AbirdA From United States of America, joined Jul 2005, 303 posts, RR: 6 Posted (9 years 6 months 3 weeks 3 days 21 hours ago) and read 2898 times:
For years I have had a small square book entitled "Boeing Jetliners" which covers each model through the 777 in some detail. I had been staring at an old photo of a silhouetted BA 757 for ages, thinking that something seemed "off" about it. It finally dawned on me just the other day. The nacelles are completely unlike the smooth, one piece Rolls Royce-specific nacelles we see even on the BA aircraft today. Instead they were much more like the nacelles on the L1011, 742 and 743.
My question is why were early 757s delivered like this, only to be converted to the current nacelle later? Why did 757s start coming off the line in the newer nacelle so soon after introduction. Did the change in nacelle mean any internal changes to the engine? What was the advantage?
AeroWeanie From United States of America, joined Dec 2004, 1610 posts, RR: 52
Reply 1, posted (9 years 6 months 3 weeks 3 days 19 hours ago) and read 2798 times:
RR started on the 757 with the RB.211-535C3. When P&W announced the PW2037, RR had to upgrade their engine to match the competition, resulting in the RB.211-535E4. The E4 wasn't ready in time for early deliveries, so they got C3s. The E4 gives a 15% reduction in fuel burn, so upgrading was worth it.
Some of the differences between the C3 and E4: the E4 lacks fan blade snubbers, which the C3 had. The E4 also had wide chord fan blades. The C3 was in a separate flow nacelle, while the E4 had a mixed flow nacelle. In theory, the mixed flow nacelle has lower drag.
AbirdA From United States of America, joined Jul 2005, 303 posts, RR: 6
Reply 3, posted (9 years 6 months 3 weeks 3 days 1 hour ago) and read 2495 times:
Quoting Avioniker (Reply 2): If I remember correctly the picture you refer to was of a TWA delivery which had the P&W engines.
Well I guess that could be correct if the TWA aircraft was disguising itself in the 1980s BA livery, if the engines looked anything like the Pratt offering, if the book had not come out before TWA even took delivery of its first 757, or if the caption didn't clearly identify the aircraft as an early BA example and detail the 757's mission at BA.
(In actuality, TWA never found it expedient to paint one of their aircraft in BA colors for some strange reason.)
Any additional info on the changeover from the 535C3 to the 535E4?
Avioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11
Reply 4, posted (9 years 6 months 3 weeks 3 days ago) and read 2477 times:
Obviously not the same book. The one I'm looking at, although it has all the same legend mentioned by my less than polite quoter above, shows the plane in blacked out silhouette and was, in fact, an aircraft not yet painted to be delivered to TWA. It makes the book somewhat of a collectors' item due to the error.
Now if you're looking at a book with the colors showing then it must be one I haven't seen.
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
My apologies. I meant for that to come across as tongue-in-cheek and as humorous humanization of an aircraft, not as mean toward you. I of course realized we had different books. Please don't take offense.
BTW, I am intriigued at the book you mention. Could you explain further the "mistake?" I'm not sure I understand what occurred.
Its a little device installed part way out on the span of a fan blade, intended to prevent the blades from touching when they move back and forth in their mounting sockets. They reduce the aerodynamic efficiency of the fan. You can see there snubbers on each blade in this picture: