The effects of freestream noise on roughness-induced transition were measured for the HIFiRE forecone model. Temperature-sensitive paint measurements were used to visualize the wake of the roughness elements under quiet and noisy flow. The transition Reynolds number increased under quiet flow, for a less-than-effective trip, by a factor of up to 6.4 when referenced to the trip location. The difference in transition location between quiet and noisy flow conditions is significantly reduced when effective trips are used, but quiet flow still delays the transition location for an effective trip. STABL calculations of the flow over the model at 0 and 6° angle of attack were used to quantify the results. The effect of an isolated roughness on the nozzle wall of the BAM6QT is also being studied. The nozzle wall features a thick laminar boundary layer, allowing measurements of the growth of instabilities. Temperature-sensitive paint measurements of the wake behind an isolated roughness element were obtained. In quiet flow, several hot streaks are visible.