One this shot, taken by moi , I notice that on the 3rd engine there seems to be a chain of circular objects on the silver/chrome part of the engine. Any ideas on why that would be there or what it actually is?!
I have never noticed it before you see, hence why I ask!
Many thanks for any feedback given,
PS: Hope y'all like my shot! I am a newbie photographer so I'm always pleased to hear what you think, Thank you.
GrandTheftAero From United States of America, joined Nov 2003, 254 posts, RR: 5
Reply 3, posted (11 years 3 months 22 hours ago) and read 3777 times:
What is the real point of this? Why do they need to add the extra metal to cover the front area?"
The "extra metal" is called a crown. It is warmed by engine bleed air and prevents ice formation. All three nacelles have this feature.
The reason that the engine is placed in the aft portion of the duct is that the hot exhaust gases would have melted the aluminum airframe if the engine was placed in the front of the duct. Also the pressure of the exhaust gas may have blown apart the duct entirely. For a forward-mounted engine to work, a duct that could withstand the temperature and pressure of the exhaust would have to be placed between the turbine rear frame and exhaust body of the engine. Additionally the exhaust end of the duct would have to properly shaped to expand the exhaust flow to optimal conditions. This is essentially an afterburner duct without the fuel nozzles, flameholders, and variable nozzle.
Given all this, it seems that Douglas made the right decision in placing the #2 engine in the aft portion of the duct. However, the penalty for the long inlet duct is that a significantly thick boundary layer is ingested by the engine, thereby deteriorating performance. Apparently the loss in performance was not substantial enough to deter Douglas, Lockheed and others to use duct-fed engines on their trijet airplanes.
747Teach From United States of America, joined Nov 2000, 176 posts, RR: 1
Reply 6, posted (11 years 3 months 12 hours ago) and read 3688 times:
Avioniker: "By the way, NW flies -40's, sorry." The Fleet Summary as of Jan. 01, 2004 lists 22 DC-10-30 aircraft in operation with the NWA fleet. There are no DC-10-40 aircraft listed in the operational fleet. There are two -40 aircraft, 1143 and 1144 listed in storage. Regards,
XFSUgimpLB41X From United States of America, joined Aug 2000, 4264 posts, RR: 36
Reply 8, posted (11 years 2 months 4 weeks 1 day 8 hours ago) and read 3575 times:
Sorry Avionker.. wrong again. Notice the straight #2 nacelle..those are GE engines, which is the quickest ID for it being a -30 series. I cant remember the exact ship numbers, but this is probably a -30EER. 580,000 mgtow...
FDXmech From United States of America, joined Mar 2000, 3251 posts, RR: 32
Reply 11, posted (11 years 2 months 4 weeks 1 day 6 hours ago) and read 3546 times:
We had a #2 change a couple months back. The old fashioned way, four manual chain hoists. To make matters worse, the chain hoist/engine cradle combo left us several inches short of mating. We had to drop it down again, switch equipment and manually hoist it back up again. OOH the pain!
Starlionblue From Greenland, joined Feb 2004, 17303 posts, RR: 67
Reply 12, posted (11 years 2 months 3 weeks 5 days 12 hours ago) and read 3444 times:
As far as I know, all planes with engines in rear ducts have the engine in the way back. Apart from the thermal issues, it is much more important to control the air going into the engine than the air going out. Although Boeing probably wished it had done something completely different at some points during the 727 test program. Those #2's kept flaming out on rotation.
"There are no stupid questions, but there are a lot of inquisitive idiots."