Analysis of deep-stall characteristics of T- tailed aircraft configurations and some recovery procedures

Montgomery, R. C.; Moul, Martin T

doi:10.2514/6.1966-13

Cited by 5 publications

(8 citation statements)

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“…After drying, the samples were weighed using a Mettler balance, to the nearest 0.01g, and then underwent a particle size analysis using the B-C. The rock dust content of the deposited coal dust and rock dust mixtures was determined using the low-temperature ashing (LTA) method which burns off the coal component at 515°C (Montgomery 2005, NIOSH 2010).…”

Section: Methodsmentioning

confidence: 99%

Factors Affecting the performance of trickle dusters for preventing explosive dust accumulations in return airways

Sapko

Harris

Perera

et al. 2019

Journal of Loss Prevention in the Process Industries

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Correctly applied rock dust can dilute, inert, and mitigate the explosive potential of float coal dust. Trickle dusters are one element of a comprehensive system to help prevent coal dust explosions in underground coal mines. Trickle dusters supply rock dust to inert fine float coal dust in areas where it is commonly deposited, such as the longwall tailgate returns, return airways, pillaring areas, and downwind of belt transfers. Dust deposition studies show that the effectiveness of trickle dusters depends on several key factors. Using multiple orifices, rock dust should be released near the mine roof in the direction of the airflow in order to spread the cloud cross the entry. The rock duster should have a mechanism to break up rock dust agglomerates as they leave the rock duster. The particle size distribution of the limestone rock dust and its airborne concentration should be proportional to the airborne size distribution and concentration of coal dust passing by the trickle duster. Specifically, rock dusts having a greater proportion of <74 µm material are more effective at minimizing downwind zones of explosible mixtures than mostly larger particles. In our testing, rock dusts having more than 95% of <74 µm sized particles were adequately dispersed by trickle dusters. Based on our results, the mass rate of rock dust discharge from the trickle duster should exceed the rate of float coal production by at least a factor of four in order to minimize accumulations of explosible dusts.

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Section: Methodsmentioning

confidence: 99%

Factors Affecting the performance of trickle dusters for preventing explosive dust accumulations in return airways

Sapko

Harris

Perera

et al. 2019

Journal of Loss Prevention in the Process Industries

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“…(2) The normal project of the total engine thrust is insignificant compared with the lift force or the weight.…”

Section: Flight Dynamics Refinementmentioning

confidence: 99%

“…Early in 1966, equilibrium bifurcation was adopted to manifest the mechanism of deep stall for T-tailed aircraft. 2 With the wide application of bifurcation to flight dynamics, numerical method such as continuation, was adopted to analyze the bifurcation property of a variable sweep fighter, 3 and the global natures of some specific phenomena such as stall departure, spin entry, flat and steep spin, nose slice and wing rock were revealed one after another. Similarly, bifurcation was utilized to study the free-to-pitch motion at a large mean AOA, 4 and showed that when the mean AOA increases beyond a critical value, the aerodynamic damping vanishes and the pitch oscillation happens.…”

Section: Introductionmentioning

confidence: 99%

Bifurcation analysis and stability design for aircraft longitudinal motion with high angle of attack

Shi

2015

Chinese Journal of Aeronautics

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Bifurcation analysis and stability design for aircraft longitudinal motion are investigated when the nonlinearity in flight dynamics takes place severely at high angle of attack regime. To predict the special nonlinear flight phenomena, bifurcation theory and continuation method are employed to systematically analyze the nonlinear motions. With the refinement of the flight dynamics for F-8 Crusader longitudinal motion, a framework is derived to identify the stationary bifurcation and dynamic bifurcation for high-dimensional system. Case study shows that the F-8 longitudinal motion undergoes saddle node bifurcation, Hopf bifurcation, Zero-Hopf bifurcation and branch point bifurcation under certain conditions. Moreover, the Hopf bifurcation renders series of multiple frequency pitch oscillation phenomena, which deteriorate the flight control stability severely. To relieve the adverse effects of these phenomena, a stabilization control based on gain scheduling and polynomial fitting for F-8 longitudinal motion is presented to enlarge the flight envelope. Simulation results validate the effectiveness of the proposed scheme. ª 2015 Production and hosting by Elsevier Ltd. on behalf of CSAA & BUAA.

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“…According to Lemma 3, we have (1) in the presence of system uncertainties, unsteady disturbances, and input saturation, the controller is given by (27), and the adaptive laws are proposed as (29). If the parameters are selected properly, the desired signal can be tracked within a small bounded error, and other signals in the closed-loop system are bounded.…”

Section: Attitude Controller Designmentioning

confidence: 99%

“…Deep stall is an uncontrollable state. When a fighter enters deep stall, the angle of attack (AOA) increases automatically and will be locked at a certain AOA far beyond the stall AOA [1]. Deep stall widely exists in aircrafts with longitudinal torque characteristics that have a ''spoon-like'' structure, such as the F-16 fighter.…”

Section: Introductionmentioning

confidence: 99%

Analysis and Recovery of Aircraft Deep-Stall Phenomena Using Bifurcation Analysis

2020

IEEE Access

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In this paper, the problem of deep-stall recovery will be studied for the aircraft without longitudinal static stability. A new longitudinal short-period deep-stall model is established in the presence of time-varying distributed delays. Based on bifurcation analysis method, the effects of actuator fault on deep stall are analyzed in depth. Considering the system uncertainty, actuator fault, input saturation and unsteady disturbance, a finite-time prescribed performance deep-stall recovery law is designed according to the bifurcation analysis results. Further, to avoid the singularity problem in traditional finite-time control, an improved finite-time control law is developed. Stability of the closed-loop system is proved by common Lyapunov functional method. And simulations are given to illustrate the validity of the proposed deep-stall recovery control scheme. INDEX TERMS Deep stall, finite-time control, prescribed performance, bifurcation analysis.

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Analysis of deep-stall characteristics of T- tailed aircraft configurations and some recovery procedures

Cited by 5 publications

References 0 publications

Factors Affecting the performance of trickle dusters for preventing explosive dust accumulations in return airways

Factors Affecting the performance of trickle dusters for preventing explosive dust accumulations in return airways

Bifurcation analysis and stability design for aircraft longitudinal motion with high angle of attack

Analysis and Recovery of Aircraft Deep-Stall Phenomena Using Bifurcation Analysis

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