# Questions tagged [airfoils]

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### Estimating fan CFM from RPM, HP, and diameter

I am trying to determine the approximate CFM of several axial flow fans being used in agricultural storage in the developing world. The only information the storers have is the power, RPM, and ...
26 views

### Display Pressure coefficient for multiple points at across the span line of an airfoil in fluent

Learning to use ANSYS Fluent as part of my computational engineering course I have previously modelled a 2D wing and been abled to XY plot for the pressure coefficient against x coordinate. my ...
1 vote
35 views

### Is standard airfoil theory suitable to VAWT blades?

Let me preface this by saying that I did my research and have r̶e̶a̶d̶ skimmed a lot of papers on new blade profiles for vertical-axis wind turbines (VAWTs). What I have yet to read about is a blade ...
135 views

### Fin airfoil holder design and technical drawings not understood

I am trying to draw a fin for my final year project, but I could not fully understand the technical drawing explanations that I marked with red markings. especially R1.281 DEFINES TANGENCY OF R1.312 ...
34 views

### Lift/Drag on sheet metal airfoils

I watched a youtube video about a propeller-driven bicycle and it brought me back to my university days of designing propellers. In college, we used NACA airfoils and used the publically available ...
1 vote
622 views

### Why does centre of pressure move forward with increasing angle of attack in this airfoil?

As a high school student, I am trying to learn more about airfoils and the theory behind it. I started off with analyzing the NACA0012 airfoil on Autodesk CFD. I modified the lower surface as shown in ...
167 views

### Positioning and size for a Joukowsky Airfoil

Joukowsky transformations are absolutely eluding me because I can't find numerical examples (I have a learning disability and formulas have always made absolutely no sense to me). I'm trying to get an ...
223 views

I am working on a propeller design, and I've came through Jblade which helped me in the airfoil design, yet as I can remember, xflr5 can also do this... doing some internet search, i found that Jblade ...
275 views

### What foil profile(s) does the MIT Decavitator (or similar vehicle) use?

I'm looking for some kind of "standard" hydrofoil profile suited for a water vehicle comparable to the MIT Decavitator (similar weight/speed/power/etc.), so I can use it as a base to get ...
1 vote
2k views

### Wingspan formula for an Ornithopter

How do i figure out what the wing area/sqft needs to be for a functioning wing-flapping ornithopter? Lets say for example there is 500# of force moving the wings up and down, and the wings and ...
1 vote
143 views

### How to modify Airfoil thickness

I'm writing a fusion360 adding to model windmill blades. My first goal is to model the NREL Phase IV in which the airfoils (S809) definitions come with thickness and also span station (wich I¿dont ...
1 vote
144 views

### Laminar flow hood/air straightener

I was looking at laminar flow filters to aid in my mycology work I'm doing. Most filters use an aluminum extrusion with fins. I figured the options out there are pretty expensive for what you get and ...
145 views

### Why don't propeller designers use multiple profiles?

I'm designing a ducted fan, and I'm deciding on the airfoil profile. NACA 16-series profiles are well-suited to M > .5 or .6, but they're not particularly efficient at lower Mach numbers. On the other ...
38 views

### Generating NACA airfoils with three digit maximal thickness numbers

I have two wind turbine blades, one that that consists of NACA 44xx airfoils and the other NACA 63-2xx airfoils. Some sections of these blades have airfoils whose maximal thickness are specified by ...
1 vote
61 views

### Can adding stationary bades after an axial ducted fan increase efficiency?

When searching for this online I did not seem to be able to find any examples of this, which might imply that this idea does not work (or I did not use the right search terms). I have seen the use of ...
34 views

### When were airfoil cross-sections first used in turbine blades?

When were airfoil cross-sections first used in turbine blades? When did this become standard practice? Did people understand the connection to aircraft, or did heavier-than-air aircraft exist at all ...
1 vote
44 views

### Determination of a Joukowski airfoil chord (demonstration)

I'm currently studying Aerodynamics, and one thing that I noticed is that the maximum and minimum $x$ coordinate of the airfoils (which are necessary to compute the chord) on the transformed plane (...
232 views

### What does high coefficient of moment mean for an aircraft?

After designing an aircraft idea I had in XFLR5, I noticed that it had a really high coefficient of moment (Cm) compared to other wings of similar size. What does this mean? I played around with my ...
5k views

### How to scale airfoil coordinates to achieve the required size?

I'm using airfoil data that is generated by a program. The generated airfoil has a chord length of 1 unit. I want to know how to scale up this airfoil to required chord length. My airfoil series ...