrected. Since 2011 with 4 weeks of battle time I have been running a 3 motor brushless setup with a total of 1 failure of the speed control, due to water infiltration into a mosfet (void in waterproofing), and 0 motor failures. This is just my personal experience and preference, others have reported having problems.
When running multiple ESCs, you should pull the power wire on all but one ESC. That way only one ESC is supplying power to the receiver. When multiple ESCs are supplying power to the receiver, there tend to be somewhat random problems that can be hard to track down.
Yes that is good general troubleshooting advice for this sort of problem rcengr, but exactly that was done before power was ever put to it, center pin pulled from the connector. Went through the EE advanced checklist, it is an internal problem with the vipers we were getting around 2011 passing garbage back through the receiver Y-harness and losing signal sync for a couple cycles, going full reverse instantly and causing pretty sparkles from the brushes and nasty gnashing from the gears. We even tried some pretty hefty power filtering. I don't know if the viper has been corrected by the manufacturer since then, and after 4 years of trouble free operation from the far cheaper (half the price) HK brushless ESC I'm not going to go back and recommend brushed to anybody, especially when a properly built and maintained brushless setup will run rings around it for years and is cheaper to boot.
Just an FYI, if you go brushless, each motor must have it's own ESC. As others have pointed out, when running multiple ESCs, you must bypass the battery elimination circuit (cut the wire) to all of them except one.
Thank you everyone for all the info! I have been reading up on brushless motors on the site and it does seem to be where the "magnificent distraction" is going. I'm just starting out, and the SD kit I got from BC has (2) 550 brushed motors in it for drive, plus the brushed pump/motor I got as well. As I am just beginning, Ill probably stay with those to begin with, and use the Viper 40 on the motors. Is it better to have separate battery for the pump? It does appear that I have more than sufficient room for one, and I can see the advantage in it. REALLY dumb question here, but I will ask anyway - don't the motors/batteries, etc. get damaged during a complete sink, or is that just my naivete showing again? I have read in all the descriptions I have read across the various websites that everything can get dried out, but just my simpleton layman understanding says that live electricity + water + bad. I can build and even do soldering, etc. But I am not an engineer- they just teach us the basics in architecture. Thank you all for your patience!
The motors we use will run in and under water. Once out of the water they usually benefit from being flushed with electrical contact cleaner or alcohol, and the bushings/bearings lubricated. The batteries (LiFePO4, SLA, NIMH) dgaf about water so long as you keep the contacts in good condition and they remain sealed. More sensitive bits like firing boards will get waterproofed with a conformal coating such as Scotchkote and/or stuck in a watertight box (often jokingly referred to as a water retaining box by those who have had them fail). Exposed servos... there are a few schools of thought on them, covering some options to make them more water resistant, buying supposedly waterproof servos and for some folk, simply drilling holes in the servo case and routinely flushing it out.
A forum is lurk about has a guy building azapods for rc tugboats and uses the cheap brushless outrunners so it is submerged the entire time and has had way less problems with them doing so. another group took that idea and uses them in submerged bilge pumps and they last 2-3 times longer than purpose built motors for the same apparently.
Outrunners in my experience are very durable, they run even when the bearings are shot. Plenty noisy but they run. When toasted then you pound out the ball races and press in some bushings, simple and then very durable.
I consider this a feature - I can check if my pump is functioning just by turning it on and listening, even from across the pond.
I try not to run leakers... no water doesn't always mean that the pump is broken, there may not be any water in the ship.
Thanks to everyone for all the info! Next round of questions is on the current recommendations for RC transmitters/receivers and modifications thereof. I have read a lot on this site, and have seen recommendations for the Hobby King T/R sets (6 channel). I have seen the recommendations to wait on radio stuff until everything else is done, as radio tech is always updating/changing. That seems like very good advice, but I would presume that I should plan the various ship functions with an eye towards the RC system I end up using, I am building the SoDak kit from BC, with the triple stern and 2 front sidemount configuration, using servos and poppet valves for cannon firing. Two 550s for drive, I have already bought an MTronics Marine Viper 40 ESC for speed control for the drive motors. Servo switch for pump. Kinda old school, as I see on the Warship Build section, but it seems like a good way to start out and learn. So: on the old Futabas (2 channel) we used to use just to drive our little plastic model boats (1/350 scale) around our creek inlet, we just used the right stick for propulsion (with ProBoat ESCs for speed control) and the left stick for steering, Pretty basic, but that's what led us into this awesome hobby... But now, I need to trigger the guns as well, as my friends and I hope to join up someday with the nearest club (Port Polar Bear) in the Twin Cities, and I'd like to do it right. I presume a 6 channel system would be minimum from what I've read, plus the BC instructions info: 1: Forward/Reverse, 2:Left/Right, 3: rear triple sterns, 4: Left Front Sidemount, 5: Right Front Sidemount, and 6: Pump. I understand how to set them all up with the ESC for the motors, servos for the poppets and pump control switch off a servo from the diagrams, but: I have been looking, but is there a guide out there for assigning functions to an RC system that would be recommended, and where would a newbie like me start? I bet its probably in this site somewhere, but I would like to get some current opinions, if anyone has some info? Thank you!
You need a min of 5 channels. Radios mostly come in 6 channel. The most popular are 2.4ghz radios. Futaba and Spectrum are the two most popular brands. You can also use 75mhz radios. I have these from Futaba. Like everything else best to get stuff that people in your area use so there are spares and help in programing. The PPB guys are Spectrum and Futaba heavy. When you are ready I will put push buttons on the radio to fire the guns. It's an hour or two job I have done countless times. Don't use popits to fire the guns. Get solenoids, these are 1000x better. If you want to "go cheap" use swicthes and servos not the electronic boards to fire them.
A lot of people seem to use the Kip solenoids, from what I have been reading on this site. Are these still the 'go-to" type or are there better/more advanced types that have not been discussed? Thanks for the radio advice too!
Strike Models sell solenoids by Sparten. I have seen them, I have not taken them apart, if they even come apart. The local guy with the just got them and has not used them yet. Battler's Connection sells the Kip brand. I have used these since 03. The only failure I have heard of was some failed wiring that lead to the magnet in the solenoid heating up and melting the wires to it. I'm not sure of either one's tech data. Sparten's are a little cheaper. Kip is in high use for a long time. The Kip work well with Clipard parts. The SParten have a bigger opening that needs an adaptor to get to the 10/32 Clipard size. Like so many things, two choices that can both be done right.
We had a long-ish talk about this at the Memorial Day battle this weekend. The end result was that we think the Kips are the way to go, if only because they are actually rated for 150psi (or more). The Spartans are rated at 60psi. They can handle 150psi (Strike has tested the ones that they sell to 180psi I think), but rated is what I look at for safety. Kips are definitely more expensive ($57 each at BattlersConnection) but I think it's a good investment. The bigger opening on the Spartans (1/8"NPT if I remember right) is not much of a disadvantage, as it lets you use push-quick fittings for better flow to the valve, although you need to use the adapter that Bob mentions on the gun side for the 1/16" tubing to the gun. For going cheap on firing Solenoids, I bought these cards at Pololu Robotics and Electronics and they are very amenable to epoxy potting (or liquid electrical tape which is on my current ones in Evstafi). They can be programmed to fire on the up-stick or down-stick motions. They cost $7.50 each and do well. Not saying that they're the best, just a good card to fire solenoids with.
