AV8N2 From United States of America, joined Feb 2001, 39 posts, RR: 0 Reply 2, posted (12 years 1 month 3 weeks 3 days 13 hours ago) and read 6637 times:
48V, pretty good, but a couple of faults, and comments:
1) Actually, rear mounted engines are just as bad, if not worse for FOD ingestion. Anything that the tires run over, or a tire itself, will immediately proceed to one or both of the rear mounted engines. This has caused a number of engine failures on takeoff.
2) Along those same lines as in #1 above, in the case of the DC-9s and MD-80s, any ice on the wings WILL go through an engine. And, yes, ice does form on the fuel tanks at temps as high as 70 degrees F - I have seen it many times! Therefore, as part of every MD or 9 preflight, you must inspect for clear ice on the top of the wings above the fuel tanks with a special stick (unless the a/c has been retrofitted with heating blankets, which many are now).
3) As far as engine out controllability, the MD-80 for instance, has it's engines closer together than say a 737, but the engines on the fuselage are actually mounted aft-down and out. This really makes it a little more squirly than the 737. I would not have thought so, untill I transitioned to the Douglas.
I will agree mostly with your last statement, that maintenance is more difficult. That is the main reason, in my eyes, that Alaska's MD-80 crashed in LA. I believe that the maintenance personnel pencil whipped the book, and didn't lube the jack screw as often as need per the manual, due to the fact that it turns into quite a project with the "T" tail.
Trident From United Kingdom, joined Feb 2000, 484 posts, RR: 0 Reply 3, posted (12 years 1 month 3 weeks 2 days 5 hours ago) and read 6600 times:
Another disadvantage of the rear engine configuration is the requirement to make the wing stiffer to counteract the upward bending tendency of a wing in flight. This, of course, makes the wing heavier. The positioning of engines on the wing is partly done to provide a downward load to cancel out the bending moment, thus allowing the wing structure to be lighter. The technique was pioneered by Boeing on the B-47 bomber way back in 1948 and has proved a sound principle. How many "brand new" designs follow the "Rear Engine - T Tail" configuration today.
The most qouted "advantage" of rear engines was that it allowed a quieter cabin for passengers. I have my doubts about that, especially for those sitting in the rear.