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Questions tagged [aircraft-design]

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

52
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8answers
21k 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 ...
0
votes
4answers
161 views

How does scaling of UAV size impact range?

Lets say you have two autonomous small aircraft, one with a wingspan of 200 cm and one with 400 cm. Both have the same general design. They are both optimized for travel distance on one full tank (gas ...
0
votes
0answers
39 views

How to determine the bulge of an airfoil?

In calculation or designing, how to determine the airfoil bulge (thickness)? What is the guideline or consideration in designing airplane's wing? We all know that the bulge (the ticker in the airfoil) ...
0
votes
1answer
133 views

What is the exact purpose of the string attached between front fuselage & the tail section of the transport aircraft's? [duplicate]

]2 228]3]3 Usually I got to notice a string attached between front fuselage to rear tail section of the transport aircraft's, what exactly might be the purpose or function of it? But comparatively, I ...
1
vote
1answer
192 views

Why is the nose cone of Russian fighters pointing slightly down? [duplicate]

Let's take SU-30 as an example: The nose cone is clearly pointing a bit downwards with respect to the level of the engines and wings. Why is this? How can this kind of a banana even fly properly? ...
-2
votes
1answer
151 views

What is the best aircraft engine to be used on small aircraft? [closed]

I intend to build small aircraft as I explained here. But I am quite confuse to chose the BEST engine to be used. My requirement is range from 60HP to 100HP. BEST in here is considering the price, the ...
0
votes
1answer
198 views

Why does Germany is not so advance in aircraft development? [closed]

I tried to see what countries are the most advance in developing aircraft. I found that Germany is not so advanced (CMMIW). Indeed, there is Dornier there beside has share in AirBus. I don't know ...
-2
votes
1answer
208 views

Would it be possible to put V-22 Osprey engine/props on a PBY Catalina Flying Boat

The larger props of the Osprey may have greater efficiency over smaller props. The high wing of the Catalina seems to have enough room for larger props. The original PBY had a range of over 2000 ...
1
vote
1answer
130 views

What is the cooling air exhaust velocity for the piston engine of a propeller driven aircraft?

Piston engines of propeller driven aircrafts need to be cooled. There are engine cowlings which accomodate the inflow of air to "wash" over the engines within them and which is then exhausted out into ...
1
vote
4answers
265 views

What is the best design to stack wings of a triplane?

I would like to design an ultralight airplane, which probably the total mass will be around 400kg. The speed should not exceed 200km/h. Forget about what the engine I will use. I intend it can land ...
0
votes
5answers
261 views

Which one is required more power between helicopter and airplane?

For the given same mass (say it 400kgs), which one requires more power (in HP) between helicopter and airplane? Say that both are designed maximum (the required material are considered during design) ...
2
votes
1answer
77 views

Does Raymer's installed engine equation include the weight of the pylon?

I am currently modelling an aero engine and require the weight breakdown of the individual components, I have the dry weight of the engine and need to verify the pylon and nacelle weight. Raymer has ...
0
votes
0answers
55 views

Raymers Installed engine equation [duplicate]

I am currently modelling an aero engine and require the weight breakdown of the individual components, I have the dry weight of the engine and need to verify the pylon and nacelle weight. Raymer has ...
1
vote
2answers
183 views

Advantages and disadvantages of air intakes above fuselage/wings in jet fighters?

I found some jet fighter designs that never went into production. All of them have air intakes above the fuselage or wings (albeit not in the same manner). I'm trying to assess if there'd be any ...
0
votes
1answer
58 views

How to determine Center of Gravity of the airplane parts? [closed]

I am building a small-medium sized airplane. Is it possible to calculate "C.G" of each part of the airplane? If yes, How? Parts: Wings, Tail, Fuselage, Propeller(?)
3
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1answer
305 views

Why is there a cutout in the pilot seat (looking as if it had separate “legs”)? [duplicate]

Why is there a gap in the seat (between the legs)? What function does it have?
0
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1answer
296 views

Why aren't cockpits airtight?

There are accidents where the pilots couldn't see the instruments and literally flew the aircraft blindly due to the excessive smoke in the cockpit, ranging from UPS Flight 6 to other accidents. ...
0
votes
0answers
94 views

Why did biplanes and triplanes go away? [duplicate]

Why did multi-wing aircraft (two or three stacked wings) eventually fade off to single-wing aircraft?
5
votes
1answer
677 views

What is the difference between redundancy and fault tolerance?

What is the difference between redundancy and fault tolerance in the context of aviation ?
0
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2answers
91 views

if center of pressure moves forward with angle of attack, then does it move forward of center of gravity also at a particular angle?

Consider an aircraft where- Center of gravity lies forward of Center of Pressure in CRUISE. Now as angle of attack increases, CP moves forward, then for particular angle, it must move forward of ...
0
votes
1answer
96 views

Why is A320's CG optimum position at 25% MAC?

I have read a320's optimum CG position is 25% MAC. But, the aerodynamic center is also at 25% of chord. So since CG and aerodynamic center at the same position, there would be no moment arm of lift, ...
2
votes
1answer
59 views

What is the Relation between Critical AoA with Chordline? [duplicate]

I read here an explanation about angle of attack (AoA) as below: Overly long (forward-back wise) wings will generally have a smaller critical Angle of Attack while smaller ones will have more ...
1
vote
0answers
64 views

Are there any aircraft designs that are (relatively) insensitive to the effects of airframe icing?

Snow and ice buildup on aircraft (especially the wings) is a well-known and feared hazard of cold-weather operations; it roughens the surface of the wings and changes their profile, which combine to ...
2
votes
0answers
68 views

How long does it take on average for a control surface to deflect by one degree

I know this should vary quite a bit (because of aircraft size / use / build / actuation / control surface weight), but I was wondering if anyone here could ball-park some numbers on how long it would ...
5
votes
3answers
189 views

Are there any specific weight or structural reasons to choose low vs. high wings for a cargo aircraft?

I have a large cargo aircraft concept and I am debating between a high or low wing. It seems like both are viable, but intuitively it seems structurally harder to support a high wing. Alternatively ...
7
votes
2answers
306 views

What is the aerodynamic purpose of an Acorn?

This is an IL-62. On the tail of the aircraft, there is a large cone, protruding out of the vertical and horizontal stabilizer which is called acorn. I am trying to figure out what is the aerodynamic ...
0
votes
2answers
115 views

How do gull wings help? [duplicate]

I know that gull wings are shaped how they are for maximum help with a decrease in induced drag and increase in lift, but how do they do it? This is my homework!!!
7
votes
2answers
215 views

Can autothrottle be used without autopilot (and vice versa)?

In commercial passenger aircraft: Can autothrust be used with A/P disabled ? And can A/P be used without using autothrust? Citable references very welcome! If the question depends on a specific ...
1
vote
1answer
169 views

Why are smaller wings in the front with these VTOL aircraft?

I would think it would be better to put the larger wings under the front or middle closer the the payload/center and have the smaller wings in the tail? Why would these designs do the opposite? With ...
0
votes
0answers
42 views

How to compute actuator torque requirement for Variable pitch mechanism??

Suggest me any reference to compute the torque requirement for actuator/motor to control the pitch angle of propeller (Variable Pitch Propeller). Thanks in advance Arun Ravindran
7
votes
1answer
264 views

What is the purpose of the serrated trailing edge spoilers on the B52?

At around 50 seconds on the linked video you can see the serrations on the trailing edge of the B52's spoiler. What purpose does it have, and what gives it advantage/disadvantage over the standard ...
0
votes
2answers
107 views

How to calculate the amount of weight my plane can takeoff with?

This is how I approached this problem- My takeoff run is limited. So, depending on my configuration I calculated the maximum possible velocity I can attain in my groundroll. I assumed that at the end ...
-2
votes
2answers
221 views

Why do drones look different from common airplanes? [duplicate]

In this video is shown Top 5 Military Drone. As we may see, the shape looks different than usual airplanes. My concern is especially with the tail. Normally we know that the tail is vertical. But from ...
1
vote
2answers
94 views

How to calculate the forces and moments required to aerodynamically actuate slats?

I am trying to make a wing where slats automatically deploy once it hits a higher angle of attack, let's say right before stall. I need to roughly estimate the forces and moments acting on the ...
5
votes
1answer
132 views

What is the material and font used on the panels of most cockpits?

I am working on a project for one of my aerospace engineering classes and was curious to see if anyone knew what type of material is used to make the panels of a cockpit (preferably a 737) as well as ...
0
votes
2answers
138 views

Would a pure flying wing in straight and level flight have zero NET wing loading?

In studying the NASA 247 foot wingspan solar powered Helios aircraft it seemed that evenly spacing the weight would create a Net Zero Load across its span when in flight, as gravity and lift forces ...
7
votes
0answers
226 views

When were the last subsonic turbojet-powered airliners retired from commercial passenger service?

The very first jetliners (Comet, Tu-104, Caravelle I-VI, 707-120/-220/-320, DC-8 series 10-30, original 720, CV-880) all used turbojet engines, turbofans not being available until later; when ...
0
votes
0answers
48 views

Calculating induced drag approximation using XFoil generated parasitic drag

I am trying to do rough predictions of induced drag using the XFoil results for parasitic drag. To do so, I am using the lifting line equation for induced drag and the Oswald efficiency number: $C_D=...
0
votes
2answers
248 views

Why overhead bin was put on top of passengers head?

Hello I'm just curious about the reason to why the overhead bin was most commonly being put on top of our seat and head.
1
vote
0answers
39 views

How to calculate the shear centre of a wing?

How is shear centre of a wings calculated? i.e. how can I calculate the wing shear centre of a two spar wing with main spar at 0% of wing chord and rear spar at 75% of wing chord? (Assuming the two ...
2
votes
3answers
153 views

Could the center of rotation of a spinning aircraft move away from CG? [closed]

Picture a barbell shape or twirlers baton spinning. Perfectly symmetrical. Rotating at its center of gravity. Now replace one of the ends with fins of equal mass an spin it again, once in a vacuum, ...
0
votes
1answer
88 views

Which pressure mode of operation has the most stress on aircraft frame

So I am want to know which mode of pressurization has the most demand on the airframe Isobaric mode constant - differential mode unpressurized I hope to get an answer because I have an exam and ...
2
votes
5answers
92 views

Is there any effect that contributes to roll stability even in the absence of sideslip?

Is there any physical dynamic-- involving high wing placement, "pendulum" effect of CG far below wing, or anything else-- that contributes to roll stability in a way that is NOT dependent upon the ...
1
vote
5answers
229 views

Which way (if at all) do the ailerons need to be deflected in a full-rudder sideslip in a Cessna 152 or 172?

Do you typically have to maintain an aileron deflection in a constant-heading full-rudder sideslip in a Cessna 152 or 172? If so, in which direction? And why -- what is the source of the roll torque ...
1
vote
2answers
164 views

Different between Angle of Incidence (AoI) and Angle of Attack (AoA)

Following discussion here, I am still confused about the difference between AoI and AoA. As I read in many references and watched in many YouTube videos especially this one: 1). AoI is tje angle ...
0
votes
1answer
63 views

what's the difference between priority and sequence valve in aircraft?

What roles do they play during retraction and extension of a landing gear ?
0
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3answers
394 views

Why do stealth aircraft generally lose in maneuverability?

Whilst stealthy built aircraft have (or claim to have) many anti-detection systems, they seem to have to compromise on less maneuverability features, and even have to keep their missiles inside, not ...
1
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2answers
167 views

Must quadcopters have the same propeller sizes?

I was flying quads today and it just suddenly popped up into my mind — do the propellers all have to be the same size in quadcopters? Mine are, but What if two propellers were larger and the other two ...
2
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3answers
170 views

What is compressibility drag?

I don't mean wave drag here. What is compressibility drag, which is understood to be a form of miscellaneous drag?
0
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2answers
125 views

What is the feasibility of solar powered drones?

What is the feasibility of solar powered drones? From my understanding, solar panels are becoming more and more efficient, in terms of weight vs energy captured, and in terms of surface area vs energy ...