Date: 09 Jan 98 00:50:48 From: Chuanga@cris.com (H Andrew Chuang) Organization: Concentric Internet Services References: 1 2
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In article <airliners.1998.2@ohare.Chicago.COM>, Karl Swartz <kls@ohare.Chicago.COM> wrote: >>... All 747SPs >>eventually had a modified pylon, where the trailing edge was a generous >>curve, staying low before ascending to the wing. Additionally, where >>the outboard pylon meets the wing was extensively modified with a >>fairing that goes over the wing leading edge and is almost vertical on >>the inboard side and curved on the outboard side. > >>... Earlier -100/-200s seem to have both pylons. My guess is that the >>-100s are the ones with the earlier pylons, while -200s have the later >>pylons. Can anyone confirm this? > >Funny, I was just sitting in the Red Carpet Club at ORD this afternoon, >looking at a parked at gate C16 and noticing the different pylons on the >#1 and #2 engines. I couldn't see the trailing edge of the pylon and >hadn't seen your message yet, but I did notice that the outboard (#1) >pylon had the fairing you describe where it meets the leading edge of >the wing, unlike the #2 pylon, just as you describe. > >This aircraft was an early 747-123 (N156UA, ln 77), so the presence of >the fairing does not distinguish a 747-200 from a -100. The trailing >edge still might. I don't think the curved trailing-edge pylon can be used to distinguish a 747-200 from a -100. My recollection is the newer pylon started to appear on the B747-200 in the late 70s. I believe the pylon modification was to accommodate higher thrust versions of the JT9D engine. The first time I noticed the modified pylon was on a JT9D-7Q-powered B747-200, which, I believe, went in service around 1978 or 1979 (but it could have been introduced earlier). I think pylons on all the JT9D-7A-powered B747-100 and -200 are of the same design.