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[Tony H]

Hi all this morning I observed two airliners overhead flying a similar course and as far as i could make out the same altitude and at one point they were side by side one was giving out the usual vapour trail but the other one had no trail what so ever got me puzzled.  anyone shed any light

[Doctor Gollum]

One was alot lower than you thought 

[Raeturbo]

Agree 100% unless one was 100 higher than you thought.

[Sir Tigger KC]

One was spraying sedatives the other wasn't. 

[zirk]

One was Flying, the other one was trying to restart its Engines, read about it in tomorrows News

[LC0112G]

Con trails form as the water in the exhaust of the jet engine freezes. This is dependent on the humidity and temperature of the surrounding air, and both of these things vary with altitude. In general, aircraft don't trail below about 30000ft. In early morning the air is colder, so the con-trail level is quite low. As the day progresses the sun heats the atmosphere the level at which con trails form generally rises. So you tend to see a lot more con trails early in the morning.

[Doctor Gollum]

One was Flying, the other one was trying to restart its Engines, read about it in tomorrows News

Another money saving tip brought to you free* of charge by Ryanair...

*once you've paid your £15 access fee and £10 per view subscription 

[biggriffin]

I thought this was about the amount of vapour that comes out of the V6.

[Lizzie Zoom]

I thought this was about the amount of vapour that comes out of the V6.

 

I wonder though if aircraft can ever slip stream like we can in motor vehicles?

[henryd]

I thought this was about the amount of vapour that comes out of the V6.

 

I wonder though if aircraft can ever slip stream like we can in motor vehicles?

They can but it doesn't end well with big planes .wake turbulence has been blamed for a few crashes

[Doctor Gollum]

That's why they tend to clump similar size aircraft together along flight paths.

Quite entertaining* to watch an RJ100 land close behind a B747 take off... Basically get it halfway down the runway and cut the throttles. Three bounces later and it's down.

*until you remember that mother is on it

[Lizzie Zoom]

That's why they tend to clump similar size aircraft together along flight paths.

Quite entertaining* to watch an RJ100 land close behind a B747 take off... Basically get it halfway down the runway and cut the  throttles. Three bounces  later and it's down.

*until you remember that mother is on it

Thanks DG and Henyrd.  Always wondered about that.

I may be dreaming, but in the past I think I heard US 8th Army Air Force WW2 bomber crews mention about their aircraft coming back from a raid and assisting another, badly damaged, hardly flying bomber (B17's I think) by flying above that aircraft and 'holding it up' with their slip stream suction until it could land on the runway. Has anyone else, like Shackeng or LC0112G heard this one?

[Kevin Wood]

I thought this was about the amount of vapour that comes out of the V6.

 

I wonder though if aircraft can ever slip stream like we can in motor vehicles?

They can but it doesn't end well with big planes .wake turbulence has been blamed for a few crashes

Given my "other" hobby I have spent quite a signlificant part of my life flying along tethered behind light aircraft. I can assure you that the slipstream is not a pleasant, nor an efficient place to fly. Just above or below it are fine, though.

It's probably partly down to those noisy, spinny things on the front, that some people need to remain airbourne.

[Doctor Gollum]

A couple of RB211s next to the winch and you wouldn't need the winch at all 

The spinny brigade could then go and do something useful like crop dusting... 

[TheBoy]

that some people need to remain airbourne.

And you need to get airbourne in the first place.  Engines are a must

[Lizzie Zoom]

that some people need to remain airbourne.

And you need to get airbourne in the first place.  Engines are a must

Yes, after running through fields, flapping my arms and never taking off (well I am a bird! ) I can confirm that.

Seriously though I have always marveled at those brave men in the WW2 who put their lives at the mercy of a pilot aircraft when flying in a glider.  Mind you, compared to what many of them would face, I suppose that was the easy part!

[TheBoy]

Being into RC Flying, I was watching a clip over the weekend of an RC glider getting up to over 500mph

[Lizzie Zoom]

Being into RC Flying, I was watching a clip over the weekend of an RC glider getting up to over 500mph

What!! That's faster than my Omega

Seriously though, that is some speed.  Is that flying in a dive?

[TheBoy]

Is that flying in a dive?

Nope. Its a technique I cant remember the name of, and Kevin Wood wouldn't attempt it due to going the other side of the slope.

Basically, you keep repeating over and over, and it gets ever faster, until the wings snap off or common sense prevails

[TheBoy]

"Dynamic Soaring"

https://www.youtube.com/watch?v=MoaWlKC3wIM

Note, you need a very fast connection to gaytube, and a very good PC.

[Lizzie Zoom]

"Dynamic Soaring"

https://www.youtube.com/watch?v=MoaWlKC3wIM

Note, you need a very fast connection to gaytube, and a very good PC.

 

I better try and watch that on my PC and not try and do that with my iPad.  Downloading anything is bad enough as it is!!

[Kevin Wood]

"Dynamic Soaring"

https://www.youtube.com/watch?v=MoaWlKC3wIM

Note, you need a very fast connection to gaytube, and a very good PC.

I got dizzy just watching it let alone trying to fly it.

So much so, that I'm sure that was Bill Clinton at the end.

[Lizzie Zoom]

"Dynamic Soaring"

https://www.youtube.com/watch?v=MoaWlKC3wIM

Note, you need a very fast connection to gaytube, and a very good PC.

 

I better try and watch that on my PC and not try and do that with my iPad.  Downloading anything is bad enough as it is!!

Now been able to watch it and, wow, that also made me very dizzy!!  That was impressive for such a small RC plane!

[Rods2]

Simple quiz to see how much you know about water:

1. How many common states for water are there and what are their names?

2. What is the chemical symbol for water in a cloud?

3. Why are snowflakes hexagonal?

[Doctor Gollum]

1. Ice, snow, rime, water ::)condensation, mist, fog, steam/vapour,

2. H₂O.

3. It's to do with the way the molecules crystallize as they cool whilst falling through the atmosphere.

Next...

[Raeturbo]

Four,    Solid, Liquid, Gas, Plasma.


H 2 O


Due to the formation of weak Hydrogen bonds.

[Raeturbo]

However you’ll need a good kettle to see the 12,000 K. Needed to turn it to plasma

And water can exist as solid, liquid, and gas, at the same time in the correct circumstances.

[Entwood]

However you’ll need a good kettle to see the 12,000 K. Needed to turn it to plasma

And water can exist as solid, liquid, and gas, at the same time in the correct circumstances.

Most substances that can take on the three states of solid, liquid, gas can, in theory, obtain such as state, known as the "triple point" .. for water the triple point occurs at 0.01 degrees C at a pressure of 6.1167 mbar

Pretty good write up here ..  https://en.wikipedia.org/wiki/Triple_point

and BTW .. water cannot exist as a plasma ... only single atoms can ionise to plasma, H20 would "split" into H (hydrogen) and O (oxygen) and form a hydrogen plasma and an oxygen plasma independently 

[Kevin Wood]

Speaking of RC planes... I just came across this...

https://www.youtube.com/watch?v=VgJkfPWyH_E

[aaronjb]

Speaking of RC planes... I just came across this...

https://www.youtube.com/watch?v=VgJkfPWyH_E

I could have done without the footage of the bloke in his Y-fronts half way through ..

[Raeturbo]

Nice, good write up here too

https://www.smithsonianmag.com/science-nature/scientists-have-discovered-new-state-matter-water-180961546/

[aaronjb]

Water has four states:

Cold, hot, my skin is melting (whenever SWMBO has been in the shower before me) and "for making tea" (which is very close to the temperature she has the shower)

[TheBoy]

Speaking of RC planes... I just came across this...

https://www.youtube.com/watch?v=VgJkfPWyH_E

That reminds me, I have a HK Bixler I need to finish off (radio configuration) and give it a maiden flight...

...I've only had it since Christmas

[Kevin Wood]

Speaking of RC planes... I just came across this...

https://www.youtube.com/watch?v=VgJkfPWyH_E

I could have done without the footage of the bloke in his Y-fronts half way through ..

Sorry. Must have missed that bit.

[Rods2]

1. Water has four phases: i) Ice, ii) Exclusion Zone - EZ (Pronounced EeeZee), iii) Liquid, iv) Gas

2. Clouds differ from water vapour H₂O where they contain bulk water H₂O & EZ which is H₃O₂ & negatively charged. A good example is on a hot sunny date by a lake or seashore where there is lots of water vapour but you can get just a single small cloud & that is because it is different.

3. Ice is a hexagonal crystal & EZ is also a hexagonal structure and even as a liquid EZ also provides the hexagonal nodes for the building up of surface water that freezes to form the snow flake with their hexagonal fractal structures. Whereas Ice crystal lattices are linked HOH which locks them together as a solid, EZ link as a HO lattice like slightly offset layers of paper.

EZ are also what bounds a rain drop and EZ boundaries are typically about 2 million atoms deep, unlike the previous wrong understanding of a boundary or surface tension of two atoms deep. The reason it is call "Exclusion Zone" is that in experiments using either dyes or micro beads, the EZ area is clear as they are excluded by this hexagonal lattice. Nobody knows what the structure of liquid H₂O is yet.

Professor Gerald H Pollack who is an international leader in muscle contraction & mobility, has written a new unifying approach to cell function in his book "Cell, Gels and the Engines of life", which I just bought but haven't read yet & his latest work & book is "The Fourth Phase of Water" which I'm reading at the moment. The books are very readable & his experiments very interesting in their simplicity along with his very good & watchable videos below.

Here is a 30 minute video on The Fourth Phase of Water:

https://www.youtube.com/watch?v=i-T7tCMUDXU

or this longer video at 1h 25 minutes where he discusses its central role in cell function:

https://www.youtube.com/watch?v=3YyJKqpWKPo

In my question 1, I deliberately asked what are the common states of water as there are also uncommon states for ice with 18 types now identified. The latest is only formed at very high pressures & temperatures as this National Geographic article explains:

https://www.nationalgeographic.com/science/2019/05/bizarre-hot-ice-xviii-seen-on-earth-superionic-uranus-neptune/?cmpid=org%3Dngp%3A%3Amc%3Dsocial%3A%3Asrc%3Dfacebook%3A%3Acmp%3Deditorial%3A%3Aadd%3Dfb20190508science-superionicicematter%3A%3Arid%3D&sf212350364=1

These also show yet again, how little is settled in science, where the understanding gets revised all the time as more is learnt.

[Vectrahed]

One was alot lower than you thought 

it was either a contrail or a chemtrail.