Maximizing Wing Lift and Minimizing Wing Drag: The Role of Speed in Aerodynamics

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In summary, the problem is that the author is not sure how to obtain speed using a Wing Lift and Wing Drag. They feel the need for speed and are not sure if using a set speed or calculating the speed is the best way to go about it. They also mention that density and area should be known, and that weight should be measured in Newtons. They need to determine the lift using a Wing Lift and Wing Drag equation, and if they are testing airfoils then they would supply their own V.
  • #1
Jones1987
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Hi guys,

Problem I'm having is, I need to obtain speed.. I'm not sure how I go about this. I need this to obtain my Wing Lift and Wing Drag.

So I'm not sure if I use a set speed of my choosing, or if there is a way to calculate the speed.

This is the equation I'm using:

Lift = 1/2 density * (v^2) * (Platform Area) * CL
 
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  • #2
V is just the air velocity. You should know this already. No calculation is necessary.
 
  • #3
I feel the need The need! for speed.
 
  • #4
What do you know about the problem?

Density should be known. Assuming you have a wing geometry you know the area, and you should know the weight and for steady level flight Lift=Weight. So you are left with v and CL. You can choose a speed and determine the CL and hence angle of attack necessary assuming you have the data for your wing or you know how to estimate/calculate CL.
 
  • #5
RandomGuy88 said:
What do you know about the problem?

Density should be known. Assuming you have a wing geometry you know the area, and you should know the weight and for steady level flight Lift=Weight. So you are left with v and CL. You can choose a speed and determine the CL and hence angle of attack necessary assuming you have the data for your wing or you know how to estimate/calculate CL.

Density and area we have from the material and total area of the wing. I've seen this Lift = Weight before but I don't understand? If the weight of the total aircraft is 10kg, then lift is equal to 10kN of force?

We have CL values as I am using already made airfoils. I did question if you give your own v value, however me and my design buddy have come out with some chronic results...
 
  • #6
Weight is not measure in kilograms. That is your first problem. Weight is measured in Newtons, as it is a force.

What are you actually trying to determine here? Is the ultimate goal to find the air velocity or the lift?
 
  • #7
What exactly are you trying to do? Are you designing an airplane or testing airfoils?

Lift = weight applies for steady level flight. If lift is equal to weight then there is no net vertical force on the aircraft so you will not accelerate in the vertical direction. If you are climbing then lift > weight. And 10kg is mass, to get weight multiply by the gravitational constant.

Force = mass x (9.81 m/s^2)

Of course you pick your own velocity, at least that is the idea. When you are flying a plane whether it be a small remote controlled plane or a large passenger jet the pilot controls the throttle. So when the force from the propulsion system is equal to the drag of the aircraft you will reach a steady speed and at that speed there will be once value of CL ( angle of attack) that will set lift equal to weight and then you will be in steady level flight.
 
  • #8
The aim is to choose an airfoil which suits the needs for our aircraft to fly. It needs to carry a specific weight for x amount of time. So currently, testing airfoils is the objective to attach to a fuselage and to analysing the different outcomes of a variety of airfoils.

So I assumed you would choose your own v values, but my friend was adamant you needed to know the v value from another source. This is where the confusion has come from.

We have the density, the area and the CL, so we need to work out the Lift. But now you have explained v is purely a value of our choice, it has cleared up one of the problems.
 
  • #9
Are you taking into account the fact that your wing lift coefficient at a a given angle of attack will be less than the airfoil's lift coefficient at that same angle of attack due to the downwash from the tip vortices.
 
  • #10
If you are testing like that, then you supply your own V. You pick a V, tune your wind tunnel or CFD code to that V and see what happens.
 

1. What is the relationship between speed and aerodynamics?

The speed of an aircraft plays a crucial role in its aerodynamics. Generally, as the speed of an aircraft increases, so does its lift and drag. However, there is an optimum speed at which the lift is maximized and the drag is minimized, resulting in the most efficient use of energy.

2. How does the shape of the wing affect lift and drag?

The shape of the wing, specifically its curvature and angle of attack, greatly impacts the lift and drag generated. A curved wing creates more lift but also more drag, while a flat wing creates less lift but also less drag. The angle of attack, or the angle at which the wing meets the air, also plays a role in determining the amount of lift and drag produced.

3. Can the weight of the aircraft affect its aerodynamics?

Yes, the weight of an aircraft does have an impact on its aerodynamics. A heavier aircraft will require more lift to stay in the air, resulting in higher drag and reduced speed. Conversely, a lighter aircraft will require less lift and experience less drag, allowing for a higher speed and more efficient flight.

4. How does air density affect aerodynamics?

The density of the air also has a significant impact on aerodynamics. As air density decreases, such as at higher altitudes, the lift and drag forces on the wing are also reduced. This is because the air molecules are more spread out, making it harder for the wing to generate lift. As a result, the speed at which an aircraft needs to fly to achieve optimum lift and drag also changes with air density.

5. How do pilots and engineers use speed to maximize lift and minimize drag?

Pilots and engineers use various techniques to manipulate the speed of an aircraft in order to optimize lift and drag. This can include adjusting the angle of attack, using flaps and slats to change the shape of the wing, and controlling the engine power. By finding the optimum speed for a given aircraft and flight conditions, pilots and engineers can achieve maximum lift and minimum drag, resulting in efficient and safe flight.

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