Questions tagged [airfoil]

The 2D shape of a section of aircraft wing.

Filter by
Sorted by
Tagged with
3
votes
2answers
126 views

Is the lift produced by a wing with a 10° flap equal to the lift created by a wing with 10° AOA but with no flap?

After reading this article I would like to know if the lift produced by a wing with a 10° flap is equal to the lift created by a wing with 10° AOA but with no flap?
3
votes
1answer
144 views

How can a small airflow that passes through a slots redirect all the outer flow?

If this is normal wing without slots behind wing will be huge wake; airflow will separate, which is very easy to predict. Why would the outer flow follow the wing's couture; how can a small airflow ...
3
votes
3answers
655 views

How do wing tip vortices interact with the airflow on an wing with winglets?

If winglets are added to an aircraft, do the vortices still interact with the airflow and create up wash and down wash. If the vortices do interact with the rest of the flow I am wondering how they do ...
3
votes
2answers
230 views

Are larger airplanes more likely to stall?

Stalls happen when the boundary layer on top of a wing slows so much that it essentially becomes part of the airfoil. My question is, as the wings on larger aircraft present a longer flow path for ...
3
votes
1answer
839 views

Why are the aerodynamic characteristics of a finite wing different from the properties of its airfoil section?

Why are the aerodynamic characteristics of a finite wing different from the properties of its airfoil section?
3
votes
1answer
3k views

How to read representations of pressure around an airfoil?

Actual representations found online I selected 6 online representations of pressure around an airfoil, mostly using inconsistent symbolization of the pressure field. Source of the individual ...
3
votes
2answers
229 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?
3
votes
2answers
8k views

What are the differences between symmetrical and cambered airfoils?

I have seen images of cambered and symmetrical wings but apart from that what are the major differences between them? I have also read that symmetric wings don't produce any lift at 0° AOA whereas ...
3
votes
2answers
378 views

What are the scale effects of GA wing tip airfoils?

[ update: I am adopting an improved description provided by Peter Kämpf: "...only looking at the airfoils in isolation..." ] The goal of this question is to determine if wing tip airfoil scale plays ...
3
votes
1answer
7k views

How to select the most efficient airfoil for low speed flight?

What airfoil (or family) has the highest $C_L/C_D$ ratio at speeds in the $50\:km/h$ range. The use case would be an ultralight with a max speed of $50\:km/h$
3
votes
2answers
816 views

Is flow turning different from the Magnus Effect? If so, how?

The production of lift is much more complex than a simple differential pressure between upper and lower airfoil surfaces. In fact, many lifting airfoils do not have an upper surface longer than ...
3
votes
3answers
235 views

How do thick and thin airfoils compare in lift generation?

I find myself confused when comparing the lift generation amongst Thick and Thin Airfoils. A paper to which I have added reference below claims that thin airfoils are better in generating lift because ...
3
votes
1answer
118 views

Is it possible that as the Reynolds number increases, a laminar bubble increases in extension?

I'm studying the Benedek 10355 airfoil (Plot), which should be a profile used in air-controlled models. While I was carrying out a boundary layer analysis, I realized the particularity that I have ...
3
votes
1answer
696 views

When calculating the lift coefficient, what area is used?

Lets say I had this rectangular double curve wing. Orange represents the chord length, red represents the airfoil outline length below the chord line, green represents the airfoil outline length above ...
3
votes
2answers
179 views

How can I tell from the location of flow separation if an airfoil is stalled?

I am in the process of completing a carbon airfoil for my track car (sedan) and I am looking to determine stall angle visually. AKA, wool tufts and highway runs with my GoPro pointed upward from the ...
3
votes
1answer
961 views

What does leading edge radius mean?

What does leading edge radius mean amongst these parameters of a st cyr 24 airfoil?
3
votes
2answers
10k views

How does centre of pressure change with angle of attack?

I've been given the distance of centre of pressure from the leading edge with a certain angle of attack and was wondering if it's possible to calculate the new position when the angle of attack ...
3
votes
1answer
747 views

Why is the numerically determined location of the center of pressure inaccurate near Cl = 0?

I am working on an assignment and I need to calculate the center of pressure of an airfoil, through a numerical method (the panel method). I am getting a weird result because it gives its position on ...
3
votes
2answers
230 views

Shouldn't the upwash on an airfoil increase the effective angle of attack?

From what I understand, induced drag comes from a reduction of the effective angle seen by the airfoil. However, from wind tunnel smoke visualization, we can see that the streamlines at the leading ...
3
votes
1answer
1k views

How to calculate the lift coefficient of a multi element airfoil?

How to calculate the lift coefficient of an airfoil section with flaps and slats if we know the Cl for the individual elements, like Cl of wing, Cl of slat and Cl of flap?
3
votes
1answer
944 views

Are there any reference values for Cl and Cd of a NACA 0012 airfoil to verify CFD simulations?

I am having trouble finding the established results of inviscid flow CL and Cd variation over NACA 0012 airfoil, for the transonic region. I need the data to verify the results I am getting through my ...
3
votes
0answers
71 views

Are empennage airfoils always symmetric in conventional airliners?

I'm specifically interested in these models: A319, B737-700, A220, E195-E2. You could call these conventional airliners, so I suppose the question is if these "conventional" planes have only ...
2
votes
2answers
3k views

Is airfoil thickness proportional to drag coefficient?

Does increase in the thickness of a camber airfoil mean more drag will be produced? Why do slow flying planes have thick airfoils when it will just slow them down even more?
2
votes
1answer
688 views

How to calculate airfoil geometry with the maximum lift to drag ratio for a given Reynolds number?

How does one determine the optimal cross sectional geometry to maximize Cl/Cd?
2
votes
1answer
266 views

What airfoil simulation software is suitable for a cut trailing edge?

I'm looking for a way to simulate airfoils used to reduce turbulence. airfoiltools.com already does this a long way. However I have width and length limits, and I'm interested in comparing full ...
2
votes
1answer
988 views

Why is this airfoil curved upwards on the bottom part of the airfoil?

Image source datawiki.net Is this to slow down airspeed. I know that the high pressure and low pressure above and below the wing both contribute to downwash, but how does this airfoil form downwash?
2
votes
1answer
310 views

How do I choose the vertical tail's airfoil?

I'm designing a fixed wing UAV and I'm having some doubts about how to determinate the vertical tail airfoil. It's important to say that we've already sized this surface. And till this moment we're ...
2
votes
1answer
326 views

How much lift do supercritical airfoils produce?

Compared to your regular asymmetric cambered airfoil, How much does lift do supercritical airfoils produce?
2
votes
1answer
308 views

Why doesn't the centre of pressure move in the case of a symmetric aerofoil?

Why doesn't the CP (centre of pressure) move in the case of a symmetric aerofoil? Also, why does the CP move backward in the case of a flat plate?
2
votes
3answers
2k views

What is the "Centre of Pressure"?

This question may sound naive but surprisingly it puzzles me. A wing has a centre of pressure, does it mean that lift acts on point and not on the whole chord of an airfoil?
2
votes
1answer
331 views

How are wingtips attached to the aerofoil while maintaining structural rigidity?

I've been trying to research various methods on the joints between the winglet and the wingtip out of interest. I'm aware that the airfoil is attached to the underbody of the fuselage by means of a ...
2
votes
3answers
1k views

What is the impact of camber on CLmax?

I was reading Aerodynamics for Engineering Students by Houghton and saw the following graph: A lot of other sources say that increasing camber increases CLmax, like the graph below. I am a little ...
2
votes
1answer
101 views

How do viscous drag and form drag individually change as a function of angle of attack?

Typically, when dealing with airfoils, the drag coefficient $C_d$ is given as a function of angle of attack. If we limit the discussion to 2D subsonic incompressible flows, then the drag is the sum of ...
2
votes
2answers
171 views

Vertical autorotation with passive rotor

Let's say we have a simple hollow cube(chosen for simplicity) with outside side length=10cm, thickness=5mm (or another arbitrary shape with arbitrary dimensions). Clarification: I am NOT talking ...
2
votes
3answers
175 views

Fabric-covered Clark Y Max Coefficient of Lift

I'm looking at the Aeronca C-3 Collegian, which had a Clark Y airfoil, and I'm finding the following: Wing area: 142 ft² Empty weight: 466 lbs Payload: 470 lbs Stall speed: 38 mph When I do the math ...
2
votes
2answers
901 views

How does the thickness of a wing affect its aspect ratio?

As far as I understand, the aspect ratio equals the wingspan divided by the chord or the square of the wingspan divided by the wing area. Given this formula factoring in only the wingspan, the chord, ...
2
votes
1answer
485 views

How do KFm step airfoils work?

I was looking for airfoils, and I came across an interesting design. It's called a KFm1 step airfoil. Those of you in model aircraft design might have heard of it. However, I've never really seen one ...
2
votes
1answer
387 views

Where can I find the aerofoil geometry of a commercial aircraft so as to design it in CAD software?

As a part of my final year thesis, I need to design a commercial aerofoil for an existing aircraft (such as Boeing/Airbus) to conduct some FEA & CFD analysis. I've been trying to source aerofoil ...
2
votes
1answer
207 views

Which airfoil to use for high subsonic flight?

I am desigining an aircraft, which shall fly up to Mach=0.9 in cruise flight in an altitude of 10 km. So when I think of which airfoil to choose, I have to consider aspects like max. lift coefficient ...
2
votes
1answer
90 views

On an aerofoil or circular cylinder why does the airflow stay attached after passing the point of maximum thickness?

Why does it follow the curvature rather than separating? Its not due to the coanda effect as the accelerated flow near the surface of the aerofoil can't be considered a jet. It's not due to surface ...
2
votes
1answer
151 views

What causes the vortex on the tip of this vertical stabilizer (CFD Simulation)

This is a computational fluid dynamics simulation of an airfoil that is oriented to look like a vertical stabilizer. After watching the video, it becomes clear that the tip of the stabilizer causes a ...
2
votes
1answer
380 views

Would adding a slat and a slotted flap increase the max CL of a multi element airfoil to 6.5?

Would adding a slat and a slotted flap increase the of a multi element foil to 6.5? I understand, as a general rule, the max $C_L$ for a classic NACA airfoil is as follows: Base: 1.5 Slat: + 0.7 ...
2
votes
1answer
447 views

Why are hexa airfoils used on rockets despite having more drag that diamond airfoils? [closed]

I was doing a study on airfoils shape for a rocket. I tested the diamond and the hexagonal airfoil with Missile DatCom, RasAero and the Shock Expansion theory and from my results it seems like the ...
2
votes
1answer
226 views

How (or where) do I find an airfoil optimized for low reynolds numbers (100,000~150,000)?

Looking to build a RC plane. Because the span is going to be small and the speed relatively low, I estimate the R-number to be around 100,000. Is there an airfoil optimized for that range of Reynold's ...
2
votes
1answer
3k views

How to calculate variable pitch propeller parameters?

I'm carrying out a project on Variable Pitch Propellers for UAVs and especially self-adjusting or Passive Variable Pitch Propellers that change pitch due to aerodynamic forces and Pitching Moments. ...
2
votes
1answer
882 views

How does airfoil thickness affect the Mach number at which it experiences transonic flow?

Roskam (book: Airplane Aerodynamics and Performance, Subparagraph: 2.5.2 HIGH-SPEED AIRSPEED INDICATORS (COMPRESSIBLE FLOW)) affirms: [...] Airplane with no sweep and thick airfoils become ...
2
votes
2answers
191 views

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(...
2
votes
1answer
93 views

Could leading-edge dynamic stall occur for a tripped airfoil?

As far as I know leading-edge dynamic stall is characterized by the formation of a Leading edge vortex. This leading edge vortex forms due to the 'bursting' of the LSB (Laminar separation bubble). ...
2
votes
2answers
174 views

How is rotor airfoil analysis different than fixed wing airfoil analysis?

What the is difference between rotor airfoil analysis and fixed-wing airfoil analysis? Intuitively, it seems that the airspeed at the tip of a rotor blade would be more than that at its root. Wouldn'...
2
votes
1answer
161 views

Do commercial passenger airplanes have cambered airfoils?

It seems to me that they logically would, since they have no need to fly upside down like an aerobatic plane would (so they would not need a symmetric airfoil for any conceivable reason). That being ...