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Thread: My sailboat Carina, a modell closer to a J-Class

  1. #1

    Default My sailboat Carina, a modell closer to a J-Class

    Dear friends

    Reading the threads in this forum I felt that I could learn a lot for my project from your comments to my project Carina. As former sailplane model builder I decided to engage into a project of something that would last longer than my sailplanes. Studying plans from sailboats I did fall in love of a model that was said to be a Class A sailboat. This plan has originally been drawn in France and after a couple of changes of the owner of the license for those plans i bought it from a german company called vth-Verlag and the plan was called Voilier, what in french just means sailboat. After some research in decided to build it assuming a 1:20 scale and that the over all length of the hull would be 165 cm or 65 inches. I had lost my job as a business development director and was unable to get employed again, so I decided to embrace a project that would be the "red line" to study technical issues I might encounter on this path. This way my grey cells would be kept in use and as budget I promissed my beloved wife i would not spend more then what she spends for cigarettes! Over the years the prices for cigarettes have increased a lot, our financial income as family stayed as it was and the prices for everything needed for living increased, so I have even less budget!

    I started studying how to build a wooden hull and after some research I decided to use a technique, were the hull is build upside down.

    The quality of the plan was lousy as you can see from the above image. So I had to invest a lot of effort to get adequate frames.

    For the frames I used a special ply wood, called Siebdruckplatte in german, a wood that is very brittle and is normally used for making concrete forms in construction. This material has the benefit that it is fairly easy to remove the frames at a later stage of the construction of the wooden hull. The hull was made using spruce strips 8x3 mm which I later treated with a polyurethane resin that when properly thinned, penetrates the wood and makes it water resistant, something I did consider important as the fiberglass and epoxy resin lamination can be damaged and water could penetrate through it.

    I loved the resulting shape of the hull. One benefit of the application of the polyurethane resin was that the wooden hull did reflect light much better helping to proper sanding the hull, a painfully long process as all of you I am sure know out of you own experience.

    This image shows a view from within the hull, the frames still in there!

    This view shows the hull top up!

    Here you see the result after removing the frames.

    As my intention is to have a deck, completely removable I build a sealing based on a U-profile aluminium around the whole hull, which also stabilizes it. Additionally this surrounds all deck constructions, which also being removable. The deck will have another U-profile aluminium which fits into the one on the hull side.

    Here the aluminium construction hull side, kind of completed:

    Next you can appreciate how filigran that part of the deck is that will fit into the open to the top U-profile hullside.

    Next you see the deck in a much more advanced state and you can appreciate the challenge left, which is to remove as much as possible of the aluminium to achieve the lightest possible deck weight.

  2. #2


    It highlights a challenge that is applicable to any long keel sailboat, it is the location of the center of gravity and is mentioned at quite a few places in this forum. I did choose aluminium to build the deck structure due to the strength of the metal and due to its low weight. Still so, after completion any material that can be removed will have to be removed.

    But to achieve the goal to have this sailboat to be navigable at not only light winds, a lot of effort has to be put into ensuring that no space below the waterline has to be left empty if space is available lower within the hull.

    Here you can see my son laminating the hull from within. The hull being made of wood, has the tendency, as wood works, to loose the plane surface achieved after many long sessions of sanding, after which you could not feel the individual wooden laths. The only way my experience tells me to make sure this does not happen is to laminate the hull symmetrically from within and from outside. This ensures the hull keeps the surfaces as plane as they are just after finishing the sanding of it. Sometimes I think I should have left the hull as it can bee seen, in the original colors of the wood. As we had to get the hull ready for my son to present it as its work at school, we colored it, keeping the structure of the wood visible, something I really regret. Now I will have to laminate the complete hull with mahogany veneer to achieve again a beautiful wooden color. if I ever build another wooden hull I will use wood premium wood. You can appreciate that by doing careful hull construction no filling material is required.

    Here you can see how, with the help of a friend I prepared the rudder mounting. At the low end there is a brass tube in which the head of an allen screw fits. This way, screwing a screw from the bottom into the axis of the rudder, the rudder can be unmounted later, by just removing that screw. This construction much later proved to be too weak as the final displacement of the model of 29kg broke the wooden noose in which the axis of the rudder is fitted on the low side. I had to fix this by mounting a steel rod at the bottom of the keel, able to resist the stress on it of a 29kg model weight resisting on it!

    Here you see the axis of the rudder within the hull. First i had the intention to have a servo pass the torque onto the axis of the rudder by the means of a cable and 2 drums. Now I have decided to replace the servo by a stepper motor and use a toothed cable instead. i have found a stepper motor, just 28x28 mm, with enough torque for the rudder function, but totally silent when being operated, opposed to the typical servo noise everybody knows. But more to those electronic elements in my model much later.

    to close the thread for today, here a picture that gives an idea of how the model will look like. The hull shows the result of the not successful tries to get the hull properly colored, before deciding to go for laminating it with veneer
    Last edited by Hellmut1956; 12-26-2013 at 07:16 AM.

  3. #3

    Default Re: My sailboat Carina, a modell closer to a J-Class

    wow.. welcome here.. you got a nice boat there..love the pics
    long live my detroit tigers

  4. #4
    Join Date
    Jun 2013
    Crete - Greece

    Default Re: My sailboat Carina, a modell closer to a J-Class

    The boat my friend is very beautiful.
    It looks really great.
    What is your target weight my friend?
    Can you post a photo of the front of the boat?


  5. #5

    Default Re: My sailboat Carina, a modell closer to a J-Class

    The target weight is 29 kg. here a foto of the front of the boat. As you can see, the color of the hull was not my tasate, but we had to do it for meeting the goals of my son for the school job! My son felt it looked like a dolphin!

    The first foto shows the hull from below

    the second from above with the preliminary made deck, mounted on top of the hull. Whats is missing of the structure of the deck is removing all aluminium to reduce its weight, to install a lightning of the deck, the 2 travellers I will install. Only then can i place the false deck on which I place the real deck planking.

    Lets go on with the report about the model Carina. Next some pictures of the details how the labyrinth sealing of my deck around the removable constructions on deck.

    As you might see you can see the U-profile, open to the top of the hull, the u-profile of the deck placed within the hulls u-profile has been opened to the inner side to allow water that passes the sealing of the specific construction to flow into the U-profile of the hull were it is being collected and can flow into a reservoir within the hull.

    here you see how every opening in the deck is surrounded by a collar, the first barrier for water, on the top of the collar there will be glued a sealing strip onto which the removable deck construction is pressed, the second barrier to water and finally the labyrinth sealing shown in the previous picture. This way I am pretty sure no water will penetrate to the hull. This is specially important as the floatation leven of the hull will be pretty close to the deck level to ensure the deepest posible location for the center of gravity in the model.

    Next a foto of the hull with the preliminary version of the removable deck mounted.

    This was the first version of the small boards for the LEDs I plan to install into the deck to make a remote controllable dimming of the indirect lightning of the deck. Night is a great time to have the models on the lake and enjoy them with lightning. The lightning should on the lower intensity side just generate a small light on the floor of the deck and on the top side illuminate the deck as if it is in Monte Carlo and a party is going on! typical for me to jump onto ideas that come up as I advance with the construction of the model!

    But this LED, a typical 20mA current LED, proved to deliver too little light, so I had to switch to high brightness LEDs that opposed to the max. 20 mA of the one on the foto can be sourced with up to 500 mA. This as a consequence opened the box of the pandorra! HB LEDs as those are called in short, generate a huge amount of heat that needs to be diffused. The consequence of this is, that not normal epoxy boards can be used but such with a core of aluminium that can take much more heat and diffuse it. But that brings other challenges! One is that you have to physically connect the aluminium core of the board of the HB LED to the aluminium structure of the deck to diffuse the heat from the LED to it, but not to have an electrically conducting connection. Means heat conducting but not electrical conducting. Well, after some research I found the adequate glue with this properties. Next was the challenge to ensure no electrical power conduct that feeds the LED would be short circuited while soldering. After some further research I found a supplier for repair coating used to fix the green coating that can be seen on commercial quality electronic circuit boards. Next is that with all this need described so far and resulting much more challenging with the use of HB LEDs I did want not more than just a small 5x5 mm square of the light source made to be visible and that it was a 100% sure that no water would penetrate the light source and cause a short circuit. Finally, as this LED making the light source was going to be build into my model I wanted to ensure that my dimming would be limited not to have the LED heated above a defined temperature. For this I found from a spin-off company from the ETH Zurich a temperature and humidity sensor in a just 3x3mm case self calibrating and providing the data digitally over a bus called I2C. This way, when I would be increasing the intensity of the light emitted by the HB LED, what means that more current would be flowing through it and as a consequence more heat would be generated within this HB LED, the temperature sensing of this electronic component would be delivering the actual temperature, measured from the aluminium core of the small board on which the HB LED was mounted and providing it to a microcontroller monitoring it and doing the dimming. As soon as a certain software defined temperature would be reached the software would consider this to be equivalent to 100% light emitting power. This way every single HB LED of the 20 plus that I would be installing on my model would limit the dimming to a temperature that assured that the HB LED suffered no damage due to overheating.

    Here a picture of the lightning element build around the LED. Remember I have to be able to place every lightning element into every receptacle in the model and to be able to produce those, even after years with that precision. Until then I had be using my Bosch drill, which here proved not to be precise and repeatable enough to meet this goals. So I bought myself a drilling and milling machine.

    With it I was able to build this setup that would ensure the repeatability of the lightning elements build using it.

    The 4 brass strips with the screws in it represent the 2 ends of the lightning element shown in the drawing above, capable to conduct the electric power to the LED and a small printed circuit board to be soldered in between would have the HB LED on it and with the protective repair coating ensure that while soldering on short circuit to the aluminium core could happen.

    Here you can see a try in making those small printed circuits boards with the aluminium core. This technology is not yet properly matured at the supplier and as a consequence, as I was unhappy with the results after a couple of tries, the provider was unable to do this boards himself. Fortunately I got enough usable of this circuits boards to satisfy my initial needs.

    Those researches to find a usable and adequate way to address the innumerable challenges resulting from doing it "my way" require plenty of time, involve many failed tracks being pursued. Opposed as some might see it, I found this activity very satisfying and when I finally found a proper solution I was able to sell this knowhow as consulting services. The more expensive it is to replace a lightning element in an application, the more smart solutions that prevent failures or allow for preventive maintenance by being able to monitor the lightning element are justifiable. Remember, my main goal in this project is not to finish a model, but to keep my grey cells in the brain active while spending as little money as possible.

    This image gives you the option to guess some of the challenges related to using a printed circuit card material that has an aluminium core opposed to the usual epoxy cores. Cutting the single board for single lightning element and soldering a HB LED on it using the reflow technique, made me aware of the challenges related. One is that cutting this small board out of the big one and having the copper surface to the edge of it, resulted in copper being connected to the core. as a result I had to sand the small board at its edges until the check with the Ohm-meter confirmed that no short circuit did exist any more. Also this picute illustrates that care has to be used to only apply very little soldering past to the pad so that after melting during the reflow process, no soldering material got in contact with the aluminium core. By magnifying the picture a ceramic coating can be seen, it is light green colored, that separates the copper from the aluminium core!
    Last edited by Hellmut1956; 12-26-2013 at 07:17 AM.

  6. #6

    Default Re: My sailboat Carina, a modell closer to a J-Class

    One reason for me to go into this level of detail is the implicacion of it! Remember that my financial situation is problematic as my last job as an employee was in 2001 and that the project is meant to keep my brain working, so that I have no intention to accelerate it. So the studies, the research and the development of my workshop to meet the needs related to this project all have a reason to be.

    In the last part of the report I did mention that I used a technique called reflow soldering to solder the HB LED onto the small board with aluminium core. reflow is a technique that uses an oven and heats the parts to be soldered following a profile set by the supplier of the part that ensures the part is no damaged in this process.

    Here I am using a general drawing that explains the temperature profile. You can see that the device has to be heated to about 180C at a moderate speed, than to ensure the complete component and the board are heated to the same temperature this 180C have to be kept during 1.5 minutes and then, and only then comes the critical timing. The temperature above 217C should be kept not more than 60 seconds or up to 80 seconds, while the temperature is heated above the threshold were the soldering paste melts and the temperature then drops below those 217C. Putting a probe in the oven and increasing the temperature shows at which temperature the soldering paste melts. From an opac grey it suddenly changes to a brilliant metal glance. This temperature is defined in the spec of the soldering paste and care has to be taken to only buy soldering paste that has a melting temperature above 217C but well below those maximum 260C. Keep the stuff you are soldering with the reflow technique aprox. 10 seconds after that sudden change of the color of the soldering paste happens and then open the oven and have it cool down. This can be acomplished manually using a multimeter with temperature sensor capable to indicate at least 250C;!

    For this I purchased at pizza oven at amazon for about 35.00 Euros and put it into a heat resistant case that allowed the heat to flow away without risking a fire in my workshop! You can see the sensor cable that came with the multimeter with the proper temperature range!

    Modern electronic components often come exclusively in packages that are dificiult to impossible to solder the old way. For just less than 40.- Euros I solved this problem.

    I has already mentioned that i purchased a drilling and milling machine due to my requirement for exact and repeatable drilling of holes and as a side effect it opened a world of new possibilities for making parts of my model. For similar reasons I purchased a lathe:

    For much more trivial reason I did build myself a workbench. My kids were still very young and due to some moving of stuff around the room they made a couple of holes into the hull of my model. I decided to build a workbench and integrate in it a hangar for my boat!

    Here a picture of that workbench while I was building a shelf to be integrated into my workbench to store the infinite number of stuff that has accumulated over time! At the bottom left you can see the hangar with the hull.

    As a good german I follow the well known pattern always attributed to germans: Why do it simple if you can make it complicated

    The name for the model is "Carina" and the home port should be the city were i was borne, Guayaquil , Ecuador! So presenting my thinking I was advised that the text should be in accordance to the rules for text in those days when the original boat was made. At the beginning of the 20th century the amount of "embellishment" has to be in line with the social status of the owner of the boat. The result is the following, first for the name of the boat:

    and for the home port:

    The result, ready to be placed on the hull as soon as it would be laminated with mahogany veneer was this:

    Last edited by Hellmut1956; 12-25-2013 at 03:31 PM.

  7. #7

    Default Re: My sailboat Carina, a modell closer to a J-Class

    Great work!

    I will wait for updates

  8. #8

    Default Re: My sailboat Carina, a modell closer to a J-Class

    Dear friends, I have continued having health problems, last on April 28th 2014. Something abbreviated "TIA", which is kind of a temporary stroke, pretty light, but having had a thrombosis in October and taking a brand new medicamentation called Xarelto, me and the doctors at the stroke unit were surprised this could happen being under this medicamentation! Well, being "special" in the way I work on my modell y probably have also to be "special" in health issues! Search for the cause of this is going on! One important part of my daily pray is to ask for enough years to pursue all those fascinating projects related to my sail ship. Lets go on!

    There is an interdependence between between the status of my workshop and the tasks popping up in the process of building my sail boat! The need for certain equipment and tools to demand to adapt my workshop. During the last more than 12 months my focus has been on the workshop, but since the work on my model presented so far in the report a lot has been done and a lot more is being embraced!

    Lets present the work on the workshop that relates closely to the projects on the model.

    Here you can see the upper half of what I now call my old workbench. On top is an empty 60 cm depp space over the complete length of the workbench, used to store long stuff. I believe you never have enough space.below it, to the left and not visible to the right are 3 cabinets to store stuff. below the center is the neon light, the switch for the light, the empty space that will be used for a total of 144 assortment boxes in which I will be able to store the many small parts in an ordered fashion. Below 3 cabinets and more shelves for more even more assortment boxes. below more contact boxes. I believe there can never be enough!

    Next the upper right side, were on the hidden wall of the right cabinet I have made provisions to store safely my welding and equipment.As you can see I have left no spare room without use. below you can see the the drawers. In an update made during the last 12 months I have shorten the drawers to be just 60 cm deep, as at the size of them at the status of this foto, was so big, that the stuff inside was a source of chaos in its own right.

    Here a detailed photo of the shelves in the center part shown earlier.

    Here a photo of the center and left lower half of the old workbench. It shows the reason for the original start of building this workbench. My kids moved a scratching post for our cat and it crashed with the hull, leaving holes in it. So I decided to build an hangar for the hull and as a result came this workbench into existence.

    In an empty spot left an the wall to the left of the old workbench and the entrance door I build my first version of an electronic lab, as the extent of the work related to electronics was proving to be huge. A side effect of this was, that I realized that of the past 2 decades I had purchased and accumulated so much electronic stuff, that it proved easier to buy something again, than trying to find what I had. In the center of the electronics workbench you can see a power supply for PCs modified to supply different tensions available in it and a a black box mounted next to it on the wall, a tension doubler that generated a 24 VDC 10 A, a value that could be added to the repertoire. Below it my unpreventable power sockets and below it another neon light. On the workdesk the sickness of my lab, I am just now finally getting this organized, huge amounts of anorganized parts!

    Here you can finally see the 144 assortment boxes! But as it was evident on the desk surface of the electronic workbench, it is equally evident of the desk surface of my old workbench. And I have to admit, that there is a second large room in the cellar filled with more stuff!

    This old workbench here did good services over about 1 decade. As the structure of it, with one exception was build using wooden beams, some of the wooden beams started to give up, rendering some of the drawers useless as it became hard to open or close them. So I decided to update this old workbench by adding steel beams to hold the wooden boards on which the drawers slide.

    This technique had proven itself during the construction of other elements of my workshop, I will describe them later, but you can see my "new" workbench on the right side of this photo!

    The result of embracing this project was that the usual chaos exploded getting impossible to work on any other project. Added to this my health problems that started with a stroke in April 2012, continued with my heart stopping beat, getting a pacemaker inserted, i am now myself y "cyborg" , problems with wrong medicamentation and a thrombosis during 2013 and finally a second light stroke in April 2014 led to me starting to get depressed by not being able to experience success stories as part of my work on the model and the workshop.

    On the floor in front of the old workbench you can see a steel beam of the kind used to support the boards that can be seen in the old workbench and on which the drawers slide.

    But having fixed this new work pops up. First I need to decide how to subdivide the drawers and what to store where.

    The large drawer that extents over the full width of the "hangar", about 180 cm and far to deep was a sink for stuff and a place where I could never again find anything in it. You can see 2 of the 3 grips equally spaced across the drawer, the hull in the hangar is 165 cm long, just to give you a feeling for its size. I have cut it in 3 equal width pieces, each with its own grip and a depth of just 60 cm. I have still not completed this, because I am missing some wooden parts I need and because simply I am bored working on the old workbench, so it waits for me to finish it.
    Last edited by Hellmut1956; 05-17-2014 at 08:02 AM.

  9. #9

    Default Re: My sailboat Carina, a modell closer to a J-Class

    After my first stroke a good friend decided to help me to get order into my workshop, while I was still recovering from the stroke. He really impressed me about with what creativity and a natural sense for organizing things and how heavy and intensive he worked , while I mostly was sitting next to him and giving instructions!

    One of the key changes he introduced was, to separate those dirty work activities from those generating less dirt into the 2 separate areas of my workshop. A consequence of this approach was, that we decided to build a second workbench, now called the new one, while the other one became the attribute of being the old one. For this we removed the bed coach from that room part with the old workbench and placed it in front of the large cabinet in the other half. One of the side effects was that I got in trouble with my wife, as access to this cabinet got very difficult!

    The space that got available in the first half by removing the bed coach was going to be the place for the new workbench. This new workbench would get the form of an "L".

    This new workbench should become the home for the milling machine and the lathe. In the picture you can see that the whole workbench is placed on top of compressed wooden boards, to protect the floor of the cellar and made using 40x40 mm steel beams, screwed together to allow for removal, should we change for a smaller residence in the future. Our current rented house has, including the cellar 4 floors and the day will come when neither me nor my wife can continue exercising going up and down those stairs!

    So far only below the lathe and that part of the workbench desk surface has the strong plywood boards covered with a surface resistant to chemicals and very strong against mechanical stress. The whole backside wall of the workbench as of the moment of the photo was made using compressed wooden boards. A lot of thinking was spend to decide exactly where to place the 2 machines. A round wooden beam, 1 meter long, was fixed in the vice. This way i could assure myself that there was no space limitation to be expected when working on the milling machine. At the same time the lathe waa placed in such a way, that a piece to be worked upon in the milling machine could extent up to the back wall of the workbench behind the lathe. To the other side there was room up to the wall next to the entrance door.

    For the lathe the same thinking took place. On one side operating the lathe forced the machine to be in a position were the operator, me, felt comfortable working on the machine. This forced to place the lathe as far to the left as possible. This also has the consequence that a part being machined on the lathe could extent to the back wall behind the milling machine side of the workbench. The pace below the desk surface is being used to store stuff in boxes which over time will be placed in their proper places. Huge steps forward have been done until today, but a lot of work is still being left.

    In this 2 photos you can see how the desk surface and the back walls of the new workbench look like. The plywood boards used for this purpose are normally used to build cases to be filled with concrete in constructions. as a result of this function, this plywood boards have extremely strong surface. My objective is to have the surfaces of the desk of the new workbench always empty after working on the machines and the surfaces have to be easy to clean. I am not yet there to achieve my goal of an empty workdesk on my new workbench, but on my way there. I am in the process of building the infrastructure to make to rows of drawers below the surface of the desk of the new workbench. I will introduce you to this now, when I describe the uplift of the second half of my workshop, the cleaner room.

    This series of pictures show you how I have completed the new workbench desk and back walls. but it also shows the ilumination and the electrical infrastructure of the new workbench. The 2 switches next to the lathe, the lower one disconnects electrically the whole workbench, the upper one the light and the power supply to the sockets and in consequence the power supply to the lathe.

    The electrical wiring goes behind the back walls to the switches, the lightning and sockets next to the milling machine. The lower socket control the power supply to the 2 sockets next to it and as a consequence switch the milling machine ON and OFF by controlling the power supply to the sockets feeding them. The upper switch controls the light and the sockets next to it.

    Here you can see my office desk and a bit to the right a second unit that will become my electronics workbench! On the front right you see a part of my band saw. This band saw was originally manufactured in the former communist part of Germany. It is simple but nearly impossible to destroy. This machine has proven its value countless times during my work on the workshop. I inherited it from somebody who had it in the stored away in a corner because he could not fix it. This very good friend who has helped me to do a lot of the work in the workshop spend a couple of hours on fixing it and now it is in perfect shape! I have my PC on it with 2 LCD screens, wonderful working tool, but cluttering my already chaotic office desk.

    Now to the building of my new electronic workbench, which originally had served as a server cabinet and as the place for the printer and its consumables.

    This picture shows how I am fixing carpet to what is going to be the bottom side of the electronic workbench. Again here, so it does not damage the floor. You can also see the round wholes in front of which I had fans installed which expelled the warm air coming from the servers in this cabinet.

  10. #10

    Default Re: My sailboat Carina, a modell closer to a J-Class

    Lets continue:
    As I have written earlier, a technical problem with my milling machine, a screw used to fix the position of the coordinate table broke and i had to remove it. The result was that I decided to extent the work to do maintenance work and to recalibrate the whole machine. The other big cause for a mayor rework on my whole workshop was that I had to get the thousand of parts I got, accumulated over nearly 2 decades had to be placed and put in such an order that I could get access to them easier and not have to go to buy something I owned again. Finally, and this gets the loop of this thread back to the initial focus, the future work an my sailboat model, I new that now I was going to start to embrace the electronics projects for my sailboat. So I decided to move from having a small electronics workbench to make the real thing:

    Here you see how I build a solid steel infrastructure into the workbench. This on one side is due to the fact that I will have to step on the desk surface to access stuff that I have on the shelves above and behind the furniture and I am pretty heavy, and also because I will ground this so that I can make a well grounded working environment

    This picture shows my electronics workbench frame. As you can appreciate, it offers plenty of space to be used to setup a good working environment. The opening below the desk surface on the right has the purpose to give access to where the phone and Internet access points for our house are.

    One thing an electronics workbench needs, besides good electrical grounding is a rich and powerful electrical power source. What I mean by rich is a large selection of different DC power sources. I do gain them from a modified PC power supply and by doubling the +12 VDC to get 24 VDC / 10A additionally. This on the other side requires robust and safe cabling. So what I did was to cannibalize my old and small electronic workbench. This foto shows a view from the rear of the "module". The foto shows the module upside down. At the top you can see the Aluminium "u" profile I have used to place the jacks for banana plugs. I have used solid copper cables to ensure that those would not even get heated, if a short circuit made a huge amount of current flow through them.

    In this foto you see the same module viewed from the front side. The bottom row of jacks are all connected to ground, the top row has 6 jacks for each of the positive voltages, for the negative voltages only 2 jacks each and the 3 jacks for the second +24 VDC set will later, when I can afford to buy a 48 VDc power supply will make that voltage available as well. This 48 VDc are required for 2 purposes. One is that as I plan to realize a winch for the sheet to control the sail using a stepper motor. In my model I will have 12 LiFePO4 battery cells connected in series, which results in a maximum voltage of approx. 40 VDC feeding the stepper motor when the batteries are fully charged. So having 48 VDC available in my lab will allow me to do experiments that cover the full range of possible power voltage to the stepper motor from 24 VDC when the cells are empty up to the 48 VDC which is above the maximum 40 VDC my stepper motor will meet in the model. The other use of the planned 48 VDC power supply and this is why it will have 3kW power, is that I will feed a high end battery charger, called Pulsar 3. I have added the link to the vendor in english so you can have a look to it.

    In this foto you can see where in the workbench the power supply module will be integrated. Also you can see something I keep as a rule on all my work. You can never have to many power plugs. On the right side on top of the desk surface you can see where I do integrate an oscilloscope. On the left side I have placed an outdated oscilloscope as a place holder for the future 48 VDC power supply.

    On this foto you can see the modified 600 W PC power supply and the strictly organized cabling. This is very important as otherwise it can be dangerous if some electric current conducting part is touched accidentally and / or it can be source to have a fire in the workshop initiated!

    This foto shows the electronic workbench, not yet completed, but used for some initial experiments with stepper motors.

    The following video, and I do ask your pardon for being such a bad speaker has been taken out of a short tutorial I have made on step motor control. The control board I use, called "stepRocker, is the one which will in my model to control the step motor to implement the winch functionality. In this video I was demonstrating how fast a stepper motor con rotate, even feeding it with what will be the smallest tension, approx. 24 VDC. I have setup the parameters to make the highest possible speed achievable and modified the so called "velocity" parameter which can have a value between 0 and 2047. I myself was surprised how fast I was able to get it rotating, before it blocked. This is why the video is relatively long. If you watch the blue tape fixed to the drive shaft you can see how fast it gets! One of the objectives why I developed my own concept for a sheet control in my sailboat was, that I want to implement the sheet control for the sail boat model in a way equivalent to that used on the original J-Class sailboats. But doing so requires to be able to change the length of the sheet by a total of 8400 mm or 330,71 inches. No imagine this drum, still being made with a length of the circumference of 400 mm. As a result just 21 full 360 turns results in a change of the length of the sheet of the desired 8400 mm!

    Imagine the drum rotating at the speed that can be achieved and seen in this video, then you can judge, that those 21 turns can easily be achieved in 1 second. Watch the DMMs displaying the tension and the current as the stepping speed of the stepper increases.Please wait a bit for your browser displaying the youtube window!

    As you can well imagine the high rotational speed shown in the video takes place with no "load" on the shaft of the motor, but it also takes place at just 25 VDC of tensin. To understand and communicate the technical details I will add this information later. The purpose is to demonstrate to you, why the electronic workbench is so important in my project of building my sail boat model.

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