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A bit of confusion over what i wrote last night (note to self dont mix the internet with rum) I did not use a piezo unit, I used ultrasonic units, the kind that are fitted to fire places to produce the smoke and flame effect. The water depth seems to be the critical factor in the amount of mist produced. I am not looking for masses of dark smoke just enough to simulate diesel exhaust. This was just a prototype that works quite well but I am going to revisit it and try to improve the output and look for an ultrasonic unit that will work at 12v
I have made a smoke generator using a piezo transducer and a P68s variable speed brush less fan controller from action electroncs. The transducers tend to be 24v dc and are relatively cheap (£2-£3 each). I am using S3 lipos so I only have 11.4 available but a very cheap variable output unit gives me 24v. The fan is connected in-between the receiver channel for the throttle and the speed controller. The fan speed increases with the throttle and follows the throttle speed regardless of direction. The net effect is quite pleasing for diesel exhaust simulation, with a steady stream when the stick is centralised and the fan just idling. On fwd/rev throttle movement you get an increasing amount of exhaust dependent on speed. I have this installed in my Forceful paddler with twin funnels. The effect is quite realistic but can be difficult to see. I am looking for a another transducer that will produce more vapour. in its present configuration it will run for around 3 hours before topping up is required.
Your probably right about the motors i just thought why not try them, might be an expensive mistake for no real advantage apart from speed and maybe a little quieter. Thanks for the advice about bracing I'd not thought of that it may be a little flimsy.
I'm considering Model Slipay Tamar Class as my next project. I have never used styrene before (other than Airfix in my youth). Every article I have read on this model have used a twin Speed 600 ECO set up. I am toying with the idea of brushless but have no idea where to start in terms of equivalent motors etc. any idea anyone?😁
I tend to use LiPo's but they can be temperamental and need the correct charger. They are smaller and lighter than NiMH and give you a much greater output. NiMH are similar in size to LiPo but are heavier and will not have the same sort of power available. Lead acid are the easiest to use in terms of charging but are much heavier and larger then the other 2 types but tend to be cheaper. Lead acid are a good option if you need the ballast or are not limited on physical size. Cost is also a consideration a good quality charger can be an hefty investment but will serve you well and if you buy the correct type will charge/discharge any battery type that you have. I have heard horror stories about LiPo's bursting into flames, which my son did with his RC car. this was down to him not understanding this type of battery. I have not had good results in terms of endurance with NiMh but Lipo's if correctly selected will last much longer, a word of warning here though, they will stop working suddenly with no indication like running slow etc so if using LiPo's you will, need an alarm on each battery. Lead acid is much easier to in terms of Voltage either 6 or 12v with real problems when connecting them in series or parallel for use or charging, a little harder with the other two types but not impossible. This has probably confused you even more but I am sure you will come the correct battery. I have to confess I have an interest in this build as I intend it to be my next project👍
I have recently constructed a rotating radar mast for my 1:48 scale paddle tug "Forceful" I have used a geared 6 volt 60 RPM motor which gives a realistic scale rotational speed. It is a little noisy but only when close up. it is driven by a direct shaft running up the centre of the mast not prototypical but gives a pleasing effect. I may rebuild this at a latter date to eliminate the noise
It may be a transmitter/receiver problem or it may be in your drive setup that rears its ugly head once your on the water and your motor is under load. I had a similar problem with a twin motor setup which was fine out of the water but after 10 mins in the water I would lose drive to one or both props or one would slow down and just go round in circles (very embarrassing). I had no problem with radio setup so it had to be in the drive chain. I ended up changing both motors for ones with more armature poles, higher torque output and a different gear ratio. It also highlighted a problem with my first choice of battery which quite frankly were pants and used to produce similar symptoms as you describe. I now use Lipo power packs, they do have disadvantages but you can not knock the power to weight ratio. The main problem I was having appeared to be down to the 3 pole motors that were fine until they were under load, this caused the motors to overheat which in turn increases the current drain on the battery's, the net result is the motor starts to arch across the commutator and effectively becomes a dead short which in turn shuts down your ESC's or drains your battery's very quickly. As you probably know if this was to happen with Lipo's there would be no need for a smoke generator! Of course this only applies to brushed motors if you are using a brush-less motor then it will probably not help you.
[Score: 5/10] 39"/6000g Forcefull Belt to a 2xMFA970D161LN Powered by LiPoly (11.1v) 4Amp/h Batteries Controlled Through action elelectronis dual 10A ESC/mixer (5Amps) ESC - Comments: This boat is still under constrution (Ive still to finish "Shell Pioneer") so a lot of the above is only guess work however a bench test at full throttle, with sound generator, amplifier and smoke generator operational it drawing less than 3A. The majority of this was the smoke generator with the drives only drawing 0.25A (under no load) so if these figures do not increase too much once in the water i should get a much longer running time from my 2 lipo packs
I am so pleased to see this blog as I am also in the midst of building my own "forcefull". Your build is much further advanced than mine so hopefully I may be able to pick your brain in future about the many problems that I am bound to encounter. Your drive system looks much like mine apart from I am using 2 x 540's low noise motors with built in 16:1 gearbox and the final drive being belt drive reduction giving me a maximum no load rpm of 230 on the paddle rims. I am using an action Electronics dual mixer & ESC's in tank steer mode for speed control. I don't know how it will handle exactly in this mode but I do have the option of a conventional mixer mode with a rudder servo. At the moment my paddles are not feathering, this is just for getting in the water quicker and will be replaced in time when I can access to a lathe to make the ecentrics
[Score: 5/10] 31" Shell Pioneer Twin Propellors (4 Blade 35mm) Direct Drive to a 2x MFA940051LN (4 Blade) Powered by LiPoly (7.4v) 4Amp/h Batteries Controlled Through 3xViper 15A (5Amps) ESC - Comments: This is my first working RC build but here goes. A bit vauqe about the fiqures because we are still on the slipway. It is scratch built from the Phil Thomas drawing "Shell Pioneer" Twin prop with Kort nozzle steering, bow thruster, working fire monitors and lights. Throtle & steering control via Action Electronics P40E mixer. 2x 2S25C4000mA lipoly's. 6 Ch radio (4 used). draws around 4.5A hope to get 30min run time minimum. Third ESC for bow thruster.