Questions tagged [aircraft-design]

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

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22
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3answers
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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 ...
22
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1answer
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What airframe designer/manufacturer is credited with the first retractable landing gear system?

A quick follow-up to Why do planes always land on rear wheels instead of the nose wheels? What airframe designer/manufacturer is credited with the first retractable landing gear system? I ran past ...
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Why doesn't the 737 have a fuel dump nozzle?

I was watching a documentary on aircraft incidents which mentioned that the 737 does not have the facility to dump fuel. Instead they're required to fly in circles to burn off excess fuel in an ...
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3answers
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How many parts does the latest-generation 737 share with the original 737?

There is an old paradox which states that if a boat sails round the world replacing worn out parts as it goes, once it has replaced all of itself is it still the same boat? I choose the 737 because ...
22
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1answer
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What was enabling control to the pilot on the Snecma C-450 Coléoptère?

Looking at the Snecma C-450 Coléoptère, I was wondering about the (4?) fins towards its tail: Source: Wikipedia Were they able to pivot to help the pilot control the aircraft? If not, what else ...
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2answers
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Which are more efficient in putting out wildfires: planes or helicopters?

A lake is near where both helicopter and plane can access the water and fire. Which aircraft (if you had access to only one) is more efficient in putting out wildfires? Which aircraft is preferred to ...
21
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2answers
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Tail Wing Dented—Is it safe to fly?

I’m sitting in the lounge waiting to board this flight. Saw a dent in the attachment of tail wing to the body. Is this common? Also I could be wrong and it is part of the design of the airplane. Any ...
21
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8answers
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Why are there no blended-wing passenger airplanes in operation?

Blended wings are more beneficial when it comes to fuel efficiency increase and noise reduction. However, no manufacturer has decided to produce these airplanes for major airline operation so far. ...
21
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2answers
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How do pilots board the B-1B Lancer?

I've noticed that there isn't any type of hatch/plug door near the canopy of the B-1B Lancer. How do pilots enter and exit the aircraft?
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4answers
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How does a large cargo plane like the C-130 Hercules take off and land in such a short distance?

So I was at an air show and saw a C-130J Super Hercules showcasing its capabilities. The take-off distance it covered was amazingly short (I guess equal to fighter jets), even though it uses ...
21
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7answers
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Why do most single propellers have a clockwise rotation?

Why do most single propellers have a clockwise rotation (seen from the pilot's point of view)? There are though multi-engine planes that have each propeller rotating different directions, but in the ...
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2answers
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What are cowl flaps?

What are cowl flaps and what are they used for? It seems I have only heard of them in connection with old planes, are they peculiar to radial engines?
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Why is the Airbus A320 permitted to carry 180 passengers, instead of the maximum 179 allowed?

The EASA regulations give the following requirement for number of emergency exits: If then the Airbus A320 is certified to carry 180 passengers, it seems to me that it falls just outside the minimum ...
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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 ...
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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, ...
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3answers
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Why the lack of faster piston-powered planes?

There aren't very many fast piston airplanes in production. By "fast" I mean, if you look back in the early to mid 20th century, before turbines won out, there were lots of piston airplanes in ...
21
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1answer
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Why are cabin doors outlined with a different color than the fuselage?

On almost all airliners I have seen, the doors are painted inside a rectangle which appear to reflect more light. This is the case whether in the aircraft has its manufacturer's paint or an airline's ...
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1answer
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What is the 'arm' at the rear of the X-29?

In this image of the Grumman X-29, there is an 'arm' just above the exhaust nozzle leading forward and, apparently, attached to the right side of the fuselage. What is this and what is it for? Source:...
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3answers
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Do fighter jets have deicing in their wings?

If there is such thing as deicing for fighters? If so, is bleed air or electric heating preferred? I could not imagine that a $50MLN fighter jet would not be able to get the ice off its wings.
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5answers
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Why is the Mooney's signature tail profile different from most planes?

In another question, someone said everyone but Mooney has the vertical stabilizer on backward. (As a Cessna driver, this looks backwards to me). Is there an aerodynamic reason or some reason other ...
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1answer
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Why did some Caravelles have a very long dorsal fin?

(Source) Why did some Sud Aviation Caravelles have a very long dorsal fin stretching half the fuselage? Initially I thought it's to keep the fin low to fit in existing hangars as a selling point, ...
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8answers
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Double deck vs wide body airliner, why would anyone build a double deck one?

I don't understand why double deck aircraft (or multiple decks in general) are a good idea. They must be, because there is a significant amount of them. But given a cross area, which should roughly ...
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Why don't airliners use noise cancelling?

Some cars have started using noise cancelling in their cabins, through the speaker system. It's a well established technique for dealing with low frequency noise like engine rumble and wind noise. So ...
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Could a blown wing ever be powerful enough to lift an aircraft at zero forward velocity?

Theoretically, could an aircraft, using any manner of self generated air flow over the (fixed) wing, ever gain enough lift in order to take off (or just simply lift off the ground) at zero forward ...
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Is it common for jets not to have backup manual control system for emergencies?

In July 1989, the United Flight 232 crashed in Sioux City, Iowa, while the pilots were trying to land on the runway without any yoke control. Today, I was reading the PHAK and found this phrase: "In ...
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Do box-wings suffer from induced drag the same way as normal wings?

Most wings suffer from induced drag due to a pressure difference above and below the wing causing air to sneak around the tip, forming a vortex. There are various methods to minimize these effects, ...
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Why do blimps have fins?

Why do blimps have fins? Can't the two (or so) engines already control direction?
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Why are vertical stabilizers always at the rear of an airplane?

Sharks and whales have them in the middle of their body, so why not planes?
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Could I build an airship (rigid dirigible) that used a vacuum rather than lifting gas?

There are other questions (c.f. What gas is used in airships to give them buoyancy?) that discuss the use of lifting gasses such as Helium and Hydrogen in airships. Helium is rare and Hydrogen is ...
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2answers
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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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Are the current seat belts used in commercial airlines safe enough?

I find myself thinking often, if the seatbelts in airlines are designed just to keep the passengers in seat or to really act as a safety belt like in cars, because in cars which go at 300kmph speed, ...
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How is supercruise achieved?

Wikipedia article tells that supercruise is a condition when an aircraft can achieve velocities above Mach one without using the highly inefficient afterburners. But still, there are not a lot of ...
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Do planes have odometers?

I'm curious to know if planes have distance counters similar to the ones in cars indicating how many kilometres/miles the plane has flown since being put in service.
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Why are almost all STOL aircraft high-wing?

Isn't ground effect a big factor in STOL operations? Don't low wings produce greater ground effect than high wings? Or is it a practical concern, that most real-world STOL operations are in ...
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Would a roll cage plus a safety harness make a small GA aircraft accident more survivable?

It seems to me that race cars (like Formula 1 and NASCAR) and small GA aircraft (like a Cessna 172 or Piper Cherokee) travel at generally the same speeds, roughly between 70 and 200 mph. Yet, if an ...
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2answers
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Does the Predator drone's design make a tail strike more likely on takeoff and landing?

I was reading an article about drones and happened to glance at an included 3-view of the General Atomics Predator series UAV. The inverted-V tail appears to leave, at most, around 6" of clearance to ...
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What is a high speed stall?

I'm told that planes can actually stall when the airflow over the wing goes past Mach 1? Why does this happen and how do you design an aircraft to avoid it?
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What aircraft has the highest suggested landing speed?

Just out of vague curiosity, what aircraft has the highest recommended landing speed for an earth bound (atmospheric) craft? And, btw, when I say "landing" I define it as thus: Controlled Powered (...
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5answers
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What are the advantages of a Trimmable Horizontal Stabilizer?

What are the advantages of a Trimmable Horizontal Stabilizer (THS)? For example, a THS is used on some Airbus and Embraer aircraft. What is the most important advantage, and why don't some other ...
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1answer
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What is the purpose of the three cylinders under the engines of the Junkers 52?

They're mounted underneath each engines on the JU-52. I saw them up close at the museum. Each one consists of bundled half-inch pipes running through the whole length, open at both ends.
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Why aren't modern helicopters quieter?

Living closer to a Sikorsky factory, I can attest that modern civilian (and military) helicopters are quite noisy. In any case, they are considerably louder than light aircraft, turboprops, and even ...
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3answers
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Why is the trailing edge sweep angle smaller at the wing root?

Many airliners have a distinct unswept part at the wing root at the trailing edge. See for example this image from Wikimedia of a B737-400. Other examples include the B777, A320, Embrear 145, and ...
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1answer
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How does NOAA's P3 Orion safely navigate hurricanes?

I've been watching NOAA's P3 Orion fly though Hurricane Matthew a bit on Flight Radar 24. Looks a bit like this for the curious: source It's the only plane actually in Hurricane Matthew. What I'm ...
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Are commercial aircraft designed with a shared data network?

In modern airliners, do systems like the in-flight entertainment system (IFE) share the same physical and/or logical network as the flight management systems (FMS)? Is there any communication between ...
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Why do aircraft with turboprop engine have black painted anti-icing system?

Everyday as I watch aircraft with turboprop engines, a question pops up: Why do aircraft with turboprop engines have black painted anti-icing system? For instance:
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4answers
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Does the Air Force (United States) help design their own planes?

I know that companies such as Lockheed Martin and Boeing design and build planes for the US Air Force. However, when I was thinking about this, I realized the Air force has no part in designing the ...
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Why does Boeing use a trim wheel in the 737 and not their other products?

Why does Boeing use a trim wheel in the 737 and not any other products? Is the trimmed state for the 737 just more important than in the 777? Or even 747? It gives the impression that a secondary ...
19
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4answers
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Why don't modern fighter aircraft hide their engine exhaust?

In many photographs, the F-4's unique geometry hides one or both engines. I've been told that this is one of the terrific accidental features of the F-4, as it would help shield the hot exhaust from ...
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3answers
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Why is the Tu-144 the only commercial airplane with canard configuration?

I understand the delta wing was chosen because of the supersonic cruise (like the Concorde), and canards were added to reduce the approach/landing speed. But canards may be used without delta wing (e....
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2answers
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Why is the APU located in the tail for almost all commercial aircraft?

I know there are planes whose APU (Auxiliary Power Unit) is located elsewhere, but for the most common commercial jet aircraft (A320, B737, B747, A330,...), the APU is located in the tail. Is there a ...

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