Rick's b.log - entry 2020/03/20

A beautiful day

As you saw last week, my blade drive belt gave up, so I measured it and found one of the same sort of size on Amazon. It was something like €15 with Prime delivery, so I decided to take a chance.

It was actually pretty easy to get the mower assembly out. Here's the old drive belt, in none too great a shape.

The new one was supposed to have been delivered on Monday, but the jobsworth post person refused to leave it despite a big notice in the window saying it's a drive belt, please leave it. Worse than that, they didn't bother to fill out the "we called but" paperwork. Luckily I was following it on Amazon so I had the notification of non-delivery and the tracking number to reschedule it for Friday.
Friday arrived, and the postman turned up just after I got the mower assembly out, so perfect timing. I had printed out a piece of paper with the tracking number and a zoomed up scan of my signature - because they can no longer come near people, and certainly it's not possible to get signatures for people, so I figured if his work phone can take photos, he could take a snapshot of that and call it my signature. Only... he said the parcel didn't need to be signed for. WHAT? What was the Monday person doing? Jeez...

Anyway, wound the belt around the pulleys and it looked good.

I reassembled everything and gave it a try. The blades spun up, it all seemed good. Well, the test was obviously to take it out for a spin. Since the sun was shining and I had Ayreon in my headphones...

Damn!

Here's part of the Western Wilderness before (you can see some that I did last week):

Further away, by where Nou used to live, again before:

And finally around back by the hangar where Felicity is parked, the "Northern Trail". Yes, there's a lot of land that needs mowed, you can see why I'm excited to have this lawn tractor thingy. Before:

Bad news, good news. Bad news, I think it swallowed around two litres of petrol to do that. The engine is remarkably guzzlicious. I'm almost out of petrol! But the good news? Did all of that in under an hour. To put that into context, I could count on maybe three hours(ish) to mow the part by Nou, never mind all the rest.

You can see there are parts not mowed. These are places where the grass is either too tall/too wet or where the ground is too uneven to take the mower. I'll need to do them the long-winded way.

There's still the area behind the piggery, the area around the hanging tree (called that because we hung a swing there back in 1997), and the veg garden. I'd guess maybe 1200 square metres? Oh, and the bits that are still to be done. There's a lot that needs done, certainly, and with the ride-on, it's probably got a good half of it sorted in a matter of hours. I'm not going to say "the easy half" because when you're walking back and forth behind a self-propelled mower cutting about a foot at a time, there is no easy half. Some parts are harder (like the ruts), otherwise it's all a bit tedious. But with the ride-on, the accessible parts got sorted really quickly.

Since I had plenty of time, I went and had a bath and washed my hair. Also washed some clothes since I was back there and had hot water. I'm now sitting outside in the nicely mown Western Wilderness because the wind is from the East and it's still a little chilly. The ambient temperature is eighteen and a bit, but it feels closer to mid twenties in the sun. I'm writing this on the tablet, enjoying a tea and sort-of-doughnuts, and there's a battery pack because the battery in the tablet is feeble. My phone is here too, acting as a mobile hotspot so I can write this in Google Docs (to copy-paste to my blog later).

Mower guts

Here is the piston:

I couldn't take a photo of the valves because they were beside the spark plug. I don't know why the engine makes a big deal of OHV (OverHead Valve), isn't that where they usually are?

The first part of the path of the fuel is the carburettor (or only one 't' if you're American). This is a device that controls the speed of the engine by regulating the fuel and air mixture. It is interesting to note that the carburettor works on Bernoulli's principle; that is to say that the faster air moves into the engine, its static pressure drops. Because of this, the control mechanism of a carburettor does not regulate the fuel, it regulates the air. As more air passes into the engine, the pressure within the tube drops, which means more fuel can be sucked into the airstream.

The carburettor is a pipe leading from the air filter to the inlet valve of the engine. In this pipe is a "venturi", a section that narrows and then widens again. This increases the speed that air passes. Fuel is sucked into the system by way of a small hole at the narrowest part of the venturi. The actual rate of fuel flow is controlled by a complicated system of floats and needles.
Just before the venturi is a butterfly valve, a disc that can be turned end-on to allow maximum airflow, or to close up the pipe to allow minimum airflow. This valve controls the flow of air into the venturi, and thus indirectly controls the air/fuel mixture which has the ultimate effect of controlling the engine speed.

However the first thing encountered after the air filter is a larger butterfly valve.

Looking into the venturi (as best we can given the camera in use), you can see the throttle valve. See the reflection of the light below that screw thing? That's because the throttle is closed. In this situation (choke open, throttle closed) the engine would be idling.

Near to the flywheel on top of the engine is a black thing. If we try to look at it from the perspective of the flywheel...

This is the "magneto". It's a little lump of iron inside some plastic. Actually, inside that plastic bit is a coil. Mounted on the flywheel is a magnet. This whizzes past the iron thing which causes magnetic flux, inducing an electromagnetic field in the coil. This causes current to flow, around 200 volts. There is a secondary coil with many more windings which is used to step up the voltage to something high enough to create a spark. Normally there is a switch, some sort of contact, that breaks the circuit. This mower has a solid state system where a third coil will have a current induced as the magnet moves. This is a low voltage, but it is enough to open a solid state switch. Opening the switch (by whatever means) causes the electromagnetic field in the first coil to collapse. As it does so, the rapid change of magnetic flux induces a burst of high voltage (25kV in this engine) in the second coil. This high voltage is directed to the spark plug where it is dissipated as a spark.
The spark ignites a highly compressed mixture of fuel and air, causing it to expand rapidly (euphemism for "explode") which forces the piston down with enough force that, with the help of the flywheel, can have the piston rise back up (to expel exhaust), slide back down (suck in fresh fuel mixture), then push back up (compress the mixture) ready for the next spark.
The mechanism must create the spark at exactly the right time, technically known as Before Top Dead Centre. Why before? Because it takes a tiny amount of time to induce the spark, and because the fuel mixture doesn't completely burn the instant the spark happens. If the spark happens too soon, the engine will fail to start due to kickback where the engine is forced the wrong way as the mixture ignites too early. If the spark is too late, the engine can lose power or even fail to start at all.
It is also useful to have a slightly early timing as the observant might ask that if the engine takes four strokes (or two cycles) of the piston each time, doesn't this imply that the spark fires twice? Correct. The second spark will happen just as the piston finishes pushing out the burnt mixture (exhaust) so it has no effect.

This isn't all the magnetic stuff inside the engine. If we poke around on the other side of the flywheel, we can see another coil. Quite a chunky one, this time.

The coils are wound in alternate directions and joined together. As a magnet on the inside of the flywheel (visible in the upper coil photo as the big silver lump on the left) passes each coil, current is induced in the coil. As the flywheel rotates, the next magnet (wound in the opposite sense) will have an inverse current induced. As this continues, the coils create current in alternating senses. Or, alternating current. This is converted to direct current by either a simple diode to keep half of the waveform and discard the rest or an array of four diodes to create a bridge rectifier that inverts half the waveform so it is all positive. This, nominally 13Vish, current is fed back into the battery to charge it.

You might ask if one needs DC, why not just use a DC dynamo? There is no such thing as a DC motor, since the magnets are fixed, either on the rotor or (usually) within the casing, it is necessary for the current in the coils to alternate to complete a full rotation. If you look at one of those little electric motors you get in toys, you'll notice that there are little "feelers" (called brushes) connecting the spindle (and the coils) to the tabs where you apply voltage, and if you look carefully you'll see that the part on the spindle where the feelers rub is actually made of (usually) four sections. Since the polarity of magnets in the casing are fixed, it is necessary to reverse the current in the coils to complete rotation. So a DC motor is actually an AC motor that accepts DC input.
Why am I talking about motors? Because the process in reverse is called a dynamo. It is perfectly possible to charge a battery by running a motor in reverse - this is what wind up radios and torches do. However in the context of a mower we need to have a mechanism that will generate useful power in a harsh environment, from cold and damp as the engine starts to dry and very heated as the engine runs. It is also expected to work for potentially many hours at a time and for many years. Because of this, mechanical systems would be a failure point. A far simpler system is to fix coils inside, spin a magnet around them, and pass the result through a rectifier. Completely solid state, may well outlive the mechanical parts of the engine!

Car alternators are a different beast - they tend to use slip rings because their criteria are to have a large current output from a small device. Imagine the sort of power requirements to have a car lit up with main beams at night, while listening to music, and having enough spare capacity to charge the battery and not drain it. But, wait, fifty amps through a slip ring? No, the power supplied is much less than that, it controls the (DC) current in a rotating field coil that replaces a fixed magnet. Controlling the current of this coil controls the strength of magnetism, and hence the voltage generated in the fixed coils. This is important because those alternators need to output useful current in a fairly narrow voltage range (usually as close as possible to 13.8V) across a wide range of engine speeds from an idle of around 1000rpm or so up to what may be 5000rpm.
The mower, on the other hand, does have a range of engine speeds (it can idle down) but it typically runs at a fixed speed. This depends upon the engine, but is usually something in the order of 3000rpm.

The final thing is the silencer (or muffler to non-Brits). It accepts the exhaust pulses from the engine and passes it through harmonically resonant chambers to cause the shock waves of the sound to cancel themselves out. You might think that, since the mower is damn noisy, the exhaust system doesn't work very well. If so, you've clearly never heard an engine running without an exhaust attached. It is a horrific series of rapid fire bangs that will ruin your hearing in minutes. You can't see much in an exhaust, but since I had a camera that fit into the hole...

Working under restriction

Asides from that nonsense (trust the French to create appropriate paperwork for The End Of The World!), not a lot has changed for me, except it is absolutely brilliant to drive on empty roads. No more dickheads whizzing by on a solid white line and a blind bend. It's "a busy day" if I pass one single car on my journey to work.

Yesterday, the boss said that people with specific medical conditions or children that need to be looked after can choose to stay at home. They will be put on "chomage partiel" (partial unemployment) where they'll be paid 84% of their salary (why the weird amount?) with no enhancements or bonuses. He added that people who were genuinely afraid for their safety could also choose to not come in to work. Pretty much immediately a quarter of the morning production shift aren't coming in after Friday. Already in stock, a team of ten people, six are absent.
Apparently there was going to be a discussion today about the feasibility of remaining open. A friend said she'd send me a text if anything changes. I've not heard anything, so I guess there are enough people to keep on going.

Me? I'm in it for the long run. If I catch this virus, I hope I don't have the nasty version as it is apparently quite awful. I've done awful already recently... But there's no saying I could get it from work. Just as easily from the supermarket. Or maybe from the postman? How long does the virus remain inert on a letter? A few days? If I catch it, I catch it. If I don't, I don't. If it kills me, it kills me. If it doesn't, it doesn't. I could just as easily be killed by being smashed off the road by an out of control lorry... I'm not going to freak out and lose sleep, pee, or my sanity over such things.

At work, some of the employees were quite emotionally upset. And some didn't even want to touch the door handles, though they don't seem to apply the same logic when it comes to picking some of the products we make out of the little metal tub in the staff break room. Yeah, everybody reaches into that tub for their dose of chocolately goodness, everybody that doesn't want to touch the door handles...

I blame a lot of this on the media. As of Thursday morning, it was reported that France has "over 9000 cases", of which 3626 needed to be hospitalised, and 921 of those are in a critical state (called "réanimation" in French).
This is horrific - nearly four people in ten will need to be hospitalised, and one in ten will end up in intensive care.
It's also bullshit.
While the media are telling an accurate truth (those figures are correct), it is a highly skewed truth as it doesn't provide any figures whatsoever for those who are off because of a cough and mild fever but nothing to get too upset about. Or those lucky ones who don't have any symptoms at all.

The "fact" that more than one in three will be hospitalised, and one in four of them in ICU explains the panic buying of toilet paper. You'll need something to help clean up the poop in your pants. But if we consider that may easily be 50,000 cases right now and that we only have 9000ish confirmations? Well, 3626 of 50,000 is a much smaller percentage. It's still important, but it's not "oh f***".
What's the truth then? It's hard to say. I believe there are many many more infections than the ones that have been tested, so it is disingenuous to mention the confirmed cases and the hospitalisations/deaths as if those are the only figures. No, those are the only known figures. Subtle but very important difference.

And the UK... what the hell? It's nice that you call it "social distancing" but with stories of groups of bored teenagers causing trouble, bars that are still open, and "key workers" able to send their children to school (isn't that usually virus central?), it seems that Britain needs to take a leaf out of Macron's book and shut the place down rather than attempting to tell people who will mostly ignore advice and think of it as a mix of an unexpected easter holiday and "a bit of a doss".
As for the media freaking out about the sharp rise in deaths, well, that's the obvious side effect of trying to implement "herd immunity" when there's no vaccine. What has been made extremely clear is that the government considered those "with underlying health problems" as expendable.
That's why I am not going to criticise the French lockdown. Imagine, if you will, if my mother - a 72 year old cancer patient with a growth in one of her lungs - was still alive. I would stay away from work so we could both isolate as much as possible (actually, I'd have no choice, driving other people to work isn't an option on the declaration form; mom would have no justification as I'm the one with the job, so I'd have to stay home). The lockdown might help her stay alive.
In the UK? My god, she'd have been little more than cannon fodder for a half-assed science experiment being played out on an entire population.

Well, it's now 6pm. My hair has dried in the warm air. It's starting to chill down (a "mere" 16!) as the sky turns hazy. Not to mention all the bugs coming out for their evening ritual. So time to go in, upload this (which will take an hour or so to process all the photos and mark up the text); then in off peak hours, be peinard with Netflix. Who are reducing their bit rates in Europe, which is bizarre since they have one of the best CDNs around.

Macron was right with one thing when he said we're at war . . . papers please. ☺

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Gavin Wraith, 21st March 2020, 10:54

The last time I saw a policeman not in a car was about six years ago when our late elderly and by then muddled neighbour called the police at 3.am because she thought people were ringing her doorbell - a dream of course. When we moved into the village 45 years ago there was a resident village policeman living opposite the pub, an appropriate location for him to keep an eye on revellers. The house was sold off years ago, in the general impoverishment of society (austerity) in favour of rich private individuals.

David Pilling, 22nd March 2020, 02:38

Antibody testing is on the way - UK has bought test - that should answer the point about how many people have caught it.  UK - it will be interesting to see how successful the current approach to social distancing is - do they have to put tanks on the streets and start arresting people.  "Doss" is a good word - takes me back to school.  Media, they've hyped things up, but on the other hand they are trying to convince people the problem is serious.  Or are they not supposed to try to influence people.  I can't say if people are taking notice or not - have not seen many.

David Pilling, 22nd March 2020, 13:42

Interesting stuff - where do you get the permits from. I can see the employer giving you one, but how about shopping. The working assumption is that there will be no shortages in the long term because food production will continue at the usual rate - your tale undermines that. There is a story that supermarkets have scrapped special lines, allowing factories to run without breaks and produce more (or if staff are missing produce the same more efficiently). Another story circulating is that Macron threatened to close UK border unless UK did better on measures.  Maybe you just have an old inefficient petrol engine. Maybe they get less efficient with age. But perhaps it needs tuning. Like with modern cars they monitor the exhaust and twiddle the settings. Too rich a mixture, too much fuel not being burnt (I am not saying sniff the exhaust). But a happy way to spend your confinement. Glued to a postage stamp here, but a lot better off than someone in a flat.

Rick, 22nd March 2020, 14:16

The form is available from https://www.interieur.gouv.fr/ (red box on the right). You can either print off a load, or write it out on a piece of blank paper.  Also, the regional newspaper "Ouest France" has been printing them in its issues.    We are continuing. It'll be more difficult, but possible. I think the employer has stated that work hours can be increased to a maximum of 42 hours per week (instead of the usual 35) in order to cover absences.  The stuff we produce is not an "essential for life" product. I think the bigger worry is that if the factory needs to close, how long for, and will the financial impact of ceasing work be too great to bear? Macron promised that French citizen and companies would come through this, but I can see *many* companies ceasing operations because what is promised and what actually happens are two different things. I don't wish that on the company I work for, nor do I wish that on any other. I hope Macron is able to keep his promise, but..... it's still early days.    Supermarkets may have scrapped specials. Also, the government is allowing the "agroalimentaire" (food production) industry to continue working, but what about all sorts of things that supermarkets sell that are not food? Gas bottles? Batteries? If this drags on, they're going to start to run out of those sorts of products.    Yes, Macron did threaten to close the UK border. That was back when the UK's big idea was "let's get everybody infected". I see things have changed, but, FFS, it's too little far too late. France was late on the uptake, the UK not only dropped the ball but ran off in the opposite direction...    Yeah, an inefficient engine alright! Sadly the carburettor is 'fixed', so there is nothing to adjust. Perhaps a clean might fix it? I'm not sure I want to mess with that right now. Given that the engine is a bit temperamental, I'd rather just throw petrol into it and have a guzzlicious but working mower rather than risk cocking anything up.    Sadly, Friday was BEAUTIFUL but the rest of the weekend has been awful. Grey skies, ambient around 7C, and a harsh wind that makes it feel closer to freezing. Yesterday I did some work with Manga, and today I'm starting creating some php for my blog to allow me to write articles and upload them into the blog mechanism without needing to turn on the PC and use WinSCP. Hopefully that will allow me to update more regularly (especially if I catch The Dreaded Lurgy where five minutes on my phone might be doable, but half an hour on the PC out of the question).    Yeah, I'm lucky. I have loads of land to walk around. I think it would be rather difficult in an urban environment; however there's a guy in Paris who just ran a marathon on the balcony of his flat, so, you know, where there's a will there's a way! ☺

VinceH, 22nd March 2020, 14:30

I'm in a 7th floor flat, which isn't great.    I don't live far from a really nice public space - the Blaise Castle estate (my main windows look out towards it) - whenever I walk to my parents for lunch, the direct/straight route is about one kilometre, so I usually take a 'long cut' and head through Blaise to make it two or three each way, depending on my exact route.    For obvious reasons, I'm not doing that at the moment. I could still head out to Blaise anyway, but I gather from comments the other day that it's been a bit packed, so probably best avoided.    For the moment, I'm having sessions now and again of walking on the spot while watching TV. :)

Rick, 22nd March 2020, 14:38

Packed?    Here, being out for an unjustified reason (and/or without the paperwork) is a fine of €135.  Being caught twice within 15 days is a fine of €1500.  Being caught four times in 30 days is a fine of €3700 and up to six months in prison.    No, the French aren't messing around.

David Pilling, 22nd March 2020, 16:21

Fixed carb - tale of my Ryobi strimmer - that was fixed to the extent it came set up to comply with emissions regs and had a new design of screw to stop the user changing it. Why do you want to change it - near impossible to start. Eventually I bought a "pac man" tool off ebay - changed the settings. They've got to be able to adjust the carb. in the factory. But I agree better it goes than not.

VinceH, 22nd March 2020, 21:06

Yes, packed. Brits just don't seem to want to take this thing as seriously as they should.    Although Johnson said pubs must close as soon as possible Friday and then remain closed, I read today that a pub near where my sister lives was open Saturday and the police had to pay them a visit - risking not only the health of the staff and customers, but also those police.    I've also been seeing picture after picture of people in crowded markets etc.    People in this country are terminally stupid.

Rob, 23rd March 2020, 12:02

It's the younger generation ... my brother-in-law (late 20s) - "I can't stay indoors, I'd get bored!" SO he's gallivanting around all his mates, and complaining that everywhere is shut!

Rick, 23rd March 2020, 14:29

Jesus - people need to get their priorities in order. Stay indoors, risk to get bored. Go out and hang with mates, risk to get dead.     Doesn't it tell them something that huge chunks of planet earth are going into lockdown? Neither world war managed to shut stuff down as much and as quickly as this virus...

Rick, 24th March 2020, 07:26

Finally... https://www.youtube.com/watch?v=Haaq59UpINI

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