About five years ago, a Kickstarter popped up for the air umbrella. It wasn’t long before the project fell apart and the company made at least some refunds. Old news, we know. But [The Action Lab] recently explored the physics behind the air umbrella and why it wouldn’t be very practical. (Video, embedded below.)
Notice we said not very practical, not unworkable. It is possible to shoot rain away from you by using pressurized air. The problem is you need a lot of air pressure. That means you also need a lot of battery. In particular, [The Action Lab] used a leaf blower and even with that velocity, there was only minimal water deflection. In other words, you are still going to get wet.
The video computes an estimate of the terminal velocity of an average raindrop. We looked at the University of Wisconsin’s The Weather Guys site and they came up with a slightly higher number, but not much higher. According to the university, it is about 20 miles per hour, depending on the size of the drop.
According to the video, the air compressor has to move air a bit faster than that terminal velocity. So the question is, do you want to have a 25 mile per hour airflow right over your head? How long can that compressor run on a small battery in the handle?
As you can see, this isn’t a practical thing, but it still managed to generate quite a bit of backing — over $100,000. We wonder if any of the backers were physicists?
We are no strangers to wild Kickstarter claims. Of course, even great products sometimes fail in the crowdfunding marketplace.
How about one that shoots water instead? Much greater kinetic energy than air! Or how about flames that instantly turn the rain to steam? Or a plasma shield? Electrostatic deflector?
Or what about a collapsible physical barrier that requires only human supplied energy?
Colin Furze made an umbrella with gas heating. Turns water into steam, keeps you warm and you can even cook bacon on it…
Ah yes, that was a good one. If memory serves it combined the ‘flames’ and ‘physical barrier’ ideas into one package.
Flip wok up side down to make a hat. You can use it as a WiFi wok to steal WiFi or stir fry dinner when it is not raining outside.
Turn that frying pan….. Into a drying pan!
Or how about an umbrella made of material that doesnt really deform when hit by rain? :P
Umbrellas of late have been afflicted by the minimum viable product syndrome, anything from $3-30, you get something that barely works, and doesn’t work for long, too flimsy. Then from $20 to $50, you risk getting the crapola in fancy packaging instead of reasonable thickness of nylon, reasonable strength of frame etc.
I paid $20 for one in the 90s that I managed to get 15 years out of, but it got damaged by being crushed. (Got a box of groceries dropped on it while it was drying) and I’ve not come across one yet to replace it.
https://www.amazon.com/slp/collapsible-umbrella/ao77vuwm3zwy5zo
You’re welcome
major whoosh right there
To do that, I’d want to make something like a 200mm diameter flat disk centrifugal blower with thin fins on it, on top of the stick, spun at 8,000 rpm.
An AI targetting each of the raindrops that do matter with a visible red laser to boil it away!
“Piuuuu piuuuuu…”
And from time to time…
“Luke, I’m your umbrella.”
Makes you wonder if they even did the basic calcs or if it was just the marketing geniuses who pushed this out. If you take the typical foldy as the effective standard it is going to take a wee bit of volume of moving air to deflect enough to stay dry. I would think you would be hard pressed to be able to drag the size of compressor needed let alone hoist it over your head.
Solar freakking roadways! Science? math? economy? f00k it we got lasers, crystals and w00d00!
so stupid, it hurts my brain just thinking about it. swap a very light mechanical umbrella for a heavy thick stick with a battery, making noise, running out of power. why on earth would this be an improvement and why on earth were people stupid enough to pledge such a sum of money?? yikes. I’m not even staring on the inverse square root law of the power of the airflow.
Obviously the air umbrella was dumb, but it does at least highlight a big problem with traditional umbrellas…they are hard to use. Well, I suspect that anyway. I’ve never had any issue with an umbrella that wasn’t broken, but if the most powerful man on Earth can’t figure them out then they must be hard to use.
Also, just for fun, what if the air umbrella wasn’t run from a compressor or tank? How about a series of rapid explosions? Or better yet, a single really big one? The nuclear umbrella!!! You might still get wet but that would be the least of your problems.
And that’s why we should always go for passive solutions whenever possible, please don’t be lazy or egocentric.
Avoid any unnecessary “Whaaaa!” factors, IoT couch potato laziness or 3rd party cloud services whenever possible.
“Stay hungry, stay foolish”, stay aware, stay alive!
:o)
So is the problem poor education, that the people who back these things either never learned or do not understand the application of Newtons laws of motion even at a basic conceptual level without any maths (That shooting peas at bowling balls does not move them very much unless the peas are travelling really really really really really really really really really fast).
Ok hear me out, I know this is totally crazy and absolutely radical thinking, but how about holding some kind of waterproof material over your head and let the rain flow down it away from you with almost no additional energy input. Maybe make it in the shape of a pyramid, or a tetrahedron, and claim that it may harnesses the mystic energies of homeopathy ( https://www.youtube.com/watch?v=HMGIbOGu8q0 ). If marketed right to Californians (add a lump of quartz to the apex), there is probably half a billion up for grabs.
I think if you would just take Newton’s laws of motion the idea is sound, a regular umbrella is moving the water in the same way as you’d want your voodoo umbrella to replicate and it’s not taking enormous amounts of power. The clever thing about the regular umbrella is that it only has to move the rain drops, the voodoo umbrella is moving a whole lot of useless air. If there were something about water that would cause to accelerate in another direction when moving through a field the voodoo umbrella could work, and Newton’s laws would be untarnished.
Water is ever so slightly diamagnetic. It’s how they magnetically levitate frogs. I dunno how big a battery you’d need for that though.
Even with poor education, apply a bit of common sense and you see a bigger problem with this concept even if it were commercially feasible: The guy walking the street with such umbrella will be blowing away the rain horizontally directly to the face of other pedestrians near him. This alone makes the concept so dumb.
Just for giggles, how much power would it take in ultrasonic transducers to assplode or levitate away heavy rain?
static electricity could redirect it for almost no power. there’s a popular experiment done in schools where a plastic rod is held near a running tap.
Yes, it’s held very close, you’d have an inverse square law problem. Also I suspect the tap flow is probably a fifth the velocity of the raindrops, so you’d get a fifth the deflection.
Lasers. Do it with laser. Vaporize a column of rain. Powered by a goldfish…. and soy.
Yah, lasers with goldfish on their heads, and fermented soy fuel cells, with rice husk supercapacitors.
Unless absorb enough energy, it won’t turn into steam. Water takes an insane amount of heats to do that while not being a good absorber at optical wavelengths. High wattage microwave would be more effective. :P
I went out and got hit by freezing rain. It is not fun at all when these pellets are coming down blown by small wind gust at your face.
rain should be deflected by the same rainwater collected and jet streamed in front of you
Rainwater has higher specific mass than compressed air
So you need large diameter reversed umbrella to collect kinetic rainwater to power up water turbine
to spray directed water jet in front of you.
Reversed umbrella serves the proof of concept only
easy cake
free energy Zero-Energy solution
You can start with your car, replacing car wipers by water nozzles to deflect water drops on-the-fly
Wipers free car is my 50-year old invention
On a car, you can set up the aerodynamics to keeps the windshield dry at speed, costs you in drag though. (Unless retrofitted to a vehicle that had a terrible drag coefficient, due to lack of windshield rake or similar, then it might actually improve things, but you’ll be a ways away from ideal still)
Blowing the windshield dry with a spoiler on the hood can work well, but i never got it to work outside of specific windows of speed. 35mph to 50mph but any slower/faster and you need wipers again… I’m sure actual tooling instead of bailing wire and a board on the hood would lead to better results.
Its a lot like trying to tune a speaker enclosure, though; or create a woodwind instrument: the air is as stubborn as water about doing its own things in its own time.
Yes, it’s complex, over 50 you might have got a bow wave off the front of your hood kind of shadowing it, but turbulence off the top of that dumping the rain back down again.
One word: Nuclear powered A.I.-controlled raindrop-targeting 2D polar MASER galvanometer.
In German maybe, I was going to have a go, but after realising we might need to go with atomwissenschaftlich just for nuclear I didn’t wanna break the formatting again today.
Pleasze exquuse mö bat “atomwissenschafltich” translats to “nuclear-scientific”.
Atomar wuld bee eine better translation of nuclear.
(Sorry, but how do I properly do a written version of a overly German English accent? Similar to IronSky Nazi English maybe?)
Oh and this whole comments section is the most funny one on HaD since quite some time ago :-)
It is easy it after english sounding to let. You must only the direct German translation use, inclusive the grammar and with a pile of false frends. A good measure would it be also, to use “ze” instead of “the”.
That is me German enough. :-D
This would have worked if they had duck taped a $2 umbrella to it. Goes to show what happens when you cut corners.
With a triboelectric or a portable van degraaf generator, you could generate a large enough negative charge field around you. Since rain drops are negatively charged, they would deflect around you to the ground (like charges repel). You’d have to have the electrodes sticking out of your hat though.
Reading other posts here I came up with a different water repelling idea: Using acoustophoresis transducers spread around the top of your hat, you could deflect rain drops away from you, It could be battery powered and be called the “Rain Hat”. Nobody could hear it but they may feel it when you walk too close to them.
Another idea would take too much technology to employ as the technology is new and some would call it fringe-science, Dr. Ning Li of the US ARMY R&D is experimenting with gravitomagnetics to deflect missiles. Why not deflecting rain drops? The diagram is in the hyperlink in my name sotb. Just click on it…
Here is the Rain Hat idea diagrammed out (just click my name satb). It uses acoustophoresis to deflect rain drops from your body. Hackaday did an article on something similar involving levitation.It just uses sound waves above 20 khz at sound power of 50 watts or more in all directions from the pith hat. You should stay dry. mostly.
Thunderf00t on Youtube has whole series on debunking kickstarter projects.
I used to hate the scammers.
But there are so many of them, and they are still pulling in so much money for the most ridiculous ideas.
Sorry, (no not sorry) but at this point I think people deserve it. If so much of the public insists on remaining ignorant, most likely because they are so anti-science then I’m going to cheer on the scammers.
This product is 100% effective if you also buy the add-on wide-brim hat and rain slicker.
Ah….another crowdfunding scam.
i wonder if Dyson could make it work
Makes it so much easier to appreciate the practicality of a plain old ordinary umbrella. That said, I’d like to see an inflatable umbrella that lives inside a sharpie sized cylindar, telescopes up and inflates with a CO2 cartrage at the push of a button. (after the safety has been released of course. :-) )