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Questions tagged [landing-gear]

The wheels of an airplane. Sometimes replaced by floats or skis.

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8
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3answers
776 views

Would adding a fairing to landing gear to spin the tires before landing yield enough benefits?

I was reading answers to this question: How long do airliner tires last? Can this be improved? and it seems to be reasonable to keep things simple and rethread tires instead of designing motors to ...
8
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2answers
653 views

How much drag do the gear doors create during retraction?

It's been said that if you retract the gear at a critical moment that performance will actually be worse than if you left the gear down. However, is this really true, and just how long is the ...
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9answers
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Can a commercial airline continue its flight if its landing gear fails to retract after take-off?

So after take-off, due to any reason, the landing gear does not re-tract, is there any standard procedure to be followed? Or can the airline continue with its flight? Also, I would like to know any ...
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5answers
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Has there ever been a seaplane with inflatable airbags rather than traditional pontoons?

Traditional pontoons are big and cause a lot of drag. It would be nice to retract them like normal landing gear but they are just too big. Has there ever been a seaplane with inflatable airbags ...
7
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1answer
13k views

How does the squat switch work?

This question came up after reading the following comments on the answer to this question: Raising the flaps right after touchdown. Good or bad? Philippe Leybaert Jan 20 at 23:00 The retractable ...
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1answer
3k views

How often is a tire replaced on a 777?

Given that it is long haul aircraft, and is most widely used by airlines in that capacity: How often do they replace the whole tire? How much does 1 tire cost the airline?
7
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2answers
4k views

What is the typical weight distribution ratio between nose gear and main gear?

On an airplane with tricycle gears, the main gear supports most of the weight and is therefore the strongest. The nose gear prevents the nose tipping down, since the center of gravity is forward of ...
7
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2answers
1k views

Should an emergency field landing be performed with landing gear down or up?

Suppose you are flying an aircraft with retractable gear and have to make an emergency landing on that big "flat" stretch of grass up ahead and have only one shot at it, what's better, do it with ...
6
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7answers
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Do some aircraft lower the landing gear mid-flight?

Are there situations in which a pilot could/has to lower the landing gear during flight for reasons not directly connected to landing? (i.e., not part of the landing checklist) Originally I thought I ...
6
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3answers
1k views

Nose gear failure in single prop aircraft: belly landing or nose landing?

Let's say we are flying a single prop airplane with tricycle format retractable gear, such as a Mooney Bravo or a Piper Comache. The nose gear fails mid-flight and is unable to be lowered. Is it safer ...
6
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4answers
2k views

Are taller landing gear bad for aircraft, particulary large airliners?

Buiding larger engines for larger aircraft as opposed to smaller but many engines has proved to result in more fuel efficiency. Having established one of the main drawbacks or impediments to building ...
6
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2answers
1k views

What are the states that the landing gear can be in?

What are the valid set of enumerated states for landing gear? My current working set is: DOWN DOWN & LOCKED STOWED STOWED & LOCKED INOPERATIVE CYCLING_UP CYCLING_DOWN Also, are there any ...
6
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2answers
811 views

Is wheel well overheat detection (not brake temperature sensor) necessary for commercial jet aircraft?

Some aircraft do have this detection system (many Boeing aircraft), some do not. Why? What's the main purpose of the wheel well temperature detection system, even though there are brake temperature ...
6
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3answers
656 views

Is it feasible to replace brakes on airplanes with electric motor/generator?

Would it be feasible to replace the brakes on airplanes with electric motor/generator drive systems? There are two problems I see with airplanes. When they land, the tires are not spinning to match ...
6
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1answer
2k views

How is a light plane's nose wheel straightened during retract?

Assuming a light aircraft has direct cable linkage to the rudders, during taking off in a very strong crosswind with the pilot correcting with hard rudder, what keeps the nose wheel from remaining off ...
6
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1answer
2k views

Runway landing with a front skid instead of wheel - how does steering happen? (Dreamchaser)

The Spaceflight Now article Sierra Nevada’s Dream Chaser performs critical glide test flight shows the Dreamchaser performing a runway landing using a front skid and two wheels. The skid extends ...
6
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1answer
267 views

Why does the A330 sit nose-down on the ground?

The passenger versions of the A330 have a small but noticeable nose-down angle when sitting on the ground: (Image by contri at Flickr, via russavia at Wikimedia Commons.) In contrast, A330s built as ...
6
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1answer
448 views

What is the material of snubber brakes?

What is the material of snubber brakes that is used for stopping the spin of the nose landing gear? KC-135, Boeing 747, 727 are the aircraft that I saw with these snubbers.
6
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2answers
307 views

How are the 747-400 rudder pedals and tillers connected to the nose wheel?

The Boeing 747-400 Before Taxi Procedure says (emphasis mine): [...] Flight controls .............................................. Check C [...] Hold the nose wheel tiller during ...
6
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1answer
819 views

Do the landing gear modules rotate?

I'm particularly thinking about larger aircraft with more than two sets of main landing gear. It's pretty obvious you would not want them to rotate while landing and take-off, but while taxiing ...
6
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1answer
769 views

What is the maximum weight on the main gear of a large aircraft at rotation and touchdown?

For a large aircraft like a B747 or A380, how much does the weight on the main gear increase when the nose gear is in the air? I mean, in these two cases: What is the maximum extra weight on the main ...
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4answers
1k views

What are the advantages and disadvantages of tail wheels that cause modern airplanes to not use them?

Photos' source: Cessna 140 and Cessna 150. According to Wikipedia here, the Cessna 150 is successor of Cessna 140. Both have two-seat capacity and a single engine. Why was the Cessna 150 changed to ...
5
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1answer
587 views

Why are there so many moving parts used in the landing gear?

This short clip of the landing gear on a Hawker 850XP being retracted seems extremely complex. I'm curious to know why there are so many moving parts but as a layman I'm struggling to make sense of ...
5
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2answers
2k views

Why is the MiG-23 landing gear nontraditional?

The MiG-23 has a very nontraditional landing gear setup. Why has it been designed the way it has as opposed to the more traditional method of a single compression strut that is raised into the ...
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2answers
454 views

What main landing gear actuator does the Boeing 777-300ER have?

I can't remember the name of this system was, but all I do know is that is a big actuator that only exists on the Boeing 777-300ER variant. It will pressurize the actuator according to the thrust ...
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2answers
501 views

Why are landing gear retraction mechanisms mostly based on the four bar system?

I would like to know about the principles of landing gear retraction system and I struggle to find clear information about it. It seems to be about a four bar systems in most cases. This seems more ...
5
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1answer
4k views

What defines a landing gear bogie?

(Wikipedia) A Boeing 737 main landing gear arrangement. What defines a landing gear bogie (truck)? In its airframe maintenance handbook, the FAA defines it as: When more than two wheels are ...
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2answers
823 views

What are the pros & cons of Autobrake?

What are the advantages/disadvantages of an autobrake system? In particular I am interested in the Fokker 100 system. Have any studies been done for the F100 autobrakes and the affects that this ...
5
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1answer
374 views

Why don’t aircraft use run-flat tyres?

Tyre failures on aircraft during takeoff are fairly common, and are usually (though not always) caused by flat or underinflated tyres (via the overdeflection and overheating experienced by tyres with ...
5
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1answer
717 views

What is the air temperature inside of a tire right after landing?

What is the maximum design air temperature inside of a tyre of an Airbus A380's and a Boeing 747-800's main gear fitted with brakes, before landing after a 10 hour flight and right after landing? Are ...
5
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1answer
1k views

How does the wheel speed sensor in a Boeing 777-300ER work?

I do have a maintenance manual that I found on Internet, but it doesn't have anything about the wheel speed transducer. Any pics along with the information would be helpful.
5
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1answer
374 views

Does the PA-44's squat switch disable the stall warning?

I've read the AFM and looked online about the gear system for the PA-44 Seminole and there is apparently a squat switch on the right main gear that disables the stall warning whilst on the ground. ...
5
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2answers
5k views

How can I calculate the force on the nose gear at landing?

How can I calculate the force applied on nose gear during landing as nose gear touches the runway little after the landing gear? I understand force calculations in this question but I think it applies ...
5
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1answer
409 views

On the new A320s when we do a brake check there is no need to call pressure 0 why?

Why do we have a give a pressure 0 call out when checking brakes while taxi on the old A320s but not in the newer A320s.?
5
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2answers
562 views

Do airliners use light alloy wheels, like cars do?

Do large and small airliners - up to jumbos like the Boeing 747 and Airbus A380 - use light alloy wheels in their landing gear to reduce weight? If not, why not? Are there reasons unrelated to ...
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2answers
532 views

Why don't nose landing gears have brakes?

Nose brakes can help the aircraft in braking and it can also help in reducing the travel on the runway length. So why don't we use brakes in the nose landing gear?
4
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2answers
3k views

How are forces on the landing gear reduced or compensated for at touchdown?

When an aircraft lands with the tires of the landing gear at rest, as soon as the the aircraft touches down, the landing gear experiences a large amount of wheel-spin up forces (because of the static ...
4
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2answers
1k views

What are the advantages and disadvantages of having a single castor wheel as compared to 2 wheels in an airship?

I am working on a project to create a mid-size airship having a payload of 25kg. I am in a bit of problem regarding choosing the appropriate landing gear design for it. Which design would be better, ...
4
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1answer
927 views

Why do some helicopters have wheels instead of skids?

I have noticed that Black Hawk helicopters have tires, but I have not seen one take off like a plane. When would a helicopter need to use a running take off or landing? When is it determined ...
4
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2answers
962 views

Are tracked landing gear systems still in use and development?

In the 1940's and 1950's, there were several tracked landing gear systems developed for the purpose of allowing landing on soft ground and/or using particularly heavy aircraft such as the B-36. Are ...
4
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1answer
3k views

What is the stress tolerance of landing gear of commercial aircraft?

Context: The landing skills of commercial airline pilots vary widely -- ranging from the ability to routinely make feather-touch landings and taxi and almost imperceptible deceleration on the one hand,...
4
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1answer
513 views

Do Airbus aircraft have an “off” position for their landing gear?

I know some Boeing aircraft feature an up, down, and "off" position for their landing gear lever. I know that some Boeing wide-body jets do not have a 3rd lever position, but still have an "automatic" ...
4
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1answer
323 views

Would shooting the tyres prevent a takeoff?

In the movie Fast & Furious 6, among other questionable parts of one scene, they try to prevent a very large aircraft from takeoff. As opposed to whatever they tried, how effective would it be in ...
4
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2answers
538 views

Why does the Grumman Bat feature inverted winglets?

I've been fiddling around with trying to make a blended wing body aircraft. While modelling, I heard from someone that the design reminded them of the Swift Killer Bee (now Grumman Bat). One distinct ...
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2answers
10k views

What is the height of the Boeing 747-8 landing gear?

I can never find any information about the height of the landing gear on any airliner(can you put it into feet and inches).And Is the height of the 747-8 landing gear around the same height as the 737 ...
4
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1answer
288 views

Do landing gear doors need repairs after a gear gravity deploy landing?

I know that landing gears can be deployed even without hydraulic power by letting them go down by gravity, as seen on this video: I was wondering: do the landing ...
4
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1answer
415 views

How does retracting the gear affect weight and balance?

In many of the POHs, in the W&B section it is indicated that there is a moment change due to gear retraction. For example : Moment change due to gear retraction +780 in-lbs. Two questions : If I ...
4
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2answers
844 views

Is there a formula for calculating the pivot point of an aircraft while turning on the ground?

I'm working on a program that requires a taxiing passenger aircraft (of any model) to perform a semi-accurate turn given a steering angle of the front landing gear. For this I need to calculate the ...
4
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1answer
155 views

Is the Dassault “ministop” related to the Dunlop Maxaret ABS?

Dassault fighters e.g. Ourargan and Mystere had Anti-lock devices called "Ministop" on main landing gear brakes. Anybody has a picture / drawing / detailed description ? Is the Ministop related to the ...
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2answers
2k views

Why complex landing gears are used instead of simple, reliable and light weight muscle wire or shape memory alloys?

Muscle wires actuators are really simple, have a high power density and are reliable. Landing gears on other hand are used only twice per flight while taking off and landing (if everything goes well ...