No, you would not notice the curvature from the pipe. Actually, that depends on your reference point. It's like if you're walking in a train, and the train is going 60 miles an hour and you're walking three. How fast are you going? Relative to the train, 3 mph. Relative to the ground, 63. In regards to the pipe, if you're walking on it, you won't notice it. Do you notice the curvature of the earth when you walk? Maybe if you look out across the ocean, but you can't feel it underneath you at all. If you're from a great distance, say orbiting the earth or farther, and you could observe the pipe, then you'd notice it. Just like we can see that the moon is curved. So it all depends on your reference point, but if you're walking on it then you won't feel any curve.