SILENCE of the OWLS may mean real-life 'Whisper Mode' for Black Helicopters Topflight boffins say they may be able to plumb the secrets of silently-flying owls and use them to make all sorts of wing and propeller machinery - planes, helicopters, wind turbines, even submarines - much quieter than they are today. "Owls possess no fewer than three distinct physical attributes that are thought to …
Yup, just like people knew a long time ago. Observations like this were made at least ten years ago, if not 20 years ago.
Same goes for analysing the bumps on whale fins to study fluid flow.
It seems someone has run out of original ideas to secure research funding and has been dredging up old papers looking for "motivation".
"Yup, just like people knew a long time ago. Observations like this were made at least ten years ago, if not 20 years ago."
Yes! I recall having some "Anklebiter's Book of Science" maybe 30- 40 years ago, with a section called "Nature Beat Man to it" (or similar). It showed how the feathers on the trailing edge of owls' wings had gaps between them. The text explained that this broke up the airflow and reduced the noise. Similar methods were used on the arse-end of jet engines to make them quieter (paraphrasing a little).
Maybe there is something new here, possibly in the mention of the softer materials and porosity.
ForthIsNotDead, don't be such a cynic! We only need to create owl wing shaped blades for the compressor and turbine and, hey presto, we have a silent jet engine. Too difficult? Alternatively, we try feeding owls into jet engines and see whether their feathers settle at the right place to create the desired outcome.
"We only need to create owl wing shaped blades for the compressor and turbine and, hey presto, we have a silent jet engine"
Silent apart from the turbulent exhaust flow that makes most of the noise. Maybe these scinetists could examine owl's bottoms, see if the cr@p comes out in a perfect laminar flow, and therefore offers the prospect of truly silent jet engines.
"...because, generally speaking, they tend not to have a couple of Rolls Royce jet turbine engines strapped to their undercarriage."
A small detail that appears to have been overlooked.
Now putting a soft porus downy coating on the leading and trailing edges of the drive turbines.......
Twin Peaks is possibly an old reference, but definitely not very old, and far far from very very old.
Now, the owls' three chief silent-flight attributes are: Tough leading feathers, soft trailing feathers, down at the top end, and an almost fanatical devotion to the pope. Hence the surprise.
Cavitation only really happens when you're pushing the blades through the water faster than they're designed to go. There's still plenty of noise from propller blades without cavitation happening which this could possibly address assuming the greater density of water doesn't preclude the techniques being applicable.
"These crafty appurtenances let hunting owls plunge down out of the night sky in complete silence, the better to surprise their prey."
Plunging down silently out of the sky is the easy bit. It's been done many times before.
Remaining up in the sky silently is a lot more difficult.
Unless you're an owl.
Crisp, did you ever consider stop engaging in criminal activities so that police choppers won't have a need to circle over you place?
What I wondered though, several times while living nearby, what military choppers (ie WAH-64) were doing over the Isle of Dogs. Were/are you living there?
I'm in the US and get much of that on a regular basis.
One good crash on the local superhighway, there are helicopters orbiting about filming the traffic snarl.
Then, to add insult to injury, there is a Boeing VERTOL plant about a mile away.
Of course, an upside to that is seeing the latest and greatest before anyone else does.
"......a seven tonne chopper doing 140 knots is never going to be in the slightest bit quiet...." Nothing to do with the speed of forward movement, chap, it's the speed the rotor blades are spinning at that matters. The wing of an owl gliding down onto pray is probably doing 30mph at most, whilst the tip of a helicopter's main rotor can be verging on supersonic. I doubt if a few fluffy feathers would make much difference if the owl's wing was slicing through the air at several hundred mph. The general rule with helicopters is the smaller the lifting surface area fan on top the faster you have to spin it just to stay up, let alone move forward. To lift a seven tonne chopper requires the fan shifting seven tonne plus of air downwards to generate the lift, which is an incomparable job with the "fixed" wing of a gliding owl. Lewis knows that, I'm surprised he didn't point it out.
Right? There is absolutely no comparison in the methods of flight between an owl an a helicopter. Though I suppose if you dropped a helicopter it would fall rather silently, like an owl does when it strikes, using that gravity stuff everybody keeps going on about. If a helicopter isn't making any rotor noise that's because it's stopped generating lift and you are about to fall.
It really makes you wonder if these scientists have ever seen an owl, or a helicopter...
Surely the excessive noise problem could be cured with the "Wonder"
substance, "Graphene"......on its way now......anytime soon......hmm....
"Graphene" must be stuck in a traffic jam somewhere.....anyway where
were we.....oh yes!...GLUE!...now what type of glue would you need to
stick an Owl on to a rotor blade.....maybe Apple could answer this?
Actually, it was specific genes that were patented.
The court found that such genes were a part of nature, hence cannot be patented.
They weren't designed genes, they were defective genes, such as with certain cancer cells and some genetic diseases.
Besides, everybody knows that scientists can't patent nature. Bill Gates beat them to it. :P
No they are not, there is all that hoo, who, hooting going on, although it would still be an improvement on our lot and most of the others I have seen/heard. My recommendation for a quiet parliament would be VX through the aircon system (well quiet after 5 minutes of coughing and gurgling) but I am afraid that's frowned upon for some reason that escapes me.
Black helicopter because I can hear someone abseiling down my chimney and it's way too early for Santa..arrgh!
PS: aren't owls quiet in flight so they can still hear their prey rustling through the leaves?
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I wonder if these people have ever seen an owl in action? They are very quiet when they strike, because they are falling through the air. After they strike and when they're flying (i.e. their wings are moving) around owls aren't silent, at all. They make a great swooshing sound with every stroke.
Maybe it's because they are city scientists and they've never seen owls in the wild? I don't know. I do however know that if you go hang out at the silos on any farm that's got grain fed animals the rats will come at night (for the dropped grain) and you can watch the owls swoop down and take them away. You can sure as hell hear the owls then. I doubt they get quieter towards the city, background noise just gets louder...
isn't so much the energy use, the noise, or the physics of flight.
It's the idiocy of the general driving population.
An awful lot of people seem to have difficulty managing a vehicle on a flat surface in two dimensions. What makes anyone think that these mobile-using, non-indicating, lane-hogging, inconsiderate prats could ever handle three dimensions?
At the very least, I'm certain the aerial fatality rate to surface fatality rate would follow the square-cube law if we allowed the common idiot unfettered access to flying cars. The only way around it would be to have the vehicle under the control of an automated central guidance system at all times while off the ground. Which, given the increasing tendency of companies to want to take remote control of our computers, wouldn't be too much of a stretch for the public imagination.
"a rolled homogenous steel umbrella"
So, with that, instead of being crushed by an airplane which is travelling at 100 knots, you'll get crushed by a rolled homogeneous steel umbrella which is travelling at 100 knots because it's got an airplane on top of it...
"At the very least, I'm certain the aerial fatality rate to surface fatality rate would follow the square-cube law if we allowed the common idiot unfettered access to flying cars"
What about the Robinson R22 & R44 mini helicopters, often flogged to the stupid nouveau riche? Surely that's a good analogy for the relationship between road versus air accidents. As I recall, not many people actually killed, just lots and lots of minor take off and landing mishaps caused by pilot error and very few "falling out of the air on unlucky passer by" accidents.
Flying cars are like guns and chainsaws: In civilised countries simply wanting one is reason enough for disqualifying most applicants from owning one.
The R22 & R44 aren't mini helicopters. They are rather small, and yes some not quite wealthy people buy them in misguided attempts to show off, but they're the most popular commercial helicopter on the planet. The big fancy Sea Kings and stuff they show in the movies are extremely rare. Most short hop business flights, many police forces and news agencies choose the R44 because it's cheap and very reliable (for a helicopter).
Mini helicopters are an entirely different thing. Kind of like how ultralights and airplanes both use propellers and fixed wings, but aren't really comparable beyond that.
But I agree completely, the public shouldn't be allowed access to flying cars.
Yep. They're real. You just don't hear about them much because most are experimental and they're all insanely dangerous. The amount of complication in helicopter functionality just doesn't do 'medium' well. It's all simply too heavy for the amount of power available in the mini form factor.
Helicopters have always struck me as one of those design ideas that's only around because of inertia, and only existed in the first place because the standards for performance were different and there weren't other options.
"Hey, I have an idea for this transportation device. It'll fly, but be very very difficult to control, and it won't be able to pick much up at all. And it'll be slow, and extremely loud, and guzzle fuel like no tomorrow. And a lot of people will get killed in them, because they're absurdly complex and drop like rocks when they break. But even so you'll have to rebuild them from the bottom up every hundred hours.
"They'll also be horribly fuel-inefficient.
"We really think that the general public should use them for sight-seeing tours purchased from cash-strapped, low-margin operators, and that it would be a great idea to send them into war zones in general since you can down one with a single bullet, unlike fixed wing aircraft, which often keep going having absorbed enough ordnance to supply every rebel group in a large south american tinpot dictatorship.
"They're going to require lots of high-risk R&D and engineering and be ridiculously expensive, too. So, who wants to sign up?"
At least, the general public shouldn't be allowed access to flying cars until autopilot technology advances to the point that flights can be made point-to-point without the occupant of the car ever touching a control, except for a power button to switch the system on before takeoff and switch it off after landing.
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