A proposal for using ultrasonic wave bird flock repellents in aircraft

[meecheekoh]

      The number of aircraft accidents involving birds are too alarming that's why I have come to an idea to use ultrasonic waves to repel them so that the incident of planes being hit by a flock of bird will not happen. I have done researches about this, but I found out that bird repellents were only installed at home, industries and at the airport T.T
      I might not be the only one to think that the airplanes itself badly need this bird repellent to be installed on the aircraft (not in the airport alone) and I wonder why they (the companies that manufactures these repellents) are not doing it in the first place?
      Could someone give me a hand with this one? I want to propose this topic on our feasibility study. (Need do some researches before i raise this topic on the class)
      Thank you in advanced!  :)

[audioguru]

Ultrasonic sound waves have a very short range. Maybe 30m.
On an aircraft it will be absolutely useless to scare away birds.

An aircraft is extremely noisy and is huge. Are birds deaf and blind??.

Birds chase my RC model airplanes around the park. Then my airplanes are chasing them. I nearly clipped them a few times. Birds are stupid.

[Hero999]

Good, the original poster or a moderator unlokced the thread.

This idea has many flaws:

As audioguru said, aeroplanes are already very loud as it is, what makes you think that making them a bit louder would help scare off birds?

To increase the sound level by 10dB (twice as loud, ten times the power) would take an enormous amount of energy and it might approach or exceed the limit to sound intensity at that altitude (a shock wave).

I'm pretty sure that jet engines already generate intense ultrasound but it will be attenuated even more at altitude than at sea level.

Most birds are not sensitive to ultrasound anyway and generally have a lower upper limit  than most mammals, even humans, but many are sensitive to infrasound, for example pigeons can hear sounds as low as 0.05Hz, so perhaps the bird scarers you're talking about are huge sub woofers pumping out  high intensity infrasound?

http://en.wikipedia.org/wiki/Cochlea#Comparative_physiology
http://geology.about.com/od/infrasonics/a/birdsound.htm

I would think that a jet engine also generates infrasound but I've not seen the spectra so I wouldn't know the frequency/intensity.

A typical aircraft also travels at a significant speed with respect to the speed of sound, especially at altitude where the speed of sound is lower, meaning there's far less warning between hearing it and being hit. I think that by the time the birds hear or see the aircraft, it's too late. Don't forget that birds haven't evolved to escape anything as large or fast as an aeroplane, the fastest birds reach 106mph (level flight) or 200mph (when diving), a typical passenger aeroplane cruises at around 600mph.
http://www.thetravelalmanac.com/lists/birds-speed.htm

[audioguru]

Jet aircraft engines are designed to "eat" birds because airplane to bird inpacts are common.

But jet aircraft and me have never seen a flying elephant.

[meecheekoh]

thank you very much audioguru and hero999  :D (that's a lot of help)

ahhh.. so those are the reasons why such thing don't exist (it is not feasible to use that technique).

well.. I also have this one idea- (I have not yet made some researches)
it is about "easy file sharing"- copying of files from a flash disk to another without using a computer. Don't know yet if this already exist~ have any ideas?

(oopss.. Sorry- i think this one is out of thread)

again, thank you in advanced! =D

[Hero999]

Birds are stupid.

Not all birds are dumb, some are as clever as chimps.

A quote from Wikipedia:
"Crows in urban Japan have innovated a technique to crack hard-shelled nuts by dropping them onto crosswalks and letting them be run over and cracked by cars. They then retrieve the cracked nuts when the cars are stopped at the red light."

http://en.wikipedia.org/wiki/Bird_intelligence