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Don't quite understand why you would want to run four props & motors. One of my fleet is a old Precident Perkasa, in all wood including the hull. Powered by a 12v 7ah lead acid battery a single 550 motor and a three blade prop. As you can probably imagine she is heavy but still gets on the plane to mimic the real thing, will admit the motor did get a bit hot untill I fitted a heat sink with fan cooling. I also have a Hooben Perkasa in injection moulded plastic, yet to be built but intend to use the same set up. Cheers for now John👍
[Score: 8/10] 46"/3000g Perkasa Twin Propellors (3 Blade 50mm) Direct Drive to a AQUASTAR 3660-1700KV (3 Blade) Powered by LiPoly (14.8v) 5Amp/h Batteries Controlled Through Turnigy (50Amps) ESC - Comments: Its fast ! Great fun fun boat. Water cooling pump switch for fast runs.
The first time I ever made a smoke generator was in the 1960s at school - for flow visualisation in a wind tunnel I was building. There there was no shortage of power, so i used a 1/4" glass tube wrapped with asbestos and nichrome heating wire, and boiled paraffin in it - no wick. Loads of lovely white smoke once it was forced through a cooling fan - but it was oily and smelly, and not ideal for lab work.... Later when I built a Revell Bluebell corvette, I made a shallow perspex dish with the glass-fibre wick, and used the smoke fluid from a disco smoke-maker. That's essentially a glycol/water mix - much less smelly. Unless they add perfume.... I suspect that paraffin would be less smelly outdoors, though fire and an oily residue would be hazards. You should be able to get a bottle of glycol smoke/fog fluid for less than a fiver....
Have just made a prototype of a fan forced smoker which seems to be working well (despite breaking the heater coil by moving it while hot, - had it apart, broke wire, screw and washer repair, not quite as hot) I bought a couple of Heng Long smokers (for R/C tanks or cars) to play with, for $10 NZ each(or 5.3 Euros to you Northerners give or take a yen) from Bangood and just bought another from Ebay. There seem to be 2 different models, as one has a long coil with a lamp wick draped over it, which is sitting in the oil reservoir, the other has a small coil inside a piece of heat resistant woven tubing (as you might find insulating toaster/heater wiring etc) which acts as a wick and that also sits in cotton wool in the reservoir, (this seems to be the better of the two) Tip - don't fill the tank right up, only enough to soak the cotton, element should be just out of the oil. The wick loads the element. The better model seems to have a black top to the tank (also maybe either brown or black tank) and the other has a brown top and dirty brown tank. As with most of this stuff you won't know till you get it what it's going to be. What I did was remove the tank and cut off the pump tube just in front of the screw lugs (see black line in photo) then fitted the tank, and a 40x40x10 5v ESC fan (voltage controlled by a UBEC set to 5v on the jumpers) into a plastic electronics utility box from Jaycar (our local electronics and hobby store). I made up a double JST lead for the 2s 1800Mah Lipo and fired it up (using baby oil). It's pretty much silent and smokes well once it gets warmed up, ( starts smoking in about 5 seconds) You could control it (on/off volume) by either a remote on/off switch or perhaps a small cheap 10A brushed ESC. I would leave the fan running and control the element to avoid burning the element. The original pump tank inlet hole seems ok as is (approx 1.5mm) but you could enlarge it very slightly to get a better flow if you could find a better oil. At the electronics store they have proper smoke machine oil for $20 NZ per litre so I may have a look at that. The reason I went for the fan idea was that I found in std pump form, if I immersed a tube from the tank in water, it sucked water back into the tank. I was hoping it would pump smoke out of my HSL exhausts at water level alongside the cooling water but it would need a very light non return valve to do this. The fan seems to pump the smoke through 2mm ID silicone tube ok, so tubing of similar ID to the OD of the tank outlets should work well. These pumps in original form work pretty well for the price, and are cheap enough to keep a few for spare elements, the only thing is they are a bit noisy but in an 'engine sounding' way, (might add to the effect on a tug or work-boat though) What you have left after this mod is a very handy little geared motor with an eccentric output wheel which could be used for winches, radar and whirly bits of any description (see pic of motor leftover and original) To avoid burnout, these should be run on no more than a 2s (around 7.5v-(suggest 8v max with fan running) The other tank is going to work a lot better than this one but I'm not making a tug, just want a bit of exhaust smoke on start-up etc to go with the 2 sound units. Very cheap to make (around $25 NZ with pump, box, fan and UBEC all through Ebay, Aliexpress and Bangood (and local electronics store) If you wanted to run an ESC to control the smoke and you have no channels left to control it proportionally, you can always try using a second receiver bound to your TX, (if your TX will allow it,) power it and a brushed ESC (wired to the element) as normal and use the throttle channel to plug in your smoke control. This should work if you want more smoke as you accelerate or if you are using only 1 stick on a 2 stick TX you could use your 'elevator' stick pushed up (or a toggle switch if available) to start/stop the smoke (through the brushed ESC setup) . This setup weighs 100g (10g more than std) The quest for lots of smoke continues Will try to upload vid later and update progress.
Because I need access to the wiring at both ends of the boat I formed the framework of an opening at the bow to make the dummy hatch into a real hatch. In a similar way a hatch was formed in the rear deck which will give me access to the wiring, rudder servo and the ESC cooling. It’s going to be quite tight to get all that into the cavity under the rear deck but I’ve done a test fit and it will all go in but will involve some ‘keyhole surgery’ through the rear hatch opening when I get to the stage of installing all of the running gear…🤓. Both of these decks were glued and pinned in place and some packing tape used to pull the decks firmly onto the frames. The side decks were also trimmed for best fit and secured in the same way and when all was dry and set a small hand plane was used to trim them flush to the hull sides. The next stage will be to fit the balsawood blocks at the bow and shape them to the hull…..it’s the tricky bit I’ve not been looking forward to…😟
I cannot see how you can mount the water cooling coil safely onto a out runner motor. Near impossible I would have thought. If there is too much vibration then I would think that it would rub on the motor and wear a hole in it and flood the boat or just jam up the motor. I would go for an in runner. Much more practical in a boat in my thoughts.
I'm new to this and was told by the guy who gave me the motor that this was the thing to do. He says the coil still provides cooling and says the warm water coming from the stern is all the evidence needed. We will see if he is right. Steve
Why would anyone even try fitting a water cooling coil on an out runner ?????? I didn't realise that an out runner was what was going to be used. Is an out runner worth fitting in a model boat, surely an in runner is a far better option.
As long as the coil toutches the motor you will be ok if it is NOT touching then simply start agaain as it will b a waste of time.............................................With regards to your painting question simplest way is to go to halfords and buy grey primer with is acrylic....if it is a wooden hull then you WILL NEED to use a coat of Halfords or Equivellent car laquer to seal the primer underneath ...rub down with 800 DRY then put your grey on top of it....reason for this is simple the primer is porous so you will need to stop water getting at the wood,if it is GRP then no need for this Dave
The HobbyKing ESC I’m using has the facility for water cooling and as it will be in an enclosed location without any free ventilation it seems sensible to utilise this feature. To keep the water circuit as short as possible I will put the pickup just behind the propeller and the exhaust on the stern but as the boat has a bulkhead just in front of the stern skin I need to make an access hole through it to allow me to secure the nut on the stern skin. I made a hole through the bulkhead large enough to get a socket on the nut and reinforced the hole with a ply plate, similarly I reinforced the inside of the stern skin where the outlet passes through it. When I was happy that the arrangement worked and I could attach the hoses and securing clips easily I glued and pinned the stern skin to the hull. The water pickup is a standard one that is readily available but it’s supplied with overly large and ugly fixing nuts, the inside one is of no consequence but I thought that the outer one needed smartening up so I put it on a threaded rod and locked it in place with another nut and put that into the chuck of a drill and used a file to re-shape the nut to a pleasing taper….who needs a lathe......😜 I had to reduce the height of the inner keel former as the pickup tube is not long enough to get a good fixing with the internal nut, as the inner keel is balsa I fitted a ply reinforcing plate to spread the load. The last ‘photo shows the location of the ESC, main battery fuse and receiver. The hoses will be secured to the ESC with spring clips throughout. I found that the silicone tube I use tends to kink rather easily if the radius of a bend is too small and I found it necessary to form a tight spring coil around the piece that loops the water back through the ESC to prevent this happening.
I have one on a 540 brushed motor which is a reasonably tight fit on the motor. Also I have a Graupner on to fit Graupner 400 speed motor and that again is a quite tight fit. There is no gap between the motor and the coil. It is acting as a heat sink so therefore surely it should touch to disperse the heat with the water flowing through it. If it isn't in contact with it then doesn't it make it pointless putting it on there. Also wont it make it rattle about when the motor is running and the boat hopping about on the water ??