I will continue to use the Liberty Ship as a learning bead. I plan to go brushless I read through the Brushless 101. Gave me a head ache. I have no desire to be on the bleeding edge. I plan on a direct drive system 1.5”, 4 blade, 27deg pitch prop. (open to suggestions here) With a speed of only 34, I would think that the motor would need to be 100kv or less. Looks like my options are either 750kv or 1000kv. I didn’t see anything in an inrunner that fits the bill. Outrunner options http://www.hobbyking.com/hobbyking/..._140w.html $14.99 http://www.hobbyking.com/hobbyking/...Motor.html $13.40 http://www.hobbyking.com/hobbyking/...000KV.html $15.99 http://www.hobbyking.com/hobbyking/...000KV.html $15.58 It’s a Liberty Ship ESC on the cheap www.hobbyking.com/hobbyking/store/_...verse.html Am I on the right track here?
Here is a motor suggestion. http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=5691 Kv(rpm/v) 860 Weight (g) 72 Max Current(A) 19 Max Voltage(V) 11 Shaft A (mm) 3.175 Length B (mm) 36 Diameter C (mm) 28 To me the important stuff is that this motor can mount on a 19mm or 16mm pattern. It already has a 1/8" shaft. So generic couplers used in this hobby will work. A bit more power and speed than needed. However that is why ESCs are awesome... just dial it back. It also has favorable reviews. I like outrunners vs inrunners because they are easier to flush out and maintain. However they spin so dont let things roll/droop/poke into their openings. Secure your internals in your ship. Also I can highly recommend the following ESC from Mtroniks also available from Strike Models. There is also a 30A version. Just in case you want a large safety margin. http://www.mtroniks.net/prod/Boat-Speed-Controls/Hydra-15.htm They are not cheap ($80-95) but the ones I have used are flawless. The BEC is very good (clean power). Aaaaand they come waterproofed from the factory. Mine took 1 minute to set up once plugged in. It is also reversable.
Thanks Mike, yes 6 volt. The motor looks like a good one. The speed controller looks too pricy for a Liberty ship. "famouse last words" if I don't get the cheap one waterproofed. Keith
Hey, Keith, The motor that Mike linked is a very good deal. Not only do you get a good motor, but a spare shaft, connectors, plus a bunch of other goodies. The ESC you linked will work well for that motor. Just be careful with it. If you accidentally short it out, consider it junk. But if you waterproof it well, and don't short it out, it works well. Might be good idea to order a few extra just in case. Also, don't forget to get a programming card for the ESC, otherwise it will be useless to you. http://www.hobbyking.com/hobbyking/store/__9550__HobbyKing_Programming_Card_for_Car_ESC.html Also, check out this, might be able to save a little on stuff. http://rcnavalcombat.com/Forum/tabid/58/aff/538/aft/443644/afv/topic/Default.aspx Good luck, Caleb
Famous last words.... still doesn't negate the fact that you can trial and error 2... run the 3rd... and have 2 backups for the same money. I just prefer the "buy nice not twice" methodology which is counter to the way many build their boats.
Still using the same hobby king ESCs and brushless motors here in my SMS Gneisenau after two years of use. I prefer nice, reliable and cheap.
I am going cheap on the Liberty ship. We will see how good of a job I can do on waterproofing the ESC. Convoy ship spend a lot of time “wet” so it should get tested. I haven’t decided which way I am going on the Barham. It will require (2) speed controllers for brushless. At $80.00 a piece plus spare. My Washington is old school with MAG switches and 550 brushed motors. Always been reliable. Nice tip on HobbyKing. I had that pop up yesterday when I left the ESC sitting open. Nice to know it will come back. Keith
I think you will be pleased with the hobby king escs. When I waterproofed mine I just unscrewed the green casing painted the board with epoxy and poured some more epoxy into the green casing and screwed it back together. I use the 60A version but they are nearly the same.
You beat me to the next question. I just ordered it, and was waiting to get it in hand. I am only ½ hour from the Western US warehouse, so with any luck I will have it tonight.
If you want to go brushed with your Barham, check out these ESC's. http://www.hobbyking.com/hobbyking/store/__32025__HobbyKing_X_Car_45A_Brushed_Car_ESC.html They work really well, and are cheap. Plus they are very durable. I've shorted one out and had smoke coming out of it and it still works perfectly. You live 1/2 an hour away from the HK US warehouse? Man, I'm jealous.
I like the price on that one. I am going to slow down and see how I like brushless. with my Liberty build. 1/2 hour from work. No shipping from HK
Wish I was that close... sort of. The shipping from WA isn't that bad though. Much cheaper than from China. Good luck on the Liberty.
The 750 Kv motors on 6 volts will work with the prop you specified. I run the 2nd motor you listed, with that prop and 6.6 volts in my Alaska class cruiser. I'm at 92% throttle to make 25 seconds, but also a lot heavier and longer than a Liberty ship. I also have the NTM motor that is first in your list. I like it better than the Turnigy, since the Turnigy makes more noise when starting.
Picked up the ESC and Motor yesterday, and I have a couple of more questions at this point. Remove 4 screws Skotchkote or epoxy on the board. Both will work, is there a preference? I assume that the “can” on the outside also gets coated in Skotchkote? What about the Key/switch. I bought the programming card. On off switch. I see it as a point of failure. Should I be able to get a jumper so that it is always on when the battery is plugged in? Three blue wires on ESC, Three Black wires on the motor. Surly it must matter what order you connect them. Keith
Skotchcoat or epoxy, both work fine. I've recently been using E6000 adhesive to waterproof stuff. Works very well, and is flexible. You can waterproof the can. I'm not sure if it makes a difference. I would just make sure to coat the solder joint to reduce corrosion. The key button, I've never had any trouble with it, and I never coated it in anything. If you don't plan on using it, might as well coat it in something to reduce the possibility of something going wrong. The on/off switch will need waterproof if you expect it to last very long. I'm not sure how to do it myself, but somebody else might know. There is no particular order that the wires need to be in. Hook the wires up and it will work, just might not spin in the right direction. If the motor is not spinning in the desired direction, just swap two of the three wires, and the motor will reverse.
I prefer using epoxy, as its more readily available. Skotchkote will work also, they are both good IMHO. That can is a capacitor, I just dripped some epoxy on the leads on the bottom side till the shrinkwrap was filled I don't believe any other part of the capacitor requires waterproofing. I believe the button is for programming the ESC without the card, since you have the card, feel free to epoxy over it. I haven't had the "on/off" switches fail on either of the ESCs I use yet. You can jumper the connection so that it is on when the battery is connected, I know some people do, or just wait till the switch fails. The three wires that go to the motor, it does not really matter what order you connect them in, unless the motor is spinning in the wrong direction. Then you can either just swap two of the leads, or reverse the channel on your radio transmitter. Hope that helps some.
I have all three. Epoxy, Scotchkote, and E6000, I think I’ll go with the Scotchkote. I’ll order some jumpers off e-bay. Looks like I can get 100 shipping included for $0.99 from China. (How do they do that???). I’ll leave the key/switch for now. I want to see how the programming card works. Keith
I've done 10 of these. On off switch, replace with a jumper. Scotchcoat the key switch, even if you epoxy everything else. The card is unreliable and probably will not last a year. I scotchcoat all the wires where they enter the insulation at either end (I assume they corrode when wet inside the insulation, especially in cuso4 laden water). I got lazy on the last 6 and just scotchcoated the outside case, including the edge of the heatsink. The moisture sensitive mosfets are under the heatsink, the heatsink cannot be removed without destroying them if you fill the case with epoxy. The first batch I did I filled the yellow case with epoxy and encased the outside in epoxy up to the heatsink. I had one of the first batch (100A) fail after a year, post mortem indicated a mosfet overheat and failure due to water infiltrating an air bubble in the epoxy under the heatsink. The rest seem to be doing OK, haven't gotten an involuntary immersion test yet though on the scotchcoat only version. Use 4mm gold plated bullet connectors, male end on the motor. It may be a good idea to add more scotchcoat every year or two, don't know about it's durability Ron Hunt
Well after opening the yellow case the circit board is two layers. No way to get scotchkote on all surfaces. I covered everythin with epoxy, then filled the case with epoxy. I will follow up with scotchkote on exterior.
