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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2
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0answers
51 views

How do jetliners age (major or notable checks and part replacements)?

As commercial airliners can be (and are) operated for many years (or even decades), I've started to ponder - how do they actually age? Or - in other words - what are major or notable maintenance-...
6
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1answer
427 views

Why don't smaller powered airplanes have better lift-to-drag ratios?

Many airliners have LDRs near 20, and it sounds like the electric Eviation Alice may have an LDR of 24 at 240 kts (https://simpleflying.com/eviation-alice-electric-aircraft/), but small planes ...
0
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1answer
120 views

Could in flight folding wing tips lead to a safer airliner design?

As a spin-off to the recent success of the Boeing 777x maiden flight, the effects of folding the wing tips in flight were considered. Folding them down in cruise, like the XB-70 should increase yaw ...
2
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0answers
85 views

Why not add more blades to a helicopter? [duplicate]

There's something that bothers me inherently, and just like the Hueys from Vietnam, 'only' having two blades. Doesn't seem enough, I mean, if despite your best planning, engineering -- whatever -- ...
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2answers
96 views

What's the difference between Stress and Strain? [closed]

There's a book for Engineers, entitled: 'Roark's Formulas for Stress and Strain', some describe it as 'High level Mathematics'. So what?
4
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1answer
138 views

What is the physical-based/theoretical reason why supersonic area ruling works?

Supersonic area ruling is used to reduce the drag rise that occurs as aircraft pass through the transonic regime. While it has been validated experimentally, what is the theoretical/physics-based ...
3
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2answers
128 views

How to correct CG on a not leveled aircraft?

I am tasked with weighing a fixed wing aircraft. the aircraft can not be leveled because the leveling points are damaged. therefor it is going to be weighed not leveled, an inclinometer will read a ...
3
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2answers
346 views

If Boeing used two sensors instead of one simultaneously, wouldn’t they be in the same position today?

this article states that the original version of MCAS was suppose to rely on two sensors, One sensor will detect a high angle of attack, therefore activating MCAS The other sensor will ...
1
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1answer
103 views

Is there a rule of thumb for aircraft design? [duplicate]

I'm wondering how to best scratch build an rc aircraft and what rough proportions the aircraft should be in. I'm aware of the fineness ratio that determines the width to length ratio of a cross ...
0
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1answer
143 views

Are electromechanical actuators used in aircraft other than the Boeing 787?

Are there any large (non-experimental) civil or military aircraft that use electromechanical actuators (EMA), other than the Boeing 787?
3
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1answer
159 views

Would a 2nd row of distributed props on a 2nd staggered wing of a biplane increase its efficiency?

Would a 2nd row of distributed props on the rearward wing of a biplane with 25% gap and 150% negative stagger increase the efficiency of a biplane ULTRALIGHT, 25MPH, Re 500K? ( rear wing is 25% lower ...
3
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2answers
112 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
240 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
53 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
239 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
227 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
230 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?
8
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5answers
429 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 ...
2
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2answers
135 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.
1
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1answer
103 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
96 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 ...
1
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0answers
195 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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0answers
62 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 ...
2
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2answers
168 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
83 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 ...
1
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1answer
101 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
209 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
181 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
541 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
271 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
84 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
154 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/
1
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1answer
107 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 ...
1
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1answer
61 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 ...
0
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0answers
40 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
78 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?
1
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1answer
181 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
123 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?
0
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2answers
211 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?
0
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0answers
92 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 ...
0
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1answer
113 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
240 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
204 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 ...
1
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2answers
383 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
139 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 ...
0
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0answers
34 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 ...