The sound comes from the rotary hydraulic motor situated in the wheel well of the jet which turns the drive shaft for the flap drive screw jacks.
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Is A380 quieter than 787? The website tinitustalk.com pulled research figures together for several widebody aircraft – with the A380 coming in lowest at 69.5 dB. The Boeing 787, for comparison, was quoted as 72.7 dB and the Airbus A350 at 74.9 dB.
It has been reported that the A350 is quieter than the B787, primarily due to the automatic Noise Abatement Departure Procedure (NADP) for the optimization of the engine thrust and flight path to reduce noise and the fuel-efficient engine. The other giant airplane, A380, is also known to have a quiet cabin.
The noise is caused by a hydraulic pump which is situated directly below the cabin. It mostly runs on takeoff and landing, but it can also run automatically at other times. Dogs have been reported to need psychiatric treatment after being transported on a 787.
Current 787 deliveries have been mostly suspended over the last year because of quality control programs involving microscopic tolerances of fasteners joining fuselage barrels together, and additional issues with electrical systems and windscreens.
To start the Boeing 777 vs 787 comparison, we must say that the 787 is a more fuel efficient aircraft than the 777 thanks to its use of composite wings and more aerodynamically efficient design.
The seats are so cramped in economy that the legroom of a similar seat on a 777 or a 747 feels like a business-class seat. Intelligent engineering allows for seat-backs to recline but to compensate, the seat bottom lunges forward — thereby only providing an illusion of a recline.
However, did the 787 truly fly supersonic relative to the air? The answer is no. The 787 is a widebody passenger aircraft capable of flying long distances at a cruise speed of 0.85 Mach (652 mph/1,050 kph).
They had very low bypass ratios and as a result, were noisy and thirsty beasts. Over the years the size of those first stage fans has grown – as has the percentage of bypass gas – to the point today where the A350 Trent XWB engine is a true giant, and the bigger the engine, the more efficient and quiet it is.
This advanced fly-by-wire system also is the key to Smoother Ride Technology – unique to the 787 family -- which senses turbulence and adjusts control surfaces automatically to dampen its effects before it reaches the passengers.
The loudest aircraft still in commercial service in any significant numbers is the Boeing 727. The 727 is banned from most major airports due to its noise levels. Among aircraft permitted worldwide, the Boeing 747–400 is noticeably louder than other widebody aircraft such as 777, A380 and A350.
The 787's latest problem mirrors production issues discovered over 2020 and 2021 that included improperly fitted shimming that led to paper-thin gaps between surfaces on the Dreamliner's fuselage.
The Boeing 787 Dreamliner has revolutionized flying for both passengers and pilots. Taking a leap into the future from its predecessors, the designers incorporated a number of new features that make the Dreamliner one of the most fuel efficient and comfortable aircraft in the skies.
This high aspect ratio wing design combined with efficiency enhancing raked wing tips allow the 787 to be one of the fastest commercial aircraft (Mach 0.85 cruise speed) while consuming less fuel than today's comparably sized aircraft.
An American Airlines Boeing 787 accelerates from rest to lift-off speed of 75.01 m/s in 29.20 s. Each of the plane's two jet engines provides a forward force (thrust) of 111.00 kN.
' For example, for the double-decker Airbus A380' superjumbo' quadjet, the service ceiling is 43,000 feet. Meanwhile, for the Boeing 787-8 and -9 'Dreamliner,' it is 43,100 feet. However, the stretched-fuselage 787-10 comes in a little lower, at 41,100 feet. Want answers to more key questions in aviation?
Flying higher gives lower fuel burn if you can get up there, so airlines take advantage. There are of course weight, wind and temperature dependencies, so every flight is different. The 787 and A350 also have a higher service ceiling compared to 777 and A330.
The longer the 787s remained on the ground, the more it would cost to get them to fly again, due to the maintenance work required. As a result, they were no longer airworthy.
The Dreamliner is a successful aircraft, still in production with more than 1600 delivered or on order. The list price for a new Boeing 787-8 is $239 million dollars. Yet even as international travel opens again for these long-range aircraft, two Dreamliners barely ten years old are waiting for the wrecker's ball.
While the 787 Dreamliners have not been grounded, the FAA had ordered a halt to deliveries of the widebody jet between May of 2021 and July of 2022 as it looked into questions about quality control during its assembly process.