Here is a list of all the postings Gareth Jones has made in our forums. Click on a thread name to jump to the thread.
|Thread: Spektrum radio|
I have to agree with Malcolm, generally I am quite happy with my Spektrum equipment but occasionally I have sworn at it, either because it has developed an intermittent hardware fault or because it has not done what I expected, usually because I did not read the instructions carefully. I do get the impression that current transmitters are not as robust as they used to be, although they are more sophisticated and do have some useful features, like being able to change modes on the sticks withouit having to take the back off the transmitter and fiddle about inside swapping springs and ratchets.
The failsafe situation is, as Dave, says confusing and some Spektum receivers set channels other than throttle to the last known good position, others can be programmed to put all servos in a preset position, chosen when setting up the system. However the throttle channel, which is the one I invariably use for a sail winch can usually be preset and I normally set the failsafe so that the sail winch puts the sails about 30 degrees out as a reasonable compromise to allow the yacht to be recovered.
Edited By Gareth Jones on 22/06/2020 12:28:06
I think Tim Rowe is correct in his explanation and the Spektrum DX6i does have protection against using the wrong transmitter settings with any previously bound receiver. The feature is called ModelMatch. The following text is taken directly from the manual:-
You must bind the receiver to the transmitter before it will operate. Binding is sharing identification codes between the receiver and the active memory of the transmitter. Once bound the receiver only connects to the transmitter when the previously bound model memory is selected.
I am pretty sure it does work like this as I have a number of different yachts programmed into my DX6i and have occasionally wondered why a model does not work, usually when testing something in the workshop, and I have found I had the wrong model selected on the transmitter. My memory is probably less reliable than the transmitters.
The basic channel settings are stored in the transmitter memory not the receiver. However some data must be stored in the receiver, apart from the transmitters identification code, if only to set up the fail safe settings. Fail safe settings might not seem so important in model boats but they can be particularly significant in model yachts with big powerful sail winches. I have had a sail arm servo tear itself out of its mountings when the arm came up against the extended keel inside the hull. It was my fault, I turned the transmitter off before the receiver, it went into the default failsafe mode which was throttle fully back and that was outside the normal travel range of the sailwinch. Nowadays I am more careful in making sure I have set the failsafe to the setting I need, not the default which is usually appropriate to a model aircraft.
Edited By Gareth Jones on 22/06/2020 08:07:01
|Thread: Inherited model identification & help|
I am pretty sure your yacht is built from a kit by Robbe under the name Inga IV. If you google it there is some information available on the web. Robbe no longer exists in its own right but the kits were taken over by Krick and are being marketed under the name Ro-Marin but I don't think Inga IV is available at present.
|Thread: Spektrum DX6e Switch Problem|
The transmitter was posted off to the repair centre at Al's Hobbies last Wednesday, postage cost, tracked £11.
I was rung up by the technician yesterday who confirmed the switch had two mechanical faults and had been repaired, cost of repair £30 and postage back £9.
It arrived back today, a week after it was sent off and is now working fine.
A much cheaper option than buying a replacement, possibly having to learn another programming process and having to set up 10 sail winches again.
Excellent service and I have no complaints. However not quite as good as a replacement UPVC door lock gearbox that I ordered for our back door last week. Time from ordering on the website to having it delivered and fitting it was less than 24 hours. (and that was just the standard delivery service)
A helpful man at Al's Hobbies Service Dept told me he thinks he knows what the fault is and it should be a simple repair to the on/off switch so I am going to box the transmitter up and send it off in the post tomorrow.
Really the only 'computerised' part of the transmitter that we use is to set the servo range and end points for the throttle channel which controls the sailwinch in various yachts. This particular transmitter has about 10 models in its memory, all different. I used to use a Servomorph in each yacht but the transmitter set up is simpler. As much as anything, I don't want to have to learn how to programme yet another transmitter which, even if it is a Spektrum one, will no doubt have had some improvements added that make the process different to previous models - and maybe incompatible to some of my many Spektrum receivers.
Thanks for sorting the post out into a separate thread Colin. It might be easier to follow now.
The switch on the DX6e is a push button switch not a slider - push for on, push and hold for 4 seconds for off.
I have had the back off a DX5 lots of times, either to investigate the on off switch problem I had with one of those or to change the mode of the throttle stick from slider to spring centered and back again, depending on whether its prime use was for powered models or yachts. Changing the mode on the DX6e is easy, its done with a switch on the back. Taking the DX6e apart though looks much trickier in comparison.
I had a cautious look inside the DX6e but could only separate the two halves of the case by about an inch. The problem is there is a lot more 'gubbins' inside a DX6e and a lot of leads across from the back section to the front. I suspect most of these leads have plugs or sockets at one end or the other but they are so short I can only gingerly separate the two halves of the transmitter by about an inch. I suspect if I separate the leads from the front or back it could be a real struggle to get them reconnected. Maybe there is some spare wire hidden in there or maybe some 'value engineering' was done in the design and someone worked out their assembly line workers only needed leads 2 inches long to put them together and they could save a penny a transmitter.
I will ring the service centre next week and see what they say and let you know the outcome. It will probably be cost effective to repair a DX6e but the response I got on the DX5 from Germany 2 years ago was its obsolete.
Edited By Gareth Jones on 24/05/2020 20:45:36
Edited By Gareth Jones on 24/05/2020 20:59:13
Thanks for that Dave I will give them a try. However I have just had a thought I will investigate first. I wonder if it is a touch sensitive switch rather than a mechanically operated one?
The initial reference to your advice Dave was because I seem to remember you became rather disenchanted with Spektrum technology a while ago and mentioned you were selling off your Spektrum stuff.
Edited By Colin Bishop on 24/05/2020 19:12:31
I have a feeling Dave Milbourn is going to come along and say I told you so but here goes anyway.
I have a Spektrum DX6e transmitter which is about 2 or 3 years old. It has been faultless up to now but has started to be very reluctant to allow itself to be switched off. No matter where, how hard or how long I press the on/off switch down it sometimes refuses to turn off and the only option is to remove one of the batteries. Has anyone else had this problem and is there a solution, other than a new switch or send it off to the repair agents, wherever they are now?
If I replace the battery the unit immediately powers up without needing to press the switch to turn it on so I am not sure whether the fault is in the switch itself or the electrical logic in the unit. Getting at the switch inside the case does not look straightforward. Ironically I bought this transmitter to replace a DX5 transmitter that also had a problem with its on/off switch, but that was a different type of switch.
Sorry I meant to start this as a new thread but somehow managed to add it to this one and now cant remove it - not my day today
Moved from previous thread
Edited By Colin Bishop on 24/05/2020 15:31:04
|Thread: LiPo storage charging|
Definitely with the balancing lead. I cant think of any reason why anyone would ever charge a LiPo without one - unless you didn't have one and were desperate enough to take the risk.
|Thread: Sweet Sue II|
Its good to see you back on the forum and about to start another project. I am sure your model will put even Dave Milbourn's Fairey in the shade when its finished to your usual high standard.
Seeing the clock on the wall of your apartment reminded me of the one I made some years ago. As a small boy my favorite toy was Meccano and I was fascinated by gears and gearboxes, In my final year at university I designed a transfer gearbox for a lorry as my design project. However it was not very good as I was never very happy starting anything from a clean sheet of paper.
One day thirty odd years ago, I told my wife I fancied building a clock from a kit. What I envisioned was assembling lots of brass gears into a working mechanism. However, what she bought me for Christmas 1989 was a complete clock mechanism and chimes plus the plans for a Vienna regulator case. Progress was quite slow as I did not have a lathe to make the columns and finials but eventually, after some improvisation the clock was completed 10 years later.
For Christmas 1999 she bought me an engraved brass plate to fit inside the case.
The clock is still on our dining room wall but very rarely gets wound up these days.
Edited By Gareth Jones on 09/04/2020 11:36:37
|Thread: Vane Steering for Model Yachts|
Its quite common to mount the vane gear on a bracket overhanging the transom on 36R class yachts as shown in the picture below. The 36R is the only formally recognised class where this is allowed. For Marbleheads, 10 Raters and A class boats the axis of the vane gear must be inboard on the hull. However since you are making an experimental installation of your own design and it is not going to be measured or registered you can of course do as you please.
It is also quite common on vane steered yachts for the lower section of the back stay to be split into two separate lines as shown in the photo, so they stay clear of the vane gear in all its possible positions.
Watch out Ray, I think Luddite was the word that got me into trouble last time.
I have to be careful what I say about Arduinos as I have been known to upset people in the past. The attraction in using them or similar devices to achieve some sort of automatic control is, to me at least, the challenge of making the system work and particularly making it work effectively. Its just another aspect of building the model like getting the scale, accuracy or painting done to the best of your ability. The fact that the control system might take away some of the skill or effort needed to sail the model is a secondary consideration. In practice the knowledge and understanding a person needs to acquire and apply to making an automatic system work would probably make that person a better operator of a purely 'manual' system.
Edited By Gareth Jones on 27/12/2019 09:52:15
Tim is quite correct in his description of a self tacking vane, The vane does not initiate the tacking manoeuver, that has to be done by the skipper or his mate on the opposite bank poling the bow of the yacht across until the jib sail fills and the vane then automatically flips over to the position appropriate for sailing on the opposite tack. The advantage that the self tacking vane gives is that the yacht does not need to be stopped to make a manual adjustment to the vane's position.
When the vane is broken it is held over on one or other side of its travel, partly by its weight assisted by the heeling of the boat, partly by the aerodynamic forces on the feather from the wind and also by a light overcentre spring. The spring prevents the vane from flipping over on to the opposite tack in the event of a gusty wind or choppy water. However the vane gear has to be set up carefully to ensure that when the boat is poled on to the opposite tack, the spring is not too tight and prevents the vane flipping over to the opposite side.
Its not unknown for boats to change tack inadvertantly and this phenomenon is exploited in guying when an overcentre spring is set up 'off centre' so the vane is held more positively at one side of its travel than the other. The boat is released on the tack where the vane is only lightly held in position. In the event of a change of wind speed or direction the vane flips over on to the opposite side and turns the boat. Because the vane is more positively held in this new position the boat should stay on this new heading. Its a useful tactic when you are near the finish line and don't want the yacht to go all the way over to the other side of the pond. However there is an element of chance in what will happen and setting just the right spring tension and offset requires great skill and experience.
I think every vane sailor is still learning, no matter how long they have been doing it. Its a big help in understanding vane sailing if you can find somewhere its practiced and watch and ask questions. Its a very sociable form of model yacht racing, much less aggressive than radio sailing. Unfortunately there are not that many sites where it is now possible as all round access to the pond or lake is required. The main centres nowadays are probably Fleetwood, Birkenhead, Bournville, Gosport, Hampton Court and possibly the Round Pond and Clapham in London - if I have missed anywhere out I apologize.
Tim - don't hold your breath, I may be a while getting started.
My plan was slightly different but also based on a staged approach
Step 1 was was to restore the yacht, which was essentially a wreck, and make it a dual control, radio or vane steered yacht. This was done and it was initially sailed under radio to get the basics sorted out and the mast in the right place. Then it was sailed as a vane boat, including a weekend at Fleetwood in their Vintage Marblehead competition. After about 20 trips each way down the pond over the weekend it was reasonably sorted and there is a picture of it below.
The next step is to fit the Arduino with a data logger and sensors to monitor what the boat is doing when being vane steered. Planned sensors are position by GPS, compass heading, rudder position to see what the vane gear is commanding and wind direction.
The third step is then to remove the vane gear and program the Arduino to try and emulate the vane gear. Its important to realise that the vane gear only attempts to maintain a constant heading relative to the wind direction and its a big assumption that the wind is blowing in the same direction all along the course you want to sail. One of the big advantages of the lake at Fleetwood is the wind is reasonably true. If you are trying to make adjustments to a vane steering system and the wind is being deflected by trees or other obstructions it gets very confusing and frustrating.
The next step is to develop the step three control system so it could be applied when tacking upwind.
The fifth step is to go one step beyond what a vane gear can do and that is to steer a course on a constant heading, in all directions relative to the wind.
Finally the aim is to get the control system to be able to sail a programmed course which would mean the Arduino would have to take control of the sailwinch as well as the rudder.
Hopefully I will make some progress on the project this year but I have got lots of other things to do so maybe it will stay on the shelf for a while longer.
You have set yourself a good challenge there. I have also planned to do something similar and bought an Arduino about 18 months ago. My objective was to try and make a self steering yacht with an Arduino processor replacing the vane gear and work up to a completely autonomous yacht that could steer along a straight course, emulating a vane steered model and eventually around a pre-programmed course setting the sails and rudder to the optimum positions. Unfortunately other projects have got in the way and so far I have only got as far as teaching the Arduino to turn an LED on and off. However its still on my list of projects and the Arduino is safely stored in the workshop. I planned to use a China Boy Marblehead as it has plenty of internal space and good access, There are several websites with information that would be useful to you.
At the moment I can't find my scanned copies of the Vane School articles and I might have to rescan them so it could take a couple of days to get them to you.
An Arduino is a small programmable processor that can be built up by linking it to other electronic modules. These can include sensors such as a compass, Global Positioning Systems, temperature, wind direction and also actuators like servos and motors The programming is also done in a modular way with lots of free to use modules available on the internet. There are lots of simple projects available on the web to get started with.
Dave, there is an introduction to vane sailing on the MYA website and a link to it here Vane sailing
In general vane sailing is done in a straight line from one end of the pond to the other, although the yacht will have to tack from side to side if sailing into wind. It would be quite difficult to combine vane and radio sailing systems on a yacht at the same time and switch between the two, mid lake, so to speak. However it is quite straightforward to modify a yacht so that it can be sailed either as a radio boat or a vane or Braine steered model. Many of the ones that my wife and I own are 'dual control' as there are few lakes near where we live suitable for vane sailing since they don't have the all round access required to cater for the unpredictability of a self steered yacht.
Edited By Gareth Jones on 24/12/2019 12:26:03
I am a member of the Vintage Model Yacht Group and have some experience of vane sailing with yachts ranging from 36R sized up to A class. There were a series of articles on vane sailing published in the Turning Pole, the journal of the VMYG a few years ago. I have scans of them and if you send me your email address by private message I will forward them to you,
There are free plans available on the web of an Ezi-build vane gear designed by Graham Reeves. I have attached a photo of the one I built to his drawings.
There is a link to the plans on the Llandudno model yacht club site here Vane gear
|Thread: Prop shaft vibration|
A single 'universal joint' coupling can only accommodate angular misalignment between the input and output shafts. It cannot accommodate any lateral offset, i.e. side to side or up and down misalignment of the shafts. A pair of couplings can accommodate lateral offset as well, the amount of offset being dependent on the length of the shaft between the couplings. However with a double universal joint, the couplings act as the locating bearings for the centre section of shaft. If there is any play in these bearings the centre section of shaft is liable to vibrate.
The geometry of universal joints is complex and subtle. For example many joints are not constant velocity, i,e, if the input shaft is rotating at constant speed, the output shaft will rotate at a speed which varies with angular position as the coupling rotates. This can lead to noise, vibration and wear. Obviously these effects are more significant with systems that are transmitting high powers at high speeds.
If at all possible its best to arrange the propshaft in your boat to be as straight as possible with the absolute minimum offset and angular misalignment.
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