Originally Posted by
BOAC
Perhaps it is worthwhile also to correct the misleading thread title? The wheels on the 737 do not 'stick out' when retracted. They are flush with the skin, but uncovered. I suspect the drag caused at this point on the airframe where I would suspect any 'laminar' flow has long since given up the ghost is not great? Therefore no 'biggie'. Also one less mechanical bit to go wrong.
Actually, one of the larger potential sources of drag in such a configuration is if the airflow gets inside the wheel well and recirculates; all that wasted energy with airflow inside the wheel well has to come from somewhere, which means drag.
That's why even with exposed wheels you'll still see an attempt to seal the tyres against the edges of the wheel well, with brush seals or similar; the extra mass of the seals is small, and the benefit woirthwhile.