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16 votes

Why are supercritical airfoils not used in GA aircraft?

Because supercritical airfoils are designed for the transonic regime of flight speeds, which GA aircraft do not operate in. Many other considerations, such as flutter, limit GA aircraft speeds even in ...
p8l's user avatar
  • 313
12 votes

Why does a flat plate create less lift than an airfoil at the same AoA?

It shows that at the same positive AoA, a flat plate generates less lift compared to the NACA airfoils. From an arbitrary guess, the lift force generated should at least be the same for both Your ...
sophit's user avatar
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10 votes
Accepted

Why are supercritical airfoils not used in GA aircraft?

Actually, Whitcomb's GA airfoils were based on experience gained with supercritical airfoils. They share the large leading edge radius and the strong rear loading with them. Other than that, ...
Peter Kämpf's user avatar
7 votes

Does more lift cause a plane to stall at a lower airspeed?

I was looking and saw this question, but the answers didn’t really address why more lift will help a plane not stall. I agree that there's a bit of confusion in the answers to that question that you ...
sophit's user avatar
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6 votes

Why are supercritical airfoils not used in GA aircraft?

The Piper Tomahawk, Beech BE.77 and the Dornier Do228 all used the GAW-1 airfoil, which is shaped like the higher speed supercritical airfoils. The certified OMF Symphony SA160 (formerly kit built ...
Pilothead's user avatar
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6 votes
Accepted

Why Cessna 152 has different airfoils at the root versus at the tip of the wing?

At the end you'll find the answer to the question plus a short question to verify if I've made myself clear ;-) An airfoil can be basically described by 3 parameters: the shape/curvature of its ...
sophit's user avatar
  • 13.5k
5 votes

Is the ideal airfoil concave on the underside?

So, is the L/D [of] a cruising aircraft best when bottom is concave? If we use gliders as a reference, the bottom of the best airfoils is only very slightly concave, almost straight, in order to ...
Peter Kämpf's user avatar
4 votes

Is the ideal airfoil concave on the underside?

Back to the roots. An airfoil can be basically described by 3 parameters: the shape/curvature of its camber line; the radius of its leading edge (the trailing edge is almost always pointy); the ...
sophit's user avatar
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4 votes

Does more lift cause a plane to stall at a lower airspeed?

A given level of wing technology (think airfoil choice and all high lift devices) applied to a planform family (same general shape wing, i.e. similar sweep angles and taper ratios and twist approach) ...
Rob McDonald's user avatar
  • 13.2k
3 votes

Why is the pressure lowest towards the front of an airfoil?

According to Bernoulli, the pressure drops where the flow speeds up. The flow hits its highest velocity as it rounds the tight corner around the leading edge -- don't forget to include angle of ...
Rob McDonald's user avatar
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3 votes

Modelling airplane wing

Is your goal to generate 3D points that lie on the surface of a wing, or to have a closed form analytical equation for a wing surface? The first is perhaps a little easier. When using this approach, ...
Rob McDonald's user avatar
  • 13.2k
3 votes
Accepted

Can a propeller with 90° pitching and symmetrical airfoils generate thrust?

The horizontal component of the total aerodynamic force $F_{TOTAL}$ would indeed be a thrust. Anyway the much bigger vertical component would be the force that had to be won by the torque of the ...
sophit's user avatar
  • 13.5k
3 votes

Can composite material be used in leading edge of airfoil instead of aluminium through Additive manufacturing?

Lots of aircraft use composite material for their leading edges. There is no need to use additive manufacturing to accomplish this. That said, you might be interested in filament winding, automated ...
Rob McDonald's user avatar
  • 13.2k
3 votes

Why does a flat plate create less lift than an airfoil at the same AoA?

Why different shapes react differently to a fluid flowing past them is ultimately subjective, trying to fit one abstract model to several of these shapes. How they react is purely a matter of ...
Camille Goudeseune's user avatar
3 votes

Are winglets symmetric airfoils? (Cessna Citation M2)

There is no reason to assume that winglets have symmetrical airfoils -- in this case or in general. Furthermore, the wing is likely twisted, and the winglet likely also has twist that manifests as toe-...
Rob McDonald's user avatar
  • 13.2k
3 votes

At what Reynolds Number does laminair airfoils stop working as expected?

The B-727 does not use a laminar flow airfoil. It may use a supercritical airfoil -- which may get some limited amount of laminar flow, but nobody would consider it a laminar flow wing. Any body or ...
Rob McDonald's user avatar
  • 13.2k
3 votes
Accepted

Which is more efficient, thickening an airfoil or adding a bottom-surface curve?

So if you were to take a standard airfoil and increase the thickness, you’d increase the lift No, you don't. Lift is determined by camber and angle of attack. Both don't change with thickness, so ...
Peter Kämpf's user avatar
3 votes

Does more lift cause a plane to stall at a lower airspeed?

Stall speed If we decrease airspeed and want to stay level, we need to increase the AoA (actually the lift coefficient $\small C_L$ in the equation below). As we continue to decrease airspeed, and to ...
mins's user avatar
  • 74.7k
2 votes

P-8A Poseidon Airfoil type

I know that in Dave Lednicers brilliant website the P-3 is listed with the NACA 0014 and 0012 airfoils. But that does not mean that a symmetrical airfoil is the best choice for a maritime surveillance ...
Peter Kämpf's user avatar
2 votes
Accepted

General Thin Airfoil Theory

You have to look at the velocity decomposition at location $y_u$. Below I made a velocity diagram at location $y_u$: If you decompose $u$ and $v$ into the red velocity (tangential to the surface) and ...
ROIMaison's user avatar
  • 7,447
2 votes

General Thin Airfoil Theory

That equation just translates the fact that the speed perpendicular to the surface must be zero since the airfoil is "airtight" i.e. no air can flow though the wing. This condition is ...
sophit's user avatar
  • 13.5k
2 votes

How do I plot Cd vs Re graphs for an airfoil?

You had the right resource in airfoil tools but didn't use the comparison feature. Here are two airfoils as an example. To compare them go to the detail page for each and then click 'add to comparison'...
Pilothead's user avatar
  • 20.7k
2 votes

Moving from 2D wing to 3D wing design

Sometimes the process may seem direct, but other elements come into play. As an initial part of the process, the designer may have an idea regarding the plane, its weight, and required power. If the ...
Thomas Perry's user avatar
  • 1,392
2 votes

Moving from 2D wing to 3D wing design

An aerodynamic engineer would maybe strive for an elliptical circulation. But not an airplane engineer. In 1933 Ludwig Prandtl published "Über Tragflügel kleinsten induzierten Widerstandes" ...
Peter Kämpf's user avatar
2 votes

Moving from 2D wing to 3D wing design

Why wouldn't you try all kinds of combinations? This is one of the fundamental ways design is performed. Design is inherently an inverse process -- we start with desired performance and work to find ...
Rob McDonald's user avatar
  • 13.2k
2 votes
Accepted

Are winglets symmetric airfoils? (Cessna Citation M2)

It is not unreasonable to continue into the winglet with the wing tip airfoil. In order to work best, the circulation (local lift coefficient times local chord) at the root of the winglet should ...
Peter Kämpf's user avatar
2 votes

Are there studies to find surface treatments to reduce the drag of an airfoil?

Yes, there are literally thousands of studies on the subject. A keyword search on this link brings up many examples. (credit to Sophit) There's also a similar question on this site that may be ...
Michael Hall's user avatar
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2 votes

Sluggish response to transients in very high L/D ratio airfoils

Just a couple of clarification from my side, sorry for being pedantic 😉 Since potential flow ignores viscosity, it cannot differentiate between a non-spinning cylinder and a spinning one. Potential ...
sophit's user avatar
  • 13.5k
2 votes

Why is the pressure lowest towards the front of an airfoil?

The pressure differential between upper and lower wing surfaces provides lift, and at both the leading and trailing edges of the wing it is zero. Your question is really why does the change in this ...
Pilothead's user avatar
  • 20.7k
2 votes
Accepted

How do I get rid of this chord line along the x-axis when importing an airfoil into XFLR5?

You most likely are importing the points with the wrong order. Usually programs are looking for points to start at the TE and go clockwise along the lower surface to the LE and then back to the TE ...
Rob McDonald's user avatar
  • 13.2k

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