Questions tagged [aircraft-design]

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

Filter by
Sorted by
Tagged with
98
votes
9answers
18k views

Is there a maximum possible size for an airplane?

Is there any theoretical or practical limit to the maximum number of passengers - and therefore size - one can build an airplane for?
94
votes
14answers
41k views

Why are the cockpit controls of airplanes so complicated?

For a layman like myself, the cockpit of every single modern airplane that I've laid my eyes on seems like a complex, intimidating mess with knobs, buttons, screens and levers literally covering every ...
80
votes
18answers
160k views

Why haven't quadcopters been scaled up yet?

Why are quadcopters not flown by human pilots yet? Wouldn't they be more stable and easier to control than helicopters?
70
votes
10answers
29k views

Why are there no “sleeper” planes?

On a recent long-haul flight I sat by the windows and was dreaming away staring into infinity out of the window. Then a thought came up, in Asia sleeping busses are very common. This made me think, ...
70
votes
4answers
17k views

Why do all commercial aircraft have carpets?

When flying I noticed that all the commercial aircraft I have been on use carpets as a floor covering. But why? If you fly in an older aircraft it looks worn out and it is susceptible to stains etc. ...
70
votes
10answers
131k 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 ...
68
votes
2answers
25k views

Why are aircraft tires not pre-spun prior to landing to preserve them?

Why has someone not designed a landing wheel with a fin or fins on it so that the air will start the wheels turning before the wheels touch the ground? Wouldn't that preserve the tires longer from ...
66
votes
14answers
17k views

Has there ever been a plane not controlled from the nose?

Has there ever been an airplane where the pilot, or cockpit were not located near the nose of the airplane?
66
votes
5answers
30k views

What determines the maximum altitude a plane can reach?

What factors determine the maximum altitude for a plane? Is it limited by wing design, engine thrust, and so on? Is there a formula by which one can calculate the maximum altitude a plane can reach?
66
votes
4answers
27k views

Why are Russian cockpit panels painted in turquoise?

Almost all cockpit panels of Russian aircraft types are painted in turquoise, whereas elsewhere the cockpit panels usually exhibit a dark grey color. As this "rule" seems to be quite prevalent, I am ...
64
votes
3answers
12k views

Do any airplanes really have this piece Tom Cruise is hanging onto in this movie?

The piece Tom Cruise is holding onto on this moving plane seems useless as a component, maybe even inductive of drag. Is this a real airplane component, or just a film prop? I don't know the model of ...
64
votes
3answers
53k views

What is the purpose of the sharp pods under airliner wings?

What are the pods with the sharp trailing edges underneath the wings of large airliners, as shown in the image below? My best guess would be fuel tanks
63
votes
8answers
24k views

Why are military drones shaped so strangely?

Military drones, such as the Predator drone or the Global Hawk, tend to have a weird shape with a whale-like head, and engines concentrated at the back. The wings tend to be of very high aspect ratio, ...
62
votes
3answers
20k views

How are brakes cooled on heavy aircraft?

As kinetic energy is not stored or recycled, large quantities of heat have to be evacuated in a short period of time when aircraft abort their takeoff or land: B777 brake test, Youtube Which ...
62
votes
1answer
25k views

What are the advantages of a Spinning Wing (Magnus Effect) and why haven't any been commercially produced?

What were the advantages and why was it never produced?
58
votes
2answers
15k views

Why do airplanes have rounded windows?

Why are the windows of an airplane usually rounded at the edges?
58
votes
2answers
5k views

Are the instrument panels in the cockpit spill / waterproof?

There are multiple switches and buttons in the cockpit, with different shapes and layouts. Are they spill proof? What if the pilot spills water or coffee on them, will they still function?
57
votes
10answers
18k views

Why is there really only one basic design for passenger airplanes?

So when I look around on the airport, I don't really see many differently shaped airplanes. They all look pretty much the same, only subtle differences. Image: Aircraft Recognition Why is this ...
57
votes
4answers
27k views

Why can't jet engines operate with supersonic air and how do they slow it down?

Typically jets cannot operate when intake airflow is supersonic relative to the engine. Why is this so? Also, why are scramjets able to use supersonic air? To slow down the air to subsonic speeds, ...
57
votes
3answers
21k views

What are these things hanging off the trailing edge of the wing?

What are these things hanging off the trailing edge of the wing? I've seen them in almost all of the aircraft I've flown in, and can't remember if they're exclusively Boeing or Airbus.
56
votes
8answers
14k views

Even after years of research, why are planes unable to keep passengers alive in case of a fiery crash?

Aviation dates back to the 18th century, and since then tremendous research has been put into making aircraft safer and more efficient. Though these efforts have resulted in better aircraft, why are ...
55
votes
9answers
37k views

Why not mount airliner jet engines above the wings?

It seems that most airliners put the engines below the wings, i.e. the Boeing 7*7 series and the Airbus A3** series. This requires long (heavy) landing gear, and the engines are close to the ground ...
55
votes
2answers
14k views

Why does the F-117 Nighthawk look different than other stealth planes?

The F-117 Nighthawk has flat angled lines where most later designs (B2, F22, F35) have very smooth lines. Why the difference? Are the newer designs 'more stealth'? Do they use a different design to ...
53
votes
8answers
26k 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 ...
53
votes
7answers
23k views

How does the Space Shuttle slow down during re-entry, descent, and landing?

Yesterday, my little brother asked me to help him build his new Space Shuttle Lego set. When we finally finished building it, he started to play with his new toy and asked me to be the "Mission ...
52
votes
3answers
26k views

Can the Airbus A380 safely fly with two engines out on the same wing?

I know twin-engine jets can safely take off and fly with one engine out (i.e. all thrust only on one side). Of course quad-engine jets are also able to fly safely in case one engine is out. But is ...
51
votes
9answers
21k views

Why don't aircraft use nuclear propulsion?

Nuclear propulsion research for aircraft was abandoned during the 50's. Why wasn't it revived ever?
51
votes
12answers
28k views

Why is the nose of the Mig-21 shaped so differently compared to other fighter aircraft?

If you look at this picture below, you will notice that the nose portion of the Mig-21 has a unique conical shape which is completely different from the nose of the F-16. (Source) (Source) So what ...
51
votes
3answers
34k views

What's the advantage of the F4U Corsair's gull wing design?

What is the advantage of the F4U Corsair's gull wing design? Is there also a disadvantage to this? The wing design just seems odd, and as far as I know it is one of the only planes to use this design....
51
votes
3answers
15k views

Could a Dyson fan scale up to be used as a bladeless aircraft engine?

Dyson has been making bladeless fans for a few years now that accelerate a consistent stream of air without exposed blades. If this concept were applied to aircraft engines, it could potentially ...
50
votes
3answers
15k views

Why does this 757 have a propeller engine attached to the fuselage?

I saw the following photo of a Honeywell Aviation Services Boeing 757-225: If it's not a fake, the airplane has a propeller mounted on a pylon on one side. What's the purpose of such strange design? ...
50
votes
1answer
9k 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 ...
48
votes
4answers
15k views

Why are the F/A-18 rudders deflected in opposing directions during takeoff?

Looking at some videos and photos of F/A-18 Hornets and Super Hornets taking off from carriers and from airfields, I recognised that the left rudder is pointing right, and the right rudder pointing ...
48
votes
5answers
23k views

Why are fighter pilots seated and not reclined?

I have always wondered about this one. Pulling high G-forces is, I assume, the most physical challenge the pilot of a high performance fighter aircraft needs to be able to sustain without blacking ...
48
votes
3answers
11k views

What are those things at the wing tip of an aerobatic aircraft?

See: The radially placed needle-like things that resemble a snowflake in the first picture. The triangular structure in the second picture. In the third picture, the object placed on only one wing In ...
47
votes
2answers
22k views

What are these wavy lines on fighters' canopy?

As shown in the images below, what are these wavy lines on the canopy of the aircraft? Do these lines have any utility? These are mostly captured in videos of cockpit views of carrier-based aircraft.
47
votes
3answers
36k views

Why are the Boeing 737 nacelles odd shaped?

Why is a Boeing 737 NG engine not completely round in shape? It seems to be flat at the bottom and round at the top and sides. Earlier Boeing 737 versions (100 and 200) seem to have a more rounded ...
46
votes
11answers
81k views

Why are push-propellers so rare, yet they are still around?

Jet engines are by their very nature push-engines, however, most propeller airplanes use pull-engines. Is there an inherent advantage to using pull-propellers except for the increased airflow over the ...
46
votes
6answers
8k views

How can this aircraft be stable/manoeuvrable?

The new wave of electric VTOL aircraft concepts (Joby Aviation, Zee, Lilium, Airbus A$^3$, etc...) has produced some audacious unconventional designs. Now my question is how Lilium's concept can be ...
46
votes
4answers
8k views

Why are many jet aircraft designed to cruise around FL350-370?

If the flight distance permits, the B737-800 will cruise at FL350, the A320 a little bit higher... Flying at FL370. Photo: Live from the Flight Deck by GolfCharlie232 (reframed) Elements such as: ...
46
votes
5answers
13k views

Why aren't airliner windows aligned with their seats?

On a recent airline flight, I noticed that the spacing of the plane's windows was different from that of the passenger seats: some of the rows had a window directly in line with them but for others, ...
46
votes
3answers
4k views

What is the offset in a seaplane's hull?

I noticed there is a little offset in a seaplane's hull (highlighted in the following picture). I suppose this is useful as it exists in all the seaplanes I know. It appears to be neither a ...
45
votes
5answers
19k views

Why do aircraft have an unusable amount of fuel?

I learned from this question that a Cessna 152 holds 5.6 litres of fuel that it can't use. Why would it be designed to hold fuel that it cannot burn, especially since water contamination of fuel is ...
45
votes
3answers
17k views

Why is the Tu-95 so efficient despite having propellers that spin faster than the speed of sound?

I've ready many, many times that propellers are not efficient near the speed of sound because it's so hard to get a tip-speed above Mach 1. Then I came across this: It's the Tu-95 "Bear", a ...
44
votes
13answers
76k 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 ...
43
votes
3answers
44k views

What are the spiral marks in the center of the engines?

When I get a chance to peek inside an engine, I noticed that many have spiral marks painted in the center. What is the purpose of these? Pictures:
43
votes
3answers
18k views

Why did most airliners have black noses in the 60's and 70's?

Here are a couple of examples:
43
votes
2answers
24k views

What is this flange on the engine?

Flying home from the Denver ComiCon, on a 737, I saw an angled flange on the engine. Could you describe its purpose? Photos by CGCampbell licensed CC0
41
votes
10answers
15k views

What stops planes from being stolen?

Related question: do planes have keys? Let's say I happen to spot a fine-looking plane at my local airport and decide the owner probably wouldn't mind if I borrowed her for a little while - what ...
41
votes
4answers
9k views

Why do flight control cables not slacken during the cold temperatures at cruise?

Image source Flight controls in airliners have long cable lengths in between the cockpit controls and the control surfaces. For instance in the picture above: the pilot operates the yoke, which ...