Just on a plane taxiing to the runway and there’s loads of short repeated motor-like noises happening.. i hear them on most, if not all, flights, before take off – what are they?
In: Engineering
Most likely the sounds of the motors that are deploying the take off flaps. Modern planes deploy “extensions” to the wings to aid take off and landing by providing additional lift at low plane speeds and allow for shorter takeoffs. Once the plane takes off, these extensions cause drag and increase fuel consumption so they are retracted during the cruise period. When the plane comes in for landing, the pilot redeploys them so that the plane can land at a lower (and therefore) safer and more comfortable speed.
airbus power transfer unit? sounds like this: [https://www.youtube.com/watch?v=XEG1ZfPHkVo](https://www.youtube.com/watch?v=XEG1ZfPHkVo)
It is likely the motors that extended the flaps on the wing. sit just behind the wing and look at the read of them just before takeoff and you can see what happens when you hear the noise,
The rear part of the wings is extended backward and downwards. The change in wing shape provides more lift but at the same time, it increases drag. Lift also depends on the speed the result is the wing shape is only something you want during takeoff and landing. For this reason, the wings are built with flaps that can move so the wing shape changes during flight
There is a max speed for a flap setting because of their physical strength, if you build a sold wing with the same shape as a wing with flaps extended it could be used at a higher speed. The problem is the fuel usage would increase significantly
[https://www.thrustflight.com/airplane-flaps/](https://www.thrustflight.com/airplane-flaps/)
Prior to takeoff the pilots are going through a list of items to check their condition and configuration.
There are loads of hydraulic pumps and transfer units that make distinct noises.
You’re most likely hearing the trim and flaps position to take off configuration and likely a few other control surfaces too.
Latest Answers