Yvr74 From Canada, joined Sep 2002, 52 posts, RR: 0
Reply 1, posted (13 years 4 months 4 weeks 3 hours ago) and read 11824 times:
I don't know about rear engine airplanes having a slow climb or not, but I do have a remark in reference to your comments about the 757.
I'm sure there are people who might know some technical reason why, and my knowledge is only from that as a passenger, but the steepest climbs I have ever experienced while onboard an aircraft have been on a 757. Once on a Delta 757 flight out of DFW, the angle of climb was so steep that I figured something must surely have gone wrong with the airplane and that we would fall out of the sky. It was incredible.
MD88Captain From United States of America, joined Nov 2001, 1351 posts, RR: 19
Reply 3, posted (13 years 4 months 4 weeks ago) and read 11758 times:
The position of the engines have nothing to do with the takeoff performance of aircraft. It has more to do with aircraft wieght, wing design, thrust available, etc. Where the engines are placed does affect aircraft handling but not takeoff performance. The aircraft you mention are either underpowered (727) or have a small wing (makes less lift). The 757 is a rocket on takeoff because its wind make alot of lift and it makes a bunch of thrust.
Bragi From Iceland, joined May 2001, 218 posts, RR: 0
Reply 10, posted (13 years 4 months 3 weeks 5 days 16 hours ago) and read 11529 times:
About the B757; it´s so powerful on takeoff, that some pilots I know and who fly it, sometimes climb much faster than the cabin has time to pressurise, so after a steep climb (in ferry flights) , they lower the nose and let the cabin catch up!
Muhammad Ali: "Superman don’t need no seat belt." Flight Attendant: "Superman don’t need no airplane, either."
CV640 From United States of America, joined Aug 2000, 952 posts, RR: 5
Reply 12, posted (13 years 4 months 3 weeks 3 days 14 hours ago) and read 11391 times:
The Lear and Gulfstreams, along with most opther corporate aircraft, are rear engined aircraft and have numerous records in the time to cimb area. Total thrust and woing design, along with weight, are the real factors for climb rates.
Boeing nut From , joined Dec 1969, posts, RR:
Reply 13, posted (13 years 4 months 3 weeks 3 days 1 hour ago) and read 11317 times:
CV640 is correct. I remember reading an article on the Gulstream IV-SP (a.k.a. Gulfstream 400) on a flight that broke several climb records. The fuel load was light, but, on takeoff, the aircraft was powered up to full thrust with brakes applied. The Tays were so strong that even with the brakes applied, the G-IV-SP was skidding. Now those are some strong engines!!!!
MD-90 From United States of America, joined Jan 2000, 8526 posts, RR: 11
Reply 14, posted (13 years 4 months 3 weeks 2 days 8 hours ago) and read 11240 times:
I'd say the 757 climbs fast because it's wing is not optimized for high speed cruise (the sweepback angle isn't that high). The 727 has a lot of sweep, and was optimized for high speed cruising, not maximum lift at low speeds. The MD-90 also has been stretched so much from what the wing was originally designed to lift, it's not surprising if it doesn't climb all that terribly well (although the steepest climb I've ever seen was on one of those tv reality shows that had an SAS MD-80, I dunno, maybe clearing a mountain or something but I've never seen an AOA that steep on any big jet before or since).
EssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 1
Reply 15, posted (13 years 4 months 3 weeks 2 days 3 hours ago) and read 11248 times:
If one runs the numbers, the 757 typically has higher thrust to weight ratios than other 121 a/c...the 717 and MD90 are in the same ballpark.
If one compares a DC9-30 w/ a 717, the wing differences are minimal...but the thrust to weight ratio is greatly increased in the 717 as compared to its older brother. One could have made the most comprehensive change to the DC9 wing possible; but if max gross weights and thrust were held constant, the climb performance wouldn't change nearly as significantly as is has with the higher thrust engines of the 717. Climb performance is largely a function of excess thrust.
Also, the 328 jet is an excellent climber...corporate jets and fighters have engines near their centerlines for a couple of big reasons...for fighters, it keeps the size of the vertical tail(s) to a minimum in case of a failed engine. For corporate a/c, engines slung under the wing force raise the profile of the a/c up far enough such that just about anything that needs to be done on the a/c from daily maint to loading pax would require ladders or larger airstairs than typically used, which detracts from the mission flexability of a corporate a/c at remote airports.