Results 41 to 50 of about 22,232 (271)

Preliminary design of small distributed ducted electric tail rotor helicopter

Hangkong gongcheng jinzhan
To address the issues of complex transmission structure, low fault tolerance, and poor safety in traditional single-rotor helicopters with tail rotors(such as high accident rates due to tail rotor transmission system failures and collisions easily ...
LIU Chaofan, DENG Haoxuan, WANG Liangquan   +2 more
doaj   +1 more source

A method for tail rotor aerodynamic force prediction under rotor interference based on coupled momentum source and blade element theory

Xibei Gongye Daxue Xuebao
Due to the influence of slip flow and wake, the tail rotor of a helicopter may produce strong unsteady aerodynamic force in its main rotor interference flow field, which may affect the helicopter control and lead to structural failure.
WEN Long, ZHAO Xu, WANG Weite, LIU Xinyuan, YU Haiyang, HE Long, HE Shun   +6 more
doaj   +1 more source

Collision‐Resilient Winged Drones Enabled by Tensegrity Structures

Advanced Robotics Research, EarlyView.
Based on structures of birds such as the woodpeck, this article presents the collision‐resilient aerial robot, SWIFT. SWIFT leverages tensegrity structures in the fuselage and wings which allow it to undergo large deformations in a crash, without sustaining damage. Experiments show that SWIFT can reduce impact forces by 70% over conventional structures.
Omar Aloui, Raphael Zufferey, William Stewart, Mohammad Askari, Simon Jeger, Dario Floreano   +5 more
wiley   +1 more source

Advances in BODIPY Derivatives for Antibacterial Phototherapy

Angewandte Chemie, EarlyView.
This review systematically summarizes the design strategies and structure‐activity relationships of BODIPY‐based antibacterial phototherapy, covering molecular engineering of small‐molecule photosensitizers and nanoplatforms, bacterial targeting and carrier design, and discussing the challenges and future perspectives associated with clinical ...
Li Lv, Heejeong Kim, Hongchen Zhai, Hanqi Ren, Silu Wang, Cong Sun, Yafu Wang, Hosoowi Lee, Juyoung Yoon, Hua Zhang   +9 more
wiley   +2 more sources

Variable-speed tail rotors for helicopters with variable-speed main rotors [PDF]

The Aeronautical Journal, 2017
ABSTRACTVariable tail rotor speed is investigated as a method for reducing tail rotor power, and improving helicopter performance. A helicopter model able to predict the main rotor and tail rotor powers is presented, and the flight test data of the UH-60A helicopter is used for validation. The predictions of the main and tail rotor powers are generally
Han, D., Barakos, G.N.
openaire   +1 more source

Bearing time-to-failure estimation using spectral analysis features [PDF]

, 2014
With the increasing use of health usage monitoring systems on helicopters, a lot of research has been undertaken for diagnosis of transmission components.
Mba, David, Reuben, Lim Chi Keong, Lim, Chi Keong Reuben   +2 more
core   +1 more source

Nonlocomotory Robotic Strategies for Dynamic Rotation Control in Terrestrial Robots: A Review

Advanced Robotics Research, EarlyView.
Terrestrial robots increasingly require rapid body rotation to maintain stability and agility in complex environments. This review shows nonlocomotory rotational control strategies that operate without ground contact, including reaction wheels, tails, bars, limbs, and thrusters.
Y. Liang, J. An, X. Zheng, D. Wang, S. Wang, X. Wang, P. Zhu, J. Pei, S. Li, J. Paripurana, Y. Han, Z. Tang, X. Gan, Q. He, X. Ma   +14 more
wiley   +1 more source

A New Algorithm on Automatic Trimming for Helicopter Rotor Aerodynamic Loads

Aerospace, 2023
In order to simulate the flight state of the helicopter effectively, it is necessary to trim the helicopter during the forward flight in a wind tunnel test.
Xinfan Yin, Hongxu Ma, Xianmin Peng, Guichuan Zhang, Honglei An, Liangquan Wang   +5 more
doaj   +1 more source

PSMA8‐Containing 20S Proteasome Regulates Spermiogenesis and Male Fertility

Advanced Science, EarlyView.
PSMA8 assembles s20S proteasome that degrades specific substrates in elongating spermatids. Degradation of s20S‐substrates activates translation of FXR1‐target mRNAs, which are essential for mitochondrial sheath formation and sperm morphogenesis.
Huiwen Cao, Qianting Zhang, Wei Xu, Anxuan Fang, Haomang Xu, Cheng Qiu, Lugeng He, Chao Yu   +7 more
wiley   +1 more source

Research of the crosswind effect on the single-rotor helicopter unintentional yaw rotation

Научный вестник МГТУ ГА
During the operation of single-rotor helicopters, aviation accidents quite frequently occur in the form of an unintentional turn or even a yaw rotation, causing, as a rule, a ground collision.
V. V. Efimov, V. A. Ivchin, K. O. Chernigin   +2 more
doaj   +1 more source