Questions tagged [airfoil]

The 2D shape of a section of aircraft wing.

Filter by
Sorted by
Tagged with
2
votes
2answers
70 views

Difference between symmetrical and cambered airofoil?

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 ...
0
votes
0answers
39 views

How do I calculate the air pressure on the maximum bulge of the airfoil?

Picture 2: source. Consider I have an airplane and it wing, of course. The cross-section of the airfoil is as the picture 1. The leading edge and the wind direction are depicted there. The leading ...
0
votes
0answers
49 views

Airfoil search engine? [closed]

I am designing some simple propellers for being used in water at a constant speed. I Wonder if there is a site familiar to airfoiltools with CL/CD plots and such? Or atleast a site with airfoils with ...
1
vote
0answers
81 views

Are there any lift or lift coefficient equations which factor in the flap deflection angle?

I'm asking this because I tested a NACA 2412 wing with an adjustable flap in a subsonic wind tunnel and I'm getting the lowest Cl values for the highest flap deflection angle.. which to my knowledge ...
9
votes
1answer
7k views

Does lift coefficient vary with the wind velocity for a given angle of attack?

I have this question in my mind. I have been trying to look for this in different books about aerodynamics and I couldn't find the answer. I know I could check the answer experimentally, if I had a ...
0
votes
0answers
33 views

Where can I find data comparing coefficient of lift (and drag) curves for any airfoil with and without flaps deployed

I'm doing my masters thesis on a FISHBAC wing so I'm hoping to find coefficient of lift and drag curves for any airfoil with and without (any type of) flaps deployed (and preferably leading edge ...
9
votes
1answer
646 views

Which books should I study to understand more about Supercritical airfoils?

I want to understand the theory behind supercritical airfoils and all the details about them. It would be nice if I could get a standard supercritical airfoil, its experimental Cl, Cd data in the ...
1
vote
1answer
164 views

How much lift do supercritical airfoils produce?

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

Foil lift question as foil get thicker/taller

I am working on a project and just need to understand one concept that I cannot find an answer to anywhere and hoping you could answer for me. The project I'm working on is with airfoils and the main ...
1
vote
1answer
157 views

Why does the stall angle decrease as camber increases?

I have a rough idea about why $C_{{l}_{max}}$ increases with increase in camber. But I can't explain why the stall angle decreases simultaneously.
1
vote
0answers
21 views

How to calculate the moment/torque at the center axis of a blade?

How do I calculate the moment/torque at the center axis (same plane with lift and drag force) of a blade with NACA airfoil standard when it is placed inside a wind tunnel or exposed to airflow?
0
votes
1answer
157 views

Is the highly optimized high subsonic cruise airfoil less safe for higher AOA flight? [duplicate]

An examination of the 737 airliner wing profile and that of a blue whale leads to the question of whether the high Reynolds number subsonic cruising airfoil and the low speed, high AOA airfoil are ...
7
votes
2answers
2k views

What airfoil design does the MQ-9 Reaper UAV use?

What airfoil design does the MQ-9 Reaper UAV use? Alternatively, what similar airfoil designs exist? I'm running simulations for the effects of vortex generators for a school project and I would ...
8
votes
4answers
3k views

Why are the wings of some modern gliders tadpole shaped?

Why are the wings of some modern gliders tadpole shaped, rather than teardrop shaped? An example is the Schleicher ASG 29. Or did they just add a flat plate at the trailing edge for the flaps and ...
1
vote
0answers
68 views

Why the lift and drag coefficients for the simulations differ from the experimental value?

I am doing CFD simulations for NACA Airfoil 2415 using K-Omega SST model on ANSYS fluent. I am using an tetrahedral unstructured mesh with 20 Inflation layers on the wall. I have been comparing my ...
3
votes
2answers
551 views

What airfoil is used on the Lazair ultralight?

This is the airfoil of the famous Lazair ultralight. What is the name of this airfoil?
1
vote
1answer
535 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 ...
6
votes
3answers
3k views

Why the dynamic pressure is not mentioned in the explanation of lift by Bernoulli's principle?

Usual "explanation" of lift using Bernoulli principle This theory is: Air over the wing is accelerated, its dynamic pressure increases with velocity. The static pressure over the wing decreases (due ...
2
votes
0answers
74 views

Where can I find airfoil data for the Beechcraft 1900D tail?

I am creating a CAD model of Beechcraft 1900D from images for a project. So far most info is available in http://www.users.on.net/~grypen/b1900d.html except the airfoil used by the tails. I have ...
4
votes
2answers
345 views

Documentation about “drag stabilized flying wings using non-reflex airfoils”?

What provides lift is the wing, but it is unstable without one stabilizer. Flying wings airfoils, or reflex airfoils, carry their stabilizer inside them, through a reversed camber of the trailing ...
24
votes
8answers
3k views

Is there an aerofoil that gives reasonably good lift for both air flow directions: forward and backward?

Could an aerofoil be designed to give reasonably good lift for both flow directions? I was motivated by this related question on Aviation SE: Can a plane fly backward if its propeller is in reverse? ...
2
votes
1answer
106 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 ...
0
votes
1answer
229 views

What is the airfoil used in the SB13 flying wing?

(Source) What airfoil is used for the wing of this aircraft?
2
votes
1answer
165 views

Do Alaskan bush pilots generate a Clmax of 5 with 90° flaps?

I understand the Alaskan bush pilots use 90° flaps in the Valdez STOL competition. I think this would stall the flaps. And if so, it wouldn't increase lift and reduce stall speed, but Javafoil says ...
6
votes
2answers
4k views

Do negative angles-of-attack create lift?

(wikimedia.org) A typical curve showing section lift coefficient versus angle of attack for a cambered airfoil. Based on the graph above, do negative angle-of-attack values create lift? How?
1
vote
1answer
51 views

How can a NACA2312 airfoil or similar have a camber location from 30 to 39% without a change in airfoil name?

How can a NACA2312 airfoil or similar have a camber location from 30 to 39% without a change in airfoil name? Was fooling around in javafoil, and noticed I could go from 30% camber to 39% camber, ...
2
votes
2answers
110 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 ...
4
votes
2answers
2k views

Which type of airfoil does the 737 use?

NACA airfoils are not used anymore except on some aircraft. So which type of airfoil does the 737 use? Which company designs it and builds it?
1
vote
2answers
412 views

Why are cambered airfoils used for horizontal stabilizers in some designs?

From what I know, usually NACA9/12 or similar symmetrical airfoils are used for the tail. Still some aircrafts use highly cambered airfoils for elevators. What are some advantages and disadvantages ...
4
votes
3answers
310 views

What are the rules of airfoil thickness from root to tip on tapered wings?

I'm doing some research on wings and airfoils used in the 30s and 40s, and I'm trying to understand the rules about airfoil proportional thickness changes across the wing (root to tip) on tapered ...
2
votes
1answer
186 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 ...
4
votes
2answers
370 views

How do we determine whether the airfoil trailing edge should be cusped or pointed?

I'm working on a project and I need to decide whether an airfoil has a cusped or pointed trailing edge given the x and y coordinates of the airfoil. What is the difference between the two trailing ...
2
votes
1answer
127 views

Where is the midspan airfoil located on the 737?

The 737 has a root airfoil, two midspans, and one outboard. Is the midspan located under the fuselage or between root and tip?
8
votes
3answers
2k views

What is the physical meaning of circulation found in Kutta condition?

The Kutta–Joukowski theorem is applicable for 2D lift calculation as soon as the Kutta condition is verified. When this is the case, there is a circulation $\small \Gamma$ around the airfoil. My ...
0
votes
0answers
52 views

What is the reason for circulation of air around an airfoil? Based upon the circulation of air, why are airfoils shaped the way they are? [duplicate]

Foreword: I am an Aerospace Engineering student and next year is my third and final year, starting September 2019. I was taught approximately 2 semesters ago that the correct theory of lift is that ...
4
votes
1answer
84 views

What is the comparative roughness of fabric surfaces?

"The Design of the Aeroplane" by Darrol Stinton (1983) lists comparative roughness of aircraft skin material (pg 154). Unfortunately it does not list dope & fabric. What is the comparative ...
0
votes
0answers
52 views

What are the effects of endplate on airfoil section?

A 3D wing cannot achieve the same high lift/drag ratio (more than a hundred sometimes) displayed by a 2D profile (airfoil section). This is due to 3D effects like spanwise flow, wingtip losses(...
2
votes
1answer
150 views

Shock wave on airfoil

I was wondering the other day, during the trans sonic regime, when the velocity over the airfoil becomes supersonic,why does the shock wave standing on the airfoil moves downstream when the free ...
3
votes
2answers
155 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 ...
1
vote
1answer
85 views

NACA Airfoil 0005.4

I have come across this NACA profile NACA 0005.4 mod and it is not clear how to interpret this airfoil. Is this considered a 4 digit NACA profile? What does the number after dot mean?
1
vote
2answers
218 views

How could I find 𝐶𝐿𝛼 lift coefficient slope?

I'm trying to find 𝐶𝐿𝛼 lift coefficient slope through the below diagram, could anyone explain for me please, how could I find it? by the way, I depend on this equation 𝐶𝐿 = 𝐶𝐿𝛼 (𝛼−𝛼0)
1
vote
1answer
39 views

How could I find the air velocity and lift force?

As shown below I have this information as shown below in the picture. I got the density according to the ISA standard 𝜌 = 1.225[kg/m^3] and 𝐶𝐿 = 𝐶𝐿𝛼 (𝛼−𝛼0) is calculated as below : α=−4: CL=...
3
votes
2answers
124 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 ...
1
vote
1answer
116 views

What was the Airfoil of Handley Page P.115?

This extreme sweptback delta was built to test the Concorde wing at low speeds, sources say it had a biconv 6% airfoil, but I failed in finding data about it.
10
votes
2answers
1k views

Do airliners like Boeing and Airbus use airfoil variation along the span for their wings?

Airfoil variation will make a significant difference in airflow over the wing, thus proper variation according to the lift profile should improve the overall aerodynamic performance. But by how much? ...
6
votes
1answer
961 views

Is drag coefficient lowest at zero angle of attack?

The drag coefficient of a symmetric airfoil is lowest when its angle of attack is zero. I'm not sure if this is true in general.
-4
votes
3answers
393 views

Why do modern aircraft have a slope on top of the airfoil? [duplicate]

I recently learned that the pressure on the bottom of the wing is increased, and air moves faster on the bottom part of the wing. The speed of the air on top of the wing is not increased. So I am ...
0
votes
4answers
394 views

Does an rc plane tail also have airfoil or is it just flat material? [closed]

I've chosen an airfoil for the wing, now i'm confused weather i should do the same for tail or just attach a flat piece of wood as tail. I'm going for conventional tail design. This is my first ever ...
1
vote
0answers
77 views

Is there a relationship between 2D airfoil aerodynamic results and a revolution body from that airfoil?

The airfoil would be symmetric and the axis of revolution would be its chord line. Edit1: To clarify the question, suppose we have a NACA 0010. Then, using for example XFoil, I'm able to get, for ...
5
votes
2answers
461 views

What is the difference between static and dynamic stall?

What are the static and dynamic stalls on the aircrafts wing? When would we encounter static and when dynamic one? What is the difference between them?