Blog

Cooling the motor - an experiment.

Whilst I don’t think I’m going to need to cool the motor it got me thinking that it may be a useful experiment to see if the ‘Stick A Fan Blade On The End Of The Rotor’ idea would actually work 🤔 So while waiting for some glue to set on another part of the build I decided to rummage through the junk PC bits box and find an old fan of a suitable size, and I did indeed have on that would fit the bill 😀. I broke away the outer fan casing to release the motor and blades and then set about separating the fan blade, which proved fairly simple. The fan blade has an overall diameter of 45mm which is ideal and there’s a moulded-in centre mark so I used a step cutter to open up a hole to 10mm and then a tapered hand reamer to carefully open up the hole to about 11mm which is the diameter of the end bearing stub on the rotor. The fan was then pushed onto this motor stub until it seated flush on the wide and end of the rotor can and is a very tight friction fit so it doesn’t need any more than that to hold it. I don’t have a dial gauge but I can tell by eye that the fan is perfectly centred and true and so it shouldn’t cause an imbalance 🤞. The motor turns clockwise when viewed at the fan end which means that the fan would be pulling air through the side vents , through the stator and around the rotor and would need to exhaust through a new panel cut into the end of the motor enclosure. The existing motor enclosure still fits perfectly over the motor and its fan and wouldn’t need any other modification than the extra opening and mesh. So in theory this arrangement will give forced and cooling of the motor in the event that there is a heat problem. In practice I’ve yet to wire up the motor to the ESC so I have not been able to run a proper test to check it actually works but I’m pretty confident of it. This motor cooling arrangement could prove useful to others when faced with a similar situation which I why I decided to conduct the experiment...... and validate my theory. Just keep your fingers away from the fan blades…..😨

5 years ago by robbob

Response

The motor cover.

I did consider somehow fixing some fins to the rotor to create some air movement or perhaps even glueing a very small fan blade, taken from a PC graphics card that I have in the junk box, to the end of the rotor but I fear that this could easily unbalance the motor and harm the bearings. I won't find out if my slots are effective until the sea trials 🤔

5 years ago by robbob

Blog

The motor cover.

I want to keep the motor cover as compact and in proportion as much as possible so I drew up a design to visualise it and get some practical working dimensions, it also needs to enclose the prop shaft and coupling, and the MT60 connection for the motor so there will not be very much free air space inside. Because of this the motor cover will need some as the brushless outrunner motor can’t be water cooled and I don’t want to fit a fan, so the side panels of the box will need some gauze covered slots so that any heat generated can escape, assisted (perhaps) by the rotation of the motors outer ‘rotor’ creating some air movement. I don’t intend to run this boat very fast so I’m hoping that the motor will not get too hot anyway🤞. I transferred the dimensions of the side panels from my drawings to some 1.5mm obeche panels and cut the side pieces to size and cut out the slots, some framing pieces and cross braces were fitted internally and the whole assembly glued and clamped together. Additional framing was added to support the part that covers the shaft and coupling and obeche panels applied to these. Some finishing details were applied around the base and the top to improve the appearance. The internal framing will later incorporate some small cylindrical neodymium magnets that will hold the motor enclosure down on the deck, I’ll fit these later when the deck floor has been fitted. The mesh is some of the stainless steel mesh that I had used in the water pickup tube on my RAF Crash Rescue Tender hoses, and this was cut to size and epoxied in place. The completed enclosure was finished with the same Teak stain as the rest of the boat. Next up will be an enclosure at the rear to conceal the control electronics.

5 years ago by robbob

Response

Motor, mount & prop-shaft.

That's a really good question that I really can't answer right now as I've yet to run the boat !. The motor enclosure does have quite large panels on either side which are covered in a mesh and I'm hoping that the motor will be able to 'breathe' as a result. The brushless in my Fire Boat doesn't even get warm after a long hard run and that's enclosed in the hull but has admittedly got a lot more free air around it in the motor compartment. This is not a racing boat remember, so I'll not be using the motor to it's full ability, scale speed is all I really want and expect. I'll report back when it's had some sea trials 😁 Robbob.

5 years ago by robbob

Blog

Plumbing the water-cooling for the ESC

The HobbyKing ESC I’m using has the facility for water cooling and as it will be in an enclosed location without any free 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.

5 years ago by robbob

Blog

aeronaut classic

i have bought a aeronaut classic kit to build over the winter , i have had to suspend other models (tugs) due to fumes and winter . it will be my first wood kit build , i would like to fit a brush-less motor in the Classic but do not know which motor i could use to replace a speed 400, can anyone recommend a brush-less motor for the classic

5 years ago by sandgrounder

Forum

Styrene Allergy?

Since Styrene itself is an oil, suspected in some countries of being carcinogenic, used in producing various polyxxx plastics, I strongly suspect the the glue is the source of the problem as you can't be coming into contact with styrene oil itself. So I repeat, good , extractor fan, thin latex surgical gloves and a face mask as one should also use when spraying. Cheers, Doug 😎 PS Sell that kit and buy something friendlier!😉 https://www.wikiwand.com/en/Styrene

6 years ago by RNinMunich

Forum

Styrene Allergy?

Not necessarily allergic to Styrene, but many are allergic to CA Glue. Once a CA Glue sensitivity develops, it is difficult to overcome. Try masks; try good . Even when cutting Styrene, ensure You have good .

6 years ago by Tug Hercules

Directory

(Other) CG-40564

DUMAS 1:14 USCG 40' UTB. REPRESENTING US COAST GUARD UTILITY BOAT CG-40564, WHICH CAPSIZED DURING A RESCUE ATTEMPT ON THE COLUMBIA RIVER BAR ON 17 JAN 1961. HER CREW WAS FORTUNATELY RESCUED. SHE WAS ASSISTING CG-52301, A 52' TYPE F WOODEN MLB, WHICH FOUNDERED WITH THE LOSS OF ALL HANDS. IT REMAINS THE WORST SMALL BOAT RESCUE DISASTER IN COAST GUARD HiSTORY. THIS IS AN UNUSUAL SCALE BALSA PLANK-ON, COVERED BY 2 OZ FIBERGLASS. I USED MINWAX POLYURETHANE FOR AN ALTERNATE TO RESIN, WHICH TURNED OUT WELL, AND CAN BE DONE WITH MINIMAL . WITH BIRCH PLY DECK & CABINS, 1/8" SCRIBED SHEATHING COVERS THE DECK BOW TO STERN AND MAHOGANY TRIM LEFTOVER FROM ANOTHER DUMAS KIT IN MY SCALE SHIPYARD. STOCK D/C FITTINGS WITH SOME SUPPLEMENTAL PREMADE AND HANDMADE ITEMS. SHE FEATURES TWIN RABOESCH 4-BLADE WIDE FLUKE WHEELS AND MATCHING RUDDERS; WORKING HATCHES WITH STOWAGE AREA FOR ANCHOR & TOWLINE, LIGHTHOUSE 9V LED NAV LIGHTS AND FLASHING LED LAW ENFORCEMENT BLUE LIGHT (RC CONTROLLED). I'M ADDING A MOUNT FOR A SCALE BROWNING M2 50 CAL THAT I WAS ABLE TO PRODUCE ON MY 3D PRINTER. THAT'S AN ADVENTURE IN ITSELF. THIS WAS MY FIRST REAL PLANK ON BULKHEAD, AND BALSAWOOD CAN BE A LIL TRICKY, BUT WILL ALWAYS BE THE STANDARD OF WHICH I COMPARE ALL MY SUBSEQUENT BUILDS. MY FATHER BUILT RC AIRCRAFT, AND ALWAYS PREACHED THAT YOU SHOULD OVERBUILD IN ORDER TO SURVIVE A CRACK-UP AND FLY ANOTHER DAY! THAT'S MY CREED WITH BOATS. OVERBUILD!!! THANK YOU DAD! BTW-FYI-MR. ARNOLD PALMER WAS A US COAST GUARDSMAN (YM3) 1950-53 (Motor: 775 JOHNSON-TYPE 6-12V) (ESC: HOBBYWING) (9/10)

7 years ago by circle43nautical

Forum

3D printing

Hi Wayne You will need holes to keep the temperature down. Hopefully this will help reduce the noise and smell! Mine isn't so bad temp wise if I don't use the heated base. It's great when it works, my advice is keep experimenting, it becomes easier the more you print. if you are using websites for help then you will know there are better software options than the basic supplied with the unit, unfortunately they come at a price. For hobby use you may decide the items you produce are OK, but for commercial use the cost may be justified. A useful first project is to make a cooling fan hood for the printhead. it helps keep the shape of long extrusions. Enjoy Dave

7 years ago by Dave M

Forum

Motor upgrade

Thanks for the info I've gone for 2x30A watercooled esc from hobbyking, the main reason was that they were £13:00 each and seemed less complicated set up than the car ones, I may be wrong, but they will be in a fairly limited space with poor . if they don't work I'll try the car ones.

7 years ago by colindavies

Blog

The spray booth.

After considering all the H&S aspects and conducting my own risk assessment (seriously !) and writing a method statement 😉 I am building myself a spray booth. The base for the spray booth is a steel framed folding trestle table that I already had in the workshop and is of ideal dimensions for the job. The framework for the booth is regular 25mm x 38mm softwood from my local DIY store. No elaborate joints here at all, just a few screws and plastic corner blocks and a few bracing fillets to keep the frames square and rigid. The idea is that I will be able to remove/discard the cardboard panels from the top and sides to de-construct it and pack it away until it's required again. The cardboard is just fixed to the frame with a heavy duty staple gun. An MDF panel with a suitable sized hole was made to hold the fan unit in the 'roof' and the flexible ducting routed to the workshop (garage) door (wooden) and connected to an exhaust vent mounted through the door. The fan unit is a brushless bathroom ventilator wired to a simple switch on the side of the frame, it can move more than sufficient air volume quite safely in the presence of propellants and solvents from the aerosols. I also fitted a 1metre LED strip-light to the same circuit to illuminate the interior. The finishing touch is an old shower curtain with a weighted hem that I had lying about to form the 'fourth wall'. it's suspended so that there's a 50mm air gap at the bottom for the air flow path. I bought a 3M 4521 Maintenance-Free Organic Vapour/Particulate Respirator for about £18 from Screwfix to wear whilst spraying. The mask filters are not replaceable so when I've finished all the painting it will be binned ! The mask is so exceptionally effective at filtering that I am able to stand at the booth and work INSIDE the booth with the curtain behind me to confine the vapours and dust and reduce the risk of dust etc. settling on the fresh paint. For those concerned for my health I can assure you that FOR ME this works perfectly safely and is very effective. So much so that there's no smell at all while spraying and I only get the slightest whiff of solvent smells in the workshop after removing the mask as all the nasty stuff is blasted out of the workshop from the enclosed booth. I expect some controversial opinions on this but in practice it is actually far safer than spraying paint in a confined area without any protection and at all, which is possibly what a lot of chaps (including me) have done or continue to do ! Now I can get some painting done...

7 years ago by robbob

Forum

34'' Fireboat

Hello Dave, I have actually completed all the wiring connections today and have tested and set-up the transmitter speed control and rudder orientation. All seems ok at this point. I note your comment about around the ESC - well of course it is in an enclosed compartment mounted on a block away from hull - do you think piping an airflow from above via tubes would be practical or necessary? PeteG.

13 years ago by PeteG

Forum

34'' Fireboat

HI Pete My ESC is attached with velcro to the plate across the hull floor. I believe I used epoxy to fasten the floor to the hull but any water resistant glue would probably work. Make sure there is plenty of around the ESC. Dave

13 years ago by Dave M

Blog

Nor-Star - KingFisher

I am proceeding with the hardware Install. Rather than buy a standard 6 cell pack, I built my own. The object was to get the weight towards the back of the boat and the easiest way to do this was to split the pack Into two, three cell packs. The Rx and ESC are located on the radio board and framed for a snug fit. The board Is cut away below the components to aid . Now the Install Is near complete Its looking llike the c of g Is at 36% when measured from the tip of the transom. Next steps will be to finish the sanding, apply primer (3 coats) and then drop It In the bath tub to establish a water line for final paint.

15 years ago by Robert

Blog

April 19th

This last week I have been preparing the boat for radio installation. Due to the small size of the model, a degree of planning needs to be done to make a neat installation. With this model the forward cabin has an open back and therefore subject to possible water intrusion. The rear deck area also has the potential to convert to a swimming pool if subject to some enthusiatic reversing. That really only leaves the mid cabin in which to squeeze the gear into. My goal was to make a drop in board that located the hardware. First I slotted the cabin sides back into place to check how much room I really had for placing and removing the board into the hull. I made a cardboard template just to confirm the clearances. First I glued four support pads in place to support the board, two to the front bulkhead, two to the back bulkhead. Then on my board I glued four location pads to the underside. These pads are a very close fit between the support pads on the bulkheads and prevent any sideways movement of the board when its dropped onto the support pads. I then cut and fixed a battery barrier to the board. This is to keep the battery packs in place against the rear bulkhead. The receiver and speed control locate into their own four sided nests. The bottom of the nest has been opened up to allow for . Not really necessary for the receiver but more helpful for the speed control. I also cut a couple of slots in the bottom of the board so that you can see the skins and keel for any water accumulation in the hull. Now I have located the radio hardware the temporary equipment wiring will be re-done now I know the necessary wire lengths. However I will probably hold off on this job until much later.

16 years ago by Robert