Wind tunnel testing of generic model of double ellipsoidal shaped hull of LTA airship

Lighter than Air (LTA) airships have been recognized as a probable way of alternative transportation and surveillance purposes. In the present study, direct measurement of volumetric lift and drag on a generic model hull of airship were estimated by using low speed wind tunnel and correction of the same was done for blockage and interference effects. Scaled down modelsused were taken as rigid and aero elastic effects were not considered. Flow visualization equipment based on Hydrogen bubble generator was used to visualize the pattern of streamline and flow separation. Since, it is very difficult to estimate the contribution of fins towards the drag and required stability, till the time one knows the contribution of hull towards drag, hence, only the hull's aerodynamics was estimated. It was found that drag forces are dominant than the lift and drag can be minimized by operating it at low angle of attacks. Calculated parameters have been analyzed for various situations under which the airship may operate and the same will be used in future for the development of 6 DOF Dynamic Model, a tool for preliminary design & analysis.