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Questions tagged [aircraft-structures]

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

0
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1answer
173 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? ...
7
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4answers
513 views

Why do cargo aircraft still have floors?

Even with dedicated cargo aircraft built as cargo aircraft (rather than converted from a passenger-carrying configuration), the cabin is virtually always still divided into an upper and a lower lobe (...
52
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8answers
22k views

Why are fuel tanks located in wings?

Passenger aircraft have fuel tanks in the wings. Why? What are the advantages and disadvantages of this location ? examples of disadvantages I would suspect: added weight increases the structural ...
7
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2answers
324 views

What is the aerodynamic purpose of an Acorn?

This is an IL-62. On the tail of the aircraft, there is a large cone, protruding out of the vertical and horizontal stabilizer which is called acorn. I am trying to figure out what is the aerodynamic ...
9
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2answers
1k views

What is the function of the leading edge strip?

I understand the function of every wing part labelled above except the leading edge strip,what is its use in a fabric wing and will the wing function normally without it,if removed?
2
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1answer
70 views

Accounting for torsional forces during wing load tests

According to this aviation.se question, wing load tests are done by placing weights on the wings (upside down). This unfortunately only tests the wings bending loads (for cantilever wings) and the ...
1
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1answer
112 views

Is the shear centre of a wing the same as its aerodynamic centre?

How can the shear centre of a wing be located and is it the same as the aerodynamic centre of a wing? Lastly, I know how the centre of pressure interacts with the aerodynamic centre but not the wing'...
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1answer
45 views

How can you relate structural forces to load factors and inertia force [closed]

Our professor in aircraft structures asked us to research how can you relate structural forces to load factors and inertia forces and i dont have a clue. Help
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3answers
233 views

Bed sheet as wing skin?

https://en.m.wikipedia.org/wiki/Aircraft_fabric_covering This article states several early aircrafts that successfully used cotton as wing skin including Wright flyer. "Colditz Cock" glider had its ...
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2answers
124 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 ...
-2
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2answers
845 views

Pilot seat - primary or secondary structure? [closed]

For design of pilot seat, would the seat be considered as primary or secondary structure?
3
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1answer
438 views

How does wing bending relief of an a340 compared to an a330 allow it to carry 30t more fuel in a center section of nearly identical wings?

From this question this reference in ymb1's answer states that the a340 and a330 have nearly identical wings. Because of bending relief from the weight of its outboard engines, the bending moment ...
6
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2answers
826 views

How does the fuselage handle the different loads?

I have been trying to find out how the loads experienced by a fuselage are transferred between structural members (bulkheads, formers, frame assemblies, skin, longerons, stringers). I understand that ...
2
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1answer
530 views

What is the structural significance of 'dimples' on the fuselage of a Boeing 747?

I recently watched the following video: In the video there is a mention that there are 'dimples' visible on the fuselage of a Boeing 747, when it is on the ground. It ...
5
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2answers
1k views

What material is used for the floor panels in the main cabin for Boeing 747-400?

Just conducting some research into materials used in construction for Boeing 747-400 and Douglas DC-3. I just found out that in a DC-3 the floor panels in the main cabin and companionway are of ...
4
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1answer
218 views

What's the name for the structure that helps stop the nose wheel in Boeing 747-400?

From my understanding the nose wheel of a Boeing 747 does not have brakes, and as such when it is retracted it is still spinning. However, there are two "plates" that make contact with the wheels and ...
1
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1answer
383 views

How to identify load paths? [closed]

How would you go on about identifying the load paths on an empennage structure, wing and fuselage (in a general sense)?
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1answer
230 views

How do you load test a wing rib?

When builders say they load tested a wing, most of the time what they are saying is that they load tested the wing spar(s) by turning the plane upside down and putting weights on the wing. This ...
5
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3answers
423 views

How can filling a tube with foam help prevent buckling?

How can filling the empennage (aluminium tube) with Styrofoam stiffen it to avoid buckling as seen in Whingding ultralight?
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2answers
171 views

Are aircraft wings airtight?

Is there any no air proof design for the wings? Or are some of the parts are equivalent to outside pressure and some have gauge pressures? Are some parts airtight and others not?
5
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1answer
338 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?
6
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1answer
850 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 ...
5
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6answers
6k views

What is the definition of load factor & 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 & moment balance analysis of an aircraft structure. The ...
4
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2answers
452 views

What is the effect of wingspan on wing stiffness?

In an article in aviationweek about flight testing the GE9X, this statement is made. To reduce aeroelastic interaction between the testbed and the big engine, GE has also stiffened the wing by ...
2
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1answer
368 views

Which FAA or EASA regulation does prevent a high wing to cross the passenger compartment?

I'm looking for reference subpart and eventually chapter in either FAA or EASA regulation where it is stated that for passenger aircraft with high wing passenger compartment can not be interrupted by ...
16
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2answers
3k 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?
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2answers
140 views

Is it possible for me to work at NASA or other research companies as aircraft mechanic? [closed]

I know NASA is huge but is it possible for me to work there or other companies similar to it? If possible, how? I currently work at an MRO as aircraft mechanic. My work is mainly on flight controls. ...
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0answers
44 views

Is TGA analysis required for composites used in low speed subsonic aircraft?

I need to analyse the temperature drop effects on glass-fiber reinforced polymer (GFRP) used in aircraft subjected to icing, how can it be done? Does thermogravimetric analysis (TGA) help or is it ...
9
votes
1answer
3k views

How do GFRP and CFRP compare?

I have seen that aircraft mostly use CFRP (carbon fiber reinforced polymer) in large composition. But in some places like the leading edge of the wing, fin, and radome, GFRP (glass-fiber reinforced ...
27
votes
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 ...
10
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3answers
2k views

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 ...
3
votes
2answers
708 views

Is it ever permissible to takeoff on an aircraft heavier than its MTOW?

I'm thinking in terms of the Concorde accident in 2000 having just read part of the report which states that they were in effect several tonnes heavier than they should of been factoring in the ...
1
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0answers
150 views

How many fuselage skin panels are there for the Challenger 605?

How many fuselage skin panels are there for the Bombardier Challenger 605 aircraft, and where are their relative positions? For example, would this be an accurate simple drawing of it?
3
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2answers
368 views

Would climbing onto fighters placed on display cause damage?

The question is about any more or less modern plane similar to Su-27 in its fuselage design. It's not uncommon to install retired planes as monuments. Here's one example in Eastern Europe (image from ...
4
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1answer
446 views

Is it viable to put an engine at the rear of the plane like in this photo?

I saw this image on a NASA page talking about hybrids and I was wondering if the back-engine placemente is actually viable and if it is why hasn't been done yet?
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1answer
2k views

Why is the wing bending so much in this video? [duplicate]

On a recent vlog, YouTuber CGP Grey mentioned how much the wing of the plane he was on bent. I understand that wings are designed to bend a little, but what actually causes so much deformation? ...
2
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1answer
702 views

Why does the aspect ratio of a wing become less important at supersonic speeds?

My understanding is that an increase in the aspect ratio (AR) of a supersonic wing won't increase the efficiency like it would for a subsonic wing. If the subsonic induced drag is: $C_{D_i} = (C_L^2)...
16
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1answer
224 views

Are helicopters reinforced asymmetrically?

Helicopters are under a constant torque due to the action-and-reaction forces caused by the rotation of the rotor(s). In the tail rotor and tandem rotors configuration, the airframe is experiencing ...
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1answer
2k views

What are the differences between types I, II, and III emergency doors? [duplicate]

What are the differences between types I, II, and III emergency doors?
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0answers
382 views

How much does a Boeing 737 wing bend/deflect in cruise conditions?

As a part of my ongoing research of a structural joint analysis of a Boeing 737, I have been looking for sources where I may be able to find the bending/deflection data during cruise conditions. I ...
8
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2answers
799 views

What is the name for the Mitsubishi A6M Zero's one-piece wing/fuselage?

The Wikipedia article on Mitsubishi A6M Zero fighter cites an article from Life magazine published on Nov 4, 1942: The Zero's fuselage and wings were constructed in one piece, unlike the American ...
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2answers
1k 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 ...
8
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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 ...
4
votes
1answer
231 views

How are further structural failures prevented if an aft pressure bulkhead fails?

In a modern airliner, if the aft pressure bulkhead experiences a structural failure, what design features are incorporated into the empennage to prevent the empennage from being overpressurized (i.e. ...
11
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5answers
8k 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 ...
3
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5answers
1k 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 ...
2
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2answers
253 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 ...
1
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1answer
91 views

Could the experience of inflatable structures in boats be applied to large aircraft design?

Inflatable structures in boats have proved extremely successful and versatile since they began to find widespread use in the 1930s. I'm aware that experiments have been made with inflatable wings - ...
2
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1answer
335 views

In which cases the lift distribution is not elliptical? (i.e. e≠1)

I understood that Oswald coefficient doesn't modify the induced drag (i.e. =1) if the lift distribution is elliptical. When is the lift distribution not elliptical? What are the physical or ideal ...
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0answers
56 views

How are the structural failures reported to pilot [duplicate]

For instance an engine separated from aircraft (though most unlikely 1E-13 probability) or wing got damaged, how is it reported to the pilot? Will it be reported as 'Engine Fail' or 'Left Wing Fail'?...