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John949

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Everything posted by John949

  1. 1. Depends who made the keel and who made the bulb. It can probably be made to fit without too much difficulty. 2 & 3. There are lots of factors to consider. The short keel has one advantage i.e. less wetted area and hence less drag (in the absence of any lateral forces). The shorter keel is less efficient at producing lift (to counteract the lateral force) and produces less righting moment. It depends a bit on the hull design, but generally, drag increases with angle of heel and aerodynamic lift (from the sails) definitely reduces with heel. So in very light winds the shorter keel is probably faster but it will be slower in stronger winds. Exactly when the changeover occurs is hard to say but maybe around 1/2 to 2/3 the wind range of the A rig?
  2. I'm afraid the explanation for this gets a bit complicated and requires a rudimentary understanding of control theory. The short answer is that you would need to re-design (re-program) the winch internals to change its behaviour. Some winches (e.g. Kingmax ones) can be re-programmed to change some of the control parameters (e.g. dead-band). I don't know if this is possible for these winches but this may be a fundamental control algorithm problem that you can do nothing about. Can you do an experiment for me please? With the winch fully sheeted in, push on the boom to simulate a sail loading. Push hard enough to move the winch a bit and then try to hold the same pressure. Does the winch stay where it is, or does the force it produces slowly increase to try and return the winch to the original position? Many sail-winches (particularly the smaller ones and nearly all the old analogue ones) use a very simple control algorithm that is fine for a servo that operates about a lightly loaded central position (like a rudder) but is not very good for a servo that needs to hold a given position under varying load. If you do understand control theory then I think what is happening is that, when the winch is moved fast, the winch very slightly overshoots the set point. The control algorithm appears to have an integral term which slowly increases the error until the winch moves back in the opposite direction. Either the winch has a pretty wide dead-band so that it stays noticeably 'further out' or they've got the control algorithm wrong and the reverse integration term isn't working properly to move it back again. You would need to put an oscilloscope on the motor terminals to see exactly what is going on. As it happens I've been playing with winch control algorithms a bit recently as I'm rather disappointed with the performance of my Kingmax winches. They seem to back off quite a long way under load - which is not ideal on a 10R. What I have learned so far is that controlling these things accurately is more difficult than you might first think as the motor's torque v current curve is hugely non-linear.
  3. If you have been doing something for several years, then someone tells you are no longer competent to do it, it's hard not to see this an insult. Add to that the necessary course is time consuming and barely relevant (it covers the measurement of full size sails) then is it any wonder that many of the previously qualified measurers have walked away. I also believe that the rule sets have become ever more complex and difficult to interpret which further alienates our existing measurers. I believe our rule sets and measurement process are no longer fit for purpose and unless they are simplified and made relevant to the majority of members then most people will not bother to have their boats measured and therefore be reluctant (or unable) to enter open events. The consequences for the sport are obvious and it seems to me that the effect is already clearly visible.
  4. Apart from this: https://www.rmgsailwinch.com.au/rmg/pages/E-Series-Rev-1-Programing.html It's under 'how to program a smartwinch' rather than an individual model listing.
  5. Paint is heavy. Some colours are worse than others. Black is good, yellow terrible. Car paints are quite soft and will chip and mark. 2K cans are better (the ones that come with a bulb inside that you break before using).
  6. I've played with several different winches and even managed to fix several of them. If you want I will take a look at it. I won't charge but I can't guarantee the repair (assuming it's possible) either. The other thing you could check yourself is to connect the battery directly across the motor and see if it spins (remove a gear wheel first). If you have a multi-meter then check the resistance of the pot as you turn the output gear. On the electronics side, older winches tend to use standard parts for which modern equivalents are probably available. Newer winches tend to use custom chips which you can't get hold of. Mechanical bits are very difficult to source apart from motors. If the electronics side is dead put the pot is ok you can sometimes use the electronic board from a modern servo instead. It really depends want you want. Old winches tend to be heavy. The Kingmax ones are about as fast, less then half the weight and a fraction of the cost. PM me if you want me to take a look.
  7. One way to look at is this. Green is on starboard so red, on port, must keep clear. Yellow must not prevent Green from doing so. I agree completely that Green should be talking to Yellow to ask for room. On a different tack (sic) I think that if I was red then I'd gybe onto Starboard (assuming we are heading for the same mark).
  8. The Tx pack should life should be very predictable as the current drain is constant. The spec for your TX should give the current. You simply divide the mAH rating of the battery by the current to get the time e.g. 1800mAH / 500mA = 3.6 hours. The Rx pack is more variable. Although the current drawn by the Rx is constant, the current drawn by the servos depends on the load and is probably more significant than the Rx drain. In other words you battery will not last as long on a windy day. If you set the boat up so there is tension on the mainsheet at the fully sheeted in position, this will definitely shorten your battery life. (Marbleheads with gizmo swing rigs are great battery eaters). It's best to experiment. You can tell how much of the capacity you have used by how long it takes to charge i.e. time x current. Just as a guide, I use a 1300 mAH Lipo with an RMG and that will do 12 (shortish) races in a day and still have plenty left.
  9. Interesting application. You could dismantle the transmitter and put pots on all 8 channels then! Worth giving some thought to the safety of such a set-up - definitely need to use failsafe positions. My understanding is that the cost of a live steam loco is such that a cheap tx/rx would be lost in the noise.
  10. You can certainly bind multiple receivers to the same transmitter (for the same model memory) - just repeat the binding procedure with the second receiver. Some of the very large flying models do this as a form of redundancy. If you do this then the outputs on each receiver would be identical e.g. the throttle stick would control the throttle channel on both receivers. So you could have the left stick doing rudder and winch on one boat and the right stick doing the same on the other boat. The servos would of course need to be plugged into different receiver channels as you suggest. Why you'd want to do this rather than use two transmitters is beyond me though. The converse is not true. You cannot bind the same receiver to multiple transmitters. The 'unique identifier' is in the transmitter and the binding process is the receiver 'learning' which identifier to respond to. Whether you can bind the same receiver to different model memories is manufacturer dependent. My old Spektrum transmitter does not allow it and calls it a feature (Model Match - although I've recently been told that the latest Spektrum transmitters allow you to disable it). The idea is that you don't accidentally try to fly one model with another model's settings. I bind the same receiver to multiple model memories so that a have different models memories for each rig i.e Marblehead A rig, Marblehead B rig etc. This means I can set the travels and trims differently for each rig. My Tx16 transmitter allows this but gives me a warning.
  11. I finally pensioned off my 30 year old JR PCM10 and bought a new transmitter. One of the major reasons for doing this was to have telemetry i.e. show information about the state of the receiver battery and the received signal strength. Exactly what information you get depends on the receiver you use but usually battery voltage is the supply fed to the receiver. (It definitely is for a Fkysky IA6B) Now if you use an RMG (or other winches where the battery is connected to the winch rather than the receiver), the voltage you will monitor is not the raw battery but rather the output from a voltage regulator (or BEC) and hence is of very little use, as it will stay constant until the battery is completely flat. The 'proper' way round this is to use an additional sensor such as: https://www.flysky-cn.com/cvt01-canshu However you could do a little re-wiring to measure the battery voltage directly. The reason that RMG winches (and some others) include a BEC is that the winch can operate from a supply up to about 9V (and has better performance if you do) but most servos are only spec'd to 6V (until recently at least). Receivers on the other hand contain their own voltage regulators and 99.9% will be happy to run off 9V. So you can connect the receiver to say a 2-cell LiPo without fear. For servos it is the current that will kill them not the voltage, so they will be fine on a 2-cell LiPo - as long as you don't leave them stalled for any length of time! So if you are happy to run your rudder servo at the higher voltage then you can get the actual battery voltage by re-wiring as shown in the second diagram below. If you are concerned about your rudder servo then use the third one. Note the diagrams show the logical wiring. The best way to actually implement the second diagram is to wire an additional Futaba plug across the battery connector and plug this into the receiver battery connection. Rather than cut a wire in the RMG plug, use a short extension and cut the red wire in that.
  12. I use a waterproof speaker (intended for use in a shower!) and this stays connected for several minutes after the voice signal stops. There are a plethora of free timer apps out there. This one has a rather nice horn at the end of the countdown. https://play.google.com/store/apps/details?id=ypsilon.app.cdn
  13. Does yours have the extra black wire? You have connected this to a spare centre pin on your receiver haven't you? First make sure the sheets / lines are not jammed. Try moving the drum by hand, if it feels OK then look for broken shorted / wires. Turn the winch to approx its mid position and try restarting it. Look at the gear wheel on the pot and make sure it is engaging with the output gear - it can move on the shaft. Failing that then most likely you have a fault in the electronics. My understanding is that an RMG will enter stall mode when the current to the motor exceeds some value (around 7 amps?). If this happens then the control circuit will drastically reduce the current supplied to the motor and the winch will beep. When mine did this it still moved but very slowly and very weakly i.e. if you pulled on the sheet the winch would unwind and then slowly move back. If yours doesn't move at all then my guess it needs fixing. Let me know if you fancy trying it yourself as they are not the world's most sensible design and if you undo the wrong bolts you have to cut open the electronics box to re-assemble them.
  14. Nigel, Can you confirm that you've done it on a 6114 please? I know others have done it on SW22HV. Which version of DSConfig are you using? The latest I can find is 2.1 Also does the LED stay green throughout the process? Thanks
  15. Has anyone succeeded in programming (or even reading the configuration of) an SW61114 servo? When I try the LED turns green when I connect the USB cable and stays green if I press reflash USB, but if I press read or write the LED turns red and I get an error message a few seconds later. It looks to me as thought the PC to programmer comms is working (hence the green light) but the programmer to servo comms is not (hence the red light). I've also tried an 45SW servo with the same result. I'm using Windows 10 and version 2.1 of the programming software and yes I have loaded the USB driver.
  16. Best thing to do it to test it since all Dacrons may not be the same. I leak test my boats using soapy water and a bicycle pump in the bung hole. I use Dacron from Profabrics and I can't detect it leaking.
  17. John949

    Deck Patches.

    https://www.profabrics.co.uk/products/adhesive-dacron Buying it by the metre is maybe OTT if you own a Dragon but my 10R & M use quite a bit. I also use it for sail re-enforcement and sail numbers so I get through it.
  18. John949

    Deck Patches.

    The stuff I use from Profabrics will heat shrink a bit. Put it on as best you can, then wave a heat gun in it's general direction and it shrinks tight. Strangely the black stuff seems to shrink better than the dark red stuff?
  19. Shrouds without spreaders doesn't make a lot of sense from a stiffness point of view. Once you have shrouds, the extra weight / windage of the spreaders is small for a significant increase in stiffness. Of course you don't need them in light airs, but if you find a crease running from the mainsail clew to about 1/3 up the mast then spreaders will help.
  20. Using the MYA ranking system is an idea I hadn't thought of and it seems to have a lot of promise. My personal view is that fairness does matter and therefore the RYA low point system is inappropriate. The Low Point System is intended for use in a continuous regatta where the number of entrants and number of starters is almost constant. If this is not the case then anomalies occur. For example, if there are ten starters in one race but only five in another: First place scores the same so it is saying that winning a race with five boats is just as 'valuable' as winning a race with ten boats - I disagree. Coming sixth in the ten boat race is a 'worse' result than coming last in the five boat race - how can that be fair? DNC is a tin of worms. Do you score it as entrants in the entire series +1 or entrants on the day +1? The former would put a huge penalty on DNC, the latter means that DNC scores different values on different days. The Low Point System penalises bad results and therefore discards are almost mandatory. Again the Low Point System is intended for a regatta with relatively few DNCs among the top boats. To cope with a 'days' worth of DNCs you need a large number of discards or else it turns into an 'attendance' competition rather than a best sailor competition. I think Stephen B's system tends to the latter. My personal preference is for a high point system e.g. 1 point for each boat beaten +1. This automatically addresses differing numbers of entrants, no need for discards and DNC is not an issue (DNC & DNF score zero). It's also possible to win even if you miss a lot races (if you're good enough). Unfortunately many people seem somehow wedded to the Low Point System, despite its shortcomings when applied to a series.
  21. I'm sure many clubs hold competitions that involve several day's results. For example say; a Spring series, consisting of 6 days racing spread over a couple of months, with 8 races a day. I'd like to know how other clubs would score such a series. Just to give you some clues as to the points I'm interested in: 1) How do you cope with the fact that the number of 'starters' on a given day / race can vary quite a bit? 2) How do you score people who don't turn up on a given day? My own view is that the current RYA Low Point system doesn't work very fairly when applied to this type of series, so I'd like to know if other clubs use alternative systems (e.g. High Point).
  22. Thanks John, It appears 18.3 was changed to apply apply to Port hand marks. Do you know what the thinking behind this change was.
  23. We used a set of videos as a rules teach-in recently including this one: Thanks to this and Nigel B's scenarios, I think I understand the rules if you tack in the zone on a Port hand mark i.e. 1) You are not allowed to make a boat to windward of you sail above close hauled. 2) If you get overlapped inside, you must give mark room (even if the overlap occurs within the zone). See second part of video. When this video was made the rules applied equally to port and starboard marks (see comments on the video), but Rule 18.3 now only applies to " a mark to be left to port". So what are the rules for a starboard hand mark? Taking 1) first. The first part of 18.3 is a restriction on a right of way yacht (* 1). So if this restriction does not apply to a Starboard hand mark the presumably the tacking yacht can force the windward yacht above close hauled? (but she must allow windward room to keep clear see *1). So the tacker has more rights on a Starboard hand mark? The second part is less clear to me. 18.3 doesn't apply. 18.2 d says 18.2 b & c no longer apply if the boat entitled to mark room passes head to wind (the tacking yacht definitely had an overlap before she tacked) . So that leaves 18.2 a, e & f. 18.2 a says the outside boat must give the inside boat room - Note there is no mention of when the overlap occurs or the zone. In 18.2 e, the meaning of 'in time' is not clear to me in this situation but if it is clear that the inside boat did gain an overlap before the mark then this doesn't apply. 18.2 f says that the tacking boat must be given time to give mark room. So my conclusion is that this situation is that 2) is the same as for a Port hand mark. Is that correct? An example below. 1) Yellow enters the zone on starboard and will cross ahead of blue. 2) Yellow tacks in the zone and slows. 3) Blue gains an inside overlap. 4)Yellow does not give mark room and there is a collision. Yellow is at fault? *1 The boat that has tacked in the zone is to leeward and therefore has windward leeward rights, but must allow the windward yacht room to keep clear as she gained these rights following a tack.
  24. For a bit more accuracy the roach area is roughly 2/3 * leech length * maximum roach width. You measure the roach width at right angles to a line joining the tack to the clew. Same formula can be used for luff round and foot round. For more accuracy still, look at how 10R sails are measured. For mathematicians - use Simpson's Rule.
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