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Questions tagged [landing-gear]

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

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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 ...
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 ...
8
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3answers
2k views

Why is the Constellation's nose gear so long?

The Lockheed Constellation has an enormously long nose gear, which causes the aircraft to slant appreciably backwards when sitting on the ground: L-049 (Image by Greg and Cindy at Flickr, modified ...
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1answer
99 views

Are hydraulic retractible landing gear possible

One of the impediments and drawbacks to extending landing gear in light of building larger engines are the larger space required for the taller gear. Would hydraulic retractable gear that works as a ...
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 ...
1
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1answer
65 views

What are the three sources that are relayed to the brakes and steering control unit of an A320?

There is the sentence: Electrical signals from the three sources are relayed to the brakes and steering control unit (BSCU) and are computed into the nose steering angle. The question: What are ...
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0answers
45 views

What purpose of the thermal relief valve in PA-44?

In landing gear part, As I know, the valve will open to relieve pressure as a result of temp and pressure changes as airplane climbs or descends, but I do not know What purpose of the thermal relief ...
31
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3answers
9k views

Why would one plane in this picture not have gear down yet?

This image (as posted in another question) is a YouTube video's thumbnail: I noticed that the lead twin (737?) has gear down, the 747 behind does not (appear to) have gear down, but the third plane ...
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3answers
213 views

Why Buy A C182/172 Instead Of An C180/170? [closed]

So a thought came to my mind which covers not only Cessna planes but all others. The Taildraggers need a little bit less runway becayse AOA on takeoff is good and that AOA eliminates the need of ...
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2answers
176 views

How does pulling back provide better steering during rollout for light GA planes?

I had requested clarification on an answer to the question, How do I keep a C172 straight on the centerline during landing/rollout? I did not comprehend how pulling back after touch down provides ...
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1answer
161 views

How to understand the kinematics principle behind landing gear retraction system (or 4 bars system)? [closed]

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 but I would like ...
3
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2answers
320 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?
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1answer
239 views

How can I find the communication with ATC following an aborted landing?

On February 7th, I was on a UA 4694 from DEN to SAF, upon approach the landing was aborted; upon second approach, we heard the landing gear come down, which we did not hear on the first approach; the ...
3
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1answer
159 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 ...
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4answers
412 views

Wheel or skid? Which advantages does each one have when used as the landing gear system compared to the other one?

I would like to discuss this topic in depth, as I have not found a clear answer yet. Which are the advantages of using skids instead of wheels (or viceversa) for the following considerations?: -As ...
3
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1answer
284 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 ...
3
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1answer
177 views

Do airplanes have sensors to detect landing gear fires?

Given that retracting a landing gear that happens to be on fire is a suicidally bad idea, for reasons that should be immediately obvious, do airplanes have temperature sensors on their landing gear in ...
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0answers
64 views

Landing gear sequence [duplicate]

{With reference to this video} Is there any particular reason that land gear retract half way then 2nd gear retract half way and then proceed to retract completely. Is it related to center of ...
2
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1answer
74 views

What are the potential threats of having the landing gear dirt from mud in a rectractable landing gear airplane?

Recently I have been flying an aircraft with the landing gear very dirt with mud due to the parking area of the airfield on grass and the meteo conditions in recent days. I wonder what are the threats ...
3
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4answers
233 views

How can drag induced by the landing gear be reduced?

What are some of the methods used to reduce the drag caused by the landing gear for aircraft with non-retractable landing gear?
4
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1answer
169 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. ...
40
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4answers
9k views

Do military bases still employ wheel watchers?

When I was in the air wing in the '70s, I had the unpleasant opportunity of pulling wheel watch. The unfortunate individual sat in a small shack (maybe 3 x 6 ft.) with a pair of high-powered ...
1
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1answer
330 views

What is the purpose for two nitrogen charged chambers in an oleo strut?

What is the purpose of a twin nitrogen charged chambers oleo, such as the one illustrated below? Why is it used and what are the advantages compared to a conventional mono-nitrogen chamber? Training ...
6
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1answer
961 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?
2
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3answers
314 views

Are all tires on an aircraft replaced at the same time?

On cars, it is often to replace all four tires at the same time. Is this true also for aircraft? I imagine the nose gear and main gear probably can be replaced at different intervals. However, are ...
15
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1answer
2k views

Are there any aircraft with powered landing gear?

My student asked me a question this morning. It was: A car drives by turning its wheels against the Earth. An airplane taxis by rolling on its wheels while the engines push against the air. Are ...
0
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1answer
194 views

How to determine the maximum servo torque required for a nose gear?

It's pretty much it. I know how to calculate the friction force on the nose gear for a three-point landing condition using the method set forth in ...
9
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1answer
2k views

What did the “gear warning horn” on the North American P-51 sound like?

I'm working on a sound project for a P51 simulation and I'm having real trouble trying to find a reference on how the P51 gear warning horn sounded like. What mechanisms were used in the '40s to make ...
6
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1answer
1k 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 ...
8
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2answers
340 views

Has there ever been an uncommanded lowering of landing gear?

Has there ever been an uncommanded lowering of the landing gear on a large commercial jet? I could not find any instance of it in a preliminary google search. Could a simple short-circuit cause such a ...
3
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3answers
329 views

Could a plane land on specialized vehicles if its landing gear failed?

This (fake) video has stirred up a lot of questions online about whether such a scenario would be possible in reality - and the answer to those questions appears to be a resounding "No, that's very ...
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1answer
269 views

Is it possible to remove an A320's main gear using one main jack and one nose jack?

I have only one set of jacks (nose-main LH and RH) and I need to swap the main landing gear from one aircraft to another. I don't have a dummy landing gear. Is this possible?
4
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1answer
395 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" ...
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2answers
358 views

How much more economical are planes with retractable gears vs. those with fixed gears?

Many small planes have fixed gears, some have retractable gears. All things being equal, the plane with retractable gears would have to be more expensive than fixed gears, as the mechanisms involved ...
2
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2answers
381 views

What are ways to reduce drag and noise generated by the landing gear?

Apart from using fairings, what ways are there, or have been studied, but not necessarily implemented in reducing drag and noise produced by the landing gear, mainly for commercial aircraft with ...
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1answer
10k views

How is tire rubber removed from the runway?

Every time an aircraft touches down, the tires are spun up rapidly. As a result, some rubber is left at the touchdown zone. (image source) As time goes on, more rubber is accumulated at the ...
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5answers
6k views

Why do landing gears smoke upon impact?

I have been observing several aircraft landings and have noticed that when the aircraft's landing gear touches down, it precipitates the rising of a cloud of smoke. Why is this? (Source: airliners....
3
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1answer
338 views

Are nose wheel tyres designed differently from the main wheel tyres?

For the heavy large Jumbos like the Airbus A380 and the Boeing 747-800, considering nosewheel tyres are not subjected to the excessive heating caused by braking from the disks and brake pads, and ...
4
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1answer
361 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 ...
11
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2answers
2k views

Do aircraft tyres have inner tubes?

Do aircraft tyres have inner tubes? Modern small single-engine turboprops to the largest Jumbos. If not, did they ever have inner tubes? And if so, why were they discontinued?
6
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1answer
515 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 ...
9
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1answer
762 views

What is the purpose of the small wheel at the end of the F-14’s launch bar?

At the end of the launch bar (catapult strop link) on the F-14 airplane, there is a small wheel. Does anyone know what this is used for?
6
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0answers
621 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 ...
8
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1answer
610 views

Does the 747-8 / A380 nose-wheel encounter more weight during braking?

Given that the nose wheels of both the Boeing 747-8 and Airbus A380, as is true for almost all aircraft, are not equipped with brakes, do they encounter more weight during braking? If so, how much ...
5
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1answer
298 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.?
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0answers
360 views

Why do we have to do an alternate brake check during preliminary cockpit preparation?

As part of the preliminary cockpit preparation in my company’s older A320s we have to perform an alternate brake system check but not in the newer ones as per FCOM Normal procedures as below. I found ...
10
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1answer
2k views

How is Spitfire landing gear powered?

I have seen a WW2 movie where the pilot of the Supermarine Spitfire has difficulties to extend the landing gear as the engine is no longer running. This would be reasonable if the gear normally needs ...
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0answers
149 views

How long does the gear extension/retraction takes on the ATR-42?

Which is typical time of landing gear extension in normal conditions ? I would like to know it especially for the ATR-42 but any other typical value is welcome ! Furthermore can you provide any link ...
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2answers
625 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 ...
3
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1answer
716 views

Who manufactures the landing gear on the Airbus A350 series aircraft?

Where are they made? I assume that they are made out of titanium. Right?