Timeline for Could the principle of owls' silent flight be used for stealth aircraft?
Current License: CC BY-SA 4.0
18 events
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| Oct 25, 2019 at 6:28 | comment | added | Tord55 | As soon as airflow starts to reach Mach 1 (the speed of sound) you'll get noise, so owls do it by flying very slow and suppressing big vortices, like some flying wings keeping flying for days without recharging. The US tried silent aircraft during the Vietnam War Era, by combining slow-rotating propeller with extremely big and long exhaust systems. Worked quite well, so the aircraft was inaudible when flying at 200 ft. The aircraft were modified Schweizer gliders, with increased inboard wing chord, and trike landing gear. One was still in use by NASA a few years back. | |
| Oct 18, 2019 at 0:16 | comment | added | Bob Jarvis - Слава Україні | The engineering to allow feathers to be grown on aircraft flight surfaces would be...fascinating. :-) | |
| Oct 17, 2019 at 17:48 | comment | added | reirab | @DeltaLima haha - That reminds me of this answer. | |
| Oct 17, 2019 at 17:44 | comment | added | reirab | @EldritchWarlord It doesn't get any easier with piston-powered aircraft. Feathers on the wings are a bit less likely to reach auto-ignition temperatures with piston-powered aircraft, but they're about as unlikely to survive flight at 120 knots as they are flight at 500 knots. Fortunately for owls, they typically don't need to fly at 120 knots. | |
| Oct 17, 2019 at 14:43 | comment | added | EldritchWarlord | OP didn't specify that they were thinking of jet-powered aircraft. They could be considering quiet helicopters or prop-planes. | |
| Oct 17, 2019 at 13:18 | comment | added | MikeB | Modern jet engine exhausts already do make use of this - they have a shape that is reminiscent of a castle turret, but rounded off, precisely so that it merges the exhaust with the general wake in a blended manner. | |
| Oct 17, 2019 at 6:46 | comment | added | user44567 | I once read a paper and watched some videos on dynamic stability from 'feathers' on the trailing edge of the wing. The videos compared model airplanes with feathered wings and without. I remember the reduction in turbulence was impressive. | |
| Oct 15, 2019 at 19:10 | comment | added | fooot | Intake and exhaust areas of jet engines are already designed to be "acoustically soft" to reduce noise. | |
| Oct 15, 2019 at 5:04 | comment | added | jamesqf | There are actually fans and such that are inspired by old feathers, e.g. cosmosmagazine.com/physics/turbine-blades-inspired-owls and cooling fans for computers. But I think part of the problem is that owl wings are low-speed aerodynamics, turbine blades are high-speed. And even with GA planes, few if any actually have adequate mufflers, so the engine noise far outweighs noise from the wings &c. | |
| Oct 14, 2019 at 18:45 | history | edited | quiet flyer | CC BY-SA 4.0 |
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| Oct 14, 2019 at 18:44 | comment | added | quiet flyer | ha didn't even notice that, is a reference to flying gliders! | |
| Oct 14, 2019 at 18:42 | comment | added | DeltaLima♦ | +1 for the combination of this answer and your user name :-) | |
| Oct 14, 2019 at 18:37 | history | edited | quiet flyer | CC BY-SA 4.0 |
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| Oct 14, 2019 at 17:52 | history | edited | quiet flyer | CC BY-SA 4.0 |
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| Oct 14, 2019 at 17:32 | history | edited | quiet flyer | CC BY-SA 4.0 |
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| Oct 14, 2019 at 17:32 | comment | added | PerlDuck | I vote for fur covered wings on aircraft then :-) | |
| Oct 14, 2019 at 17:29 | history | edited | quiet flyer | CC BY-SA 4.0 |
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| Oct 14, 2019 at 17:20 | history | answered | quiet flyer | CC BY-SA 4.0 |