The significant initial time commitment to create online content required for flipped classrooms may pose an obstacle to their implementation, despite the known learning benefits. We hypothesize that flipping only specific, problematic topics may still provide benefits to students with less instructor preparation. In this study, we targeted a flipped classroom toward a single, difficult course unit (the Reynolds Transport Theorem in fluid mechanics) to reduce the total time required for course preparation. Six lectures on this topic were converted to online videos and in-class time was used for group-based problem solving. Comparisons were made between a traditional lecture section (n=8) and flipped classroom sections (n = 15). A statistically significant improvement was seen when comparing exam performance on a question-by-question basis. Student survey responses about the method were unanimously positive, and students specifically noted the ability to rewatch sections of the video as a benefit to their learning. The interview responses also produced an unanticipated result. Students indicated that they preferred the partial approach to a hypothetical full course flip, stating they felt "it would get old. " While the use of a targeted flipped classroom was investigated here to reduce the initial faculty time commitment, this finding may warrant future investigation on reaction to partial versus full course flipped classrooms.