And if you ever flew 707s equipped with JT3D turbofans, you'll remember it too. This is a NATO 707 taking off from Konya, Turkey in 2006: I am a bit surprised the pilots hadn't "cleaned up" the wing by the end of the clip.
The airplane is still climbing and accelerating. Interesting to see the auxiliary inlet doors operating under load. The propulsion guys refused to change the sharp radius on the inlet cowl because it was the best low drag configuration for cruise. So the doors were needed to feed air to the fan section at low vehicle speed because of lip stall at the inlet.
I had a question asked about why the aux inlet doors were needed when the air was drawn into the intake from the front. So, I had to explain to the lady that the air was pulled in from all directions radially and even from a little behind the intake. It couldn't turn the sharp corner and broke away into a stall that starved the engine. Douglas didn't have that problem.
By the way, if you just want to see the takeoff, go to about 4:00 on the video. Kinda reminds me of Joe Patroni firewalling the JT3Ds in "Airport" to get the stuck 707 out of the snow. When I was watching Pan Am 707s take off at San Juan, viewing from the Clipper Club, the reduction in takeoff roll when the JT3C turbojets were replaced by the JT3Ds was incredible!
