AFC_Ajax00 From United States of America, joined Nov 2000, 775 posts, RR: 0
Reply 1, posted (7 years 1 week 3 days 16 hours ago) and read 3701 times:
Those 3 pictures all feature different engines! Those are J57s on the KC-135, early turbojets, if memory serves, they have small "lip" inlets on all 4 engines. The 2nd pictures the fairly common JT3D on a 707, with 3 out of the 4 engines having a supercompressor inlet. The 3rd picture is of a 707 with RR Conway engines, don't know what the inlet situation is there!
Once you have tasted flight, you will walk the earth with your eyes turned skyward; for there you long to return
KELPkid From United States of America, joined Nov 2005, 6525 posts, RR: 3
Reply 5, posted (7 years 1 week 3 days 13 hours ago) and read 3604 times:
The 707's were almost, but not quite, bleedless. The "supercompressor" was driven by bleed air, as the CAA (predecessor to the modern FAA) didn't like the idea of feeding bleed air (engine air in the minds of the certification folks) to the cabin...so bleed air was indirectly used in this instance The 707/KC135's also used bleed air for ice protection, as I recall...
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
Viscount724 From Switzerland, joined Oct 2006, 26668 posts, RR: 22
Reply 8, posted (7 years 1 week 3 days 6 hours ago) and read 3511 times:
Quoting AFC_Ajax00 (Reply 1): The 2nd pictures the fairly common JT3D on a 707, with 3 out of the 4 engines having a supercompressor inlet.
AA's 707s only had 2 turbocompressors on #2 and #3. Look at any AA 707-123B or -323B/C photos and you'll note the narrow engine pylon on engines #1 and #4 (like the 720B). Since AA had no long overwater routes when those aircraft were acquired they apparently considered they would be close enough to a diversion airport to make the 3rd turbocompressor unnecessary in the event of a pressurization problem.
Quoting AFC_Ajax00 (Reply 1): The 3rd picture is of a 707 with RR Conway engines, don't know what the inlet situation is there!
As far as I know the 707-420 had the usual 3 turbocompressors but engine #1 without the turbocompressor had the same pylon design (like the non-turbofan P&W 707-120/220/320) so the lack of a turbocompressor wasn't obvious as it is with JT3Ds. I recall reading that Air India's 707-420s only had 2 turbocompressors.