ir3

Nearly there. All of the geometry is now correct. All the rudders are moving at the same rate and I am just about finished with this setup. I do notice a bit of flex in the rudder tubes so these will be reinforced. There is a little bit of skewing of the sled so I moved it as far back towards the stern as I could. The skewing seems to be a bit less. The only test to see if this works will be on the water. Next will be the installation of the Action electronics. Until next time, IR3

Thanks for the input, Lou. I will have to go through your explanation a few times to fully understand it. I have a Vario CH53 that I will be finishing in the late spring and the comments will be very useful. After giving it a great deal of thought, the first implementation was too complex. Geometries were all off. I didn't like having two different connectors on the large servo arm which caused the sled to move differently than the main rudder. The solution is to have the servo push/pull the sled and have the sled push/pull the rudder. In this way all the linkage is kept in a straight line. The position of the connector on the servo horn is exactly the same distance of the connector on the main rudder horn. Geometry is perfect! Now it's off to putting the Lurssen servo on the new sled. This will be positioned so that the angles to the small rudder connectors will be exactly the same. The result is that when the large servo moves the sled the main and outboard rudders will track exactly the same. Here is the new main rudder implementation. Now its back in the shop to install the small servo and put this part of the project to bed. Until next time, IR3

Well, after banging my head against the wall trying to get the outer rudders aligned, it became perfectly clear that the small servo must be centered between tiller arms. The geometry is all wrong with the current implementation and the rudders do not sync. I will be widening the sled to accomplish this. Now that I know how to build the sled, it should go quite quickly. I should have it all posted by tomorrow afternoon. The discussion is great. Lurssen was quite an innovator. Till next time, IR3

Thanks for all the likes and the input on the Lurssen Effect. It is quite intriguing as Ben pointed out. The reason I chose this model is because of this implementation. Seeing this working on the water will be quite amazing. As far as the work goes, getting the geometry of the 3 rudders correct is getting to be a bit difficult. Unfortunately the two outboard rudders are quite close to the back of the hull so getting the tiller arms at the correct angles requires a bit more work. Moving the outer rudders with the small servo can be limited to about 30 degrees. The problem is with the center rudder movement. I may not be able to get a full 45 degrees on the main rudder but this would be quite drastic anyway. The small servo definitely needs to moved off center to get the angles to the outer rudders as close to equal as possible. This is a bit more trickier than I expected. Until next time, IR3

nThanks for the question, hope this helps. My total knowledge about this effect is well below the marine engineers level of expertise but the concept makes a lot of sense. The larger servo, the one on the left moves the center rudder and pulls/pushes the sled simultaneously so that all 3 rudders track together. This is the normal, no effect configuration. Note that all the tiller arms are pointing in the same direction so the sled just acts as an extension of the larger servo arm. The smaller servo does not turn (until the Lurssen effect is desired) thus the outer rudder arms pull/push as if they are being controlled by the larger serve. So they track in a straight line AND while turning. Normal operation for 3 rudders. Now the Lurssen effect. The faster the boat goes the deeper into the water the stern sinks. Note the parallel with hulls that are designed for racing. At low speeds the hull is deep in the water but at speed they are almost riding on the prop only. The S-Boat hull is optimized for up to 20 knots for a long cruising range so the smaller servo is not turned as the outer rudders would drop the efficiency of the boat. Now at higher speeds the stern lowers in the water and the nose comes up dropping the efficiency so the smaller servo is activated to move the outer rudders away from the center line. This changes the way the water moves under the stern and lifts the stern up and the nose back down for a more efficient configuration. When the boat turns at speed steering by the large servo still keeps the movement of the outer rudders in sync with the main rudder. So if it is a turn to starboard at speed, as an example, the starboard outer rudder increases its angle from the center line and the port outer rudder lessens its angle from the center line thus maintaining the effect through the turn. The starboard side of the boat wants to sink into the water further, in this example, as the boat turns. So the starboard outer rudder deflect s the water more than the port outer rudder does thus lifting the starboard side of the hull out of the water more than the port side making the turn more efficient. Very difficult to explain in words as I am not 100% fluent in the dynamics but the principle makes a lot of sense. It allowed a hull which was optimized for around 20kts (normal cruise speed) to be very efficient at attack speed of around 40kts. A lot easier to alter the shape of the water going under the stern than change the shape of the stern. 😊

-- THIS ITEM HAS BEEN SOLD OFFSITE -- If anyone is interested in a Proxxon DSH/E variable speed scroll saw I am parting with mine. When I thought about scratch building this was probably a good scroll saw to have. As it turns out it is much too big for me. I am doing small wood and plastic boat kits and my Micromark scroll saw is perfectly adequate for my needs. I have 6 packs of extra blades to go with it. It has been used sparingly and so it is pretty close to new. It is 120V version. It's a bit dusty but will be perfectly clean when shipped. Asking $300 and will split shipping. I am not sure of the actual box size or weight but will be very happy to work out the numbers if anyone is interested. Thanks for looking.

The mounts for the servo tray are tacked in will be finished by next update. The clearance between the main rudder pushrod and the small servo is a bit tight. A washer or two under the main rudder tiller arm should take care of that. Tomorrow the servo testers will be put to use to fine tune the linkages and get the rudders aligned. Until next time, IR3

I now have the basic setup for the rudder controls. There are a few minor problems to work out but the principle is there. Unfortunately one of the deck mount hull spacers had to be cut away to make room for the pushrods but this should not be a problem. The original designer had the same problem. The only item I would like to find a solution for is the main rudder push rod and the sled push/pull rod attachment to the servo arm. Notice how they are spaced in order to fit on the servo arm. If anyone knows of a way that I can install them the same distance from the center of the servo please let me know. The way the setup is, the outer rudders/deflectors will not track the main rudder exactly. Perhaps it is not a problem??? Until next time, IR3

Started on the RC components. The first part is the rudder/deflector mechanism. This is not my idea but just adapted from another build. It is very clever and above my creative abilities at this time. There are two servos, the large one that controls the central rudder and the smaller servo which controls the outer rudders/deflectors. The small servo is on what I will call a sled. With rudder amidships the linkage from the small serve to the output is adjusted to keep the rudders parallel. There is a link between the large servo and the sled. When the main rudder servo turns to deflect the main rudder the sled is push/pulled to keep the outer rudders in alignment with the main rudder. The small servo remains centered thus allowing the rudders to track. At speed, the smaller servo is turned to move the outer rudders away from the center line thus adding the Lurssen effect. This is manual but I suppose with a computer radio this servo could be controlled by the throttle?????. The two pictures show the sled in the fully extended and fully retracted positions. Next, this servo tray needs to be installed in the hull. Until next time, IR3

Thanks Lou for the suggestion. Never passing up a good idea, the pieces for the shaft support behind the U-Joints is fabricated and test fit. The shafts turn smoothly so the next step is to tack it all in and finalize the installation. Getting the center prop shaft in position is a problem since it can not be installed from the stern like the outer props. The center motor needs to be removed and I need to make sure I can do just that when the boat is completed. In order to install the RC Gear and make it removable, I need to get the main deck fitted and make sure that it can be removed for making repairs. This will probably keep me busy for a day or two. Until next time, IR3

Hi Lou, Thanks for the heads up on possible vibrations at high speed. I will be installing the electronics in the next few days and will test the props at speed to see if vibrations occur. Putting in bearings sounds like a good idea anyway. I just need to find a way to that it doesn't block the ability to get at the screws that hold the motors on the bulkhead in case of failure. Until next time, IR3

Thanks for the likes. I believe it will be quite fast. It will be interesting if the Lurssen effect actually works at this scale.

The couplings have arrived. The motor bulkhead was cut from 1/8" styrene. To get the shape I used a piece of soft brass strip and formed it to the inside of the hull where the bulkhead will go. Then transferring to the styrene and cutting and drilling. Temporary installation with the bulkhead slightly tilted. The shafts do turn smoothly. A slight misalignment in the starboard prop shaft. Very difficult hollowing out the stuffing box covers and getting perfect alignment. The slight difference should not be a problem. Now for a permanent installation. Until next time, IR3

After posting a question on removing large amounts of plastic from parts of the model I was encouraged to start a build thread. This will be an RC Conversion inspired by ojays on RC Universe. One of the main reasons for building this model is to implement the Lurssen effect as was done on ojays thread. I am not so sure the effect scales down to a model of this size but implementing will be an interesting experience. The Lurssen effect is to adjust the angle of the outer rudders/deflectors to reduce the effects of the stern wave at speed. By changing the angle to proper value the stern wave produces minimum drag. The angle is optimized for a particular hull. The hull halves were fastened together and installation of running gear was started. The running gear was purchased on eBay as a package including the rudders, prop shafts, stuffing boxes, and props. It also included the center strut and outboard struts but for some reason they did not fit this hull so were excluded. It will use 380 motors and electronics from Action. The pictures show the startup. There is a bit of filling and cleanup still to be performed. Since I am waiting for some items from overseas I decided to scatter the work using what I have available at the moment. PE will be Eduard 53212 and Eduard 53214. The kit comes with some PE and I will be using pieces from each. I dread using PE as it is nothing but a struggle for me but I decided to take my time and be patient. We shall see what results follow. Until next time, IR3

Thanks for the inputs. Drilling out the center with the largest drill possible helped a great deal. Most of the other work was done with a Dremel drum sander except near the hinges. These needed a fine file and very sharp Xacto blade. There were no narrow chisel tips in the LHS which would have helped a great deal. Thanks for the suggestion on the build thread. I wasn't planning on one but there are not very many on the net so I think I will. I thought they may be skylights for the crew but being the engine room skylights makes a lot of sense. I'll continue in a build thread. IR3

I'm working on a 1:35 Schnellboot and will be using almost all of the PE upgrades. The main issue is the removal of the skylights for the crew quarters. There is a lot of plastic to remove. The picture shows some removal progress on 4 of the skylights. So far I have been using Dremel sanding drums, fine chisels, and sand paper. It's a tremendous amount of work. Any suggestions to speed up the process or is it just a lot of toil and hours of work to get it done. Thanks in advance, IR3

This is the last of my scratch build tools, the Dominoff PL 3.2 rope making machine with the programmer module. I did not purchase the power supply for it as I have a hobby power supply in the shop. It requires a 18V 2 Amp power source. It can be ordered from Domonoff if needed. Since I will not be scratch building the rope maker is for sale. It is still in its original wrapping and one can check the Domonoff website for the details. I am asking $275 shipped USA which will save a bit for anyone who is considering purchasing one. Thanks for looking.

The Byrnes Thickness Sander has been sold to a fellow modeler on MSW. Thanks for all the input.

Thanks for the interest in the Thickness Sander. Yes I do accept PayPal. Shipping to 78557 is $40 UPS Ground making the total $330.

Sorry, 120V.

Jolley Roger, let me know the shipping address and I can check the shipping fees. I CHECKED USPS AND UPS AND THE POSTAGE IS STAGGARING. IT LOOKS LIKE SHIPPING OUT OF USA IS PRETTY HIGH. IT APPEARS THAT THE TRANS GLOBAL EXPRESS ROUTE IS FOR SHIPPING TO UK ONLY. THE BOX IS 14" X 10" X 10" AND WEIGHS ABOUT 30 POUNDS IF YOU CAN CHECK SOME OTHER SHIPPERS.

Not a waste at all, getting the link is very helpful for International shipping.

Pavlo, I just signed up at Trans Global Express and the shipping cost will be 62 Pounds or about $80. Let me know.

Thanks for the link. Yes, it appears that the cost is about half of the USPS charges. It looks like the charge might be about $80 US but I would need to contact them directly to get the exact quote.

Thanks for the question. Shipping to UK is quite expensive for this weight. USPS charges approx. $150US and UPS is in outer space. I think Jim Byrnes had a discussion about shipping his items out of the USA on some forum. It may be on MSW somewhere. I hope this helps.