Things you always wanted to know the answer to [Vol. 3]

[Bluedot]

Thanks for all the replies, always good to learn something new

[DoubleSix]

Why do maps habitually draw the UK completely out of scale?

Even Google Maps has the UK as big as France, why?

[Einion Yrth]

DoubleSix said:

Why do maps habitually draw the UK completely out of scale?

Even Google Maps has the UK as big as France, why?

All projections from a sphere to a plane will involve distortions, either of distance, angle or both. The most common projection, Mercator, preserves angles between end-points, so useful for navigation, but tends to make areas progressively oversized away from the equator.
AFAIAA Google maps is a Mercator projection. Gall-Peters q.v. represents area better, but makes a pig's ear of relative directions. You pays your money...

[DoubleSix]

Einion Yrth said:

All projections from a sphere to a plane will involve distortions, either of distance, angle or both.

Understood, but that surely can't explain the gross outsizing of our little isle?

[gowmonster]

DoubleSix said:

Einion Yrth said:

All projections from a sphere to a plane will involve distortions, either of distance, angle or both.

Understood, but that surely can't explain the gross outsizing of our little isle?

probably done as some part of the celebration of how big the british empire was.

[Einion Yrth]

DoubleSix said:

Einion Yrth said:

All projections from a sphere to a plane will involve distortions, either of distance, angle or both.

Understood, but that surely can't explain the gross outsizing of our little isle?

The rest of my reply, and a little Googling, does.

[glazbagun]

DoubleSix said:

Why do maps habitually draw the UK completely out of scale?

Even Google Maps has the UK as big as France, why?

The earth is a sphere but most maps are rectangular. So some way must be used to fit the earth on a flat surface. One of the most popular is to use Mercator Projection, which is good for flying/sailing as the angle of your course doesn't change so you can draw straight lines on a globe.

A side effect, though is that the further away frkm the equator you go, the larger countries appear. Really cool subject that must have been a ballache to crack back in the day. Now we just ask google!

https://en.m.wikipedia.org/wiki/Mercator_projectio...

[DoubleSix]

I totally get that the world is round. I promise.

Why is the UK as big as France on globes then?

[Einion Yrth]

DoubleSix said:

I totally get that the world is round. I promise.

Why is the UK as big as France on globes then?

It isn't. Although, taking useable endpoints; Land's End - John O'groats is about 620ish miles and Calais Marseilles is about 680, so easily comparable.

[DoubleSix]

Wtf ate these sort of images all about then?

[talksthetorque]

DoubleSix said:

I totally get that the world is round. I promise.

Why is the UK as big as France on globes then?

Because it is.
Wikipedia:
The straight-line distance from Land's End to John o' Groats is 603 miles (970 km)

Fr.routieres.himmera.com:

Bray dunes - Cerbère
Vol d'oiseau: 961 km (597 mi)

[MissChief]

From one of my favourite shows, this explains it quite well: https://www.youtube.com/watch?v=vVX-PrBRtTY

[DoubleSix]

talksthetorque said:

DoubleSix said:

I totally get that the world is round. I promise.

Why is the UK as big as France on globes then?

Because it is.
Wikipedia:
The straight-line distance from Land's End to John o' Groats is 603 miles (970 km)

Fr.routieres.himmera.com:

Bray dunes - Cerbère
Vol d'oiseau: 961 km (597 mi)

Perhaps I need to recalibrate then, but I know France has 3x our landmass and I don't feel that's accurately reflected in the images or globes I've seen.

[talksthetorque]

DoubleSix said:

Perhaps I need to recalibrate then, but I know France has 3x our landmass and I don't feel that's accurately reflected in the images or globes I've seen.

Where France is fairly square, Britain has lots of inlets and peninsulas.
The cartographers/printers have to fill in all the wiggly bits (sorry for using technical jargon) as the resolution can't reproduce them accurately.
Also France includes Corsica, and an even broader definition geographically includes faraway foreign territories. Are you comparing like with like?

Edited by talksthetorque on Sunday 2nd April 21:37

[fomb]

DoubleSix said:

Perhaps I need to recalibrate then, but I know France has 3x our landmass and I don't feel that's accurately reflected in the images or globes I've seen.

It may do, but we have the same 'height' so to speak. France is wider and more square than our spindly little island.

[Hugo a Gogo]

DoubleSix said:

Perhaps I need to recalibrate then, but I know France has 3x our landmass and I don't feel that's accurately reflected in the images or globes I've seen.

this is a good site for comparo-maps
overlapmaps.com
overlay anywhere over anywhere else

[arnie12]

When an item has a battery and mains option how does it switch to the mains power option when the batteries are still in said item? Also is there any power drain on the batteries while plugged in?

[talksthetorque]

arnie12 said:

When an item has a battery and mains option how does it switch to the mains power option when the batteries are still in said item? Also is there any power drain on the batteries while plugged in?

The external power will switch a normally closed relay to open, thus opening the battery circuit. This also means the batteries won't drain.

[BristolRich]

FiF said:

Ayahuasca said:

matchmaker said:

Halmyre said:

SpeckledJim said:

Bluedot said:

I recently watched an old Top Gear, the episode where Clarkson was the stoker in a steam engine racing Hammond (on a motorbike) and May (in a car) from London to Edinburgh.
What struck me was the level of engineering that goes into a steam locomotive yet getting the coal into the fire was a back-breaking manual 'shovel job'. Was a better solution never found ?

I guess labour was cheap, and a bloke can fine-tune and distribute the coal in the furnace more accurately and efficiently than a machine could? You had a relatively well-paid bloke driving the train, so a cheap stoker was a useful chap to have around.

And the coal was stored on the opposite side of the fire-plate to the furnace, so moving it forward by machine might have been pretty difficult.

Not to mention the power needed to drive any such mechanism.

Also wasteful of fuel - the coal was very fine so a lot of it was wasted being blasted out unburnt. These small unburnt particles of coal also abraded the firetubes in the boiler wearing them prematurely.

There was a docu (bbc?) not long ago that just filmed a fireman and engine driver as they drove a locomotive from somewhere to somewhere in the UK. As I recall the fireman's job was quite 'technical' as he controlled the power that the engine provided. He would shovel in more fuel just before a hill for example, and less coal on a down slope. His task was to anticipate and provide just the right amount of fuel, neither wasting it or allowing the engine to become underpowered.

Flying Scotsman from the Footplate: www.bbc.co.uk/iplayer/episode/b086kn87 via @bbciplayer

It's not just shovelling coal, which as that programme shows you can even get that a bit wrong, but sorting water levels in the boiler, watching gauges, looking out for signals, dealing with tokens on single track sections, plus getting the bacon and eggs sorted on the specially polished shovel, only kidding on that last bit.

If you watch the linked programme there were four on the Footplate of Flying Scotsman on a fairly slow, non stop journey down Severn Valley. Driver, fireman, engineer and supervisor from railway museum at York. The last two helped with some of the various jobs floating about, bet it gets busy with just two on the footplate, no wonder proper firemen are seriously strong and fit.

Mechanical stoakers were trialed on some UK locos following sucessful use of the technology in the US. One of the main reasons for them not being sucessful here in the UK is that they were found to be far less efficient than a fireman (who knew when and where to put the coal, rather than just shoving it in). They also required coal to be supplied in an optimum and apropriatly sized lump. Traditionally the fireman broke up coal stored on the tender using fireirons. Later coal briquettes were trialed but added cost and reduced efficiency.

Considering the size of UK locos at the time were relatively modest (compared to US standards) they were also not seen as a necessary expense and could only be integrated into some of the "largest" UK locos.

The service speeds of UK locos were also greater which casued reliability issues what with a moving tender, footplate/firebox opening and ultimatly proved unreliable for a system conceived for ships boilers which are essentially by design stationary.

Edited by BristolRich on Monday 3rd April 11:57

[Speed 3]

Currently on holiday and the river boats in Bangkok ( James Bond MWTGG stylie) have always had me puzzled. Why do they have such a long propshaft ? Other outboards have a 90 degree elbow, surely that's a better packaging. They certainly don't need to worry about shallow waters on this river.