777 questions
Thread Starter
Joined: Mar 2003
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From: EGOS Field 24
777 questions
Having just enjoyed my first trip in a 777 (LHR-EZE and return) I'm curious about one or two things and hope this might be the right forum to ask them.
1. On the outbound flight I was sitting in 10A, which gave an excellent view of the engine and in particular the strake on the inboard side of it. At rotation a very powerful visible vortex was shed from the forward edge of this, which made its way over the top of the engine and still appeared to be going strong well aft of the trailing edge. I've seen something similar on a 737 but it was nowhere near as energetic! Is the strake there to generate the vortex? If so, why? Or does it serve some other purpose and is the vortex a by-product?
2. Both landings were so gentle as to be almost imperceptible. I'm sure this was mainly due to immaculate piloting technique, but is the triple-wheeled undercarriage something to do with this?
3. On the return flight I was sitting in 15K, which gives a very good view of the wing. Coming down the approach I was trying to puzzle out the lateral control system. This seemed to involve at least four spoiler panels, a flap section that also seems to work as a low-speed aileron (with some very large deflections) and also an outboard aileron that I hardly saw move at all. I don't remember seeing other airliners with similarly elaborate lateral control -- is the 777 unusual in this respect?
As one who's strictly a light-aircraft pilot but thoroughly enjoys big aeroplanes, I'd greatly appreciate any information.
John
1. On the outbound flight I was sitting in 10A, which gave an excellent view of the engine and in particular the strake on the inboard side of it. At rotation a very powerful visible vortex was shed from the forward edge of this, which made its way over the top of the engine and still appeared to be going strong well aft of the trailing edge. I've seen something similar on a 737 but it was nowhere near as energetic! Is the strake there to generate the vortex? If so, why? Or does it serve some other purpose and is the vortex a by-product?
2. Both landings were so gentle as to be almost imperceptible. I'm sure this was mainly due to immaculate piloting technique, but is the triple-wheeled undercarriage something to do with this?
3. On the return flight I was sitting in 15K, which gives a very good view of the wing. Coming down the approach I was trying to puzzle out the lateral control system. This seemed to involve at least four spoiler panels, a flap section that also seems to work as a low-speed aileron (with some very large deflections) and also an outboard aileron that I hardly saw move at all. I don't remember seeing other airliners with similarly elaborate lateral control -- is the 777 unusual in this respect?
As one who's strictly a light-aircraft pilot but thoroughly enjoys big aeroplanes, I'd greatly appreciate any information.
John
Joined: Jul 2003
Posts: 191
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From: Cheshire
The strakes are there to produce a vortex yes. I think these were introduced on the 737 to produce extra lift at high AoA an low-ish airpeeds.
A guess at question 2 would be that the T7 has alot of travel in the oleo on the MLG, but also the tilted bogie helps "smooth" out the transition to touchdown.
The 777 is not unusual in it's use of spoilerons and flaperons. Roll contol consists of a single outboad aileron, five spoilerons and a flaperon system.
Hope that helps,
A guess at question 2 would be that the T7 has alot of travel in the oleo on the MLG, but also the tilted bogie helps "smooth" out the transition to touchdown.
The 777 is not unusual in it's use of spoilerons and flaperons. Roll contol consists of a single outboad aileron, five spoilerons and a flaperon system.
Hope that helps,
Thread Starter
Joined: Mar 2003
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From: EGOS Field 24
Oh, I wasn't being sarcastic. The smoothness of both landings was very striking; in about thirty years of travelling on business, I can't remember anything as creamy. If any of my Chipmunk landings were as good, I'd be a very happy bunny!
John
John
Joined: Apr 1999
Aviation Qualifications: ATPL
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From: In front of a computer
Jet II
As a BA 777 Capt I can count on the fingers of one hand how many autolands I have done in the past three years! The aircraft is a joy to fly and getting smooth landings just needs a little finesse - even pilots new to the fleet soon learn to pull off greasers.......
PS Most of our destinations do not support autoland anyway.
As a BA 777 Capt I can count on the fingers of one hand how many autolands I have done in the past three years! The aircraft is a joy to fly and getting smooth landings just needs a little finesse - even pilots new to the fleet soon learn to pull off greasers.......
PS Most of our destinations do not support autoland anyway.
Joined: Jul 2002
Posts: 171
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From: London
Regarding Q1, the RR powered 767, had a similar strake, and I was reliably informed (???) that it was designed to take the engine down, and away from the wing/fuselage should the engine decide to detach itself from the wing.
However, I'm sure there is someone much more technically qualified out there to confirm/rubbish this theory!!!!!!!!!
However, I'm sure there is someone much more technically qualified out there to confirm/rubbish this theory!!!!!!!!!
Joined: Sep 2003
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From: temporarily unsure :-)
thats an interesting theory indeed.
i know that many acft have these strakes,and i always believed they were for greater lift at low speed,and also to act as 'gates' preventing airflow downwars around the engine.
indeed,the md-11,dc-10,a340 and 737 ng all have such strakes.
i know that many acft have these strakes,and i always believed they were for greater lift at low speed,and also to act as 'gates' preventing airflow downwars around the engine.
indeed,the md-11,dc-10,a340 and 737 ng all have such strakes.
