Simulation of Store Separation for the F/A-18C Using Cobalt

Tomaro, Robert; Witzeman, Frank C.; Strang, William Z.

doi:10.2514/2.2614

Cited by 17 publications

(7 citation statements)

References 13 publications

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“…They used polynomials as a function of piston stroke suggested by Fortin et al 10 to simulate the ejector forcing history. Tamaro et al 16 demonstrated a model to predict the captive carriage flight loads and used the same model to predict the trajectory of an external store (JDAM), which uses the ejector model supplied by Navy Generalized Separation Package-NAVSEP. In another recent study, Drobik and Tutty 17 summarized the store separation efforts.…”

Section: Introductionmentioning

confidence: 99%

Modeling of aircraft effects on external store ejection

Kozak

Yildiz²,

Yazıcıoğlu

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part G:

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Modern fighter aircraft, together with their interceptor roles, are utilized as aerial bomb and long-/short-range missile carriers. Separation of those external stores from aircraft is still a challenge where the external store has to clear the carrier aircraft following the ejection process. Aircraft and store aerodynamics coupled with their individual flight conditions may result in an unsafe ejection where the store may interfere with the carrier aircraft instead of a clear separation. Store ejection is the initial phase of the launching process, which dominates the separation of the store by generating the initial conditions. Any error introduced to the store separation analysis during this phase will propagate to the complete trajectory solution, which is used for determining whether the store separation is safe or not. The objective of this paper is to present a computational methodology that includes not only the store aerodynamics but also the interactions of the store with aircraft rigid body motions and deformations, together with ejector dynamics. In this study, store aerodynamics, aircraft aerodynamics, aircraft aeroelasticity, and pylon elasticity are used to characterize the ejector dynamics for determining the ejection end-of-stroke parameters.

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Section: Introductionmentioning

confidence: 99%

Modeling of aircraft effects on external store ejection

Kozak

Yildiz²,

Yazıcıoğlu

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part G:

View full text Add to dashboard Cite

show abstract

“…A great deal of three-dimensional coupled solver based on the unsteady Euler equation and six-degree-freedom rigid body equations have been developed [11][12][13][14] . The coupled solvers have been used to solve the problems of air-to-air missile launching [15] , cluster bomb separation [16] , store separation [17] , store trajectory optimization [18] , store aerodynamic performance optimization [19] and store stability analysis [20] . In order to balance the simulation accuracy and performance, a quasi-steady approach has been implemented to model the dynamic responses of the store separation [21][22] .…”

Section: Introductionmentioning

confidence: 99%

The influence of the elastic vibration of the carrier to the aerodynamics of the external store in air-launch-to-orbit process

Yang

2016

Acta Astronautica

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The separation between the carrier and store is one of the most important and difficult phases in Air-launch-to-orbit technology. Based on the previous researches, the interference aerodynamic forces of the store caused by the carrier are obvious in the earlier time during the separation. And the interference aerodynamics will be more complex when considering the elastic deformation of the carrier. Focusing on the conditions that in the earlier time during the separation, the steady and unsteady interference aerodynamic forces of the store are calculated at different angle of attacks and relative distances between the carrier and store. During the calculation, the elastic vibrations of the carrier are considered. According to the cause of formations of the interference aerodynamics, the interference aerodynamic forces of the store are divided into several components. The relative magnitude, change rule, sphere of influence and mechanism of interference aerodynamic forces components of the store are analyzed quantitatively. When the relative distance between the carrier and store is small, the interference aerodynamic forces caused by the elastic vibration of the carrier is about half of the total aerodynamic forces of the store. And as the relative distance increases, the value of interference aerodynamic forces decrease. When the relative distance is larger than twice the mean aerodynamic chord of the carrier, the values of interference aerodynamic forces of the store can be ignored. Besides, under the influence of the steady interference aerodynamic forces, the lift characteristics of the store are worse and the static stability margin is poorer.

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“…When the aspect ratio of the plane is large, the elastic deformation of the plane should be considered, and the aerodynamics interference caused by the elastic deformations may have great influence on the unsteady aerodynamics of the store. Nowadays, a great deal of work has been taken in the dynamic responses prediction of the store separation, among which flight test [3][4][5] , wind tunnel experiment [6] or numerical simulation methods [7][8][9][10][11][12][13] are used. The flight test and wind tunnel experiment, which can model the store separation accurately, would take a long time and high cost.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, many codes and numerical methods are developed. With the automated Chimera methodology or remeshing methodology, the multiple moving body problems that involve store separation are simulated [7][8][9][10][11] . To improve the simulation efficiency, the parallel computing technology is widely employed [12][13] .…”

Section: Introductionmentioning

confidence: 99%

The interference aerodynamics caused by the wing elasticity during store separation

Yang

2016

Acta Astronautica

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Air-launch-to-orbit is the technology that has stores carried aloft and launched the store from the plane to the orbit. The separation between the aircraft and store is one of the most important and difficult phases in Air-launch-to-orbit technology. There exists strong aerodynamic interference between the aircraft and the store in store separation. When the aspect ratio of the aircraft is large, the elastic deformations of the wing must be considered. The main purpose of this article is to study the influence of the interference aerodynamics caused by the elastic deformations of the wing to the unsteady aerodynamics of the store. By solving the coupled functions of unsteady Navier-Stokes equations, six degrees of freedom dynamic equations and structural dynamic equations simultaneously, the store separation with the elastic deformation of the aircraft considered is simulated numerically. And the interactive aerodynamic forces are analyzed. The study shows that the interference aerodynamics is obvious at earlier time during the separation, and the dominant frequency of the elastic wing determines the aerodynamic forces frequencies of the store. Because of the effect of the interference aerodynamics, the roll angle response and pitch angle response increase. When the store is mounted under the wingtip, the additional aerodynamics caused by the wingtip vortex is obvious, which accelerate the divergence of the lateral force and the lateral-directional attitude angle of the store. This study supports some beneficial conclusions to the engineering application of the air-launch-to-orbit.

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Simulation of Store Separation for the F/A-18C Using Cobalt

Cited by 17 publications

References 13 publications

Modeling of aircraft effects on external store ejection

Modeling of aircraft effects on external store ejection

The influence of the elastic vibration of the carrier to the aerodynamics of the external store in air-launch-to-orbit process

The interference aerodynamics caused by the wing elasticity during store separation

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