Questions tagged [aircraft-structures]

For structural engineering questions about airframes and the mechanical structures aboard aircraft

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6
votes
1answer
1k views

What is the average weight difference between composite and metal airliners?

Is there any rule of thumb for weight savings using composite materials. For example, is there an early model large airliner like the B747 or even B737 that later was modified with composite wings or ...
14
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3answers
18k views

How are engines mounted onto wings?

I've heard that the engines on a commercial air transports are typically mounted with 2 or 3 bolts. Is this true? If so, how big are these bolts and what are they made of? I'm optimizing a bolted ...
10
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3answers
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What is the purpose of a wing Yehudi? [duplicate]

Apart from covering the landing gear leg, the Yehudi also increases the wing root cord which allows the build height for the root to increase for the same wing relative thickness. This is useful as ...
16
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3answers
4k views

How come planes can endure more positive than negative g's? I.e. how come V-n diagrams are not symmetric?

In this question A380 reverse thrust on only half the engines some doubts were raised about the strength of structures in certain directions. Specifically, Peter Kämpf states: Aluminium and ...
5
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1answer
537 views

What physical tests are involved with verifying a wing spar is suitably constructed for a homebuilt aircraft, such as the piper cub kit from wicks?

During construction how is a spar tested to ensure it can adequately cope with bending and twisting forces of the completed structure, or is this performed after complete?
10
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3answers
3k views

Could winds of up to 150 km/h impact the structural loads on a Boeing 777?

From 15 October 2016, AI 173 from Delhi to San Francisco started flying over Pacific. Jet streams over Pacific helped Air India in reducing the flight time by 2 hours, despite increasing the travel ...
7
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3answers
3k views

Why are modern aircraft wings often pointed instead being more rectangular?

When viewed from the Z axis (above or below), why are modern aircraft wings often pointed as they get towards the wingtips instead of maintaining the same surface area for their entire length? This ...
3
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2answers
294 views

Is pilot alerted of any physical or structural failures?

Current crew alerting system messages, I believe, are displayed basing on the software detection of the failures basing on the sensor information. What kind of structural failures can occur to an ...
6
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7answers
12k views

What is the definition of load factor and how do you apply it?

I'm a little confused about the definition of the load factor, n, as the definitions I found seem to contradict its application in force and moment balance analysis of an aircraft structure. The ...
3
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5answers
2k views

Why don't aircraft (commercial and military) use reflective visor windshields?

Just like those used on an astronaut's helmet, these reflective visors can help in better visibility when facing the sun (or any bright light source). But the windshields of most aircraft (commercial ...
14
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1answer
2k views

What are the tube shaped structures on the back of the fuselage of this 737?

A previous question asked what the little metal plates between the horizontal and vertical stabilizer were (they are vortex generators), however I am much more interested in what the gray tube shaped ...
2
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2answers
401 views

How much lift does the wing attach fitting actually carry?

How do I calculate the lift force that the the bolt that join the wings to the fuselage of a strutted or braced airplane carry? I know in a cantilever airplane,the bolts have to carry all of the lift ...
27
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4answers
6k views

Why are empty pylons weighed down?

(airplane-pictures.net) Airbus A330 no engine option. Why are empty pylons weighed down? The plausible answer is to maintain the correct center of gravity. But why not just load ballast pallets in ...
20
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2answers
4k views

Why do T- tail airplanes have a shorter vertical stabilizer?

Airplanes with a T-tail design have a shorter vertical stabilizer than the conventional design , what is the reason?
9
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2answers
2k views

Are lockwires still preferred over self-locking nuts and other ways of bolted joints` safety?

I've watched some of the lockwiring videos and if I understood it right then there are two most widely used ways of ensuring that a bolted joint does not get loose: Lockwire Self-locking nuts ...
7
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1answer
3k views

How are folding wings managed?

There exist several aircraft - especially carrier-based ones - that have folding wings, to save space. How is this structure strong, taking into account the considerable amount of force on the hinge-...
6
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2answers
2k views

Can delamination be detected early?

When a composite structure is hit, the impact causes shockwaves which travel through the structure, and cause delamination. Delamination reduces the strength of the composite structure and may cause ...
13
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1answer
2k views

Are modern airliners still stressed-skin aircraft?

Can modern airliners still be seen as stressed-skin aircraft? i.e. is the skin, whether it be aluminium or composites, still an integral structural member of the airplane?
11
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5answers
10k views

Why do airliners have “pressure bulkheads”?

Image source: FAA What part of the fuselage aft of the bulkhead would leak pressure? Or is it just there to reduce stresses? How does a DC-9/MD-80/90 incorporate aft bulkheads when there's a ...
1
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1answer
676 views

Question about Eurofighter structure

I was researching for the Eurofighter and I came up with a picture of its structure. I have three questions about its parts. I can't understand the role and the usage of them. Can anyone help me? ...
1
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2answers
433 views

What is the function of interplane strut of a Biplane?

What kind of load does the interplane strut(s) carry,is it compression, tension or shear? In order words,what's their function and how do you calculate the force that the interplane strut carries?
0
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2answers
231 views

How can one calculate the maximum instantaneous bank angle a plane can do in a certain time? [duplicate]

I know that there is a limitation to do an instantaneous banking angle a plane can do. These limitations are due to the airplane (infrastructure - aerodynamics) and limitation on the pilot (due to his ...