Funny that the musical definition didn't come up. Like the drone pipes of a bagpipe, or drone strings on some instruments.
The sky full of drones has sort of been covered by science fiction as long ago as 1930 Last and First Men - Wikipedia. In this case the sport of choice for thousands became flying around all weekend in private autogyros.
I actually do worry what will happen when they realize all this fantasy is just that.
I actually do worry what will happen when they realize all this fantasy is just that.
+1
So I will be needing a chain-link dome over my house soon then?
Or some crafty jamming transmitter that is triggered by low fling objects...
Some idiot at a shopping mall was flying one around last Christmas season, was imagining what I was going to do with it if it hit me or my kids...
A definite idiot. The FAA rules for use are similar to the CAA rules here, and he was clearly breaking them, the sort of behaviour that harms everyone...
I miss the good old days when relatively quiet radio controlled blimps slowly flew around making our deliveries and spying on the neighbors. It's unfortunate that with progress, using lots of energy and making thrust/power has become cheaper, and now it looks like a drone problem is brewing.
Maybe the fan blades need feathers. This afternoon I disturbed a big hawk that was dining on roadkill and it made no sound as it flew away.
That reminds me of a tale about a drunken government employee running around inside 10 Downing Street (UK) during World War II, shouting "Kill all the fools!"
According to the story, Churchill stuck his head out of his office, grunted "An ambitious program, sir!", and withdrew to continue his work.
Seventy-plus years later, with 7.5 billion humans on the planet, and widespread signs of arrested development in many societies, there are a heck of a lot more fools to deal with.
Attempting to ban sales to morons would be an ambitious program, indeed.
-Gnobuddy
Try a good-sized Tesla coil. The one at the Maker Faire in Vancouver shut down every wireless microphone in the building every time it was turned on...
Invasion of privacy via drone has been an ongoing issue for some years now. I recall a case where someone shot down a drone that appeared to be shooting video of his sunbathing teenage daughter.
Major creep factor there, peeping-toms with yet another technology to assist them in getting their jollies.
-Gnobuddy
It's absolutely amazing what evolution has managed to achive, with a few hundred years of fine-tuning. Owls are like that too, completely soundless in flight. Even mice don't hear them coming until it's too late.
Along the same lines, I remember being in a fairly fast boat on the ocean off Southern California about twenty years ago. The boat was pounding along, engine roaring, bow smashing into the waves, spray flying everywhere, huge white wake trailing behind us. Then a pod of dolphins came alongside, and swam silently beside us for a good 30 seconds or so. No wake, no white water in front of their faces, no roaring engines, and they were so much more powerful than the boat for their weight, repeatedly leaping out of the water and re-entering with barely a ripple.
At least our best (human-made) gliders do better than the best that soaring birds can. But we have to use carbon-fibre and other exotic materials to manage that, while the birds get by with feathers, bone, and muscle.
-Gnobuddy
Shooting drones out of the sky is unsurprisingly a bit of a sport in the USA, especially Texas, apparently... Most use either the 2.4G or 5GHz ism bands for control, a cheap high power TX will either drop them out of the sky, or trigger return to base..
Still evolving (basically left behind in terms of enforcement of existing rules)
Unmanned Aircraft Systems
Getting Started
Fly for Fun under the Special Rule for Model Aircraft
https://www.faa.gov/uas/programs_partnerships/uas_arctic/media/Sec_331_336_UAS.pdf
Ref propeller noise reduction, for chatting level, ducting the small diameter rotors would have been a good suggestion (uniform blade loading, efficiency increase), if ducting wouldn’t require rotor higher rpm to show it’s benefits, which generates other noise issues.
Fan rotor noise is a complex subject with many variables and a few decisions to be taken. Refined blade geometry is usually adopted, forward/backward swept blades, even adding winglets (no free lunch as always).
A lot of serious reading is required
Leading Edge: Quiet Please - Rotor & Wing International
http://drum.lib.umd.edu/bitstream/1903/8752/1/umi-umd-5771.pdf
https://dspace-erf.nlr.nl/xmlui/bitstream/handle/20.500.11881/1779/ERF 1981-04.pdf?sequence=1
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19840010982.pdf
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810013374.pdf
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770012126.pdf
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960008053.pdf
George
Attachments
About the only use for a drone where silence is necessary is clandestine deliveries to correctional facilities. Drones are being used to deliver drugs firearms and cellphones.
If you want quiet, try a trebuchet.
Didn't they start out by delivering missiles from a height they couldn't be seen or heard?
Fixed wing 'drones' use height / distance for stealth.
Mutli rotor drones use surprise, lack of size and background noise as stealth.
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