Effect Of Missile/Rocket Plume On Helicopter Pitch Channel

Preliminary research is carried out in this paper on the effect of missile/rocket launching plumeon helicopter pitch channel. A mathematical model of UH-60A Black Hawk flight dynamics isestablished by using FLIGHTLAB. Model validation is then carried out. Physical properties of jetplume from helicopter-carried missile/rocket are studied. Its property of highly underexpanded isdetermined. Engineering calculation and numerical computation methods of highly underexpanded jetplume are discussed. An engineering simplified model of helicopter-carried rocket jet plume isestablished. Numerical simulation of jet plume from a certain type of helicopter missile/rocket launchis done by using common software-FLUENT. An engineering simplified model of helicopter-carriedconcentric-cylinder is established by considering helicopter rocket launching characteristics.Distribution and changes of plume temperature, velocity, pressure etc. at Black Hawk horizontal tail isthen calculated by using FLUENT. Instantaneous airloads of horizontal tail suffered in the plume fieldis calculated by using classical lifting line theory. A disturbance module for engineering analysis ofhelicopter missile/rocket launch is developed and embedded into the Black Hawk mathematical model.Preliminary analysis on the effect of missile/rocket launching plume on Black Hawk pitch channel inhover is done by launching one and seven rockets at both side.Preliminary research results and the developed disturbance module for engineering analysis ofhelicopter missile/rocket launch in this paper can provide basis for pilot control, helicopter flightcontrol design and real-time simulation during missile/rocket launch process.