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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3
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2answers
124 views

Why do airfoils in an airplane's wings have different shape and size along its span?

Why wings of an airplane consist of different shape and size of airfoil. What will happen if the thickness of wing are same throughout the wing?
28
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3answers
8k views

Why is the most common hydraulic fluid so poisonous?

The usual hydraulic fluid, Skydrol, is poisonous. If it makes it to the air conditioning system, it causes fume events that may have adverse health effects up to and including at least one fatality. ...
2
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3answers
242 views

How to adjust the center of gravity of an aircraft if not level when being weighed?

how do you adjust the center of gravity when weighing an aircraft in not-leveled position using platform scales under the nose and the main gears, and dropping a plumb bob to mark the gears locations.
2
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1answer
57 views

What is the relationship between aspect ratio and divergence speed?

Why do longer wings with higher aspect ratios have lower divergence speeds?
3
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2answers
286 views

What is the length of the escape rope in the cockpit? specifically A330-300 (If possible)

I understand you could measure from height of the cockpit window, but is there any official dimensions stated anywhere such as FCOM or FCTM documents?
4
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1answer
235 views

Why were the F-35B lift fan doors changed after flight testing?

Why were the F-35's lift fan doors redesigned from those used during flight tests? The original design had two main doors which opened to each side, rather than the “car hood” style door used in ...
-2
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1answer
240 views

Do the F-16's leading edge flaps lock up at +2° when the aircraft as a whole is supersonic, or when the airflow over its wings is supersonic?

My question is: do the leading edge flaps lock upright when the aircraft as a whole is supersonic, or when airflow over wings of the aircraft is supersonic?
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5answers
450 views

What factors influence the maximum speed of an airship?

I'm interested in learning about the physics of airships; in particular, how you determine an airships maximum speed. For example, the Hindenburg topped out at about 80 mph. The ship itself weighed ...
3
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2answers
142 views

Why don't the noses have the same de-icing metal surface like that of the wing's leading edge, engines, tail, etc.?

For reference, let's take the A320. The nose is painted like the rest of the body. Image Source
13
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3answers
2k views

Why were the windows on the Concorde about the size of a hand?

I just saw a comparison between the 787 and Concorde windows. I could be wrong but it almost seems like a hand could cover the majority of the window.
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1answer
104 views

How did the Brazilian Civil Aviation Authority have MCAS on paper from Jan 2018?

how could they know but nobody else did? Did they buy the extra sensor or something?
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1answer
128 views

Is there a database of airfoils for a given Reynolds number?

I'm trying to design my ultralight airplane. I know the basics of aerodynamics and airplane design, however, my question is if there are any tools (online, software, database ) that suggest the best ...
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0answers
199 views

How efficient would it be to have a plane with the cockpit in the back?

Would it be efficient to have a passenger planes cockpit move to the back of the plane, rather than the front? What I have in mind is cameras on the fuselage and nosecone that connects to the cockpit ...
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2answers
111 views

A320 flap settings

Can anyone please explain about the 5 types of A320 flap settings - Up, Flap 1, Flap 2 and FULL. What do these mean? I've read that the A320 gives 2 outputs for the corresponding flap settings. What ...
3
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2answers
178 views

Why are winglets swept back and not front?

A winglet is defined by its airfoil shape, profile, sweep angle and height. In case of the sweep angle, why does it always mean that the winglet is swept back. What is the disadvantage of having a ...
2
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3answers
84 views

Technical factors to consider for retrofitting aerial refueling for commericial aircraft

What are the factor that need to be taken into account to retrofit and an airliner like an a330 or 777 or maybe even a business jet like a global 5000 to an aerial refuelable (receiving) aircraft. Is ...
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1answer
103 views

How to improve engine-out handling on a multi-engined aircraft?

Hypothetically, if I wanted to create a multi-engine airplane with the best single-engine handling characteristics/lowest Vmc, would moving the vertical stabilizer far back be beneficial (even if it ...
1
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1answer
215 views

Why can’t aircraft use GPS to generate the IAS, instead of using pitot tubes? [duplicate]

I’m mostly asking after reading about Aeroperu Flight 603, which was caused by a piece of tape blocking the sensor. Is there any other way to gather IAS or is this the best way to do it?
17
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7answers
3k views

How does increasing the size of a jet engine make it more fuel efficient?

The design trend is there: 8, 4, 3, 2 jet engines on powering the large cargo or passenger aircraft. Is it mostly to accommodate the larger, more efficient fans, or are there also benefits in the ...
0
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1answer
185 views

What are the correct fixes for the MAX's pitch control systems? [closed]

At this point, the ramifications of faulty data input from only one sensor into the MCAS system of the 737-MAX are well understood, having allegedly led to 346 deaths, losses of almost 10B USD for ...
3
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3answers
603 views

Why can't Centre of pressure and Centre of Gravity coincide?

I understand that normally CG is placed ahead of COP so that a tail down force can make the aircraft stable. But why can't the COP and CG be placed in the same position so that there needn't be a tail ...
4
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2answers
294 views

I analyzed 2 nearly identical flying wing in XFLR5, how come the one with the thinner tip chord has a higher cD?

I made two flying wings, one with half the wing tip chord as the root chord and one with the root and tip chord being equal. I then did VLM2 analysis on both at 7 m/s, and used the same airfoil on ...
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0answers
85 views

Supersonic propellers for supersonic aircraft? [duplicate]

A propeller is a spinning wing. Supersonic wings work. So, provided that the blades are made wide-chord and thin like supersonic wings are, with a supersonic airfoil, can they not power efficiently a ...
3
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0answers
92 views

What effect did the AWACS radar dome have on the stability of the 707?

The large disc shape of the AWACS radar dome, and its attachment pylons to the fuselage, above and behind the wings, seem to have the potential to actually improve the pitch and yaw stability of the ...
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2answers
158 views

Can planes go to space? [duplicate]

What are the reasons why planes can't go into space? https://thehumble.co.uk/aircraft-with-forward-swept-wings/
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1answer
109 views

How do I choose the correct params?

I am very new to airplane design. I am working on this project to design a flying wing glider (no propeller) that would glide in a circular pattern with a fixed radius of 250 m after being released at ...
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1answer
64 views

What parameters to focus on when constructing a wing for turning? [closed]

I want to construct a flying wing (glider) with the sole purpose of performing a helical turn (or a circular turn with no propulsion attached) with somewhat of a fixed radius. What should be the main ...
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0answers
42 views

How do I calculate the air pressure on the maximum bulge of the airfoil?

Picture 2: source. Consider I have an airplane and it wing, of course. The cross-section of the airfoil is as the picture 1. The leading edge and the wind direction are depicted there. The leading ...
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1answer
81 views

How to decide the wing span? [closed]

How would you decide the wing span for a delta wing glider? Also how would it relate to the main chord length?
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1answer
192 views

There is any technical reason for the new Airbus shades? [duplicate]

There is any technical reason for the new Airbus shades? Or they exists just because it is sexy?
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1answer
125 views

Is the Airbus approach more friendly (in case of incapacitated pilots) in terms of a passenger being able to fly the plane? [closed]

Is the Airbus approach technology more friendly to a new pilot or passenger than a Boeing haptic approach?
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2answers
213 views

Why do we use composite aluminium or titanium stacks in airplanes? [closed]

Why do we use composite aluminium or titanium stacks in airplanes? What are their machining conditions?
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0answers
96 views

Why is Roskam's aircraft design methodology divided into two classes?

In a book titled "Airplane Design" by Jan Roskam, why has he divided the complete design cycle in Class 1 and Class 2 methods, where Class 1 involves fewer calculations (data-based estimation) while ...
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1answer
115 views

Does the F-16's neutral stability also extend to the negative-G flight regime?

If an F-16 pilot pushes the stick forward hard enough to send the aircraft into negative-G flight, does the jet tend to accentuate the new flightpath, requiring the pilot to counter that, or not?
4
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2answers
246 views

If, one day, we have an electric airplane, will it be easier to control than a fuelled airplane?

Elon Musk said that Tesla will make battery which can last for million miles. So probably in the next few years there will be a (small) airplane powered by an electric motor rather than by fuel. If ...
4
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1answer
205 views

Is it coincidence that the B-2 and YB-49 flying wings have exactly the same wingspan?

Development of the Northrop Grumman B-2 Spirit began as far back as 1979; however, this was nearly thirty years after the last flight of Northrop's earlier flying wing the YB-49. There aren't many ...
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2answers
392 views

Is it possible to have a fully electric airliner?

Is it possible to have a fully electric airliner? How much room would have to be sacrificed for a power bank in these aircraft to allow similar range to the current models (e.g., A320, 737, etc.)? ...
6
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1answer
154 views

Why do UCAV/UAV designs mostly use lambda wings instead of pure delta wings?

Why do recent UCAV/UAV designs mostly use lambda wings (such as Taranis and Dassault nEUROn) instead of pure delta/diamond wings (such as X-47A Pegasus and Lockheed D-21)? As for stealth ...
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0answers
35 views

Where can I find data comparing coefficient of lift (and drag) curves for any airfoil with and without flaps deployed

I'm doing my masters thesis on a FISHBAC wing so I'm hoping to find coefficient of lift and drag curves for any airfoil with and without (any type of) flaps deployed (and preferably leading edge ...
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1answer
118 views

Can pressurized aircraft be flown without pressurizing

Are there any pressurized aircraft models which can also be flown without pressurizing the cabin? For example, if there were a short ferry flight, or a flight where the aircraft never got high enough ...
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0answers
37 views

MTOW Calculation with Roskam Wempty and MTOW corellation

I'm an aerospace engineer and as a semester project, I've been assigned to do a conceptual design of a wide-body passenger aircraft(320 PAX, 9500 NM, M=0.89). Our handbook uses Roskam's equation, ...
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0answers
107 views

Did the “feeler” ailerons of the B-52A-F make air-to-air refueling easier than with the B-52G/H?

The B-52G/H uses 8 spoilerons (so it has 8 burning and 8 turning on its wing) and a shortened vertical stabilizer. Spoilerons seem to be very effective for this design, further reducing the need for ...
2
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2answers
38 views

Change of Roll moment with change of wing position (z-direction)

If I compare two identical configurations, which only differ from each other in low wing and high wing position. We assume that the lift and drag remains constant. Will I get the same coefficients in ...
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2answers
83 views

Why do we need a negative derivative of the pitching moment? restoring moment should be enough?

I am wondering why I read everywhere, that for static stability (longitudinal) the slope of the lift coefficient has to be negative. Imagine a curve (cm= coefficient of moment , alpha = angle of ...
2
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2answers
172 views

How to calculate position of a canard?

does anybody know how one can calculate the position, shape and size of an aircraft with a canard? So the main goal of a canard configuration: increase lift + increase agility/maneuverability So at ...
5
votes
1answer
162 views

Why are some aircraft's life limited by both cycles and flight hours?

For instance the Pilatus PC-12 life is either 27,000 cycles or 30,000 flight hours, whichever comes first. I understand that the limit life in cycles is mainly due to fatigue in terms of ...
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0answers
97 views

Why don't commercial aircraft have variable sweep wings? [duplicate]

I was wondering why commercial aircraft don't have variable sweep wings just like the Bell X-5 did? By sweeping the wing further at high altitude it helps the aircraft move faster and also it helps ...
1
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1answer
70 views

Why does the moment coefficient for angle of attack = 0° not have to be negative?

I know for static stability reasons, the derivative of the moment coefficient of an aircraft has to be negative. What I do not understand, why the moment of coefficient (cm) at all is allowed to be ...
1
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1answer
56 views

What is the sense of the Aerodynamic Centre for Design Process?

This topic has been discussed already several times, but I do not really get it. I think this one is a quite nice explenation: enter link description here So I understand that the Aerodynamic Centre ...
6
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1answer
323 views

Why does the A330 sit nose-down on the ground?

The passenger versions of the A330 have a small but noticeable nose-down angle when sitting on the ground: (Image by contri at Flickr, via russavia at Wikimedia Commons.) In contrast, A330s built as ...

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