Regardless of talking nonsense or not experiencing cold weather and driving enough in it and you get to know about cold, air, humidity and freezing windscreens.

& as to windchill that as well. 

There are days and nights you might might well spray a cold screen and the wipers clear it, interior warm and windscreen as well,

this morning was not one like that here and it was only minus 2*oC and i had -30*oC winter wash.

 

Funny how old style single jets scooshing windscreen wash and good wipers might well be OK and fan type nozzles and wipers like a window cleaners squeezy can just smear and ice up in exactly the same place in the same weather.

Edited 8 March, 20197 yr by Skoffski

8 minutes ago, Skoffski said:

this morning was not one like that here and it was only minus 2*oC and i had -30*oC winter wash.

So it froze?

If so it was due to the wind passing across it on the screen and the latent heat of evaporation. Did you learn about that at school or were you smoking behind the bikesheds?

 

OK, back up at #2, my serious (if implied) point was that "protection to -Nc" may not be enough in severe weather.

@Wino

Stationary out of the wind. 

Did you learn to actually just observe sometimes, and never assume. Or to surmise.

Cars side by side in same parking places with the same Windscreen washes can behave differently. 

But then that just how things are, observe.

 

Fun for the children.

 

 

 

Edited 8 March, 20197 yr by Skoffski

1 hour ago, xman said:

Yeah, just like my neighbours.

 

They look like the rock group "MONTY CREW".

1 hour ago, Skoffski said:

@Wino

Stationary out of the wind. 

Did you learn to actually just observe sometimes, and never assume. Or to surmise.

Cars side by side in same parking places with the same Windscreen washes can behave differently. 

But then that just how things are, observe.

 

Fun for the children.

 

 

 

Not a relevant observation to the effects of wind then.

Chill, guys

12 minutes ago, xman said:

Chill, guys

Jack's best film. Nearly poh@d myself the first time I watched it. Super scary particularly the maze scene.

I feel like I've just done a sneaky smelly fart, and left the room and closed the door! 

 

Anyway, all I know is that on a recent trip to Aviemore the screenwash and wiper combo was easily able to cope with the snow and crud that hit the windscreen. 

 

As soon as we got onto the more exposed and windy sections of road, the wipers and screenwash couldn't clear the screen as easily.

 

Now if I've just observed a new scientific discovery, I would be most grateful if you could all nominate me for a Nobel Prize. 

 

I could really use the money for screenwash and wipers. 

I love how scientific fact gets debated as being pure "opinion" from time to time... here and the internet as a whole. 

Wind chill affects everything... by increasing the rate at which heat energy is stripped from an object by a measurable amount with ambient temp of the object, surrounding air mass and wind speed. Thats it in its most simple. It doesnt just "make it feel colder", you will go hypothermic faster too..  thats the weather people trying to explain it to betty in dorset who has no understanding of the science but needs to know to wear an extra layer going outside...

Love how as a car up to temp gets along a wintry road at 50 or 60 miles per hour and the wipers deal with snow or hail and when in an exposed area with winds and cross winds and maybe the temp dropping the windscreen is harder to clear and that is about wind chill. 

Not wipers lifting, or failing to clear well but actually thought to be the colder screen. 

Often people end up with screens not clearing and getting behind and alongside a lorry or bus in the crawler lane sections as this is a good way to get the screen wet and clear in the stiller air. Then drop back behind again and get an easier drive.

But then when driving the A9 regularly you get use to how things are and where the wind blows. Where people will pass and them mess up your screen again.

Personally i have been there often enough waiting for the snow gates to open and the longest i was stuck on the A9 in the 1980's was 2 days, but we were back and fore to the pub a few times before getting dug out and moving south.

 

As to hypothermia, there are lots of people ride motorbikes in the most extreme of conditions with the right gear and flesh not exposed and are just fine and dandy and toasty.  I have done that in winter, and winter on the A9, and camped out in the snow, and water and gas OK when stopped then frozen overnight.

Wet and cold, that is a different thing altogether, or cycling and hot and sweating and stopping & then cold.

http://phdesigns.co.uk/windchill

 

I used to be up and down the A9 in my Land Rover with a heater what was not deserving of the name and wipers that were a joke and it was necessary to  full winter gear on due to panel gaps that a dog could escape out of.  

 

Edited 8 March, 20197 yr by Skoffski

This.... is starting to feel like the aircon setting debate in the mk1 octy section....

Evaporation processes are a combination of heat and mass transfer phenomena. Evaporation very often happens at temperatures a good deal below the boiling point of the liquid due to the interplay between the heat and mass transfer phenomena.

 

A temperature difference between the liquid and the air will heat or cool the liquid: if the air is warmer then the liquid will heat up and vice versa. In this case, the liquid is going to cool if the air is very cold but may not freeze. Temperature has an effect on mass transfer by changing the diffusion coefficient of the liquid (higher temperature increases it).

 

The mass transfer bit involves a phenomenon known as diffusion. Diffusion will proceed in the direction from higher to lower concentration. So in this case, the driving force for diffusion is for the liquid to move towards the air as the concentration in the air is so much lower. At a liquid-gas interface, there will be a boundary layer just above the liquid surface which will be full of vapour at a high concentration.

 

In still air, the boundary layer will be thicker and diffusion must occur through this boundary layer before it can reach the lower concentration air beyond and will be quite slow. In windy conditions, the wind will tend to make the boundary layer much thinner plus it will carry away any localised higher concentration regions in the air beyond, so the concentration gradient from the liquid surface to the air will be stronger and diffusion will happen faster.

 

We can observe this day to day when we look at how wet ground dries up very quickly on a windy day, or at how clothes dry faster on a windy day than a calm one. If the humidity of the air is especially low, the water evaporates faster because the concentration gradient to the air is increased. Northerly and Easterly air flows around these parts are particularly good for drying because the air from North and East of us is much dryer having passed predominantly over land rather than the ocean.

 

So on a winter's day with a strong Northeasterly wind, it's perfectly possible for screenwash to evaporate off the windscreen if it's exposed to the wind, even if the air is several degrees below freezing.

This thread is getting far too serious/complicated/silly for me.

 

Perhaps someone just should have told the OP that B&M sell cràp, so don't expect miracles.

Edited 9 March, 20197 yr by xman

1 minute ago, xman said:

This thread is getting far too serious/complicated/silly for me.

 

Perhaps someone just should have told the OP that B&M sell cràp, so don't expect miracles.

My £1.99 for 5 litres from Aldi may be cheap & cheerful, however it never freezes and always comes out as a liquid. I do live in the Tropical East Midlands however.

11 minutes ago, shyVRS245 said:

My £1.99 for 5 litres from Aldi may be cheap & cheerful, however it never freezes and always comes out as a liquid. 

 

Whereas in a previous episode....

 

Quote

...No I don't shop inAldi/ Lidl so avoid a lot of EU stuff that way, 

 

Still time  to get to confession  Shy 

1 minute ago, xman said:

 

Whereas in a previous episode....

 

 

Still time  to get to confession  Shy 

Fortunately not a Catholic. Stop stalking me. It was one of my famous typo's, should been I do shop at Aldi.

16 minutes ago, shyVRS245 said:

Stop stalking me

 

Are you having a Dianne Abbott moment? 

 

AFAICS you have a habit of turning up whenever I make a superfluous comment...

 

 

Edited 9 March, 20197 yr by xman

1 hour ago, xman said:

 

Are you having a Dianne Abbott moment? 

 

AFAICS you have a habit of turning up whenever I make a superfluous comment...

 

 

Unlike Dianne I can actually count. Why should you have all the fun. Good to share. At least Dianne has an excuse for not knowing what she is talking about being friends (and more) with Jew loving Core-Bin Laden.

On 08/03/2019 at 21:18, Skoffski said:

Not wipers lifting, or failing to clear well but actually thought to be the colder screen.

OK, please explain the mechanism by which "wiper lift" causes liquids to freeze?

Wiper lift nothing to do with screen freezing.   To do with not getting snow or grime cleared quick enough in Blizzard like or just winter conditions.

Is the screen freezing, or getting covered in salt and grime, and not enough washer fluid hitting the screen if you try squirting, or is the snow just hitting the screen too hard and blowing across and not head on?

All types of conditions might occur. All types do as you drive North of Pitlochry on the A9, but usually -10 to minus 12C is about it.

That is between there and Inverness.

Wet snow is not freezing on a screen while driving when the cars interior is at a normal sort of temp 18*oC plus.

 

Edited 11 March, 20197 yr by Skoffski

On 08/03/2019 at 18:48, Fin69 said:

I feel like I've just done a sneaky smelly fart, and left the room and closed the door! 

 

Anyway, all I know is that on a recent trip to Aviemore the screenwash and wiper combo was easily able to cope with the snow and crud that hit the windscreen. 

 

As soon as we got onto the more exposed and windy sections of road, the wipers and screenwash couldn't clear the screen as easily.

 

Now if I've just observed a new scientific discovery, I would be most grateful if you could all nominate me for a Nobel Prize. 

 

I could really use the money for screenwash and wipers. 

 

3 degrees per thousand feet ?

Is that 3 degrees of farting?

3 degrees heat loss per thousand feet climbed

Is that Fahrenheit?