Timeline for What is this sound on a B737-800 Takeoff?
Current License: CC BY-SA 4.0
5 events
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| Dec 30, 2021 at 16:30 | comment | added | leftaroundabout | @infinitezero it's pretty hopeless to eliminate all resonances, short of filling all cavities with a heavy viscous liquid or so. The important thing to get rid of are those resonances that can actually excited without bounds. The resonances in question here are apparently not excited by wind, but only by the wheels – and those can only provide so much energy, because the more resonance there is the quicker the wheel also slows down – so you can always only get a small fraction of the wheel's rotational-kinetic energy into the resonance mode. Much less stress than during a landing. | |
| Dec 30, 2021 at 14:03 | comment | added | John K | The level of balancing required to prevent any spindown shaking on 5 or 6 foot tire assemblies would require dynamic balancing machines that few airlines would be willing to pay for and I've never seen an airliner-size dynamic balancer machine like is used for cars. Everybody uses static balancers that hold the assembly with its axle horizontal, like motorcycle tire balancers. Spindown shaking happens on just about all airplanes when you take off, some more noticeable than others. It can be especially bad on Cessnas with the spring steel gear, since the gear acts like a harmonic amplifier. | |
| Dec 30, 2021 at 12:43 | comment | added | Martin Argerami | @infinitezero: someone might come with a more technical answer, but from a practical point of view, millions and millions of flights without incident seem like a good proof that this is not an issue. | |
| Dec 30, 2021 at 12:18 | comment | added | infinitezero | Given that some bridges were subject to catastrophic resonance failure and modern bridge designs have shifted resonance frequencies, so it can not be excited by wind, is there a reason why it's allowed in air craft wheels? Seems like it could cause a lot of stress. Although I don't know how it compares to stress when touching down. | |
| Dec 29, 2021 at 20:19 | history | answered | John K | CC BY-SA 4.0 |