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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1answer
69 views

Is/why isn't the Antonov 124 to 225 wing upgrade method common?

I'm told that wing redesigns are difficult, so variants of a model often do with a common wing optimized for the middle member. But then I read the following: Based on Antonov's earlier An-124, the ...
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1answer
81 views

RC airplane required engine power

I'm going through the process of designing an RC airplane. I know that probably most calculations on scale models might be non-precise ones, but I'm trying to do it as correct as possible (it's a ...
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0answers
55 views

Aircraft fuselage [closed]

Are they anyone that knows about carbon-epoxy fibre composites as fuselage ? I have read about Boeing 787 dreamliner fuselage but couldn’t find anything useful there.
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1answer
90 views

Why is CL/Cd equal to L/d?

I'm making a school project where I intend to design and calculate an rc airplane. Reading some books I found something I can't understand, it says that CL/Cd is equal to L/d, but the only possible ...
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41 views

What are the most common professional software for aircraft design and aerodynamic/stability analysis? [closed]

What are the most common professional software (free if possible & user friendly) for aircraft design and aerodynamic/stability (static & dynamic) analysis? I recently designed my aircraft ...
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4answers
171 views

Why are true and indicated airspeed different?

So, I understand that True air speed is the motion of aircraft relative to air around it. And, indicated airspeed is speed arising due to dynamic pressure. Considering a true airspeed of 100 knots, ...
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2answers
87 views

What is the aspect ratio of T-tail for common twin turboprops?

I'm trying to figure out typical AR values for a T-tail configuration (at the conseptual design phase). Working with Raymer I found this table: I can see the typical AR values for the vertical tail ...
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0answers
60 views

What kind of motors are used in electric autopilot servos?

In terms of general aviation/experimental autopilot servos for control surfaces, are these motors usually brushless DC or stepper motors? Some examples are: Garmin GSA 28 (brushless DC) Dynon ...
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2answers
164 views

Is the Batjet Design Physically Feasible?

I realize the plane is fictional. However, in the Batman Animated Series by Warner Bros, we see this Batjet. So this got me thinking (and I'm not a physicist): is this air frame configuration even ...
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1answer
44 views

How do you calculate the wing moment coefficient knowing the moment at each spanwise station?

A lot of theoretical formulas exist for finding the moment coefficient for airfoils, but I have been confused by how to get the moments for a wing. I came up with three related questions that have ...
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0answers
24 views

Why don't most business class seats fold out fully? [migrated]

My issue is as follows: Why almost all business class seats do not recline to a full flat configuration? Is it a design challenge that is difficult to overcome? I understand that it may save space (...
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0answers
109 views

How can a designer deal with a strict requirement when designing an aircraft?

I'm working on designing an aircraft with some specific requirements (Vstall, Vmax, Ceiling, Payload, Range, RoC, Slanding/takeoff etc). I'm following Anderson's and Raymer's ways (trying to find the ...
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1answer
83 views

What is the angle of Incidence of wing of Airbus A320?

What is the Angle of Incidence/ Mounting Angle of the wing of AIRBUS A320?
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1answer
95 views

Is this how ailerons are actuated?

I was wondering how ailerons work on fighter jets. I came across this after hours of research. https://forum.flitetest.com/index.php?threads/airplanes-in-real-life.63837/#lg=post-580884&slide=0 Is ...
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10answers
6k views

Is there an aviation career where I would help design an entire aircraft and its systems?

If I want to design and build planes, what career would that be? Would it be a mechanical engineer, systems engineer, or what else. (I feel like saying aerospace engineer is too vague and most ...
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1answer
189 views

Is it possible for Mig 21 at corner speed to extend the flaps to minimize the turn radius? Or this is not an option?

The corner speed is around 330knots if you want to turn better than the enemy is possible to lower the flaps?
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1answer
93 views

Did the Mig 21 have differential stabilators to help the ailerons?

The MiG 21 had all-moving tailplanes or stabilators. When rolling, did one stabilator pitch up and the other down to act as secondary ailerons and help the main ones on the wing?
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0answers
85 views

Why are the wingtips of the Fairchild-Republic A-10 bent downward? [duplicate]

Why are the wingtips of the Fairchild-Republic A-10 bent downwards?It is subsonic aircraft .
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0answers
45 views

Are the firewall and forward pressure bulkhead different components? [duplicate]

Suppose in a single engine aircraft, where the engine is located near the nose of the aircraft. If the cabin is pressurized, I know there will be a requirement of pressure bulkheads, both in the rear ...
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1answer
180 views

How can jet engines be more efficient than propellers? [duplicate]

If jet engines are smaller in diameter than propellers, is it fair to say that propellers accelerate a lot of air a little while a jet engine accelerates a little air a lot? Basically, a jet engine ...
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1answer
68 views

Will a quad fan arrangement on an aircraft help with pitching moments during VTOL flight transition?

The phenomena of ducted fan assemblies inducing pitching moments whilst in transition from vertical to horizontal flight paths is a problem I have seen mentioned by many designers and engineers of ...
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0answers
74 views

How much thrust does the Lilium aircraft produce?

I have been researching the Lilium aircraft and can’t find information about thrust. An early version of this aircraft was 2 seats with a loaded weight of 1,400 lbs, 36 ducted fans and 320 kW peak ...
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0answers
21 views

How can we find maximum lift coefficient of Airfoil?

I am trying to find the maximum Lift coefficient for airfoil NACA 64A-404. I chose this airfoil for wing. I am stuck at finding the Clmax. I tried to use javafoil but javafoil is showing Cl less than ...
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1answer
108 views

Why do small jets usually have one low flap setting?

For example, the CRJ has a flap setting of 0, 8, 20, 30, and 45 degrees. The Learjet has similar features across their models, as far as I can see which is 0, 8, 20, and 40 degrees Why do smaller ...
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2answers
201 views

Does the payload of an ICBM or regular airplane bomber explode if the ICBM or bomber is shot down?

As the top says, does the payload of an ICBM or regular airplane bomber (please excuse my ignorance) explode if the ICBM or bomber is shot down? So, say a defense laser in space (yes, I know; this is ...
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1answer
72 views

How do the vortex created by wing tips affects the lift? [duplicate]

I’ve been reading about how improve the aircraft performance and I found that for low aspect ratios, the vortex created by the wing tips decrease the lift generated by the wings. Why is this happening?...
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4answers
146 views

Why should I not use a “lifting tail” on my ultralight design?

In my misspent youth I designed and built many rubber, gas, and RC models. When I wanted good climb and glide I used a aft CG [60 to 80%] and a lifting tail. I had no stability or control problems, ...
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1answer
81 views

At what point of the design process the manufactures build their first prototype?

I would like to know when the aircraft manufactures decide to put in practice their designs building the first scaled prototype (or maybe the actual size). Does the design have to accomplish a list of ...
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1answer
61 views

Relationship between wing aspect ratio and speed [duplicate]

For some reason, I cannot find a relatively straightforward source online which discusses the relationship of wing aspect ratio and how it affects speeds of an aircraft. Specifically, is there a ...
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1answer
88 views

Why does pitching moment coefficient decrease with an increase in the angle of attack?

Slope of Cm vs alpha graph is negative, why it is so? The attached graph is from https://en.m.wikipedia.org/wiki/Pitching_moment , this graph is for cambered airfoil, as pitching moment is zero for ...
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2answers
793 views

Does an increase in lift always cause an increase in lift-induced drag?

An increase in lift causes an increase in drag. Is it always true? I am confused with two points. Lift increases with an increase in airspeed but induced drag reduces with an increase in airspeed. ...
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2answers
384 views

What is Neil Armstrong teaching in this image?

It seems to me that in this image Neil Armstrong is teaching something related with aerodynamics forces (lift, drag...), but I don't know exactly what is that "Triangle" that He drew (It doesn't seem ...
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1answer
41 views

What are the applications, advantages and limitations of Gyrodyne rotorcraft?

Gyrodyne is a VTOL rotorcraft. It has ability to power both rotors and propellers for generating lift and thrust. What makes it of lesser popularity than helicopters. Are there any applications of ...
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1answer
2k views

In aircraft construction, what is the difference between a firewall and a bulkhead?

I'd like to know the difference between a firewall and a bulkhead. They both separate segments of an aircraft, so how are they different as it pertains to their design and purpose in aircraft ...
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0answers
72 views

How to create a simple forces diagram using only lift and drag forces?

I would like to create a simple forces diagram (like a sketch). The lift produced by the wing depends upon to the distance from the the longitudinal axis, but, in order to make it easier, I’m taking ...
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0answers
23 views

How is the wingspan of a wing measured if it has a dihedral? [duplicate]

I am having some confusion regarding how the wingspan is measured, I just wanted some clarity because this was bugging me while I was reading about aircraft wings. According to NASA's "Wing Geometry ...
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1answer
235 views

How do aircraft window size compare to each other? What are some possible improvements on them?

I'd like to see a comparison about the window sizes of various commercial aircraft, maybe to give evidence of eventual progress in it over the generations. For example, I surely know that the B-787 ...
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1answer
235 views

How do Airbus and Boeing aircraft handle Dutch roll?

I have some homework about Dutch roll filters. Dutch roll is something that is corrected by yaw damper systems, but I would like to know the different ways Boeing and Airbus deal with the issue of ...
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1answer
90 views

How does the RQ4-Global Hawk improve stability? [closed]

I have seen several videos recorded from an UAV in which the stabilization of the camera is almost perfect. Cameras are installed in a gimbal, of course, but do new drones introduce some new ...
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1answer
130 views

When does an UAV need an internal structure?

I´ve seen some UAV models without internal structure (stringers, longerons and frame). I guess the drone´s shell is the frame itself. So what is the best approach to calculate the shell thickness to ...
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2answers
45 views

How can we physically define reynold number variation in terms of characteristic length? [closed]

How can you define it physically that greater the characteristic length in $Re=\frac{\rho v L_c}{\mu}$ greater the Reynolds number. Like on wing surface $Re$ is higher than the horizontal tail surface ...
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1answer
135 views

Why do airlines not paint the wings on their livery? Why? [duplicate]

Does anyone know why airlines do not paint the wings on their aircraft? What is the reason why?
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0answers
229 views

Why aren't 757 scimitar winglets flush with the ailerons?

Over my many past flights aboard 757s, I have seen changes being implemented with their design. One of which was notably their refit of scimitar winglets. Although one of their most notable ...
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1answer
64 views

Does increased fineness ratio decrease skin friction drag?

From the Wikipedia article on parasitic drag: a designer can consider the fineness ratio, which is the length of the aircraft divided by its diameter at the widest point (L/D). It is mostly kept 6:1 ...
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2answers
878 views

Why do some T-tail aircraft have a protrusion on the top front of the tail? [duplicate]

Aircraft like the Tu-154 and VC-10 have a "point" on the T-tail, while others like the 727 do not. Is this structure a shock body, or otherwise related to the tail's aerodynamics? And why is it only ...
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1answer
152 views

Why are some A350s missing SSA probes on their nose?

I recently just noticed that some A350s are missing their iconic set of 3 main SSAs (Side Slip Angle Probes) on their nose. I'm not sure if its an issue of newer variants or varied airline options, ...
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3answers
163 views

Can an automatic gearbox improve engine transmission for an ultralight? [duplicate]

I am working on my dream to build and fly an ultralight aircraft so I wouldn't like to know the following: Does adding a motorcycle automatic gear box to an engine improve on the strength for an ...
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1answer
147 views

Why does the Embraer E-Jet Family have doors of different sizes?

I just noticed yesterday that the right and left forward doors of all E-Jet Family aircraft have different sizes (both in height and in width). What is the reason behind this design difference?
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2answers
379 views

Can aircraft fly without wings? [duplicate]

Is it possible that a aircraft can fly without having wings? I am wondering if somehow it can fly then will aircraft will be able to maintain the balance.
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2answers
206 views

Would this hovercraft be stable? [closed]

Would this two-rotor hovercraft design work? The bold black line is weighted metal on the lower to stable it. If it helps, this is a human sized hovercraft. Would it work if: prop1 lift > prop2 lift ...

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