Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft

Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and water, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research were simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in water resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design.

Parameter Optimization of Nose Landing Gear Considering Both Take-off and Landing Performance of Catapult Take-off Carrier-Based Aircraft

Optimization of the parameters of landing gear systems with double-stage air springs of catapult take-off carrier-based aircraft is here studied based on the mathematical equations of the classic dual mass spring-damper dynamic model.Certain standards for both take-off and landing performance are put forward.The contradictory factors between take-off and landing processes are analyzed.The optimization of oil in the pin area and the area near the rear oil hole is performed.Then these optimized parameters are used to assess the influence of the initial pressure of the low chamber,the ratio of the high chamber to the low chamber,and the tire inflation pressure on the performance of arresting landing and catapult take-off.The influences of these parameters on carrier-based aircraft and the aircraft-carrier on aircraft catapult take-off is also assessed.Based on the results of the simulation,respective take-off criteria must be drafted considering different types of aircraft and different take-off load cases,all of which must be matched to parameters relevant to catapult take-off.

The Influence of Climate Change and Variability on Aircraft Take-off and Landing Performance;a Case Study of the Abeid Amani Karume International Airport-Zanzibar

Climate change (CC) and variability have been world widely reported to pose number of risks in aviation industry including accidents, astray, and other operational difficulties. The impact of weather on landing and take-off performances has been several times experienced at Abeid Amani Karume International Airport (AAKIA);however, the influence of climate change and variability to the aircraft performance needs to be assessed. Thus, this study investigated the influence of climate change and variability on aircrafts take-off and landing performances. Specifically, the study investigated;i) the influence of climate change on Take-off Distance Required (TODR) and Maximum Take-off Mass (MTOM) for different types of aircraft;ii) the influence of climate variability to the aircraft landing performance on light, medium and heavy aircraft and lastly, iii) the study investigated the seasonal and annual variability on aircraft landing performance due to climate variability. The datasets used in this study include the eight years (2014-2021), aircraft operational records (diversion and missed approach events) and Aviation Routine Weather Reports (METAR) records which were utilized as the indicators for landing performance, the long-term (1990-2020) annual maximum temperatures (Tmax) which was used to determine the TODR and MTOM. Statistical tools including mean, percentage changes, correlations, regression, and the chi-square test were used for analysis and hypotheses testing. The results revealed that light and medium aircraft categories were significantly most affected on diversion events as compared to the heavy categories;however, for the missed approach events the impact was vice versa. Moreover, the seasonal and annual variability on diversion and missed approach events were significantly different (at p ≤ 0.001). As for the take-off performance, results show that the TODR and MTOM were significantly increasing and decreasing (at p ≤ 0.001), based on increasing air temperatures. Therefore, the study concludes that the changing climate has significantly affected aircraft by increasing the TODR and decreasing the MTOM, while the climate variability has significantly affected landing performance by influencing the diversion and missed approach events. Thus, the study recommends (i) further research works including the feasibility study on runway extension for the safety of future aircraft operations at the AAKIA and (ii) proper maintenance and improvement of the Instrumental Landing Systems (ILS) as an adaptation measures to the landing aircraft during bad weather events.

Performance analysis of aircraft low-power thermoelectric refrigeration system

An optimal design method for an aircraft low-power thermoelectric refrigeration system（TRS）is proposed using an existing experimental model as the research platform under given aircraft flight conditions.The variation curves of the cooling capacities and the refrigeration coefficients of the system running at three flight altitudes are investigated.The performance of the system is evaluated by the minimum-entropy-generation method and the performance penalty is also calculated.The power variation curves of the cooling system are obtained by an electric power experiment.The peak values of these curves are less than the maximal electric power supply of airborne equipment,proving that the use of the low-power TRS for airborne equipment is feasible.The COP,cooling capacity and entropy generation of the system are relative to the flight altitude and the current of the TRS.Through the analyses of these data,the optimal values of the COP are obtained,and the optimization measures are proposed to maximize the use of the advantages of the TRS.

INFLUENCE OF AIRCRAFT DEICER ON FREEZE-THAW DURABILITY OF HIGH PERFORMANCE CONCRETE

The influence of glycol,the main composition of the most frequently used aircraft dicer,on the freeze-thaw durability of high performance concrete（HPC）is investigated.Freeze-thaw durability of HPC is tested by accelerated freeze-thaw test.Four kinds of the solution,i.e.,tap water,3.5% NaCl solution,glycol solutions,and a LBR-A type commercial aircraft deicer are employed.Results show that freeze-thaw durability of HPC exposed to glycol solutions is closely related to the solution concentrations.The failure of HPC exposed to 3.5% glycol solution is similar to that of those exposed to 3.5% NaCl solution,i.e.,serious surface scaling.While the damage of HPC exposed to 12.5%—25% glycol solutions is postponed.Compared with glycol solution,the commercial aircraft deicer has much more negative effects on HPC freeze-thaw durability compared with 3.5% NaCl solution.In the presence of commercial aircraft deicer for HPC subjected to freeze-thaw cycles,the deterioration is mainly due to scaling and spalling.

Modeling of Carrier-based Aircraft Ski Jump Take-off Based on Tensor

A general mathematical model of carrier-based aircraft ski jump take-off is derived based on tensor. The carrier, the aircraft body and the movable parts of the landing gears are treated as independent entities. These entities are assembled into a multi-rigid-body system with flexible links. Dynamical equations of each entity are derived on the basis of the Newton law and the Euler transformation. Using the invariance property of the tensor, the dynamical and kinematical equations are converted to tensor forms which are invariant under time-dependent coordinate transformations. Then the tensor-formed equations are expressed by the matrix operation. Differential equation group of the matrix form is formulated for the programming. The closure of the model is discussed, and the simulation results are given.

Space range estimate for battery-powered vertical take-off and landing aircraft

A novel method for estimating the space range of battery-powered vertical take-off and landing(VTOL) aircraft is presented. The method is based on flight parameter optimization and numerical iteration. Subsystem models including required thrust, required power and battery discharge models are presented. The problem to be optimized is formulated, and then case study simulation is conducted using the established method for quantitative analysis. Simulation results show that the space range of battery-powered VTOL aircraft in a vertical plane is an oblate curve, which appears horizontally long but vertically short, and the peak point is not located on the vertical climb path. The method and results are confirmed by parameter analysis and validations.

Problems and Barriers Impeding the Implementation of MagLev Assisted Aircraft Take-Off and Landing Concept

Nowadays, the success of the new technology development and deployment process depends not only on technical, technological solutions, but also on solving the non-technological problems and crossing the societal and psychological barriers. A large international European projects, GABRIEL1 had developed a maglev assisted aircraft take-off and landing, that was applied to conceptual design of aircraft and required on-board and ground systems, had analysed all impacts (effects of concept deployment on effectiveness, safety, security, noise, emissions) and had demonstrated the safe applicability by concept validation. The applied methodology, used methods and the results of the Gabriel projects had been described and discussed by 55 project deliverables. This paper has a special goal: investigating the problems and barriers of possible implementing of the radically new technology, aircraft MagLev assisted take-off and landing. The study was started by identification and classification of the problems and barriers. After it, the problems were systematically analysed by use of special methodology containing the understanding (description) of the problems, investigation of the possible solutions and discussing their applicability (mainly by use of the Gabriel project results). The paper has three major sections: 1) description of the Gabriel concept and project results, 2) introducing some related thoughts on general aspects of new technology developments, and 3) discussion on the problems and their solutions. The major classes of the problems are the 1) technical, technological problems as developing a radically new solution, landing the undercarriage-less aircraft on the magnetic tracks, 2) stakeholders’ problems as decision makers kicking against supporting the developments of so radically new technologies and 3) society barriers like society worrying on and fear of future passengers on flying by aircraft have not conventional undercarriage systems. The paper will show that these problems have safe and cost-effective solutions.

Investigation of Nonlinear PI Multi-loop Control Strategy for Aircraft HVDC Generator System with Wound Rotor Synchronous Machine

In order to enhance the transient performance of aircraft high voltage DC(HVDC)generation system with wound rotor synchronous machine(WRSM)under a wide speed range,the nonlinear PI multi-loop control strategy is proposed in this paper.Traditional voltage control method is hard to achieve the dynamic performance requirements of the HVDC generation system under a wide speed range,so the nonlinear PI parameter adjustment,load current feedback and speed feedback are added to the voltage and excitation current double loop control.The transfer function of the HVDC generation system is derived,and the relationship between speed,load current and PI parameters is obtained.The PI parameters corresponding to the load at certain speed are used to shorten the adjusting time when the load suddenly changes.The dynamic responses in transient processes are analyzed by experiment.The results illustrate that the WRSM HVDC generator system with this method has better dynamic performance.

Switching Tracking Control for Planar Systems with Transient Performance Constraints

这份报纸学习与被 overshoot 和安定时间决定的一些给定的短暂性能限制为平面系统的一个类追踪问题的输出。与产量限制(SSOFTOC ) 追踪的交换静态的产量反馈的问题第一次被建议并且解决。静态的输出反馈控制器和一条所谓的圆锥形的切换法律在没有违背短暂性能限制，靠近环的交换系统的输出能 asymptotically 在哪个下面追踪步信号下面被设计。而且，最佳的加权的短暂表演被解决一个非线性的编程问题获得。最后，到飞机扇涡轮引擎的一个数字例子和应用被给说明有效性和建议方法的适用性。

飞机高速牵引滑行制动模式分析

在传统牵引车牵引飞机的运动过程中,其制动行为是通过牵引车独立制动来完成的,主要用于低速推出牵引和轻载中速维护牵引工况。针对未来飞机牵引滑行的高速重载新特征,仅靠牵引车实施制动能否满足牵引系统制动性能需要重新评估。为此,文中考虑了由飞机和牵引车联合制动的新模式,即由飞机主起落架机轮刹车系统和牵引车轮刹车系统同时制动,通过分配制动力来实现牵引车-飞机系统的制动行为。建立了飞机牵引滑行时制动过程的动力学模型,并以B737-200型飞机和TBL-180型牵引车为例,分析对比了牵引车单独制动和牵引车-飞机联合制动两种模式下的系统制动性能和制动安全性。结果表明:牵引车-飞机联合制动时的制动性能远优于牵引车单独制动时的制动性能,是飞机高速牵引滑行时紧急制动的优选模式;在安全性方面,牵引车-飞机联合制动时的前起落架横向载荷也远小于牵引车单独制动,会为飞机前起落架结构保留更大的横向冲击安全裕度。

舰载机前起落架缓冲性能参数敏感性研究

为了同时满足缓冲和突伸性能,舰载机前起落架常采用双腔缓冲器设计。以某型机前起落架为研究对象,建立前起落架缓冲性能分析动力学模型,并将仿真计算结果与试验结果进行验证对比,验证理论模型的有效性和正确性。对缓冲器高、低压腔初始压力以及体积占比进行参数敏感性分析。结果表明,高、低压腔初始充填压力和体积占比对起落架缓冲性能的影响有别于它们对突伸性能的影响,所以对舰载机前起落架缓冲器的设计需不断优化,同时兼顾缓冲和突伸性能。

串联驱动变弯度机翼设计与气动性能分析

针对飞行性能要求,采用NACA4412翼型设计了一种串联驱动变弯度机翼方案。将机翼沿弦向分为5个翼段,前缘部分为主承力结构固定段,后缘4段翼面由4个舵机实现串联驱动。偏转翼段内部采用空间五面体桁架结构,表面敷设复合材料弹性蒙皮。翼段间采用连杆止动以限制相对转角。建立了机翼的运动学分析模型,计算了变弯度机翼的作动速度。建立了机翼的气动分析模型,对4个典型飞行工况的气动性能进行了分析,并与传统舵面机翼性能进行对比。研究表明,在相同飞行工况下,弦向四级串联驱动变弯度机翼的作动时长仅为传统机翼的25%。起飞阶段升阻比增大71.94%,滚转机动时力矩增大12.46%,进近阶段升力增大11.19%,接地后减速阶段阻力增大104.83%。串联驱动变弯度机翼相对传统舵面机翼具有更优的操纵特性和气动性能。

考虑电系统热限制的倾转翼eVTOL巡航性能优化

为分析倾转翼eVTOL在考虑电系统热管理对巡航性能的影响,以及不同工况下性能参数的选择,根据飞机二维动力学、阻力、能耗和电系统热管理计算模型,以飞机巡航速度作为控制变量,以巡航时间和电能消耗作为目标函数,建立倾转翼eVTOL巡航仿真模型。结合实际飞行条件设定不同权重,根据模型的具体特征,基于改进粒子群算法进行优化求解,以典型倾转翼eVTOL飞机Vahana为例,得出性能参数并对比分析。仿真结果表明:模型在各种权重组合下,对减少飞机巡航时间和降低电能消耗均有良好的优化效果;最快到达与最节能到达的飞行工况相比,可以节省约50%的时间,但同时会多消耗120%的电耗;与既考虑时间又考虑能耗的折中情况相比,节省了20%时间的同时能会多消耗28%的电能。

基于超星平台的飞机性能工程课程群线上教学质量监控指标研究

针对线上教学质量不均衡和难以监控的问题,有必要对混合式教学模式下的线上教学质量进行监控和评价。以飞机性能工程课程群为对象,开展学习效果和线上学习行为的关联性研究。基于超星平台4个学年的统计数据,初步形成6个一级指标、24个二级指标。首先通过数据预处理删除无效和共线性指标;然后通过描述性统计分析,得出样本数据的分布规律,删除异常指标;接着对15个指标进行相关性分析,得出影响期末考试成绩的相关性指标;最后对剩余指标进行主成分分析并进行排序,形成飞机性能工程课程群线上教学质量监控指标的依次为签到完成率(x_(8))、章节测验总均分(x_(24))、视频观看时长(x_(3))、章节测验参与均分(x_(23))、章节学习次数(x_(1))、任务完成率(x_(5))、章节测验参与率(x_(22))7个学生线上学习行为指标。

运动模型式飞行器气动力参数测试系统研究

为了对飞行器进行气动布局、飞行性能评估,提出了一种运动模型式气动力参数测量方法,并研制了一套运动模型式测试系统,通过运动模型来模拟飞行器在空气中的运动,其构造主要包含载具、测试支架、六分量天平、风速测量模块、数据采集模块、控制模块、便携计算机等部分;该类测试系统在某些特定工况下能准确模拟飞行器的飞行状态,对流场参数和模型所受载荷进行实时测量,预测各运动状态下飞行器的气动特性;通过数值模拟分析和风洞试验对车载试验数据进行了对比验证,结果表明,该测试系统能够准确获得模型的气动力特性数据;该系统具有一定的拓展性和通用性,可使用火箭橇等其他载具开展高速运动模型式气动力参数测量试验。

基于神经网络的高原机场飞机离地速度计算方法

针对现有飞行理论中对民航飞机在高原机场起飞离地速度计算研究不足,且计算方法单一、复杂的问题,利用MATLAB仿真平台构建在高原机场飞机起飞滑跑阶段模型,通过计算不同飞行条件下的飞机离地速度,得到大量训练样本,建立BP神经网络模型,将机场海拔、飞机质量、安全起飞速度、温度和可用起飞距离作为输入量,飞机离地速度作为输出量,对神经网络进行训练和测试,直至均方差达到要求。将神经网络所求估算值与仿真数据进行对比并进行分析。均方误差为4.1289,均方根误差为5.6121。使用神经网络计算方法效率高,误差小,可应用于不同高原机型在不同影响因素下的离地速度计算,对高原机场运行和机场跑道长度设计有一定参考价值。

转速对航空动力装置动力性能和经济性能的影响

为探究发动机转速对某中空长航时无人机动力装置的动力性能和经济性能的影响,结合发动机速度特性曲线、耗油率特性曲线、高空特性曲线及螺旋桨效率曲线,在某无人机飞行速度范围内,选取典型发动机油门匹配不同发动机转速,通过理论计算与试验相结合的方法,评估动力性能和经济性能的变化情况。研究表明:对于所研究的航空动力装置,在所研究的发动机转速范围内,推力随着发动机转速的增加而增大,单位推力耗油率则随着发动机转速的增加先减小后增大,即存在最经济转速,且发动机油门位置越大,对应的最经济转速也越高。为保证动力性能和经济性能,各油门设定的转速应避免设置在最经济转速之下。对于所研究的航空动力装置,在最大连续工况条件下,当飞行速度一定时,动力装置的推力、螺旋桨效率随着飞行高度的增加而降低,单位推力耗油率则随着飞行高度的增加先增加后降低。在飞行高度一定时,动力装置的推力随着飞行速度的增加而降低,而螺旋桨效率、单位推力耗油率则随着飞行速度的增加而上升。

新型动力轻型飞机飞行性能仿真评估

为评估新型动力轻型飞机的飞行安全性,基于民用航空器适航审定理念和方法,选取飞行关键的阶段,应用MATLAB软件模拟该型飞机起飞地面滑跑和起飞爬升性能,计算滑跑距离和爬升率。结果表明混合动力型轻型飞机的起飞地面滑跑距离缩短了10%,爬升性能提高了22%,同时混合动力型飞机对起飞机场的高度和温度环境适应能力也明显提升。该方法可作为混合动力轻型飞机适航审定中验证符合中国民航CCAR-23-R4规章第23.2115条款“起飞性能”和第23.2120条款“爬升”要求的一种方法。

燃料串/并联的航空SOFC-GT混合系统性能对比分析

固体氧化物燃料电池-涡轮(SOFC-GT)混合系统作为电推进飞机的动力源时,会面临低温低压的大气环境以及对重量有严苛的要求,因此通过优化系统构型使得该混合系统满足航空应用是一种有效的解决方式。为此本文提出了燃料并联和串联的两种SOFC-GT混合系统构型,并从热力循环理论、系统热力学性能以及系统功重比等方面依次对其进行了对比分析。结果表明,并联系统的热力学性能要优于串联系统,对于系统发电效率、比功和功重比分别提高3.32%,113.14%和34.04%,CO_(2)排放率降低3.22%。随压比的提升串联系统的效率存在最优点,随燃烧室温度的提升并联系统的效率持续下降。在空燃比为4~6的变化范围内,串联系统的输出功率变化幅度更大,相对并联系统为116.29%~87.11%。除此之外,虽然SOFC-GT混合系统的功重比相对较低,但基于其优异的效率,在系统能量密度方面整体要优于锂电池,这有利于提升电推进飞机的性能。