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Member postings for Malcolm Frary

Here is a list of all the postings Malcolm Frary has made in our forums. Click on a thread name to jump to the thread.

Thread: Help with identifying wooden yacht, and rigging
12/10/2021 09:29:07

My favoured way is to have the line appear above deck either via a small hole in a rearward facing vertical panel, or through the deck using a fairlead, or bit of plastic tube. Or copper or aluminium tube. In any case, with the exit hole facing backward to avoid creating a scoop.

This will invariably put the line where it is not wanted for the final trip between a point on the centre line and the boom (i.e. where the existing hole is). A three-point bridle sorts that. One ring, three adjustable lines each with a hook on the end to fix to three convenient points on the deck. One adjusts fore and aft, the other two centre the ring over where the hole was. Through deck pulleys look nice, but costa lot and provide a hole in the deck.

Electronics are best mounted as high as they will go so that any wet that gets in doesn't slosh into them. That, and generous use of Vaseline and/or something like CorrosionX so that any wet that hits them falls off. And storing with the hatch open so that damp air can dissipate. In the case of a 2G4 radio, they usually only have a short aerial lead. Since the aerial needs to be as high as possible, so does its attached radio.

11/10/2021 09:04:29

It is an R36R (restricted 36", radio). No idea what particular design, but it does look a lot like the line drawing that appeared in a list of plans.

Rigging is a fairly standard sort of arrangement - most of it is to either stop the mast falling over, or to relieve strain. The backstay stops it falling forward in a following wind and offers some tension to help sail shape. The masthead crane might be either a rigid fitting or might be a seesaw with a tension line on the other side. The sidestays stop it falling over sideways when the sails are collecting force to drive the boat. They are also very useful when picking the yacht out of the water without bending too far.

Some boats have a forestay to prevent the mast being pulled over backwards by the force of the backstay. Most racing classes dispense with that in favour of using the foresail, which is carried on a luff line on its leading edge and the pivot arrangement that hooks it to the fore deck. To stop the pull of this line stretching the rear edge an adjustable line is fitted from the top to the rear end of the jib boom.

As this looks like a deck stepped mast, all of the support lines are vital for transmitting the forces gathered by the sails down to the fin under the boat via the hull structure.

While the running rigging lines are very tidy above deck, I would prefer a rearrangement. I don't like lines carrying strain going through hatches. Similarly I have misgivings about any line that simply pops out of a flush hole in a deck. Yachts go in windy weather (its what they are for) which usually involves lumpy water which in turn means water on the deck. Any hole is an invite for water inside, where it is not wanted.

Thread: Robbe receiver
06/10/2021 09:55:32

It is rarely reliable trying to join different generations of RC together. My first radio was a Maplin brand one. Servo plugs in a very substantial housing (industry "standard" "Molex", maybe) but had the pins on the usual 0.1" spacing. But with the three sets of connections in one row across the receiver. "Modern" low profile plugs would fit.

Apart from a couple of old Futaba servos I was given, which had pins and unequal spacing. The copper tube adaptors worked but it was, at best, a bit iffy. If the receiver had had receptacles rather than pins, pins could have been easily created by using the right size nickel silver wire, but would still have had that bit of uncertainty.

Then there was Sanwa, who kept to the expected mechanical standards, but shuffled the pin order. Everybody else went -,+,signal. Sanwa didn't, and if you mixed without rearranging the wire order, you had a reverse connected radio battery. Thankfully, nowadays everybody has settled on one standard of plug layout, any manufacturers foibles of using locating key tabs can be cured with a sharp craft knife.

I don't know what the signals were on the old 4 wire servos that I have heard of, but since before I started, everybody has worked to the same signal standard, so if the wires can be plugged in in the right order, it will work.

E&OE

Thread: Motor size/ set up
05/10/2021 09:12:56

For working a ramp, something like

https://kitronik.co.uk/products/2589-fs90r-360-degree-continuous-rotation-servo

or

https://www.digikey.co.uk/en/products/detail/adafruit-industries-llc/2941/5823442?utm_adgroup=Motors%20-%20AC%2C%20DC&utm_source=google&utm_medium=cpc&utm_campaign=Shopping_Product_Motors%2C%20Solenoids%2C%20Driver%20Boards%2FModules&utm_term=&productid=5823442&gclid=EAIaIQobChMIyryH9-Wy8wIV4-jtCh18LARvEAQYASABEgKr7fD_BwE

might do.

The first is a servo with continuous rotation, the second a motor and gearbox requiring an ESC or switcher. Neither is proportional, you just turn it off when the ramp has got there. From posts about similar projects elsewhere, the ramp needs some extra weight to ensure that it will drop.

If it is the foot long one like the Italeri one, a 385 might be overkill. A 140/1 as sold by Component Shop might be more appropriate, and much easier to hide.

Thread: Robbe receiver
03/10/2021 09:44:30

No experience with this particular EC other than what a google search has turned up. From the very scant information, it has no BEC, so needs a 5 volt input, the red 2 pin does that. It has the conventional pair of big thick wires for main power, and two more for motor connection.

The weird bit is the signal connection. Most manufacturers use a 3 pin connection that caters for both control power and signal. This one uses a 3 pin receptacle, but only the outside two points. Presumably black for ground and white for signal.

So, on a modern radio, the radio battery would plug into the "Batt" or "Ak" hole, the signal plug into the preferred channel, the steering servo into the chosen channel for that, and the ESC red plug into a spare channel to give control power to the ESC.

Unfortunately, with a 2 channel set, there are not enough slots, so a choice needs to be made.

1 Get a Y lead. Plug it into the throttle channel, plug the black two (3 connection, only 2 used) pin into one leg, the red power into the other. This might entail a bit of minor surgery on the red plug, Y leads are generally intended for flat plugs. Receivers have pins, the plugs that fit them are usually shrouded receptacles, thus technically, sockets. I tend to wait for a show and go to the Component Shop stand for things like that. Or, over the last couple of years, mail order.

2 Winkle the red wire out of the red two pin (assuming that its a floating socket) and insert it into the centre hole of the black three. This will cause it to be wired like every other ESC on the planet.

3 Go modern radio. 2G4 sets tend to start at 4 channel with a 6 channel receiver and cost less than a replacement second hand 27MHz receiver.

4 Get a more conventional ESC. Mtronics and Quickrun spring to mind. Unless you already know that the Bobs board is a perfect match to the motor, vastly better control will be had with an electronic unit.

I have no notion of why the makers thought that this was a good idea without illicit substances being involved, but there might be a reason in there somewhere.

Thread: 1:33 scale boat fittings and people
26/09/2021 09:01:27

Another check is the height of railings. These should come about half way up any figures. Doorways on work boats are not always a reliable guide.

Thread: Robbe receiver
26/09/2021 08:57:06

Being Robbbe, the markings are likely in German. At a guess, "AK" is short for "akkumulator". Maybe Dr for direction? or maybe drive?

Channel 1 is traditionally steering, and is usually the furthest away from the battery connection. Throttle is the one in the middle. Normally receivers use the outermost connection pin as the black/negative/ground line with the next inboard being red/positive line. These pins are usually common across the rows, only the innermost pin on the two columns is unique and carries the signal for that channel.

If using an ESC with a BEC, you don't need to use the battery connection anyway, it's been done for you.

Thread: 1:33 scale boat fittings and people
24/09/2021 10:10:39

Boat kits tend to be fairly "round number" scales. If metric, 1:10, 1:50, 1:100 etc. If imperial, usually something convenient for reading off a ruler, like 1:12 (inch to the foot), 1:48 (1/4 inch to the foot) and similar, or a binary scale, like 1:16 or 1:32. But occasionally, a model is designed to be a certain size to fit either the drawing board it was designed on or the box that the kit is going to ship in. This does result in strange and unlikely numbers.

Figures can be got from other hobbies that have other ideas about suitable scale, but it has to be remembered that while people are all the same scale, they are not the same size. Answer is to look for figures the right height, or near enough. A bit smaller usually fits more easily. Boats are very much a minority hobby, and this is reflected in the supply of the extra bits. Very specific scales require the right tooling, which is a big outlay for a small market. 3D printing is one way forward, but such figures, if they are scaled for one single application, will take expensive time to produce.

Fittings in the model boat world tend to go by size. Things like cleats and bollards tend to keep the same broad design whatever the size - bigger ships/boats get bigger fittings, but they look the same.

Careful measuring on a 1:33 model might show that it is really 1:32 or 1:35 anyway.

Thread: How Big is your Club Lake?
20/09/2021 18:19:23

For casual individual visitors, there is a very definite speed limit in the Lake District, but it is recognised that organised groups can and do get dispensations for events.

https://www.facebook.com/recordsweek/

The information is a bit dated, and times might have moved on. Usually, they don't move on for the better when officialdom gets involved. Speed week usually happens the first week in November.

Thread: Help with Project for School Children
13/09/2021 09:29:56

Hopefully the original kids have benefitted from the experience. The next lot could also benefit.

Thinking about sail power, in the elder days I used the plain plastic bags from supermarkets as sail material. This was before they discovered how to print on them. A suitable alternative is white, handled, bin liners. Ordinary sellotape is excellent edge strengthening. Extra science point - anybody going this way learns a great deal about static electricity. Rigging line, no point looking for alternatives, a 300 metre bobbin of 0.48mm fishing braid can be got for £10. Adjuster can be readily made from buttons from dead shirts.

Thread: Returning modeller
09/09/2021 20:26:47

Winches come in two varieties.

The most common type on sailboats is a proportional type. Whatever position the stick on the transmitter is in, or5 is set to, so the winch assumes that position. Sometimes eventually, sometimes very quickly. Depends on the particular type.

Non-proportional winches have a couple of sub-types. If everything is adjusted as it should be, "spring centre" should result in neutral.

Easiest to understand is the simple motor + gearbox worked by switches off a servo. Throw one way, it winds in, throw the other, it winds out, in both cases, flat out.

Easier to fit is effectively a continuous rotation servo which is really a motor and gearbox driven by its own self contained ESC. When at neutral, like any other servo, it sits still. When the stick is moved, it drives, one way or t'other. As its movement approaches that indicated by the stick, the motor slows. If it drives without the stick being moved, the system "thinks" that the stick is not at neutral.

A non-proportional setup is best with a centring stick - a ratchet stick is more suited to a proportional winch. Less stress keeping the left thumb steady. Getting the centre offered by the stick to match that required by the winch is the trick. If there is no adjustment option on the winch, what is left is the transmitter trim slider.

It doesn't matter what it was set up for, in radio control, what matters is the pulse length that comes out of the receiver. As a sort of standard, a bit longer than 1.25mS corresponds to a servo plugged into that channel being full left. 1.5mS puts the servo centre. 1.75mS puts it full right. On a normal boat ESC, this corresponds to full reverse, neutral, full forward. Or if a winch, drive out, stop, drive in. On a "forward only" ESC, 1.25mS is stop or maybe idle, 1.5mS is half speed, 1.75mS is full forward. This is true whether the transmitter is sprung or ratcheted.

If it drives to one end and stops there and won't be controlled back, its broken. Or the winches centre is so far out that stick movement doesn't go far enough. The servo tester will show this fairly instantly.

Thread: Esc for twin motors
08/09/2021 11:22:17

Running 2 brushless motors off one ESC has been done successfully, but with great care. Identical motors, identical wiring, identical loading, great care taken to ensure that the ESC chosen could handle the power of two motors. The idea can only work with unsensored motors, as sensors would only create confusion.

Much simpler to use one ESC per motor on a Y lead. Has the advantage that you get to put the (smaller) ESCs where you want them, rather than planting one larger one where it decides.

Thread: Blunders and Co-k ups
08/09/2021 11:14:53

I heard a similar story about the Wyre Light, a wooden lighthouse structure off Fleetwood. As part of a lifeboat display, they were to fire a flare, which, at the appointed time, they did. Straight up, on a very calm day. Fortunately, the lifeboat was on hand. The remains can be seen from Fleetwood prom.

I have no doubt that I have plenty of bludners in my past, but I have the ability to forget in a self protective manner.

Thread: Returning modeller
07/09/2021 08:57:04

A servo tester is a wonderful thing. So cheap that everybody should have one.

A working servo can only do what the signal from the receiver tells it to do. How it interprets that information depends on the actual servo, a google for the make and model number of the servo should help.

A proportional winch should just settle to a position decided by the transmitter stick position, moving the stick should cause it to move to the new position. It really just another servo that turns a few hundred degrees rather than the usual 90.

If it is a continuous rotation servo, it should rotate continuously in one direction or the other either side of neutral.

A retract servo might be different again - I've never had one, somebody who has might chime in.

The motor and gearbox are OK, but the electronics might not be. The servo tester helps there, it cuts out anything that the radio system might be doing. A servo with added damp can run to one end of its possible travel and stay there because the damp has created a new component or two. A winch does the same, but takes longer to get there.

Thread: Old sailing vessel, need help identifying type, rig, scale etc.
04/09/2021 20:21:01

While it might be beamy for a particular clipper, there might be some useful stuff here -

http://mcjazz.f2s.com/ClipperShipPlans.htm

In all probability, there was a 3rd mast. Also a considerable bowsprit. The rudder would have been a tall, narrow and with parallel sides. Not really used for steering as much as for trimming direction once that had been determined by use of the sails after much shouting by the sail master and a lot of sweating by the crew. This aspect of the days of sail rarely makes it to the movies.

Thread: Names
22/08/2021 22:01:30

When making printed circuits, the "etch resist" is basically paint. The etching solution is formulated to attack metal, usually copper, but it likes brass as well, but paint isn't metal, so is let alone by the etch solution. The result being a lower surface where the paint (resist) wasn't.

Whatever Letraset is made of might have the required properties.

As long as the surface is lowered by more than the thickness of a coat of paint, painting and abrading the surface should, in theory, leave brass letters on a coloured background.

I have usually cheated by making a vinyl sticker using a colour laser printer, but then, I keep my standards in check.

Thread: Lubricant
20/08/2021 10:00:09

Metal rubbing or thumping metal, lubrication has always been a good idea. Metal to metal gear teeth, definitely lube. Metal to plastic, less so. Any atmospheric muck will incorporate into the lube and be thumped by the metal gear teeth into the plastic teeth.

Plastic gears have been touted as self lubricating, but that depends on the plastic involved. Bearings are another thing again.

The gearbox on top of a servo has lots of gears and usually a smear of grease, but I suspect that that is there more for the rubbing faces of gears against each other in a pile, and bearing surfaces, rather than the teeth, and that space is generally clean and sealed.

E&OE

Thread: Returning modeller
07/08/2021 08:50:52

Using the 50" length as the main clue, I'd say it's a Marblehead of some type. What particular design within that class, no idea. Maximum mast height is 85", but there is nothing to stop shorter rigs being used as long as the sail area measures at 800 square inches or less.

Since it has a registration number, the MYA might be able to fill in a bit of history.

Edited By Malcolm Frary on 07/08/2021 08:53:20

Thread: LCT Front Ramp
06/08/2021 08:46:31

A HS-785HB is just an ordinary servo with more travel. Instead of 90 degrees of travel, it does 1260 degrees (3 1/2 turns) with a typical transmitter on a proportional channel. Depending on the particular transmitter.

Plug it into a switched channel and see how many turns you get between one switch position and the other. Once you know that plus knowing the diameter of the drum, you know the travel available. After that, its just a case of working out the best arrangements for the string, matching the travel you have with the travel required for raising and lowering the ramp. And stopping when you get there. With a 1" diameter drum, thats about 11" of travel, but the settings on the switched channel might be different.

Thread: Returning modeller
29/07/2021 20:24:48

With a 2 channel set, if differential steering is wanted, yes, two ESCs and a mixer. Choice of 1 battery or two is dependant on whether the one battery can supply the demands of two motors.

If differential steering is not needed, then one ESC "can" work both motors if it is rated for the motors used. The battery needs to be rated for the job as well. Or, one ESC per motor plugged into one channel using a Y lead. Number of batteries becomes optional, although one per ESC is probably the simplest option.

There are plenty of 4 channel outfits available, shopping for a "best buy" is a fraught business since unlike 27/40MHz, there is little compatibility between makes, although at the lower end of the market HobbyKing/Turnigy/Flysky receivers work with the other transmitters and replacements cost about the same as a pair of crystals used to cost.

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We welcome well written contributions from Website members on almost any aspect of Model Boating with a particular emphasis on practical hints, tips, experience and builds.

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