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Questions tagged [lift]

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

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24 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 ...
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0answers
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Why do aircraft fly so high? [duplicate]

Now I know aircraft fly over 30,000ft for the following reasons -less air resistance (less drag) hence more fuel efficient ,no need to worry about any weather related events and to avoid skyscrapers ...
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5answers
204 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 ...
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3answers
409 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?
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1answer
66 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
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1answer
97 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?
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3answers
632 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 ...
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1answer
84 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 ...
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1answer
247 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,...
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50 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 ...
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1answer
103 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, ...
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1answer
105 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 ...
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4answers
1k 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 ...
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1answer
53 views

Can the back tail of an airplane move the center oft lift 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 ...
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1answer
125 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?
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51 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(...
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2answers
164 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 ...
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1answer
129 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, ...
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4answers
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 ...
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2answers
333 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 ...
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1answer
38 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=...
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2answers
146 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)
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3answers
512 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 ...
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2answers
171 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 ...
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2answers
101 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 ...
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1answer
143 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 ...
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79 views

What operational aspects of Alphabet's Wing drone delivery service will be the same as that of an airline?

The NPR News article and podcast FAA Certifies Google's Wing Drone Delivery Company To Operate As An Airline begins with: The Federal Aviation Administration has certified Alphabet's Wing Aviation ...
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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 ...
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2answers
319 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?
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4answers
12k views

How do conventional missiles fly?

With the exception of cruise missiles, most missiles don't have any obvious lifting device. If you watch a missile being fired, prior to its rocket firing it does exactly what you'd expect: ...
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3answers
149 views

How much can 3 fans 7 inches in diameter and each a generating 160 cubic feet per minute airflow rate lift? [duplicate]

I'm working on a hoverboard project and am having trouble finding out the maximum weight these fans could lift.
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5answers
369 views

Do horizontal stabilisers provide any lift?

Do jumbo and smaller airliners' horizontal stabilizers provide any lift? Apart from maintaining the aircraft's angle of attack, can they perform the dual function that includes adding some lift as ...
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1answer
343 views

How fast do four Tire-Propellers have to rotate to lift 2000 lbs? [closed]

I just saw this come out, Goodyear's Tire-Propeller Concept – a combination tire that can also act as propeller (well, more like a ducted fan I guess). There's a neat video that goes with it, ...
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1answer
282 views

What effect does the angle of attack have on lift and drag?

In general, what effect does the angle of attack have on lift and drag? I understand the the B-25 take-off run was normally in excess of 1500 ft, the exact value dependent upon load, density altitude,...
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3answers
7k views

Was the Space Shuttle aerodynamically neutral while piggybacking, or did the combination act like a giant biplane?

Trying to investigate this question, I see that 'Ask the Captain' says: The weight of the shuttle is calculated like any payload. The 747 produces enough lift to fly and to carry the weight of ...
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1answer
192 views

What disadvantages does flying a drone close under a ceiling have?

If I want a drone (quadcopter) to be flying always under a surface and close to this surface (i.e: under a table 5cm away from the surface), which are the disadvantages this would have in the lift ...
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4answers
374 views

How is vertical speed managed in Airliners? [duplicate]

When an Airplane starts to take off, the Horizontal velocity would generate it the necessary lift, and then Airplane pitches up to further increase the lift. As the Airplane is climbing up, the net ...
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2answers
469 views

How does wing aspect ratio influence lift and drag?

I know simmilar questions are all over the internet (and this website too), but there's one thing that i just cannot comprehend and none of the articles i read could explain it properly. According to ...
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37 views

Determine “basic lift distribution” over a wing that has a circulation distribution

I don't understand what they mean with basic lift distribution. I have calculated C_L which is 5a (a is alpha in radians). I added the relevant equations here.
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1answer
240 views

How do we derive Lift Coefficient of an airplane's wing?

In many references I read that lift coefficient ($C_l$) is a product of wind tunnel test. But many times I read the formula to calculate the coefficient of lift. From the lift equation, $$L=\frac{1}{2}...
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1answer
307 views

What was the lift equation used by the Wright brothers?

NOTICE: The modern lift equation and the lift equation used by the Wright brothers in 1900 are slightly different. The lift coefficient of the modern equation is referenced to the dynamic pressure ...
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5answers
477 views

How to recognize the horizontal winglet in the Horten design, or the experimental glider in this video?

Comments below the NASA Armstrong Flight Research Center video Proving Prandtl- With A Twist! incclude: This video is entirely a hidden jewel in youtube, it deserves much more attention than ...
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4answers
513 views

What would be a simple aerodynamics simulation software for a student? [closed]

I have a project due 2 weeks from now that demands we make a glider using Styrofoam. I'd like to simulate the results as I plan my glider before I build it. Which simple software, which allows ...
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2answers
462 views

What prevents BFS from becoming unstable when pitching from horizontal to vertical?

In this video from (SpaceX's BFS landing) there is a point where the ship tilts from horizontal « belly first » terminal velocity freefall, to vertical « engine first » landing position. The graph ...
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3answers
266 views

Why hasn't anyone tried making two propellers facing upwards and the other two facing downwards? [closed]

Within a quadcopter, I know usually it's all the propellers facing upwards or all of them facing downwards. Why hasn't anyone tried making two propellers facing upwards and the other two facing ...
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2answers
387 views

Does lift generation create a vacuum over an airfoil? [duplicate]

According to Bernoulli’s principle, airflow speeds up over an airfoil which decreases the pressure, and I read somewhere that when airflow speeds up over an airfoil, this creates a vacuum. Is this ...
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2answers
300 views

Does the Lilium VTOL wings produces lift during takeoff?

I just had a look on some of the recent development in the personal VTOL electrical aircrafts. I am wondering if the Lilium VTOL wings produces lift during takeoff? I would expect a quit high wind ...
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1answer
80 views

Calculate g's per radian

I'm currently attempting to assign handling qualities to the A-4D, and I would like to know how to find the term: $ n / \alpha = \overline{q} \times C_{L\alpha} / (W / S) $ where $C_{L\alpha}$ is ...
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4answers
509 views

Descending on a given glide slope (e.g. ILS) at a given airspeed— is the size of the lift vector different in headwind versus tailwind? [duplicate]

We had a discussion with friend and we were talking about if the airplane is on approach and the one is landing with tailwind and the other one is landing with headwind, so both have the same value of ...
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1answer
153 views

Why do I see moisture coming from the middle of the wing as well as wingtip vortices? [duplicate]

A lot of times I see small tube like streams of visible moisture training from the middle of an airliners wing. I assume this is induced drag created by wingtip vortices, when the aircraft is heavy, ...