Japan's aerospace agency hooks up with Boeing to make planes quieter when they land
- Reference: 1629460753
- News link: https://www.theregister.co.uk/2021/08/20/jaxa_boeing_acoustic_research/
- Source link:
Aircraft noise is an issue around the world, and the aviation industry is keenly aware that its social licence depends on operating as quietly as possible – especially at urban airports that travellers prefer because they're closer to big city centres.
One such airport is Tokyo's Haneda, which in 2020 opened new routes. Although the numbers of flights arriving were suppressed by unexpected subsequent travel bans, pre-COVID the new routes would have increased Haneda's annual international arrivals and departures from 60,000 to 99,000. The result would be many aircraft flying at low altitudes over Tokyo, as seen in the following tweet.
Second day of tests for the new Haneda landing routes today - gonna be interesting to see the reactions. [1]#haneda [2]#tokyo [3]#lowaltitude [4]pic.twitter.com/rQA6k98VmP — Halldór Elís Ólafsson (@halldorelis) [5]February 3, 2020
Any city dweller, city planner or unfortunate person living along a flight path can see this plan's inherent noise pollution problem.
Japan's Transport Ministry has tried different methods to combat the acoustic by-product of international travel. It has even ordered planes to descend at steeper angles – a tactic which can lead to an increase in hard landings and has caused some planes to divert to Narita, 70km outside Tokyo.
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Aircraft and engine manufacturers have worked on the problem for a while, too. Turbojet and turbofan engine designs have helped by increasing bypass ratios, thereby improving efficiency and dramatically reducing sound.
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But ballooning volumes of air travel has made such progress insufficient.
All this puts the aviation industry in a bit of a tricky spot as it strives to meet future passenger traffic demands and, in the case of Haneda airport, maintain an internationally competitive facility.
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JAXA worked with Japanese aircraft industries, universities, and NASA to further quiet aircraft by tackling airframe noise for six years starting in 2013 through the [10]Flight Demonstration of Quiet Technology to Reduce Noise from High-lift Configurations (FQUROH) project.
FQUROH researchers have largely considered noise coming from flaps, slats and landing gear – all indispensable equipment that slow the aircraft while descending without thwarting lift. Aerodynamic noise caused by turbulent airflow from these sources at times exceeds engine noise as the pilot closes the engine throttle during approach procedures.
[11]Engineers' Laurel and Hardy moment caused British Airways 787 to take an accidental knee
[12]United, Mesa airlines order 200 electric 19-seater planes for short-hop flights
[13]'Fasten your seat belts, raise your tray table, and disconnect your Bluetooth headsets from the entertainment unit'
[14]Japan assembles superteam of aircraft component manufacturers to build supersonic passenger plane
Probable solutions determined by FQUROH to reduce the noise-causing turbulent flow are practical flap-edge configuration devices, serrated lower parts of the slat to break down large-scale vortices, and perforated fairings on the landing gear.
Testing such designs with wind tunnels and computer simulations only gets you so far, hence JAXA's partnership with Boeing to build on the FQUROH research and their development of a plan for validating designs in flight tests.
JAXA [15]said it will continue working with Japanese manufacturers on the noise-reduction design concepts in the meantime.
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The agency also said it will finalise design concepts by March 2022 and that these would be ready for flight test in 2023 "or later." ®
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[1] https://twitter.com/hashtag/haneda?src=hash&ref_src=twsrc%5Etfw
[2] https://twitter.com/hashtag/tokyo?src=hash&ref_src=twsrc%5Etfw
[3] https://twitter.com/hashtag/lowaltitude?src=hash&ref_src=twsrc%5Etfw
[4] https://t.co/rQA6k98VmP
[5] https://twitter.com/halldorelis/status/1224242125664948225?ref_src=twsrc%5Etfw
[6] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2YR-RuPr5uDxoUdGZJPbvZAAAAEE&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[7] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YR-RuPr5uDxoUdGZJPbvZAAAAEE&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[8] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33YR-RuPr5uDxoUdGZJPbvZAAAAEE&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[9] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YR-RuPr5uDxoUdGZJPbvZAAAAEE&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[10] https://www.aero.jaxa.jp/eng/research/ecat/fquroh/
[11] https://www.theregister.com/2021/07/19/ba_787_landing_gear_pin_aaib_report/
[12] https://www.theregister.com/2021/07/15/united_mesa_electric_aircraft/
[13] https://www.theregister.com/2021/06/30/united_airlines_bluetooth_to_the_seat/
[14] https://www.theregister.com/2021/06/17/japan_supersonic_research/
[15] https://global.jaxa.jp/press/2021/08/20210820-1_e.html
[16] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33YR-RuPr5uDxoUdGZJPbvZAAAAEE&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[17] https://whitepapers.theregister.com/
Well, you are trying to slow down and descend, and all that energy has to go *somewhere*.
It's not practicable to use regenerative airbrakes just yet...
Why not go the whole hog
I'd have thought it obvious that the engine noise would reduce when throttling back to descend. Why not go the whole hog and turn them off totally. Then you'd only have the wind noise to worry about. And perhaps the screams of the passengers.
Re: Why not go the whole hog
I assume you're not being serious - the engines are required for stopping (thrust reversal) and for aborting in case of issues (go around)
Re: Why not go the whole hog
Why land at all? Just drop the passengers out the back by parachute at altitude, and land the plane at some airport out in the sticks.
Re: Why not go the whole hog
Mr O'Leary, gentleman on line 2 says he's got an idea to stop our customers complaining about how far away we land from our alleged destinations...
Re: Why not go the whole hog
G R Goslin,
The aircraft is insulated - so I doubt passenger screamage will be externally audible. So that's not a problem.
The problem is clearly operating engines at low level. So I think the solutions should borrow from existing, well understood, technology. I suggest we consider aircraft carriers.
In order not to have to slow the plane so much, we can dispense with slats and flaps, simply have a few arrestor wires - and that will slow the plane down nicely. You'd get some problem with tyre noise, carrier landings can be have significant tyre squeal. Maybe oil the runways, to make them extra-slippery?
Or another, long forgotten, piece of carrier tech as tested by Eric Brown. Simply remove the undercarriage entirely and have a rubber trampoline thingy fitted above the runway. Simply stall the aircraft above that - and have a nice bouncy landing. Extends aircraft range by saving weight as well - actually tested by the Royal Navy due to the pathetically short range of early jets.
We can also think further into this. Why must people put up with low level engine noise? Simply have catapult launch. With a decent length of runway, I'm sure you could get the plane up to takeoff speed, and with a nice ramp get the aircraft launched, and only turn the engines on, once above a certain height.
It all seems very sensible to me...
Arrestor wires
In order not to have to slow the plane so much, we can dispense with slats and flaps, simply have a few arrestor wires - and that will slow the plane down nicely.
[1]Already available!
Simply have catapult launch.
Here you go. Available for both [2]land and [3]sea .
[1] https://marshalladg.com/our-stories/rhag-paag
[2] http://www.defense-aerospace.com/article-view/release/121238/electromagnetic-catapult-launches-first-aircraft.html
[3] https://www.ga.com/alre
Re: Why not go the whole hog
>I'd have thought it obvious that the engine noise would reduce when throttling back to descend
Joking aside it's a big part of our flight path planning.
Decrease engine power slowly and descend slowly you have slightly less engine noise - BUT you spend a lot more time at low level above houses.
Fly at full power for longer and then approach the airport like a dive bomber you are only at low level inside the airport perimeter - BUT it annoys passengers who don't enjoy roller coasters and occasionally you experience lithobraking
Others use ...
Outside broadcasters find fur fabric very good as reducng surface turbulence. It would make planes look nice too.
Re: Others use ...
Hmmm. I like the idea of a nice leopardskin print airliner. Fly the kinky skies...
Re: Others use ...
"Outside broadcasters find fur fabric very good as reducing surface turbulence. It would make planes look nice too."
Two problems:
1) The fur would absorb water so flying through a rain shower, would cause the weight of the plane to increase significantly, resulting in either a need for bigger wings and/or more engines.
2) You'd need a lot of fur...the animal rights activists would not be pleased and thefts/kidnappings of domestic animals might increase as the criminal trade in fur would increase.
A better idea might be to put dimples on planes (as it works for golf balls), or maybe design the body of the plane with flutes (like the rifling inside a gun barrel) - both of these supposedly make for less air resistance and better directivity....
Re: Others use ...
" animal rights activists would not be pleased
Actually it's fur fabric that's used, so no animal rights issues. It's used as the outer layer on microphone wind shields to eliminate turbulence at the surface of the shield, so it has to have an open weave to avoid blocking the sound. Some folks who don't understand the principle have tried real fur, but of course the impervious leather stops the sound getting to the microphone.
Re: Others use ...
" design the body of the plane with flutes "
It's not the flutes on a bullet that make it fly straight - it's the spin imparted by the spiral flutes of the gun barrel. I don't think most passengers would appreciate a plane that revolved at high speed on its longitudinal axis.
Take a cue for the Shuttle?
Why not deploy a large (re-useable) parachute from the rear end of the plane?
It worked for the shuttle...
Then you don't need to extend the noise-producing "flaps" from the wings and can keep them smooth.
Re: Take a cue for the Shuttle?
I've never flown an airliner, but my impression is that flaps are engaged quite a long time before any parachute could be used effectively and safely. Military planes deploy the parachute after touchdown, not while in the air. If they did the latter they'd probably just fall out of the sky.
Re: Take a cue for the Shuttle?
> If they did the latter they'd probably just fall out of the sky.
But that would be ok cos they have a parachute
Japan has a space agency? Next thing you know you'll tell me Canada has a navy... ;-)
I did hear that Luxembourg has (or had?) a Grand AdmiraL
Presumably the job came with a little fleet for the chap's bath...
I'm not sure Boeing is the ideal partner for this - their solution will probably be to crash further away.
But quietly
Interesting, I remember reading a piece in the RAeS journal years ago where they estimated the noise from some of the proposed super-jumbo aircraft would exceed the limits even with the engines turned off. Surprised it's taken so long to tackle it as it least some must be from inefficiencies, a lot though is presumably required if you're turning a few hundred tonnes of air through 90 degrees to generate lift.