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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0answers
78 views

Why don't I see this kind of split ailerons on aircraft?

Why don't I see split ailerons that work like spoilers going up and like normal ailerons going down? Isn't that a good way to get rid of adverse yaw?
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5answers
360 views

What is the principle behind flight of airplanes?

What is the principle behind flight of airplanes? Need a simple answer for grade 7 student. Thank you
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1answer
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Angle of Attack influence on Adverse Yaw

we are analyzing an aircraft's lateral-directional control characteristics with self-made code. We have observed that the aileron's influence on the body axis yaw moment is quite sensitive to the ...
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2answers
94 views

How are cabin pressure and oxygen level maintained inside the airplane? [duplicate]

How are cabin pressure and oxygen level maintained inside the airplane?
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What's this outlet on the wing of Eurofighter Typhoon EF2000 for? [duplicate]

I was seeing this image and saw this outlet. It's not the outlet of an APU, is it?
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1answer
111 views

What is the dihedral angle of the A380?

It is understood that the A380 has a sweepback angle of 33.5 degrees and a taper ratio is approximately 0.3. However, what is the dihedral angle of this aircraft?
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Why was the minimum turbulence intensity that commercial airliners have to withstand increased?

From 50 fps turbulence intensity at VC to 90-100 fps turbulence intensity at VC. The amended FAR design criteria was introduced in 1980 or 1981 for commercial airliners. What prompted this change?
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1answer
166 views

What trailing edge flap design does the A350 use? Is it similar to the A380?

Both Airbuses have similar flap deployment based on some YouTube videos I have watched, just wondering if they both have the same flap design being "Single-Slotted Fowler Flaps".
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What flap design does the A380 use? Is it Fowler flaps, slotted flaps or a combination?

I have looked at maintenance manuals, the Airbus website, and Wikipedia but still could not find a definite answer as to what trailing edge flaps the Airbus A380 uses.
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Why should Mach wave angle be less than wing sweep angle?

This is from my lecture notes: I see that this is so you can have subsonic flow over the wing planform, but why is this desirable? And are there more reasons? I can think of heat being an issue if ...
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2answers
120 views

Ground effect and Lift coefficient

Is there a correlation between the lift coefficient and the proximity between the wing and the ground? I know that the lift coefficient is dependent on angle of attack; However, based on experiments ...
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1answer
134 views

When the F 16 landing the flaperons are used for rolling due to the functionality as ailerons, but after touching the ground it is the same?

In landing gains the flaperons are down 20 degrees. If you have to do corrections of the bank angle on approach then you move upward only one of the flaperons. But after touching the runaway it is ...
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191 views

How can I make a serious wind tunnel?

I am looking for specifics of building and the operation of low speed wind tunnels, but most diy wind tunnels on internet are improved versions of science fair projects at best. What would I need to ...
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1answer
99 views

What causes air flow towards fuselage near the winglet?

I am trying to understand how winglets are beneficial in reducing induced drag and I came across this article; https://www.boldmethod.com/learn-to-fly/aerodynamics/how-winglets-work-to-reduce-drag-and-...
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2answers
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How can I calculate the tail area required to achieve longitudinal static stability?

I've got a longitudinal stability question. I've not attempted this question yet as I didn't know where to start from, also my lecturer hasn't explained static stability to us clearly and I needed a ...
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1answer
357 views

Are the emergency exits on a Boeing 747-400 plug doors?

Rossiya Airlines flight FV5625 to Antalya suffered an incident at the gate when a passenger opened an emergency exit (seems to be the L3 door, from what I can tell) "because they felt too hot&...
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3answers
111 views

Is the classical definition of induced drag merely a mathematical construct?

I understand that the presence of vortices at the wing tip cause part of wing to see a higher angle of attack and cause more drag. But the explanation that lift vector tilts backwards seems like a ...
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3answers
256 views

Can any helicopters use negative collective to descend rapidly?

On a helicopter, the collective is used to adjust the attack angle of all the main-rotor blades in the same direction by the same amount, causing the amount of lift generated to increase or decrease ...
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1answer
71 views

When, and how to calculate this, you can expect too much Wing Dihedral generates Dutch Roll, increases in Drag? [closed]

The question comes from the Arup designs, and the engineer who turned it into blueprints, Hoffmann, ('A Novel All Wing Airplane', Raoul J Hoffman, Popular Aviation, March 1935, pp 163 and 196), they ...
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1answer
113 views

Why is sweep angle measured at the 25% chord?

If you look at wing planforms of e.g. the Spitfire, you can see that the sweep measured at the 25% chord line is 0°. However, the leading edge is rounded/slightly swept and therefore induces spanwise ...
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0answers
62 views

Do high wings aircraft create an additional vortex in the middle?

At the same time, the air on the upper surface has a tendency to flow in toward the fuselage and off the trailing edge. This air current forms a similar vortex at the inboard portion of the trailing ...
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2answers
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Why does a Cessna 172 have dihedral wings if it has high wings?

"Dihedral goes hand in hand with low wing aircraft, and anhedral goes with high wing". This is what I assumed till now. But when I see a Cessna 172, the wings are a little dihedral. So why ...
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Why was the C-5 considered the largest plane possible?

We started to build the C-5 and wanted to build the biggest thing we could https://en.wikipedia.org/wiki/Lockheed_C-5_Galaxy The An-225 is 50% larger and has a shorter life. Did they mean the C-5 was ...
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How are Fan pressure of and Static pressure in the turbofan engine related?

If the fan air is ducted to the rear, the total fan pressure must be higher than the static gas pressure in the primary engine's exhaust, or air will not flow. By the same token, the static fan ...
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Matching the Drag Equation to Real Airplane Data

I am trying to compute airplane performance for a piston-driven airplane with constant speed prop using the standard equations for Lift, Thrust and Drag. I have found that there are a couple of useful ...
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How do engineers estimate the aerodynamic effects caused by jet engines or propellers in wind tunnels?

When aircraft models are tested in wind tunnels they don't seem to have engines or propellors on them. So how do engineers get correct parameters from the experiments? Do they just seal the air inlets ...
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1answer
100 views

Which types of aircraft need a gust lock? Is there a size / performance influence?

Which aircraft require gust locks on control surfaces? Is there a certain range in the middle in terms of size / performance where gust locks (external / internal) are required? From a cursory ...
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1answer
96 views

How critical is trailing edge geometry/sharpness on wing performance?

This question occurred to me when I was meshing an airfoil for CFD analysis having a sharp trailing edge. The upper and lower side smoothly converge having tangency at the end. After hours of ...
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How to calculate Longitudinal dynamic stability derivative for a wing? Mq and Mα

How to calculate Moment due to rate of change in pitch(Mq) and Moment due to rate of change in AOA(Mα) manually and How to extract from CFD software? Consider a fighter aircraft is in Case 1- Cruise ...
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2answers
190 views

What are the effects of placing the vertical stabilizer at the front of the aircraft? [duplicate]

I am experimenting with different aircraft designs. The one I am trying right now is a canard (horizontal stabilizer at the front) and the main wings are quite far back. I wondered if it would be of ...
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Does this Max Faget April 1, 1969 design for the Space Shuttle look familiar? Is it similarity to existing aircraft at the time?

This answer to Who are the actual lead designers of manned spacecraft? in Space Exploration SE says (in its entirety): Max Faget was involved in the design of every US manned spacecraft flown to date....
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How can I design a slotted flap?

I have not been able to find satisfactory methods on design of slotted flaps, or flaps in general. Most of the answers are about eyeballing or experience. Can you guide me on what could be good ...
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1answer
37 views

What is the relationship between aspect ratio and lift-dependent drag? [duplicate]

It has been a long held view that aspect ratio of the wing has a significant role to play in the lift-dependent drag. However, mixed opinions have been expressed on the importance of aspect ratio in ...
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1answer
414 views

Why are there large gaps in the spoilers of the Airbus A300?

The spoilers on the Airbus A300 have large gaps at the bottom: (A300-600R, modified from Wikimedia Commons, original picture by Tennen-Gas, CC BY-SA 3.0) I have never seen any other aircraft with ...
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1answer
173 views

Why do large civil airliners use cold rather than hot thrust reversers?

Is it because cold thrust reversers are best for turbofans and most civil airliners have turbofan engines?
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1answer
63 views

How do i find a supercritical airfoil for my preliminary design?

The following information is available but i don't exactly know where to get the information about SC Airfoils from. Do Airbus , Boeing use secret airfoil that they don't disclose? Cruise Speed = 240 ...
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Is Bell eVTOL Nexus the only tilt ducted rotor aircraft among the major aircraft manufatures' eVTOL?

I saw some of multicopters have ducted rotor structure but only Bell Nexus has ducted rotor among tilt rotor eVTOL aircraft. Is this just because It is really challenging to control during transition ...
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4answers
382 views

Would this mechanical apparatus be a new means of creating aerodynamic lift? [closed]

I recently came up with a conceptual idea for creating aerodynamic lift which would use an unconventional centrifugal impeller. I would like to know if this conceptual design of mine is something that ...
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2answers
195 views

What is the structural impact on the wing if no fuel is stored in the wings and just in the fuselage?

What is the structural impact on the wing if no fuel is stored in the wings and just in the fuselage and how to counter possible advantages/disadvantages? Has this topic already been researched?
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1answer
137 views

How could Airbus better tailor the A380 to the modern market? [closed]

I understand any company do things that give net profit. But, had not manufacturing newer engines that increase its Endurance and Range saved it from its decline? Airbus had designed the A380 to ...
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1answer
72 views

Can a normally poorly handling airframe with high moments of inertia actually have superior flight dynamics under autonomous control? [closed]

I’m not a pilot but know a thing or two about flight dynamics. As you know there are currently quite a few aircraft under development designed for low-and-slow and (eventually) autonomous flight. ...
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1answer
127 views

Would mid-air refueling for an air-to-space vehicle that flies like a plane be a viable advantage if the tech was available? [closed]

Let's take the style of an F-22 Raptor (awesome!), build the fuselage, wings, etc to handle runway takeoff horizontally and then vertically (if needed) up to orbital space flight to reach the ISS in ...
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1answer
162 views

Why does the Cessna 208 Amphibian have extra tail surfaces?

Mark Harkin, CC BY 2.0, via Wikimedia Commons I've seen extra tail surfaces that look like additional vertical stabilizers on the C208 Amphibian. Why is there a need for this? I can't imagine that ...
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1answer
103 views

Why does the Information Manual say “C172S - Flaps 10 (Preferred) for Normal Takeoff”, when the models before S-model do not have this note?

Do Flaps 10 really do anything performance-wise other than reducing ground roll and distance over a 50-foot obstacle? If not worried about clearing an obstacle, does a Flaps UP-normal takeoff make ...
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2answers
93 views

Why is a reciprocating engine air intake a reverse bell shape? [duplicate]

Why would this inlet for the induction system get wider as the air approaches the filter? What net effect does this have on intake pressure, and how would an inlet that starts wide and then narrows ...
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2answers
915 views

Would fitting a T-tail on the 737 Max make MCAS unnecessary?

This is pretty far out, so I just pose it as a question for notion or ideas, rather than conclusive answers. Considering the differences in flight characteristics between the Boeing 737 Max-8 and ...
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2answers
104 views

Airplane Parachute [duplicate]

I want to ask two questions. Why don't they have parachutes on a passenger airplane? Could it be possible to have a parachute designed for their airplane? Like a big parachute that can safe the ...
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3answers
208 views

How heavy are modern cantilever monoplane wings?

Aircraft need to reduce weight in order to reduce induced drag. The modern shallow cantilever beam wings carry a massive weight penalty, as most of the material is wasted inefficiency absorbing the ...

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