From kls Sun Dec 17 02:11:49 1995 Newsgroups: sci.aeronautics.airliners Path: bounce-back From: Jennings Heilig Subject: Re: Difference between engines 1 & 4 of the boeing 707 References: Message-ID: Approved: kls@ohare.Chicago.COM Organization: CyberGate, Inc. Sender: kls@ohare.Chicago.COM Date: 17 Dec 95 02:11:49 On 10 Dec 1995, Marcelo F.Cosi wrote: > Does somebody know why the engines-arm were different in most of the > 707's????? The 707s carried an accessory turbocompressor, and depending on what type of 707 (and what customer) you're talking about, the arrangement of them on the pylons varied. Most 707-320B/C series aircraft (except for American Airlines) had T/Cs on all but number one engine. The number one pylon was a straight line all they way from the leading edge down to the cowling. The others have a "hump" on them with a small intake at the leading edge. This is the intake for the turbocompressor. On USAF EC and some RC-135s, there were T/Cs on numbers 1, 3 and 4 leaving #2 without one. It looks decidedly strange, but that's the way they did it. On most 707-120B and 720B aircraft, there were T/Cs only on the two inboards, leaving both outboards with "humpless" pylons. Jennings Heilig (my other car is a 707)