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Unusual Losses of Aircraft
Published in Stephen J Wright, Aviation Safety and Security, 2021
The reader must be aware that the service ceiling of the Boeing 777-series aircraft is limited to 43,100 ft. The service ceiling is the maximum safe altitude that an aircraft can fly to when carrying passengers and loads. While it is possible to exceed the manufacturer’s altitude limit, the aircraft will not perform correctly or safely. For instance, the aircraft pressurisation system and ECS (as described in Chapter 4) will not be able to function correctly. The pressure differential between the low-pressure atmosphere outside and the pressure inside the passenger cabin exceeds the aircraft’s structural tolerances. The low cabin pressure will exceed the safe levels for effective respiration (breathing) as pressure will be too low for effective gas transfer in the lungs (i.e. - oxygen absorption and carbon dioxide release in the alveoli). Occupants in a low-pressure cabin environment, such as an aircraft exceeding its service ceiling, will suffer the effects of hypoxia. If not remedied with the return of pressure to safe limits, incapacitation will occur, with death following rapidly.
Straight-level flight
Published in Mohammad H. Sadraey, Aircraft Performance, 2017
Another very important criterion for aircraft performance is the ceiling. Ceiling is defined as the highest altitude at which an aircraft can safely have a straight-line level flight. Another definition is the highest altitude that an aircraft can reach by its own engine and have sustained flight. The higher the ceiling, the better is the aircraft performance. This performance parameter has limited application in civil airplanes, but is very significant for military airplanes. For instance, if the ceiling of a fighter is higher than the ceiling of missiles in a specific region, this fighter can operate freely on that region and survive. The aircraft parameters that positively influence its ceiling are the lower weight, higher engine thrust, and lower drag. The materials in this section do not apply to an aircraft with rocket engine since there is no limit for their ceilings.
Aerodynamic analysis on unsteady characteristics of a ducted fan hovering in ceiling effect
Published in Engineering Applications of Computational Fluid Mechanics, 2023
Yiwei Luo, Tianfu Ai, Yuhang He, Zhiran Zhao, Bin Xu, Yuping Qian, Jie Peng, Yangjun Zhang
It has been reached a consensus that the range of ceiling effects on the aerodynamic performance of ducted fans is within 4R (R is the radius of the fan rotor), and significant effect is observed below 1.5R approximately. As the distance from the ceiling decreases, the duct thrust, rotor thrust and total thrust are all improved due to the ceiling effect. However, current researches on the ceiling effect were conducted by steady simulations without exception. The unsteady characteristics of flow field caused by ceiling has not been captured and analysed, especially at an extremely close distance from the ceiling. Ceiling effect acts as a threat to UAV operations, not only because it will lead to the shifts in thrust, but also bring unsteady changes, which has not been addressed in any prior research.
Comparison of frequency and magnitude of head impacts experienced by Peewee boys and girls in games of youth ice hockey
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Andrew Post, Clara Karton, Odette Thevenot, T. Blaine Hoshizaki, Michael Robidoux, Michael D. Gilchrist
The pendulum was a rigid steel cage that included weighted plates inserted to attain the target mass (Figure 3). The steel cage was attached to the ceiling via four aircraft cables. The impactor tip of the pendulum was changed to the shoulder, elbow, head, or punch impactor depending on the event type being reconstructed. To conduct an impact, the pendulum was attached to a winch via an electromagnet, pulled the appropriate distance from the helmeted headform and released to attain the target velocity at contact. The velocity at impact was measured via high speed camera (Fastcam PCI 512; HSI inc.).
Reduced Pressure Effect on The Centerline Plume Temperatures of Elevated n-Heptane Fires in an Aircraft Cargo Compartment
Published in Combustion Science and Technology, 2023
Jie Wang, Gongyousheng Cui, Kaihua Lu, Xuepeng Jiang
The fire plume impinges on the ceiling to form an impact point at the structure of the aircraft cargo compartment. Once the ceiling temperature reaches the ceiling material tolerance threshold, it is likely to burn through the ceiling and affect the structural stability. Hence, the maximum temperature rise of the cargo ceiling at reduced pressure is worthy studying practically. The maximum ceiling temperature rises of the elevated fires at reduced pressures are drawn in Figure 10.