Things you always wanted to know the answer to [Vol. 5]
Discussion
President Merkin said:
Dissenting view- Gulls are an endangered species upon whose environments we have relentlessly encroached & they have adapted admirably. They are also a pain in the arse but still.
True, and being seriously affected by avian flu.My question (prompted by an epic thunderstorm last night):
Why is it that a flash of lightning only lasts a second, but the sound it creates lasts a few seconds?
President Merkin said:
I think i know that one. Lightning flashes travel at the speed of light, so practically instantaneously to a viewer but thunder at the speed of sound, so roughly 750mph & also bounces off hills, buildings etc. creating echoes & hence outlasts the lightning flash by seconds.
Ah, that makes sense - the echoes and stuff.Last night was a little odd, lots of the thunder was a long rumble, then a big short but bloody loud single deep bang. Really didn't seem to match the flash, nor indeed would it make sense for echoes to arrive before the biggest bang!
The lightning travels from the clouds to the ground (or the other way), and all along that path it is making thunder. That "thunder path" is not all the same distance from you. The distance from your ear to the lightning strike on the ground is different from the distance to where it originated in the clouds, and every point in between. All of that sound arrives at your ear more or less sequentially.
Edited by mko9 on Friday 3rd May 07:20
shirt said:
i saw this earlier, emirates flights routing from EU to DXB.
how closely would an airliner need to follow another to see a notable drop in fuel consumption? is this gap allowable by the normal 'rules' of the air? if so, then why don't they do it?
Think how close a F1 or Indy car has to be to another to get a tow, and then imagine two aircraft being that close. how closely would an airliner need to follow another to see a notable drop in fuel consumption? is this gap allowable by the normal 'rules' of the air? if so, then why don't they do it?
Clockwork Cupcake said:
shirt said:
i saw this earlier, emirates flights routing from EU to DXB.
how closely would an airliner need to follow another to see a notable drop in fuel consumption? is this gap allowable by the normal 'rules' of the air? if so, then why don't they do it?
Think how close a F1 or Indy car has to be to another to get a tow, and then imagine two aircraft being that close. how closely would an airliner need to follow another to see a notable drop in fuel consumption? is this gap allowable by the normal 'rules' of the air? if so, then why don't they do it?
Let's not forget Goose died due to jetwash!
But no, planes cannot legally fly close enough together to either help or hinder each other. There's not only linear separation, but vertical too.
shirt said:
i saw this earlier, emirates flights routing from EU to DXB.
how closely would an airliner need to follow another to see a notable drop in fuel consumption? is this gap allowable by the normal 'rules' of the air? if so, then why don't they do it?
So close the pilot will be able to smell what the pilot in front had for breakfast.how closely would an airliner need to follow another to see a notable drop in fuel consumption? is this gap allowable by the normal 'rules' of the air? if so, then why don't they do it?
Slipstreaming isn't possible for planes due to turbulence from jet engine and wing tip vortices. The coloser you get the worse it becomes so there is mandatory separation for aircraft as Sway mentioned.
The jets in that screenshot will be miles apart, they just look close together.
Surely you'd need to be a in a V formation rather than line astern in order to get any benefit, or have geese got it wrong?
It does actually work and Airbus reckon there's about a 5% fuel saving, which on a trans Atlantic flight is several tones of fuel
https://www.airbus.com/en/newsroom/press-releases/...
It does actually work and Airbus reckon there's about a 5% fuel saving, which on a trans Atlantic flight is several tones of fuel
https://www.airbus.com/en/newsroom/press-releases/...
RizzoTheRat said:
Surely you'd need to be a in a V formation rather than line astern in order to get any benefit, or have geese got it wrong?
It does actually work and Airbus reckon there's about a 5% fuel saving, which on a trans Atlantic flight is several tones of fuel
https://www.airbus.com/en/newsroom/press-releases/...
Different sources of wake/turbulence.It does actually work and Airbus reckon there's about a 5% fuel saving, which on a trans Atlantic flight is several tones of fuel
https://www.airbus.com/en/newsroom/press-releases/...
For geese, it's like the wake of a speedboat - hence the V formation (and diamond). You see the same in marathon kayak racing and cycling. They're not necessarily benefitting from a 'hole in the air' with reduced resistance, but actually kinda surfing on the wake. When I was racing kayaks, there'd be positions in the pack where you could sit and not paddle and be dragged along by everyone else.
It'd appear that the Airbus test was actually doing the same thing - the following plane is riding on the updraft of the wake disturbance.
Cool idea, but wonder how they'll manage it in practice when it's only the following aircraft that gets the benefit...
Edited by Sway on Thursday 2nd May 16:06
Sway said:
Cool idea, but wonder how they'll manage it in practice when it's only the following aircraft that gets the benefit...
Yeah, great in theory, but only really a 2.5% saving across both aircraft, and you'd probably get a greater saving by using a single aircraft twice the sizestemll said:
The head forms from dissolved CO2 by a process called nucleation. To do that they need somewhere to do it. In a clean glass the only nucleation sites are either dirty bits of glass or irregularities in the surface. In a used glass there will be residue left from earlier beer so there are more nucleation sites and hence more head.
This is the right answer, though I will add that some beer glasses (I acquired some recently like this) have nucleation sites built into the inside of the glass, often on the inside of the base, maybe try one of these and report back. President Merkin said:
Dissenting view- Gulls are an endangered species upon whose environments we have relentlessly encroached & they have adapted admirably. They are also a pain in the arse but still.
Adapting in Aberdeenhttps://youtu.be/Kqy9hxhUxK0?si=YYGyxw4ok2a-2ePt
&
https://youtu.be/OpSCGOdM3f8?si=hJNL2iYE23ZJ6p_1
Did Bill Nighy have an epic 60’s like he seems to have done?
Everything I see him in he is basically the same cool old dude, effecting a louche but knowing mien whereby he doesn’t give a toss what’s going on, and just drifts along.
Most likely he was treading the boards in rep hamming up Arthur Miller or whatever.
If only there were online resources available to check this stuff.
Everything I see him in he is basically the same cool old dude, effecting a louche but knowing mien whereby he doesn’t give a toss what’s going on, and just drifts along.
Most likely he was treading the boards in rep hamming up Arthur Miller or whatever.
If only there were online resources available to check this stuff.
The Don of Croy said:
Did Bill Nighy have an epic 60’s like he seems to have done?
Everything I see him in he is basically the same cool old dude, effecting a louche but knowing mien whereby he doesn’t give a toss what’s going on, and just drifts along.
Most likely he was treading the boards in rep hamming up Arthur Miller or whatever.
If only there were online resources available to check this stuff.
Look for "Charles Paris" on BBC Sounds.Everything I see him in he is basically the same cool old dude, effecting a louche but knowing mien whereby he doesn’t give a toss what’s going on, and just drifts along.
Most likely he was treading the boards in rep hamming up Arthur Miller or whatever.
If only there were online resources available to check this stuff.
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