# All Questions

44 questions
Filter by
Sorted by
Tagged with
107 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?
94 views

### Is there a database of airfoils for a given Reynolds number?

I'm trying to design my ultralight airplane. I know the basics of aerodynamics and airplane design, however, my question is if there are any tools (online, software, database ) that suggest the best ...
40 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 ...
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 ...
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 ...
86 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 ...
128 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?
171 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 ...
437 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 ...
261 views

### What is the relationship between the Center of Pressure and flap deployment?

I have been reading regarding the Center of Pressure of an airfoil (Cp) and the relationship with angle of attack. What is a good way to explain in layman's terms why the pressure changes in such a ...
114 views

### What airfoil type is used on the B727-200F?

What airfoil type is used on the Boeing 727-200F? Is it a NACA profile or something else?
260 views

### What to be considered in designing airplane tail (vertical and horizontal stabilizer, elevators and rudder)? [closed]

I would like to make a small amateur triplane with it maximum weight approximately 400 kgs with maximum speed 100 knots (180 kph). I have read many discussions about how to calculate the wing ...
119 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.
3k views

### Why isn't there a single best airfoil for subsonic flight?

Why does airfoil used by modern subsonic aircraft (this is true for transonic airliners too) vary from plane to plane? Haven't we figured out a single best airfoil shape, with the highest lift to ...
128 views

### What is the function of a sweep cable?

This is Goat3 ultralight with sweep cables,what is the fuction of these sweep cables?
2k views

### Which airfoil would be optimum for a glider?

The glider I am designing has a mission requirement to fly for as much time as possible. It will fly in the low Re range of about 150,000 to 250,000. While comparing different airfoils I am looking ...
328 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 ...
159 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 ...
444 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 ...
594 views

### What is the purpose of thinner airfoils used near wing tips?

I know that a thicker airfoil at root will strengthen the root spar but what is the reason behind using thinner airfoils at the tip? Is it because thinner airfoils have higher stalling angles of ...
3k 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 $50\:km/h$
126 views

### What are the effects of rotating airfoil sections to match wing's dihedral?

While designing a wing, what are the advantages and disadvantages of rotating the airfoil sections to match a linear dihedral (airfoil sections always perpendicular to the dihedral line)? Does the ...
581 views

### What is the mathematical relation between CLmax and Reynolds number?

I know that Reynolds number influences CLmax, but I am not able to find any formula with which I could plot a graph!
3k views

### How do I choose the correct airfoil?

I am currently working on a personal single seat, piston aircraft that I would fly myself and I am currently in a bit of conundrum when it comes to my wing design. In this project, I assigned us in 2 ...
2k views

### Which are some planes shaped like an inverted wing?

To understand my question better, let's consider the priciple behind the lift generated by the wing - The upper surface of the air-foil is curved to deflect the air downwards using the Coanda effect. ...
234 views

### What is the airfoil used in the SB13 flying wing?

(Source) What airfoil is used for the wing of this aircraft?
2k views

### Can this design provide more lift force than thrust from engine?

The problem is depicted in the picture: Generally, why we don't use engine blow wings to fly? Can we use wind-tunnel-like wing to generate lift force? Can it generate more lift than thrust? If it ...
2k views

### What are the disadvantages (if any) of using a supercritical airfoil?

The title sums up my question pretty well. I've searched all over this site, having read many of the questions and answers to various supercritical wing topics, but I haven't found any mention of ...
2k views

### How to design the blade twist angle in propeller design?

I am designing a scale propeller for small UAVs and I have computed blade twist distribution for the blade airfoil sections. While I was modelling the propeller I have set the angles to twist about ...
2k views

### How to locate the coordinates of the Center of Gravity of an airfoil?

I am working on the inertial effects on a variable pitch propeller and i need to define the location of the center of gravity on the airfoil to calculate moments of Inertia and angular momentum. What ...
1k views

### What is the meaning of the percentage used to describe the thinness of this glider's airfoil?

In a glider review for the Schempp-Hirth Discus, I encountered the following paragraph: The Discus 2 airfoil is thin (about 14.5 percent), incorporating studies by K.H. Horstmann and Dr. Wuerz (...
1k views

### Was the B727's wing supercritical (even if not so designed)?

The Boeing 727's wing upper surface appears unusually flat, especially at the root (Albeit at an angle). Refer to the images linked below: airlinereporter.com Flickr Also from Flickr Was the B727'...
1k views

### How to determine if flow transitions or separates from a Cp plot?

I came across this image: My question is: given a general Cp plot, how does one tell from the shape of the curve if flow transitions or separates? Specifically, what features on the plot do I look ...
434 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 ...
2k views

Why do toy (RC) helicopters have curved flat surfaces and larger rotors on true helicopters have a solid aerofoil shape? If the rotor was mechanically strong enough to lift the desired weight, is ...
143 views

### How is the chord length defined if the wing (whale flipper) is tapering like a wing and has a twist throughout the span? [duplicate]

Let me be more specific: I have a 3D scan of a whale tubercle. The tubercle is tapering and twisting along its half span. I want to find the mean chord length. Now let us say that my airfoil ...
1k views

### What software is used for aerodynamic wing shape optimization?

I can see lots of research articles around aerodynamic shape optimization of airfoils and wings like this MDOlab program. But all stuff like that don't seem to be available for a simple customer. ...
541 views

### Is there any use for variable shape wings within aviation?

I am working on a variable shape airfoil which is originally intended for sailboats. However, I am wondering if there might be an application for such a design within aviation? The design I am working ...
260 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 ...
485 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 ...
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?
13k views

### Are NACA airfoils used in modern aircraft design?

I know that NACA is famous for its ducts: Gratuitous Ferrari F-40 from Wikipedia. Mmmm... pretty... It is also well known for its airfoils, and many planes in the early years of aviation used NACA ...