# Questions tagged [lift]

The force acting on an aircraft in opposition to gravity which keeps the aircraft in the air.

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151 views

### What is the amount of lift produced by friction?

As Mr. John D. Anderson states, the aerodynamic forces on a body are due to only two sources: pressure distribution over the body and shear stress distribution. Shear stress is acting tangential to ...
749 views

### What is boundary layer tripping?

I came across the term "Boundary layer tripping" but I can't really underastand it. After searching on internet I cannot find any video or an image explaining that concept. Could you please explain ...
158 views

### Tapered Wing Providing low Coefficient of Lift

Hi I am currently analyzing different wing designs using ANSYS Fluent. One of my designs has a straight leading edge but a swept trailing edge thus it is tapered with wing root chord at 50mm and wing ...
188 views

### How does an aircraft maintain an orientation that was actually caused by a external disturbance?

What is the difference between centre of pressure, aerodynamic centre and neutral point? At this link, there is an image used to explain the answer, but not much has been spoken about it. I ...
723 views

### Why do autogyros exist? [duplicate]

This question has been intriguing me for some time. In Autogyro the rotary blades merely acts as what fixed wings act in normal aircrafts to generate lift. So why not simply have a fixed wing instead ...
229 views

### Can lift be increased by increasing the angle of incidence of the wing? [closed]

Can the lift of a plane be increased by increasing the Angle of Incidence (angle between the chord line of the main wing and the axis of the fuselage)? Meaning, can more lift be generated while the ...
151 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 ...
199 views

### Would it be a good idea to use dihedral on a biplane?

My engineering class uses model plane kits to build "frankenflyers" which use parts from multiple model planes to make one plane that will carry a maximum load (pennies). I was wondering what the best ...
96 views

### At which angle tiltrotor's rotors generates more lift?

[Tiltrotor 1] [Tiltrotor 2] I can't name these tiltrotors. I just want to know which of the tiltrotors generate more lift considering aerodynamics and based upon the rotors ...
66 views

### Is there any bibliography for triplane aircraft design?

I've been tasked with designing an RC aircraft that has the greatest lift force for a specified wingspan, total length and takeoff velocity, and thus have been studying the different wing ...
398 views

### Does downwash increase or reduce lift generation?

I’m wondering about the impact of downwash on lift generation. I've read that, because downwash creates lift according to Newton's third law of motion, increases in downwash due to greater AoA (...
39 views

### What is the effect of wing flex on wing's airfoil shape and its performance effect on wing?

There are good amount of discussion on wing flex in this forum. I am more interested in understanding the effect of flex on aerofoil shape of the wing and its impact on flight performance. Do ...
663 views

### Why don't smaller powered airplanes have better lift-to-drag ratios?

Many airliners have LDRs near 20, and it sounds like the electric Eviation Alice may have an LDR of 24 at 240 kts, but many small planes typically have LDRs of only 8-10. It seems like they could ...
291 views

### Aerodynamics of Flight Control Surfaces

From what it appears to me, flight control surfaces seem to be taken for granted. In terms of how they actually work and what kind of physical outputs they give in terms of forces and such. Take for ...
132 views

### Derivation of the Takeoff equation

I am trying to understand the derivation of some simple equations to calculate the neccecary takeoff speed for an airplane (under ideal conditions). Which is taken from 15. Takeoff and Landing. My ...
278 views

### What is the definition of Lift?

Lift is a term that is used very frequently here, but I cannot find any post explaining what it is exactly. I am looking for the exact definition of lift, not an explanation of how it is generated. ...
7k views

### Can a wing generate lift in excess of its aircraft's weight?

"For a plane or bird to fly, its wings must produce enough lift to equal its weight. " I got that excerpt from "https://www.sciencelearn.org.nz/resources/300-wings-and-lift". My questions: (1) Can ...
383 views

### How is d(Cl)/d(alpha)@stall and Cl increment to stall defined in Xrotor?

I hope there are some people around here with some experience in Xrotor than me. (Xrotor is:"XROTOR is an interactive program for the design and analysis of ducted and free-tip propellers and ...
1k views

### What is suction peak?

Can anybody explain to me what suction peak is and does it have anything to do with lift and drag? I've read that suction peak is the point where the coefficient of pressure is the least and is ...
184 views

### Was the Coanda effect known in 1868 to Matthew Piers Watt Boulton (the one who described the first ailerons)?

Matthew Piers Watt Boulton is known as the inventor whose 1868 British patent No. 392 nullified any claim of the Wright brothers that they discovered the ailerons (see FIG. 5-7). It seems now that ...
282 views

### How do I factor sweep and dihedral in the lift equation?

I'm guessing that you add cos(angle of dihedral) to calculate lift loss by dihedral, but I'm not sure how to factor in the lift loss by the wing swept. Could someone help me include lift loss due to ...
35 views

### Calculating Lift of a closed-wing drone

A group of students and I are designing a theoretical closed-wing drone and need to calculate lift based on the NASA lift equation. We've designed fixed-wing aircraft before and when it came to ...
363 views

### How much of an airplane's forward energy is lost to lift?

An airplane needs to move forward to generate lift, and because energy isn't created from nothing, all the kinetic energy of lift comes in the form of drag, where air (air resistance) turns forward ...
768 views

### What is the purpose of the propeller?

The propeller generates thrust, but what is the purpose of thrust of propeller? Is it to help the aircraft move forward or to produce lift to rise up?
125 views

### What is difference between pitch & lift? [closed]

What is the difference between pitch and lift of an aircraft?Please kindly try to include graphics with your answers
106 views

### Is there a V speed for the point an aircraft starts an ascent at 0 angle of attack?

Some aircraft with an angle of incidence or cambered airfoils are capable of climb without any angle of attack, Is there a V speed for the speed at which an aircraft starts a positive climb?
5k views

### In the Cl vs Cd graph, Why the drag coefficient decreases initially with the small increment in lift coefficient?

Cd = Cdo + KCl2 Total drag = Parasite drag + Induced drag When Cl = 0 , Cd = Cdo Increasing in Cl introduces another component of drag (Induced Drag) and therefore the total drag Cd should be ...
155 views

### Downwash distribution on basis of Lift distribution

I am new here so I might make some elementary mistakes. Correct me if I am wrong. I just stumbled upon the downwash distribution for a given lift per unit span distribution along the wingspan. I have ...
339 views

### What are the relative contributions of the body and wings to missile lift?

Slender bodies like arrow shafts, airliner fuselages, and submarine hulls are all capable of generating lift, albeit much less efficiently than a high aspect ratio wing. They also generate little drag,...
1k views

### How do I calculate the center of lift?

See my other question here for the background context. Consider this simple plane. I have applied the 4 basic forces: lift, drag, weight, and thrust. My question is, where, precisely, do I apply the ...
404 views

### Why is ground effect greater over smooth hard surfaces?

Helicopter Flying Handbook: Ground effect is the increased efficiency of the rotor system caused by interference of the airflow when near the ground. The air pressure or density is increased, ...
154 views

### What is an example of a quantitative analysis for the lift using Newtonian mechanics?

There are several different ways of explaining how an airplane generates lift. The simpler qualitative explanation uses Newtonian mechanics (the third law is invoked to explain how the wing pushes air ...
3k views

### How does speed affect lift?

I understand the lift coefficient shown above. But does lift increase with speed, and how? I understand I can't apply this to the graph as it is a coefficient, but if I had an angle of attack of 10 ...
231 views

### Can the back tail of an airplane move the neutral point backwards?

I'm currently in the process of designing a prototype aircraft and since I don't have very much experience with this I have the following question: I know that the center of gravity of an airplane ...
135 views

### Is lift generated only by wings? [duplicate]

In modern aircraft is lift only generated by wings or can other parts of fuselage generate a significant amount as well, to the point it needs to be accounted for when designing a plane?
121 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(...
364 views

### Why do Wingtip Vortices affect the upwash ahead of the aerofoil?

I understand that wingtip vortices increase the downwash aft of the aerofoil and the theory that they will alter the effective airflow angle, reducing effective angle-of-attack, with the total ...
391 views

### How beneficial are flaps when landing with a tailwind?

I understand that flaps are devices used to increase the amount of lift and drag. When landing with a tailwind your groundspeed will be higher. Therefore, flaps would help reduce this groundspeed, ...
3k views

### How can lift be less than thrust that is less than weight? [duplicate]

Physics in schools teaches two contradictory and mutually exclusive things: That the upward lift force on an airplane in flight equal its weight (Lift = Weight = Mass x Gravity). This is based on ...
631 views

### How much lift does the wing attach fitting actually carry?

How do I calculate the lift force that the the bolt that join the wings to the fuselage of a strutted or braced airplane carry? I know in a cantilever airplane,the bolts have to carry all of the lift ...
59 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=...
3k 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)
5k views

### Is there a simple relationship between angle of attack and lift coefficient?

Is there an equation relating AoA to lift coefficient? I have been searching for a while: there are plenty of discussions about the relation between AoA and Lift, but few of them give an equation ...
219 views

### Will creating a strong back pressure within a ducted propeller enable an aircraft to attain a higher altitude?

I would like to know if creating a strong back pressure within a propeller duct will enable an aircraft to attain a higher altitude. Please reference the conceptual drawing below. This is showing a ...
165 views

### Trying to find the vertical acceleration by subtracting weight from lift

I'm trying to determine the vertical acceleration component of a plane with the following specifications: Density of air: 1.29kg/m3 Speed: 33 m/s Wing area: 13.97 m2 Lift Coefficient: 1.5 Mass:560 kg ...
630 views

### How do changes in flight affect L/D max and the speed at which I must travel to maintain it?

I have an plane flying at L/D max and I want to maintain L/D max. Firstly, if this plane burns through a portion of fuel and becomes lighter, how would I have to change the speed to maintain it? My ...
62 views

### What is the relation between solidity and lift coefficients?

I've seen this graph in a couple of places. I'm not sure what it's supposed to mean, as the formulae I've seen in the papers cannot be found in any standard book or reference. Please let me know if ...
980 views

### Why isn't the bell distribution used?

Why has the bell distribution not become widely used? Is the bell distribution only ideal in inviscid flow scenarios or is there another reason for the lack of use?