An experimental investigation has been carried out which used a transient wind tunnel to measure heat transfer coefficient in a fifteen times engine-size model of a blade mid-chord convergent cooling passage. Tests were performed with ribs and film cooling holes and also with rib-grooves and film cooling holes located in one of passage walls. Thermochromic liquid crystals were used as high resolution surface temperature indicators to provide highly detailed distributions of internal heat transfer coefficients. The data are presented as contours of enhancement factors for a range of suction ratios from 0 to 8.00 and for a range of engine representative Reynolds numbers from 1.04 × 105 to 1.76 × 105. It has been revealed that the area-averaged enhancement factors of 4 or greater are obtainable in the passage studied. The complex recirculating flow between the ribs with five 8 mm film cooling holes in a staggered arrangement has been successfully investigated using shear sensitive liquid crystals. The velocity through the passage tested has been measured at different suction ratios.