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Questions tagged [aircraft-design]

Questions about the different choices that aircraft designers (typically aerospace engineers) make in order to create an aircraft.

14
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5answers
4k views

Why are military and civil aircraft landing gear generally so different?

Why do military aircraft have a lower landing gear than civilian? I have in mind the difference between a Lockheed C-130 Hercules and a Boeing or Airbus. The first possibility that jumps to mind is ...
7
votes
3answers
6k views

Why Pitch Trim Up/Down & Roll Left/Right switches on yoke or control stick?

My understanding is Pitch Trim should hold current Pitch position, Roll Trim should hold roll position and Rudder Trim should hold Rudder position to relieve pilot of holding the yoke/stick or pedal ...
19
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3answers
3k views

How are Virgin Galactic's SpaceShipTwo's windows so large?

From Virgin Galactic on SpaceShipTwo: Windows in the passenger compartment will be 13 inches (33 centimeters) wide by 17 inches (43 centimeters) tall. IMO that's enormous for an airplane, ...
34
votes
5answers
54k views

Why do large aircraft have their engines mostly on the wings, while smaller ones tend to have them in the tail or the tip?

Large passenger planes almost always have their engines hanging from the wings, Fighters usually have them in the rear, and small Cessnas have them on the nose. What is the reason for these ...
9
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2answers
952 views

Does a quadcopter have flight modes beyond traditional aircraft?

Quadcopters, by virtue of software-piloting rather than human-piloting, are capable of new modes of flight. I've seen one in which the machine maintains altitude despite the loss of two rotors by ...
2
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2answers
2k views

Is it possible to prevent plane accidents due to fuel explosion?

We know that most of the plane accidents and deaths result from the explosion of fuel tanks in the planes, like when two planes collide, or when the plane falls on the ground. With the advent of ...
13
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2answers
2k views

How do “fundamentally unstable” aircraft deal with the risk of computer failure?

As technology becomes more advance airplanes are becoming less and less stable. In flight school I learned that it's dangerous to load a Cessna out of it's CG range, and now in college (for aerospace ...
22
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4answers
3k views

Do similar angles on a plane make it more stealthy?

I learned in my intro to engineering class at my college that 5th gen fighters (which are stealth aircraft) are designed with similar angles to evade radar. Why is this true? Also, does the angle ...
5
votes
3answers
1k views

What is a flying fuselage aircraft (FFA)?

I'm fond of ultralight flying and stumbled over the SF-1 Archon site. Specifications for more details. I found it very appealing as an ultralight and feel like flying it even though i don't have any ...
13
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3answers
11k views

What is differential braking?

How is differential braking different from regular braking? How do you accomplish differential braking and why would you need to use it?
17
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2answers
36k views

What is the difference between flaps and slats?

I have heard pilots talk about flaps and slats, seemingly interchangeably. Is there a difference between a flap and a slat or they are the same thing?
6
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1answer
241 views

Where can I find nice animations of flutter?

Where can I find nice flutter animations/videos (other than YouTube) to add to a presentation without violating Copyright regulations ? It can either be for wings as well as blade arrays. Are you ...
15
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1answer
63k views

What is the difference between OAT, RAT, TAT, and SAT?

When I first started flying jet aircraft, I found different instruments that measure temperature in different ways and it was quite confusing. What is the difference between Outside Air Temperature,...
16
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1answer
3k views

Why is there a difference between nosegear retraction directions?

I've noticed that on almost all aircraft (Boeing, Airbus etc.) the nose gear rotates forwards for retraction. However, on a some aircraft, in particular a few Russian models, the opposite is used: ...
9
votes
4answers
2k views

Where can I find detailed dimensions of an aircraft engine compressor blade?

I am currently working on the modeling of blade/casing interactions in aircraft engines. The work is carried out in partnership with a company, therefore, there is a limited amount of it that could be ...
24
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3answers
7k views

Why are the throttles of aircraft such as the Twin Otter placed on the overhead panel?

Some aircraft such as the DHC-6 Twin Otter, have their throttles on the overhead panel: Is there a reason that they are not on a center console between the pilot seats or mounted to the panel like on ...
48
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1answer
8k views

Why do DC-9 and MD-82 have engines that are slightly angled upwards?

As per subject, I see that the above mentioned aircraft and some others that have engines mounted on the rear of the fuselage, have the engine intakes tilted slightly upwards. Why has this solution ...
25
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4answers
33k views

Does temperature affect takeoff performance?

A few days ago, a Copa flight from Porto Alegre to Panama was delayed from noon until 12:30 AM. The company explained that the high temperature (about 40 degrees Celsius) would require a longer runway ...
17
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6answers
3k views

Do two of the same model of aircraft feel different to fly?

How does it feel when you change from an aircraft to another but of the same model? Sometimes when you change a car and drive another one of exactly the same model you do feel differences due to ...
16
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3answers
15k views

How long do airliner tires last? Can this be improved?

I imagine that the tires on commercial jets wear out pretty fast with all those squealing landings as the tire suddenly has to spin up from zero to the speed of landing. 2 questions: How many ...
40
votes
12answers
67k views

How can I tell apart an Airbus from a Boeing?

When looking at an airplane, what are the main external features I should look at if I want to determine if it is an Airbus or a Boeing (shape of the tail, fuselage, winglets, wings, etc.)? Same ...
67
votes
10answers
115k views

What happens when an airplane stalls and why do pilots practice it?

When a non-pilot hears the word stall, it brings to mind what happens when a car stalls - the engine quits. It seems like that would be a dangerous scenario in an airplane. From a non-pilot ...
23
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4answers
20k views

How do conventional and T-tails differ?

What design considerations go into the decision between conventional tails and T-tails? Functionally the horizontal stabilizer/stabilator are the same in both cases, providing negative lift, the ...
31
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4answers
21k views

How does the mounting location of a jet engine affect aircraft performance?

Different jet airplanes mount the engines in different ways. For example: Under the wing To the fuselage How does the engine location affect aircraft performance? Is one better than the other?
13
votes
6answers
18k views

Why are propeller airplanes still made?

Airplanes with propellers were invented a long time ago. After that, jet engines came into existence. My question is: why do we still have propeller engines? The reasons I can think of are: They are ...
9
votes
2answers
3k views

What is the benefit of spoilerons compared to ailerons?

Some airplanes like the B-52 or the MU-2 use spoilerons instead of ailerons to control roll. What is the benefit of ailerons vs spoilerons and vice versa?
11
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2answers
6k views

What are the risks involved when doing a classic zero-g maneuver?

I suspect most pilots have done it at least once: briefly experience zero g when flying a parabolic path. It's quite an experience (if your stomach can handle it). Question is: are there any risks ...
16
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2answers
4k views

Why is “heavy braking” recommended in an aircraft with carbon fiber brakes in order to prevent brake wear? That seems backwards!

I get that standard brakes and carbon fiber brakes are made out of two different materials, but some of the procedures are different between them. For instance, they recommend "heavy" braking on ...
10
votes
1answer
681 views

How exactly is the 51% rule applied for amateur-built aircraft?

I understand that for an amateur-built that you are required to build at least 51% of the aircraft yourself, but how can there be kits which appear practically completed, just some quick assembly jobs?...
12
votes
1answer
3k views

When Boeing designed the 737NG, what factors influenced the change in the flap system?

The early Boeing 737 models had wings with triple-slotted flaps that appeared to be derived from the 727. When the 737 was redesigned as the Next Generation series (dash 600 through 900), these flaps ...
31
votes
2answers
4k views

Did the Space Shuttle really wait until 50 feet above the ground before they put the gear down?

I saw a sign at the Smithsonian about the Space Shuttle where it said that their gear was not extended until 50 feet above the ground. I've searched and searched for something definitive that had the ...
19
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4answers
5k views

Are there any aircraft with a nose wheel braking system?

I'm pretty sure that there are no aircraft equipped with a brake on its nose wheel, however two of my colleagues think there might have been. Are there? Aircraft with retractable gear of course have ...
5
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2answers
870 views

Structural design software for airplanes [closed]

What are the main structural design software packages that are used by the most of the aircraft manufacturers. There are a number of software packages but which one is widely accepted and used for the ...
4
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2answers
1k views

Where are the first structural damages after maximum speed is passed? [closed]

What 2 parts of the airframe are the first to have structural failure after exceeding maximum speed? Sorry. I just thought there might be a part that usually failed first.
14
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3answers
3k views

What makes the ailerons on an aerobatic airplane different than the ailerons on a non-aerobatic airplane?

I often hear a spec of the "roll-rate" when talking about aerobatic airplanes and the term "fast ailerons." What exactly does that mean, and what makes the ailerons on an aerobatic airplane different ...
16
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3answers
9k views

What are design or functional differences between sticks and yokes?

I've been flying Cessna 172 & 182's my whole flying life up to this point. I know that Cirruses (Cirri?) have a "side yoke" and Diamonds, Citabrias and others have control sticks coming up ...
9
votes
2answers
582 views

Is it possible to “pimp up your aircraft” with an audio system?

Can aircraft be modified to have an enormous audio system, like the ones in cars? Has the FAA got any regulations on this (or maybe on in-cabin maximum noise volume?), would power be a limitation for ...
11
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5answers
6k views

Is constant air pressure maintained inside the fuselage?

I just heard it somewhere but I'm not sure about it. If it is, then why don't they build airtight fuselages?
29
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3answers
10k views

Why do some aircraft have multiple ailerons per wing?

In a recent flight on an Airbus A380 I noticed that its ailerons are split into three segments which move independently. What advantages does this design have? Do other aircraft have split ailerons (...
32
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3answers
4k views

What happens when an airplane gets struck by lightning?

I know that they certify airplanes for lightning strikes (at least some of them anyway), but does it cause any damage to the airplane or to the electronics? Are there any required inspections if an ...
16
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3answers
15k views

What dictates the aspect ratio of an aircraft's wing?

When designing an aircraft, there has to be a decision as to the aspect ratio of a wing. It's been said that having a higher aspect wing will reduce drag for the same wing area, however most of the ...
39
votes
9answers
60k views

What are the pros and cons of high-wing compared to low-wing design?

What are the advantages and disadvantages of a high-wing vs. low-wing aircraft design? When might one prefer one to the other? Is the answer the same for large and small aircraft?
30
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4answers
42k views

What materials are plane windows made of?

I've always wondered, what are those dual-layered (bonus: sometimes they have a little <2mm hole, why is it there?) windows commercial jets put next to their seats made of?
21
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5answers
4k views

Why the pitot tube is heated but the static port isn't?

In some light aircraft, like a Cessna 172, the pitot tube is heated but the exterior static port isn't. The usual reason I've heard is that static ports are much less susceptible to icing, but why is ...
9
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4answers
3k views

How to go about designing a custom airfoil?

I am familiar with the NACA 4-digit and 5-digit airfoil design system where airfoils, but I was wondering if anyone had some good reference material or software for designing a completely custom ...
26
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3answers
3k views

Is it safe to roll an airplane that isn't approved for it?

I have heard of pilots rolling airplanes that aren't approved for it (Cessna 172, Learjets, etc.), and other than the obvious legal issues, are there any mechanical or safety reasons to avoid it? ...
2
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2answers
655 views

Quadcopter Design [closed]

What would be the most optimal shape for a quadcopter design? I have tried the cross beam design, but the center joint, though epoxied, is extremely prone to shearing off on impact.
21
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5answers
7k views

How does an aircraft tailplane work?

How does an aircraft tailplane keep the aircraft stable, and prevent it from tipping over? Also, how does the lift generated by a tailplane compare to that generated by the wing?
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3answers
1k views

How common are conformal fuel tanks?

I know that the F-16 (F-16I and Block 50/52/60 models) have conformal fuel tanks standard now on top of the wing/fuselage area. The Silent Eagle model of the F-15E proposed by Boeing for South Korea, ...
9
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2answers
988 views

Why should isobars be aligned with the leading edge of the main wing for a transonic cruiser?

When designing an airplane meant to cruise at transonic speeds (or supersonic speeds), I heard that one should look at the isobars on the main wing in order to assess if the shape, sweep angle and ...