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Some can do fibreglassing as easily as shelling peas. I have fibreglassed 3 models so far and have yet to master the technique. I've spent far too much time sanding the results to make them smooth. For my next project I plan to follow the guidance shown here:https://www.youtube.com/w atch?v=ujk-wBQDUSk. He talks about 'denatured alchohol' which, in the rest of the English-speaking world is referred to as methylated spirits.
I was able to test the new paddle wheels on the water today and they have proved to be the solution to the old wheels digging in. She no longer develops a list when under way. The other advantage is that there's no longer a big wave from the paddles, and it's possible to get up to a realistic maximum speed. Hope to have some video to post in the near future.
Screw holes for holding the support beam in position were marked in the sponson supports and drilled. At this point the assembly could be installed permanently. - Removed the nut and washer from the centre of the master rod and attached the support beam to it; replaced and tightened the lock washer and nut. - Slid the wheel onto the shaft until the locating holes for the support beam lined up with the screw holes in the sponson supports and fitted the screws. - Final check of rotation on the shaft.(see video) - Tightened the wheel drive collar onto the paddle shaft. This was a 3/16” collar drilled for a short length of 1/16” brass rod, which was soldered in and then bent to fit into one of the drive holes near the centre of the inner side wheel. The video shows the motion for the starboard wheel. It has been operated under radio control, but even at its lowest speed it goes too fast unloaded to see the motion clearly. All that is required now is some liquid water to try it out and learn whether the objective has been achieved.
I will be interested to learn how your electronic solution to speed control and steering works. I have not run my model at full speed because the paddle wheel throws up quite a wave behind it and would throw a lot of water onto the aft deck. I typically operate the paddles independently to try and minimise the list, and use the rudder for steering. Roy
A beam was needed to support the pivot for the feathering mechanism. It was made to straddle the gap between the two sponson supports. There’s even less information available about this than there was for the feathering mechanism. My second attempt was the best solution and comprised the following parts. - Two 3/8” lengths of ¼” brass angle; with a clearance hole drilled in the top flange near one end, to suit the small sheet metal screws I had on hand - A length of 1/8” x ¼” rectangular brass tube to span the gap between the sponsons. - Approx 2” length of ¼” x 0.030” thick brass strip - A ½” length of ½” wide by 0.030”thick brass strip - A 7mm length of 3/16” brass tube as a bushing for the pivot. The rectangular tube was cut to length to fit across the sponson supports and inside the paddle boxes. The two pieces of ¼” angle were soldered at right angles under the ends of the 1/8” x ¼” tube. The paddle wheel and the beam were placed in position. The paddle wheel was set up while stationary to position the paddles so that one was on bottom dead centre and vertical. The axial position of the pivot point centre was marked on the beam, and the distance below the edge of the beam measured. The top edge of the ½” square strip was intended to be flush with the top of the beam, and a 3/16” hole was drilled through the former at the pivot point centre. This was soldered to the ¼” wide brass strip, and then the 3/16” tube soldered into the hole. The drill press was used to set it at right angles to the strip for soldering. The strip was joggled, to ensure the rotating paddles cleared the support beam, and with the 3/16” tube on the side nearest the hull. The brass strip was clamped to the support beam, with the complete assembly in place, and the pivot position adjusted to give the optimum motion of the mechanism. The brass strip was soldered to the support beam, and then removed and painted.
The paddles were cut from 0.050” styrene, the attachment points for the support arms drilled, and the support arms fitted and glued in with epoxy. The paddles and the side wheel assembly were painted black, with small pieces of masking tape over the pivot holes in the paddle support arms, where the pivot tubes were glued to them, and painted over later. When it came to assembling the parts, the sequence was as follows: - Fastened one end of the links to the inside face of the master rod (looks like a banjo); using #2-56 UNC bolts with the bolt heads on the outside face, a 4.5mm length of 1/8” brass tube as a bushing, and two #4 washers, and a #2-56 nyloc nut. - Inserted a #4-40 UNC bolt and washer in the centre of the master rod from the inside, secured it with a 5/32” brass tube bushing, lock washer and nut - Fastened the outer end of the links to the paddle arms, with the links on the outside of the paddle arms, with the bolt heads on the inside face, otherwise same as inner end of the links. The next step is to make the support for the pivot of the feathering mechanism.
The two side wheels are held together by 5/32” outside diameter brass spacer tubes. Seven tubes were cut to the same length, one for each paddle pivot location. There is an additional central tube of 7/32” OD to fit over the drive shaft. The assembly was placed on a drill press with a 7/32” size drill through the centre to align the two wheels, and hold them at right angles to the centre shaft/drill. The pair of side wheels were first soldered to three brass spacer tubes. A drill or a piece of steel rod was used as a mandrel to align them. Unfortunately I used the wrong flux and the rods and drill were soldered in, so had to be de-soldered. They were re-soldered using a different flux and aluminum tube to align the wheels. The remaining tubes were soldered in the same way. Some of the solder found its way into the clearance space inside the brass tubes, making the aluminum tubes a tight fit. After they were pulled out this solder was cleaned out with a reamer. Dave, Stephen says the only way (other than Youtube) to display a video was as I did.
The holes in etched parts are not always as accurate as drilled holes, so some holes had to be opened out with a reamer. The pivots for the moving links were to be held together with nuts and bolts, all in stainless steel. The bolts fit through a 4.5mm length of 1/8” brass tube which acts as a bushing. The links were bent slightly to ensure that the bolt heads and nuts cleared other parts. One side wheel was assembled with its associated links and set up temporarily, using styrene fixtures made to suit, to check that it operated as planned.
This model sails well but lists slightly to one side or the other when the paddle wheels start turning. I have been told this was not uncommon on full size paddlers, a phenomenon known as “digging in”. The only improvement I can think of for this is to fit feathering wheels. After waiting many months for the one remaining supplier who lists them to have them available for purchase, I concluded I'd have to make my own. So I prepared artwork for the parts using Inkscape, and had PPD in Scotland photo-etch the pieces in 0.9mm thick nickel silver. The only parts not included were the paddles which I planned to make from styrene to save some weight. (The big pointy part is for something else).
You might find this useful, although I haven't tried any of the methods: http://www.wikihow.com/Patina- Brass I've used the special patina fluid shown here: https://www.etsy.com/listing/9 298547/8-oz-black-patina-chang es-silver-solder Roy
How about a rectangular wire frame lying on the ramp with the RIB sitting on the frame. Attach the upper end of the frame to a short vertical arm of material, and have that sit in a narrow slot at the centre of the ramp. Open the door, have a servo push the arm with the frame and RIB down the sloping ramp and into the water. Retrieval would be the reverse. Painted a suitable colour the frame would be almost invisible. This assumes the gate will go low enough for the frame to clear it. Looks like it's going to be a great model.
That could well have been a solution. However, a trial I ran this morning has established the minimum axial length for the rudder. With a 40mm length and greater, straight line sailing was very good, with 35mm it now tends to wander away from a straight line. So one of my winter projects will be to make two new rudders 40mm long. Thanks to everyone who provided input into this quest. Roy
Hi Haverlock, In my original post I mentioned that I had tried a couple of different gyros and neither had made any noticeable improvement. The rudder movements were very small in off-water trials, presumably because helicopters are much more sensitive. I have increased the size of the rudders and that has made a big improvement. I am in the middle of tests where I am reducing their size step-by-step. I have not yet got down to a size where I get the original poor sailing. Roy
That's true, but I need much more capacity for powering the motors than for the lights. Another option is to put two batteries in parallel for the motors, with a third 6V battery in series for the lights. The batteries are already being charged individually. Interesting option. Roy
I'm happy to report that increasing the rudder area has made a significant improvement in this model. The as-built rudders on the model are ~8 sq.cm, and I have temporarily increased this to ~27 sq.cm., more than 3 times. The biggest dimensional change is in the fore-and-aft length, so they are as long as they can be without projecting beyond the stern of the hull. Today was not windless, but even with slight gusts of wind it sailed along serenely with barely a touch on the rudder to keep it straight. Also surprising is that it will no longer "turn on a tanner". Also , turns are much smoother and better controlled; can only be due to the rudder change. As on the last trial, it is sitting slightly lower in the water, but I think I'll leave it that way. The next step will be to reduce the length of the rudder in decrements of 5 sq.cm. and see what effect that has. Roy
I have seen reports that the units using oil (or "distillate") leaves deposits, although I have not experienced that problem. They also smell. Glycol is used in the fog units you see in theatrical shows, so I don't think they will leave a deposit. I have not experienced a stability problem. The SMU unit will hold about 350ml of water, but can only use about half of it (the top half :-). So the weight reduces but the centre of gravity also lowers.
The Steam Master Unit uses water which is vaporised by an ultrasonic nebuliser. It looks very effective and draws a reasonably low current. For both of my models, I built my own tank from styrene to suit the size and shape of my model. It comes supplied with 20mm dia discharge piping. One of my models had a 13mm dia funnel discharge. This cuts down on the flow (but still looks effective) but also requires a conical reducer from 20 to 13mm to make it work. Another model has the Harbor Models oil-filled smoke unit. It has a 1/2" discharge, a small tank, and draws 3A. I have not come across a unit which uses glycol, but would be interested to learn about one. Roy
I'd suggest building it around a white LED, choosing the size to suit the scale of your model. A standard domed-top LED gives a very focused beam. I've attached a photo of a searchlight on my 1:48 scale tug. It uses a 10mm dia LED. The back plate is a circle of styrene, and the case is 1/2" styrene tube. The legs of the LED are bent down and around, with extension wires soldered on, and then another styrene tube slipped over them to form the vertical support. The exposed wires at the back are hidden with modelling paste-type epoxy.
I followed Mark's suggestion and gave the motors some running-in. After that, I found that with a small tweak on the stbd trim tab I was able to get a good speed match on the shafts with the radio control sticks at the same setting. I dropped the voltage to 6V, which is entirely adequate for the model. (I need 12V for the lighting, so I'll have to fit a voltage reducer for propulsion at some point.) During the testing I had a mishap with the batteries and have replaced the four 1600mAh batteries with two 2500mAh. These are heavier, so the model sits a little lower in the water, which will have an effect. Today was the first run in the pond after all the experimenting. Not the best conditions because there was an intermittent breeze. It appears to be better, will sail further in a straight line before it wanders off and makes a circle; still random. Next step will be to fit the larger rudders and wait for a windless day to test it. No video yet, but will try and get some on that occasion. I think progress has been made.
Hi Mark, I'll give that a try. I have a question for the experts. Are the bronze bearings in the Mabuchi motors plain bronze, or a sintered bronze with a lubricant such as graphite or PTFE embedded in them? The reason I ask is that information I found on the Mabuchi website suggests suitable applications for these motors are automotive, inkjet and laser printers, and massagers. These are devices which are unlikely to have any kind of follow-up intermittent lubrication.
Very soon after my last post I was offered two motors matching the specs given by Dave to try out, so I did. With the stbd ESC feeding the port motor: - Ahead rotation, servo on mark 1, Port .46A, 1450rpm; Stbd .4A, 1800 Rpm. -Astern rotation, servo on mark 1, Port .24A, 315rpm; Stbd .14A, not turning - Astern rotation, servo on mark 2, Port .54A, 1700rpm; Stbd, .28A, 1800 rpm With the stbd ESC feeding the stbd motor: - Ahead rotation, servo on mark 1, Port .38A, 1390 rpm; Stbd .34A, 1610 rpm - Astern rotation, servo on mark 1, Port .1A, not turning; Stbd .2A, 440 rpm - Astern rotation, servo on mark 2, Port .42A, 950 rpm; Stbd .32A, 2450 rpm Battery voltage 13.0V. So generally a better match between these motors in the ahead direction, than the 365/14's. Difficult to say, based on this data, if the motors are better running in one direction vs the other. With some trim adjustment on the control sticks I'll be able to obtain closely matching ahead speeds. I have also learnt that motors to the same spec are available from the USA via Ebay for US$8 each. I have used Banggood, but delivery of anything from China to Canada takes a minimum of 6 weeks.
We're talking about the 'fish and chip' Royal Iris, built 1950, diesel-electric, currently moored on the Thames downstream of the Thames barrier. In the course of investigating the random steering problem, it has become clear that there's a motor problem. It appears to be fairly consistent, but there might be a random element. So I'm trying to resolve that, before I move on to some trials with larger rudders.
A scale model that mimics the behaviour of the prototype has to be a good thing, and that description certainly fits my model. But it's not so relaxing sailing this one. The props are 3-bladed 40mm dia. Current readings taken today are as follows: Stbd ESC feeding Port motor, and vice versa - Ahead rotation; servo tester set on mark 1: Port 0.62A, Stbd .54A - Astern rotation; servo tester set on mark 2: Port 0.7A, Stbd .4A Stbd ESC feeding Stbd motor, and port ESC port motor - Ahead rotation: servo tester set on mark 1: Port 0.5A, Stbd .42A - Astern rotation: servo tester set on mark 2: Port .42A, Stbd .54A Battery voltage was 12.6V. Since the port motor runs slower and generally draws more current than the starboard, all suggests that I should at least replace the port motor. But I am inclined based on the comments and this experience to replace both with the larger size. That may have to wait awhile since suppliers with good stocks of motors are on your side of the pond, and we have a threatened strike by Canada Post. Roy
The motors currently fitted are Electronize model 365/14. Does anyone else have experience with this model? Electronize motors are generally not cheap, but this model is one of the cheapest in their range. What would be a recommendation for a "good" motor? The test data above is with load on the motors - I should have mentioned that. Motors in the hull and the hull in the water, loaded down to the waterline. The prop shafts are Raboesch waterproof shafts, with a "G" seal, so they are water-lubricated. The connectors to/from ESC are as supplied on Mtroniks Viper models. To motor are all bullet type. THey are sound - clean and a bugger to separate. On the input side they are Tamiya connectors - look clean but how to test? Battery supply wires to ESC connectors are from screw terminal strip - I'll check cleanliness and retighten. Wouldn't it be nice if the motors were made with a shaft extension at both ends; just a thought. Roy
First of all, disregard all the speed information in my last post. After a frustrating few hours trying to understand inconsistent and erratic readings, I discovered I was holding the tacho incorrectly. There was no guidance in the instruction manual, but I learnt that it is necessary to hold the body of the tacho at right angles to the shaft, ie athwartships not fore and aft. At least the readings are reasonable, and repeatable, so I think they're correct. Having said that, removal of the port shaft revealed no evidence that would account for any slow running. Turning by hand indicated it was quite free. So fresh test data is as follows: Stbd ESC feeding Port motor, and vice versa - Ahead rotation; servo tester set on mark 1: Port 750rpm, Stbd 1060rpm - Astern rotation; servo tester set on mark 2: Port 530rpm, Stbd 650 rpm Stbd ESC feeding Stbd motor, and port ESC port motor - Ahead rotation: servo tester set on mark 1: Port 840rpm, Stbd 1210rpm - Astern rotation: servo tester set on mark 2: Port barely moves, Stbd 1550 rpm The port motor runs consistenly slower than the starboard, whichever ESC is used, and whichever direction it rotates. Suggests that there's a problem with the port motor. Next test will be with the radio to learn the control stick settings necessary to match the speeds. Might be worth testing with another new motor. Any other thoughts? Roy