Timeline for What is the purpose of the fin at the Boeing 787 APU exhaust?
Current License: CC BY-SA 3.0
5 events
| when toggle format | what | by | license | comment | |
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| Mar 16, 2023 at 7:53 | comment | added | sophit | Albeit being a technically perfect answer, it does not answer the question and it is actually formally wrong: vortex generators and/or strakes and/or fences and/or... are used to improve the airflow on the surfaces behind them. Behind that fences there's nothing, so its purpose is anything but aerodynamics... The only aerodynamic thing that it is doing is most probably producing additional drag | |
| Jan 2, 2018 at 23:38 | comment | added | Mark Jones Jr. | Actually, it is more likely that unburned fuel pools after the APU is shut down and would re-ignite once the APU is restarted. | |
| Jan 2, 2018 at 23:36 | history | edited | Mark Jones Jr. | CC BY-SA 3.0 |
Added references to define and illustrate the stagnation point. Clarified the relationship of pooling fuel to airflow through the exhaust duct.
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| Jan 2, 2018 at 22:38 | comment | added | Ralph J♦ | Can you cite a source to back up your answer? The article that @mins linked in comments to the OP indicates that the purpose is to allow fuel to exit the tailcone during flight rather than pooling in the tailcone. What you describe regarding airflow is consistent with that explanation, but you're talking about exhaust gasses; the article about fuel before the APU is turned on. Can you provide sources for your answer, and/or additional clarification, reference that article? | |
| Jan 2, 2018 at 21:22 | history | answered | Mark Jones Jr. | CC BY-SA 3.0 |