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http://dx.doi.org/10.5139/JKSAS.2018.46.1.41

Unguided Rocket Trajectory Analysis under Rotor Wake and External Wind  

Kim, Hyeongseok (Seoul National University)
Chae, Sanghyun (KARI(Korea Aerospace Research Institute))
Yee, Kwanjung (Seoul National University)
Publication Information
Journal of the Korean Society for Aeronautical & Space Sciences / v.46, no.1, 2018 , pp. 41-51 More about this Journal
Abstract
Downwash from helicopter rotor blades and external winds from various maneuvering make an unguided rocket change its trajectory and range. For the prediction of the trajectory and range, it is essential to consider the downwash effect. In this study, an algorithm was developed to calculate 6-Degree-Of-Freedom(6 DOF) forces and moments exerting on the rocket, and total flight trajectory of a 2.75-inch unguided rocket in a helicopter downwash flow field. Using Actuator Disk Model(ADM) analysis result, the algorithm could analyze the entire trajectory in various initial launch condition such as launch angle, launch velocity, and external wind. The algorithm that considered the interference between a fuselage and external winds could predict the trajectory change more precisely than inflow model analysis. Using the developed algorithm, the attitude and trajectory change mechanism by the downwash effect were investigated analyzing the effective angle of attack change and characteristics of pitching stability of the unguided rocket. Also, the trajectory and range changes were analyzed by considering the downwash effect with external winds. As a result, it was concluded that the key factors of the rocket range change were downwash area and magnitude which effect on the rocket, and the secondary factors were the dynamic pressure of the rocket and the interference between a fuselage and external winds. In tailwind case which was much influential on the range characteristics than other wind cases, the range of the rocket rose as increasing the tailwind velocity. However, there was a limit that the range of the rocket did not increase more than the specific tailwind velocity.
Keywords
Unguided Rocket; Trajectory Prediction; Actuator Disk Model; Downwash; 6 DOF Modeling; External Wind;
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  • Reference
1 Lee, H., Kwon, O., Lee, B., Noh, K., "Aerodynamic Simulation of Air-Launched Missiles from a Complete Helicopter", Journal of the Korean Society for Aeronautical & Space Sciences, Vol. 39, Dec. 2012, pp.1097-1106.
2 Wei, F., Gjestvang, J., "Store Separation Analysis of the Penguin Missile from the SH-2G Helicopter", 39th AIAA Aerospace Sciences Meeting and Exhibit, Reno, NV, U.S.A., Jan. 2001.
3 Gong, H., Kwak, E., Lee, S., Park, J., "Prediction of Trajectories of Projectiles Launched from Helicopters", Journal of the Korean Society for Aeronautical & Space Sciences, Vol. 42, Mar. 2014, pp.213-220.
4 Ozge K., Ozan T., "Main Rotor Downwash Effect on Separation Characteristics of External Stores", AIAA Atmospheric Flight Mechanics Conference, Gaylord Texan Hotel & Convention Center, Grapevine, U.S.A., Jan. 2017.
5 Kim, T., Oh, S., Yee, K., "The Development of Rotor Analysis Solver Based on Actuator Model using Open Source CFD Code", Journal of the Korean Society for Aeronautical & Space Sciences, Nov. 2013, pp.72-75.
6 Caradonna, F., Tung, C., "Experimental and Analytical Studies of a model helicopter rotor in Hover", NASA TM 81232, NASA, U.S.A., 1981.
7 Elliot, J. W., Althoff, S. L., and Sailey, R. H., "Inflow Measurement Made with a Laser Velocimeter on a Helicopter Model in Forward Flight-${\mu}$=0.23", NASA TM 100542, NASA, U.S.A., 1988.
8 Dahlke, C. W., George, B., "Hydra 70 MK66 Aerodynamics and Roll Analysis", NASA RD SS 90-6, 1990.
9 Missile Guidance and Control Systems, George M. Siouris, 2004.
10 Charubhun, W., Chusilp P., "Effects of Aerodynamic Coefficient Uncertainties on Trajectory Simulation of a Short-Range Solid Propellant Free Rocket", 26th International Symposium on Ballistics, Miami, Florida, U.S.A., Sep. 2011.
11 http://en.wikipedia.org/wiki/Hydra_70
12 Andrzej, Z., "Numerical Simulation of the Effect of Wind on the Missile Motion", Journal of Theoretical and Applied Mechanics, Vol. 52, Dec. 2014, pp.335-344.