Edit: Note the absolute phrasing of the parent comment and that the spray force in a strong downpour isn't much less than what's done with firefighting planes in situations that call for that level of pressure.
This video doesn't prove your point. Not only are they actually not directly under that, but this is spread over a much larger distance than trying to target the cathedral would be. They configure their release to spread over a larger area than that.
It proves you can effectively firefight with water from a plane without even snapping tree branches, thus there'd be no reason the same pressure couldn't be used on a building.
I think I found out the reason everybody is going so crazy over this - a controversial figure from the wrong tribe apparently mentioned flying water tankers. Thus even neutral debate over the subject is wrongthink and has to be extinguished.
Why don't you step back for a moment and just admit that given the premises
-Firefighting airplanes can effectively spray in a way that doesn't harm trees
-Buildings are fine in extended substantial downpours
That it must follow
-Spraying a building with a plane in such a configuration would not collapse it
Otherwise you are the clueless one. This is absurd. At least you downvoters (who are ignoring the site guidelines) are letting me see some aesthetically pleasing upvote configurations again when it goes back up, so I appreciate it.
"The weight of the water and the intensity of the drop at low altitude could indeed weaken the structure of Notre-Dame and result in collateral damage to the buildings in the vicinity."
So, yeah, I'm gonna trust the experts on this one, not random armchair Internet quarterbacking.
I was clearly talking about the subject in general, in response to a blanket statement against water on buildings made by tomswartz07. Of course an ancient building might fare worse. Also noteworthy is that their comment said collapse would be inevitable but all this tweet says is "might weaken the structure."
It's not so much that it's an ancient building, it's that its structure is heavily compromised by the fire. It might fare better against an assault of water than lots of modern buildings. You can imagine one of those big warehouse spaces could fold up like a house of cards under an assault.
The larger point is that by the time you release high enough to not concentrate a huge amount of force from the water on the building, you're just not doing that much, not that much more than a really heavy natural downpour for a few seconds (which wouldn't be nearly enough to put out a fire this large).
And the trees aren't an apt comparison because the trees aren't taking the brunt of the water; the ground is. However, the roof of the structure would be taking the entire brunt of the falling water. Several tens of thousands of pounds times whatever speed its falling at squared equals a lot of kinetic energy.
The facts stand, as have been reiterated in the thread above:
- Firefighting airplanes can effectively spray in a way that doesn't harm trees (by releasing the 12,000+ gallons over a very large area)
- Buildings are fine in extended substantial downpours (which is significantly less water per second than an air-tanker dump)
To your thought's end:
- Spraying a building with a plane in such a configuration would not collapse it
Yes, it's possible to spray the cathedral with water in such a way that it will not collapse it, but that configuration is that very little water gets on the cathedral, and is instead spread over pretty much the entire island in the Seine.
At this point in time, however, it likely doesn't matter. Since most of the building has collapsed already, due to the fire. Like we said it would.
That's much more volume at once in any one area and much closer to the subject (so less time to dissipate) than any of the actual flying water tanker videos that have been posted.
The rain falls over an extended period of time, not all at once as one glob. Only several drops are hitting you at any given instant in the rain, so you are only subjected to minuscule amounts of force at any given instant.
The difference would be like standing in the shower for 40 minutes, versus being hit my an entire tub full of water going at the same speed all at once.
I remember during the Khan Academy controversy a few years back, an educator commented on reddit about the difficulty in teaching some kids about rates. Some kids just don't get rates. They think of speed as something like "a feeling of intensity." They just don't have an abstract, generalized understanding of "N things per unit time."
Think about that for a moment. Think about all of the potential for miscommunication.
Yes, but the water sprayed from those tankers isn't much more intense than a severe downpour plus wind. The branches aren't snapped off the trees they're sprayed on here and people are standing right inside it: https://www.youtube.com/watch?v=87hfWatbVPY
I'm comparing strong rain to water plane spray. Maybe the output of some would be too severe, but clearly some are suitable.
If you drop water on a structure like this, you end up having a collapsed building that is also on fire.