Questions tagged [aerodynamics]

Aerodynamics is the study of how air moves and interacts with solid objects. It is an essential part of aircraft design.

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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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What is the purpose of rudder trailing edge flat plate?

These are photos of Tecnam P2006T rudder trailing edge. Why it has such flat plate mounted at the trailing edge?
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Is it correct to say that inertia is the centrifugal force in a turn? [closed]

I came to this thinking using the law of inertia. If the centripetal force (aka. horizontal component of lift) is suddenly removed, the airplane will continue on its straight-line path. My additional ...
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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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What’s the difference between an AIRSPEED LOW warning and a STALL warning?

Just an enthusiast here; pardon the dumb question. Im a little confused between the difference of a stall and airspeed low. “An aircraft Stall Warning System is that system which provides the pilot ...
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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 is washout built into a fibreglass wing?

How is washout built into a fibreglass foam core wing of a GA Airplane with 40% span flaps, 40% span ailerons. Does the angle of indigence change gradually over the span of the wing, or is the airfoil ...
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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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Modeling of the aerodynamic characteristics of the wing

As a part of the engineering thesis I work on the methods of modeling of aerodynamic characteristics of wing. In it, I rise an issue related to the impact of changes of aircraft attitude during ...
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Is total upwards vertical force higher than weight in a steady climb? [closed]

And again related to questions on forces in a climb: if any aircraft is climbing with a constant velocity, is total upwards force higher than weight?
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Formula for comparing drag on planes flying at different speeds at different altitudes. Ex: Mach .80 at 40,000 ft, vs Mach 5 at 100,000 ft

I am interested in getting a sense of how much extra energy is needed to overcome drag at different speeds and altitudes. For example, for me a baseline would the drag on an airplane flying something ...
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Why are vortices produced at wingtips a source of drag, while vortices from the leading edge (harnessed by delta wings) good?

From my understanding, wingtip vortices produce a downward force on the aircraft, effectively increasing drag. Meanwhile, when considering leading-edge vortices on delta wings, we only consider the ...
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Model of aircraft banked turn

I'm trying to write a model of aircraft motion during a banked turn, so for say a 60Degree roll angle constant altitude turn will require 2g lift. However to achieve this lift the aircraft has to ...
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Does a wing produce an appreciable amount of lift during the takeoff roll prior to rotation?

I was hoping for some insight on this, perhaps also from pilots who have used AOA indicators. This because I assume that an AOA indicator is the only means to get at least an idea of how much lift is ...
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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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Is thrust larger than weight in a vertical climb?

Image source Very much related to the many questions and great answers to lift and weight in a climb - if an F-16 climbs vertically at a constant speed, is thrust greater than weight?
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What's the difference between an accelerated stall and a dynamic stall?

I am a commercial pilot. I always like to understand everything in detail, so here's my question: What's the difference between an accelerated stall and a dynamic stall? For example, in a high-speed ...
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Servo-actuated aerofoil

I intend on calculating the the servo torque required to actuate a 75mmx38mm NACA0012 airfoil. The example at the end of the page in the link https://github.com/build-week/hover-jet/blob/feature/start-...
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Is it possible for an airplane to enter another airplane? [duplicate]

I was making some cool fictional airplane designs and realized that most of my larger airplanes have a bay inside that stores a plane or two. But then I thought, is it even possible to make a plane ...
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Will a lift force be created by the Coanda effect if high velocity air flows under a half-toroid shaped saucer? [migrated]

I would like to know if a lift force will be created by the Coanda effect from high velocity air that is directed under a half-toroid shaped saucer by a centrifugal impeller. To illustrate how such a ...
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Does it make sense having a MiG 19 fuselage 'area ruled'? [closed]

If the MiG 19 fuselage diameters followed the Area Rule, instead of being a constant size cigar, perhaps transonic performance will be improved; someone answered to this question elsewhere indicating ...
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Getting the cl vs aoa plot from Cp distribution

I am making a CFD simulation where my goal is to calculate the section lift coefficient vs angle of attack plot of an airfoil. From Fundamentals of Aerodynamics (Anderson, 2018), I get the following ...
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Is there a limit to how large an airplane wing can be? [duplicate]

There are some agreeably large planes out there, like the C-5 Super Galaxy. But how big can these planes' wings really get? The heavier the plane, it is usually larger, and with size of the fuselage ...
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Could the Mars helicopter Ingenuity have been test-flown outdoors at JPL just for the heck of it? (not that they would)

The Ingenuity helicopter that has flown on Mars is designed for roughly 0.01 bar pressure and a colder atmosphere made of mostly CO2. See links (including video) in this answer to What JPL laboratory ...
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Definition of aircraft longitudinal axis?

I know that longitudinal axis connect nose and tail, but at what exactly point? What definition says? I have a glider and I want to draw with pen longitudinal axis to measure angle of incidence for ...
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How much drag does the wings of a Winged EVTOLs like Lilium produces while take-off?

I looked into several questions related to liliums design, and it is confirmed the wings of lilium produces drag during take-off but i just don't know how to calculate the drag produced due to the ...
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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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Can gliders and single-engine planes have vortices?

I read, A third physical explanation of the source of induced drag is that the wing tip vortices contain a certain amount of rotational kinetic energy. This energy has to come from somewhere; indeed, ...
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In constant speed propeller, if i increase RPM lever from 2300 to 2500, will the Blade AOA decrease?

Assume I am flying straight and level with power setting 21 inches of MAP and 2300 RPM with TAS=100 kts, now I change my Prop lever only (MAP = no change & TAS = no change) from 2300 to 2500, ...
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What is the correct definition of “spanwise” and “chordwise” with a swept wing?

What is the correct definition of "spanwise" and "chordwise" with a swept wing? For example, in the context of "spanwise airflow" and "chordwise airflow"? a) ...
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In this MD-11 stall test video, are we seeing the tail stalling first?

Watching this short stall test video for the MD-11, one can notice obvious buffeting (starting at about 0:04) of the tail section, while at the same time – at least apparently – there doesn't seem to ...
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Does lift-to-drag ratio asymptote to 4 (or 6) at high Mach numbers?

The Kuchemann equations for L/D at high mach numbers, approximately verified by wind tunnel tests, were: $$\left(\frac{L}{D}\right)_{max} = \frac{4\cdot(M+3)}{M}$$ and, for wave riders $$\left(\frac{L}...
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What is causing these “corners” on this F-104 V-n diagram?

In this V-n diagram for an F-104 (source: this Wikipedia link), on the left-hand edge of the flight envelope, what is causing the "corners" that we see at the following points? (Numbers are ...
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How does the turbulent boundary layer thickness affect separation?

I read that for a turbulent boundary layer, a thicker boundary layer separates earlier than a thinner boundary layer? Why is that? Or is it the other way around?
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Why do X-wing configurations missile/guide bombs use symmetric airfoils?

From all the missiles/guide bombs I have come across, I've always observed that a symmetric airfoil is used for both the wing and tail. Why not have a cambered airfoil for the wing and a symmetric ...
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How are foam cores shaped for tapered and swept back wings?

How are foam cores shaped for tapered and swept back wings? I understand that many constant chord, constant thickness rectangular wings use the same sized airfoil shape from root to tip. Let's assume ...
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Why does Vx have a relationship with thrust but Vy has a relationship with power?

https://www.boldmethod.com/learn-to-fly/performance/vx-vy-altitude-and-where-they-meet/ After I watch this article, now I understand the relationship between altitude and the rate of climbs. But I ...
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How does airfoil affect the coefficient of lift vs. AOA slope?

I'm trying to understand whether the airfoil shape can affect the slope of Cl vs. AOA (coefficient of lift vs. angle of attack) in the "linear" portion, e.g., from a few degrees negative to ...
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Does altitude affect glide ratio?

Lower altitude means higher air density, which means more liff, which means a glider can maintain a given glide slope at lower airspeed. As a rule, aircraft tend to have higher peak L/Ds at low ...
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Do manufactures list the maximum speed of an aircraft based on its theoretical maximum speed or dive speed?

I know that the absolute maximum velocity of an aircraft is based on the thrust available. However the aircraft is usually limited beforehand by other speed limits such as dive speed and Mach Never ...
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What is the Mach Never Exceed number for a C-130J Hercules under ISA conditions (approximations are welcomed!)

I am looking for the Mach Never Exceed number for a C-130J Hercules so that I can create an approximate 1g envelope. Does anyone have any idea what this can be? I am trying to find the value for ...
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What is the CLmax of the CF-100 Canuck?

I've been struggling to find specifications for the CF-100 Canuck. What is the CLmax of the CF-100 Canuck and how can I find it?
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What differentiates the entry procedures for spins and snap rolls?

Both a spin and a snap roll are aerobatic manoeuvres involving stalling one of an airplane's wings earlier and more deeply than the other. Both are entered by pitching up sharply to stall the ...
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What is the approximate thrust at sea level for a C-130J Hercules?

I am looking for the approximate thrust of a C-130J Hercules under ISA sea level conditions. Also the efficiency of its propeller would be of help. An answer to this question would really help my ...
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Swept back wing theory

I'm a beginner in airfoil design. I just came across swept-back wings. There is a point that I couldn't understand that theory. Why is the only perpendicular component of the airflow to the wing(...
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Why don't we simulate similarity parameters simultaneously in the same wind tunnel?

As 'Fundamentals of Aerodynamics' by JD Anderson suggest Today, for the most part, we do not attempt to simulate all the parameters simultaneously; rather, Mach number simulation is achieved in one ...
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What exactly causes pitch moment in the Phugoid mode?

I am trying to figure out exactly what causes the pitching moment for the Phugoid mode? We know that alpha remains mostly constant, so what is causing the pitching moment? I thought maybe it is the ...
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Is the Bede BD5 actually a tandem wing airplane, and not a mono wing?

Is the Bede BD5 a tandem wing airplane, and not a mono wing? The following picture (Source: Wikipedia.org) shows a Bede BD5 with a high angle of incidence on the horizontal tail, estimated at about 5 ...
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Why am I getting a low L/D of 4.3 for this supercritical airfoil in Autodesk CFD?

I am a high school student learning to analyze aircraft models in Autodesk CFD for the first time. My current project is analyzing a supercritical airfoil on Autodesk CFD (that was designed in ...
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Relation between lift force and torque produced in propeller used for vertical take-off and landing aircrafts

There are many answers for this question but none of them are specific. I need to find the exact relation between the lift force of a propeller of specific pitch, attack angle , dimensions and ...

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