View From The Front - Ask The Pilots Thread
Feb 28, 2009 | 2:55 pm
#151
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Thanks for the explanation.
One quick follow-up question. I noticed in the Boeing cross-wind landing video that when the plane was "crabbing" the wheels remained aligned with the direction of the runway. Is this set in advance or is this something else that you are controlling during touchdown?
Thanks.
One quick follow-up question. I noticed in the Boeing cross-wind landing video that when the plane was "crabbing" the wheels remained aligned with the direction of the runway. Is this set in advance or is this something else that you are controlling during touchdown?
Thanks.
Feb 28, 2009 | 4:36 pm
#152
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The B-52 is the only airplane that I know of with crosswind gear. They may be others but it's pretty rare.
Feb 28, 2009 | 4:55 pm
#153
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One quick follow-up question. I noticed in the Boeing cross-wind landing video that when the plane was "crabbing" the wheels remained aligned with the direction of the runway. Is this set in advance or is this something else that you are controlling during touchdown?
Thanks.
Thanks.
Feb 28, 2009 | 5:26 pm
#154
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Actually I believe that on the 777 the main gear do swivel and have some sort of alignment capability. Haven't flown that plane, but many of the guys that I fly with were FOs on that aircraft, and described something along those lines.
Feb 28, 2009 | 5:44 pm
#155
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Saw that on the old Discovery Channel show "Wings" on the 747...
Feb 28, 2009 | 9:21 pm
#156
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Feb 28, 2009 | 9:29 pm
#157
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Instead, it has what is known as bicycle landing gear with wingtip outrigger wheels.
The main landing gear can swivel 20 degrees.
Feb 28, 2009 | 9:40 pm
#158
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I know it's bicycle gear, but the thought of something that large having to land with the nose pitched down even a little bit just gives me the creeps. The U-2 was bicycle and outriggers, and that was a special case of the willies because the length of the nose required the chase vehicle to talk the pilot down from about 20 feet to landing. The designers obviously got it to work, but it's not my cup of vodka.
Feb 28, 2009 | 9:53 pm
#159
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I know it's bicycle gear, but the thought of something that large having to land with the nose pitched down even a little bit just gives me the creeps. The U-2 was bicycle and outriggers, and that was a special case of the willies because the length of the nose required the chase vehicle to talk the pilot down from about 20 feet to landing. The designers obviously got it to work, but it's not my cup of vodka.
Feb 28, 2009 | 9:59 pm
#160
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(As a guy who used to build what lives in the bomber's belly - I was USAF Ordnance - I have a soft spot for large high-order detonations...and most preferably ones that take out lots and lots of bad guys.)
USAF AMMO: Providing the enemy the opportunity to die for his country.
Feb 28, 2009 | 10:04 pm
#161
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Long live the BUFF. ^
(As a guy who used to build what lives in the bomber's belly - I was USAF Ordnance - I have a soft spot for large high-order detonations...and most preferably ones that take out lots and lots of bad guys.)
USAF AMMO: Providing the enemy the opportunity to die for his country.
(As a guy who used to build what lives in the bomber's belly - I was USAF Ordnance - I have a soft spot for large high-order detonations...and most preferably ones that take out lots and lots of bad guys.)
USAF AMMO: Providing the enemy the opportunity to die for his country.
Feb 28, 2009 | 10:07 pm
#162
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Somewhere in my files is a blurry shot of me riding a 2,000-lb. penetrator. I jumped up on a dummy bomb body during bomb school. It was (circa 2001) and hopefully still is a tradition passed down among AMMO troops, to be done while the instructor is out of the room during the week of school that focuses on bomb buildup.
Mar 1, 2009 | 7:52 am
#163
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Mar 1, 2009 | 3:57 pm
#164
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Mar 1, 2009 | 7:14 pm
#165
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I was contemplating the best way to answer this question, and I kept getting hung up on the words 'problem' and 'dangerous'. I think the best way to answer a question on winds, would be to address strong crosswinds, which I would describe as 'challenging'.
Wind direction obviously impacts the work level on landing. Picture yourself trying to push a feather through a room and down onto a table......with a bit of wind, that task becomes a bit more challenging.
With a headwind, our relative speed over the ground is reduced, and our landing rollout will likewise be reduced.
With a tailwind, our speed over the ground is increased and our landing distance increased. We've got to analyze our landing weight (heavy/light?), runway condition (wet/dry/snow/ice?), runway length (construction?), and any other factors which will impact our ability to stop (reverser inop, etc.).
A strong crosswind (with gusts) is probably the most challenging. The aircraft is 'crabbed' into the wind to maintain a track down the extended centerline of the runway. The crab is maintained until just prior to touchdown, and the aircraft is aligned by the pilot with the runway centerline. This is accomplished by what what we call a 'wing down, top rudder' maneuver. As the aircraft is flared we lower the 'upwind' wing, and apply opposite rudder. If done correctly, this will bring the nose around to the centerline and keep the wings relatively level. The big challenge on all of that is touching down at the exact moment that both of the mains are perfectly aligned with the runway. If you are off at all....wheels not level, or not tracking down the centerline......you'll all feel it in the back. Picture yourself trying to pull into your garage with your nose not quite pointed where you want it, and your tires not pointed in that direction either.
On touchdown, we'll use the rudder to get over to that centerline, raise the control stick into the wind (which raises the aileron/spoiler and kills lift on that side - - keeping that wing from wanting to fly) and open the reversers.
Sounds rather busy, but after you do it one or two (hundred) times it becomes almost second nature. Still more of a challenge though than a 'calm' wind day.
Different planes have different characteristics.....
An interesting video to watch is the one on YouTube that shows the 777 crosswind landing flight testing. Type 'Crosswind landing testing' into the search and it should take you there.
DRW
Wind direction obviously impacts the work level on landing. Picture yourself trying to push a feather through a room and down onto a table......with a bit of wind, that task becomes a bit more challenging.
With a headwind, our relative speed over the ground is reduced, and our landing rollout will likewise be reduced.
With a tailwind, our speed over the ground is increased and our landing distance increased. We've got to analyze our landing weight (heavy/light?), runway condition (wet/dry/snow/ice?), runway length (construction?), and any other factors which will impact our ability to stop (reverser inop, etc.).
A strong crosswind (with gusts) is probably the most challenging. The aircraft is 'crabbed' into the wind to maintain a track down the extended centerline of the runway. The crab is maintained until just prior to touchdown, and the aircraft is aligned by the pilot with the runway centerline. This is accomplished by what what we call a 'wing down, top rudder' maneuver. As the aircraft is flared we lower the 'upwind' wing, and apply opposite rudder. If done correctly, this will bring the nose around to the centerline and keep the wings relatively level. The big challenge on all of that is touching down at the exact moment that both of the mains are perfectly aligned with the runway. If you are off at all....wheels not level, or not tracking down the centerline......you'll all feel it in the back. Picture yourself trying to pull into your garage with your nose not quite pointed where you want it, and your tires not pointed in that direction either.
On touchdown, we'll use the rudder to get over to that centerline, raise the control stick into the wind (which raises the aileron/spoiler and kills lift on that side - - keeping that wing from wanting to fly) and open the reversers.
Sounds rather busy, but after you do it one or two (hundred) times it becomes almost second nature. Still more of a challenge though than a 'calm' wind day.
Different planes have different characteristics.....
An interesting video to watch is the one on YouTube that shows the 777 crosswind landing flight testing. Type 'Crosswind landing testing' into the search and it should take you there.
DRW
Just wanted to add one thing... the icing/rain consideration is not only something we think of during tailwind landings but also crosswind landings since it is possible to be literally blown off the runway once the wheels are on the ground if they don't have enough traction. The tail (and fuselage too) acts like a big sail at that point.