Ok boys has anyone built this great mans hydroplane and either re engined or insralled a brushless outrunner. Bearing in mind that i am building this boat to operate at correct scale speed not bat out of hell speed. Correct acceleration and speed always enables the model to perform correctly during turns etc, anyhow. The only modification other than the powerplant is using a flex drive.
For sale is my 1/12th scale model of the Waveney Lifeboat - "The Scout" Kit produced by David Metcalf. Built to a good standard with an array of working features: Working radar controlled through a voltage reducer Navigation lights, mast lights, front and rear searchlights, flashing blue light and well lights all controlled by an Action Electronics P62 quad switcher. The flashing effect of the blue light is controlled by an Action ElectronicsP73 multi flasher. Powered by two Turnigy 3542/5 1250kv brushless outrunners controlled by two Fusion Hawk 60amp electronic speeed controllers. Fitted with Raboesch propshafts and 3 bladed brass left and right handed propellors. Batteries and radios are not included in the sale. The model is available for pick up only with cash on collection from Stafford ST16 which is approximately 1/2 mile from Junction 14 of the M6 motorway. Price £700 ovno
Hi Rowen, I have had water cooling on all my patrol boats running at 12Volts, whether brushed or now brushless. For the brushed motors I have used aluminium tube coils with water pickups between the propellers and rudders. I did try water jackets a couple of times but found too much friction loss and therefore lack of flow. For the newer brushless outrunners I use a brass tube soldered to a brass plate across the front of the motor fitted between it and motor mounting bracket. I agree with Doug with regards to the disconnection of the red wires on the ESC's. This is now common practice, especially if you have an external receiver battery.
Hello Canabus. Please can I take you up on the pdf files of the plans for my boat. I have an A0 printer so should be able to print them full size. I have looked all over for the originals without success. I am learning a lot as I go and wonder, looking back, if I have made a mistake. I bought the 3648 1450kv motor, yes, the beast. Just cannot help myself!!😁 Now that I understsnd these motors a lot more, I realise that it is an outrunner. Do you think I need water cooling and if yes, how is this done when the main outer can is rotating.😊🤔 Thanks.
Hi - I've got one of those and once I've progressed with some of my other builds I'm planning on replacing the old MFA 850 with a brushless. Being quite a heavy beast and wanting decent speed but not manic I'm looking at one of the Overlander 50 dia. brushless outrunners which will provide the torque required and use a 45 or 50mm 3 blade prop. Definitely LiPos for me. The 7.3v lead acid was fine in the boat weightwise on the water but too heavy and unwieldy for moving around and launching and with LiPos you can easily up the volts without much increase in weight. Chris
I think you might need pointing in a direction, so I had a quick look on Hobbyking, and this motor is the sort of thing you can use, although this particular one would need you to swop the shaft around, this is just a guide, other s will no doubt add comment, its the right size, 5mm shaft, right kv and watts. https://hobbyking.com/en_us/turnigy-g15-brushless- style='background-color:yellow;'>outrunner-810kv.html brushless esc https://hobbyking.com/en_us/hobbyking-90a-boat-esc-4a-sbec.h... you don't need the high amp capability, but its reversing, programmable, water cooled, and has an sbec, so the main battery power this 5 mm shaft, move your motor to the centre section meaning weight distribution is more central, and you can now use a shorter shaft, and get a couple off plastic "x" props, I would say 40 to 45mm will be the one. This will give a good speed, and you can power on 3 cells or 4 cells lipo, get higher c rating (40c or more) and higher mah so you have fuel in the tank available https://hobbyking.com/en_us/turnigy-battery-3000mah-4s-40c-l... This is just a guide, a starting point, as I feel you are unsure where to start, others with more knowledge will come in regarding this, having experience with lipo, brushless, 3 foot ply boats, and esc's, depending on budget, this would be the sort of thing I would be getting.
Hi Graham If we are talking about the Graupner Brushless Speed 500 ECO no 7295 https://www.graupner.de/Brushless-Speed-500-ECO/7295/ then yes the Kv is 500 which equates to 7500 at 14.8v. It's 50mm x 80mm with a 6mm shaft so really a heavy duty motor and in a Aeronaut Queen 36" still much too big and powerful. You really need to resolve the drive train and shaft problems and this will be easier if you choose a motor of smaller diameter and power. A 36xx or very similar size motor at about 1000Kv or less (500Kv with 14.7v) will be ample. The prop should be less diameter than the motor. There are many examples of 36" model boats on this site and I do believe the majority of our members have used similar set ups, to those we have suggested, in their models with a large degree of success. It could be we are talking about a different motor as you refer to " the small outrunner motor". If so please post a link to a pic of the motor.
Hi all, what do we all think of the Graupner 500 ECO? it only does 7500 rpm but high torque, about 1500 watts, 14.8 volts. The say it is especially built for boats. I would like to know your thoughts on the small outrunner motor? Regards Graham
Graham - don't tell me you ran the boat at anything like full throttle. If so, it wouldn't just be the prop shaft that you'd have to worry about! If you did it must have been virtually uncontrollable! I take it you bought the boat with the motor already in it? Whatever, it couldn't really have been a worse choice! With such a high kv and being an inrunner (if I've got the right motor) it's really meant for a lighter, race type boat running on 2S to keep the revs down to a reasonable level. As you now know, for your type of boat you need a kv around 1000 or even a bit less as torque is what you need and also go for an outrunner. 3S or 4S is fine and if it is too fast limit the amount of throttle. Without seeing photos it's impossible to say if your existing prop shaft is up to the job but as you've removed it anyway and if you don't mind the expense I'd change it for one of the Raboesch maintenance free ones. I'm using these for my builds and my Fairey Swordsman at 33 inches is a similar size and weight. These are rated for 10k. and 15k. rpm, I've gone for the latter and in 5mm shaft size to be on the safe side. I doubt that a shorter prop shaft will be feasible as usually the motor is already pretty low in the boat and a shorter shaft will increase the angle and you don't want it too steep. Also you would have to redrill the hole for the different angle. What dia. is the existing prop shaft? The other thing you need to consider is the prop. What are you running at the moment? A photo of the boat would be good. Chris
Hi peter, do you want a brass 3 blade prop for cosmetic reasons, if so they do look nice. I did extensive testing with my 3 foot fireboat using brushed, then brushless motors, and then prop testing. I was using eagle tree data logging for watts, amps, gps speed etc. The plastic two blade cheap as chips props actually produce similar readings to the more expensive brass 3 blades. Personally, as you are at the "guess work" stage, just use the plastic two blade ones, but use "x" pitch, standard wont give you the speed. Get a few sizes, 30, 35 40 mm and test. When you have the optimum set up you can then go to the expense of the brass prop. I sent Simon Higgins (ex prop shop) my readings and he made a specific prop for my boat, its a 35mm cleaver 3 blade. He has his own company now but I've forgotten what it is! He was at Blackpool last year so someone might have the list of traders. His props are balanced and one piece, very nice. I also experimented with a belt driven gearbox. The set up I have at the minute is this motor https://hobbyking.com/en_us/turnigy-t600-brushless- style='background-color:yellow;'>outrunner-for-600-heli-880kv.html overkill really! but my 3 footer is an original very heavy aerokits boat.
Looking at the specs ROXXY BL Outrunner 4240/10, 980rpm / Volt, 130g For electric sailers up to 4500g Scale and sport models up to approx. 2900g. If you have the 34" Fire Boat then this is too big. Mark suggested above a 3542/1000 and I agree. The smaller model is very light with a small transom and I found it has tendency to lean under the tork effect of the prop. Turning had to be slow and gentle to avoid capsize. This is not such a problem on the 48" version. Props should be no greater in diameter than the motor and should be chosen to keep well within the motor and ESC ratings. A wattmeter will help you check this and a good rule of thumb is to run at about half max current for best results.
I' doing somehthing very similar, rebuilding one from the 60s, when I get time to finish it. I picked up a Brushless outrunner, Robbe/Roxxy Outrunner 4240/10 - is this about right? - Will it be OK with a 4S/5000mAh lipo? - What prop would you suggest to start with?
No, that's less powerful than in Pilot's opening post and like his suggestion is an inrunner motor. The consensus is that a 50 mm diameter outrunner ( the first part of the model No.) is what is required for a big boat like the Huntsman. The second part of the No. is the length of the motor. That size plus a kv figure of around 700 to 1000 will provide plenty of torque to get it moving and high enough revs to get it on the plane. Once you start getting a kv figure well over 1000 you start to get into higher revs which is useful for smaller batteries (e.g. 1000kv x 7.4v = 7400 rpm) which as said is good for fairly small, light, sports and race type boats. Conversely if you have quite a big displacement boat then you want quite a big motor but with a low kv figure as you don't generally want to tear along but want torque! Chris