Linked Questions

13 questions linked to/from Is the induced drag independent of wing span?
21 votes
3 answers
19k views

What dictates the aspect ratio of an aircraft's wing?

When designing an aircraft, there has to be a decision as to the aspect ratio of a wing. It's been said that having a higher aspect wing will reduce drag for the same wing area, however most of the ...
• 10.4k
10 votes
4 answers
3k views

Why do we use dimensionless expressions in flight mechanics and aerodynamics?

Why do we use non-dimensional expressions in flight mechanics and aerodynamics? We could as well directly calculate forces and moments; would that not be more relevant to the specific problem?
4 votes
3 answers
19k views

How does the aspect ratio of a wing impact its lift?

The wing lift formula shows that lift of a wing is proportional to its area. \$ L = {\dfrac 1 2 \times \rho V^2 \color{magenta}S C_L} {\small \begin{align} &{} &&\text{where:} &&L =...
• 165
6 votes
3 answers
4k views

What is the relation between drag and weight?

Given an aircraft type and fixing its wing configuration (flaps, slats) and fixing its speed and altitude and assuming it flies horizontally, what is the relationship between the aerodynamic drag and ...
2 votes
4 answers
1k views

Explained intuitively, why does aspect ratio affect induced drag?

Over the last few hours, I've been trying to intuitively understand induced drag, and how aspect ratio affects it. I already know the equations, but while they explain the relationship, they do not ...
3 votes
4 answers
5k views

How can I find the optimum chord wing length for this wing?

This Aviation SE forum looks the perfect place to ask this question: people here usually make maths the root of most solutions and I think this may solve my aerodynamic optimization problem! I am ...
• 203
5 votes
2 answers
2k views

Is there a downwash equation?

I need to find an equation for the following problem: Suppose a full-size glider passes 10 feet over my head at high speed. No doubt I will feel the downward air pressure (downwash) caused by the ...
3 votes
2 answers
1k views

What is the relationship between angle of attack and wake turbulence?

It is said that when the preceding airplane is heavy, clean, and slow, wake turbulence is much hazardous due to greater angle of attack is requried. However, why does increasing angle of attack result ...
• 1,737
1 vote
2 answers
2k 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 ...
• 113
4 votes
1 answer
550 views

How can a designer maximize the glide ratio of an aircraft with low aspect ratio wings, other than by increasing the aspect ratio?

As I understand it, the gliding range is given by a lift to drag ratio—hence to increase the gliding range, I would want to increase the lift and reduce the drag as much as possible. To that end, ...
• 161
0 votes
4 answers
332 views

Why should I not use a "lifting tail" on my ultralight design?

In my misspent youth I designed and built many rubber, gas, and RC models. When I wanted good climb and glide I used a aft CG [60 to 80%] and a lifting tail. I had no stability or control problems, ...
1 vote
2 answers
205 views

Need to add elevator downforce to total lift when sizing wing area?

Do I need to add elevator downforce to total lift when sizing wing area? Say a small airplane weighs 1,000 lbs, and both the wing and elevator have a max Cl of 1.5, and my elevator is 20% of my wing ...
• 1,507
0 votes
2 answers
183 views

Why Lift-induced Thrust Required(Tr) decreases and Zero-Lift Tr increases with the increase of velocity? [duplicate]

As the minimum Tr is at the point where L/D (lift/drag) ratio is the most. And Lift-induced Tr depends on the Coefficient of Lift, (Cl)^2 and Dynamic Pressure (q) which also increases as velocity ...