Red oak branches sweep upward, white oak outward, and pin oak downward.
I've had pin oaks in my yard for many years. The reason that pin oaks have drooping branches is because they can't shed their leaves during a drought. To conserve moisture, the lower branches droop to lessen the evaporation rate of the ground around the tree. They also have a shallow root system which makes them good for transplanting.
I had the biggest pin oak in Macon County IL in my yard until it was hit by lightning twice. We had to take it down. It was cut up for firewood but I saved one small piece for nostalgia. I wasn't into wood that much back then. Here is what it looks like quarter sawn. I don't remember seeing any pin knots, but this was from a 36" dia. tree. Gary