The influence of multiple delta wing vortex generators on the wall of rectangular ducts on the pressure loss penalty has been experimentally investigated in this study. The combined effects of geometrical parameters of multiple delta wing and duct aspect ratio on friction factor ratios are reported in the Reynolds number based on the duct hydraulic diameter in the range of 8000-24000. The geometrical parameters of vortex generators systematically varied in this study were the pitch to vortex generator height ratio (p/e), vortex generator height to duct hydraulic diameter ratio (e/Dh), aspect ratio of vortex generator (ar). The number of vortex generators (N) on a wall at a given axial location were also varied - an integer number of equal sized vortex generators spanned the entire width of the wall on which the vortex generators were used. Results are reported for 0.1 < e/Dh < 0.5, p/e=4,8,12,16, (ar)=2.31, N=2 in ducts having aspect ratio AR = 2.