I think most of the air noise in the cockpit was caused by the sharp edges on the windows and to a lesser extent the windshield wipers.

The 727 was so noisy that most pilots did not fly above 300 KTS IAS. Below 300 KTS it was tolerable, but the level of noise went up sharply as you flew faster. Same for the 747 and to a lesser extent the 707. The 757 and 767 were whisper quiet compared to the older Boeing planes.

As I've said before, the windshield wiper noise on the 727 was beyond anything else in aviation. It was so loud that you could not talk to the other pilot and it did little to remove rain to boot! The wipers were powered by different motors and would operate at different speeds and get out of sync. I would laugh at the scene of the two wipers violent trashing as they flung back and forth. The 757 / 767 were much better.

Don't talk to me about rain repellent (Rain Bow) because that was just useless and only tried once by most pilots. If you hit the rain repellent button on a too dry windshield, you had messed up your vision for the rest of the flight until someone was able to scrub the stuff off.

Lou