Linked Questions

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1answer
241 views

Why is subsonic lift at 25% of chord? [duplicate]

I pretty much understand the way a wing works and the different ways of explaining it, what I donĀ“t understand is why the lift on a subsonic wing manifest itself at the 25% chord.... The 50% chord ...
0
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1answer
389 views

Why is the Aerodynamic Centre not affected by changes in Angle of Attack? [duplicate]

I understand that the Aerodynamic Centre (AC) is the point in the aircraft where the pitching moment never changes with a change in Angle of Attack (AoA). My understanding of the Centre of Pressure (...
5
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3answers
2k views

Why do tailplanes provide down force, if not for longitudinal static stability?

We can see that most conventional aircraft have their horizontal tail surfaces arranged to provide a down force. This question asks if that is required for static longitudinal stability, and the ...
5
votes
1answer
10k views

Where is the best center of gravity?

I'm designing a plane, and I have a question. What is the best place for the center of gravity, relative to the center of lift? I've heard that it's best put just behind the center of lift, but I ...
3
votes
3answers
5k views

What is the physical meaning of Mean Aerodynamic Chord?

I have not been able to find a consistent definition of what it really is. I have come across definitions such as: "Physically, MAC is the chord of a rectangular wing, which has the same area, full ...
3
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2answers
9k views

How does centre of pressure change with angle of attack?

I've been given the distance of centre of pressure from the leading edge with a certain angle of attack and was wondering if it's possible to calculate the new position when the angle of attack ...
8
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1answer
1k views

Are the vortex generators on the Cessna Caravan necessary and sufficient for safety of flight?

I've been doing some reading about the C208B (Cessna Caravan) in prep for my new job flying cargo; I came across this article which (as far as I can tell) is a transcription of litigation surrounding ...
5
votes
2answers
3k views

Why do we calculate the pitching moment coefficient about quarter chord point?

Why do we calculate the pitching moment coefficient about quarter chord point, when force and moment system can be transferred to any convenient point?
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3answers
4k views

Why should the centre of mass be ahead of the centre of pressure?

Why is the centre of mass located ahead of the centre of pressure? And what would happen if centre of mass would be too close or too far away from the centre of pressure?
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3answers
6k views

Why does centre of pressure (drag?) move forward when transitioning from transonic to supersonic?

I am studying aerospace engineering at college and I am wondering why the centre of pressure moves forward when the aircraft changes from transonic flight to supersonic flight? Also, is centre of ...
4
votes
2answers
1k views

Is setting elevator to certain angle equal to trimming the horizontal stabilizer?

(I was trying to understand the longitudinal stability of aircraft and how it is related to elevator) If I pull the stick back by, say 2 inches, will it have the same affect as trimming the ...
1
vote
1answer
3k views

How can I calculate effective wingspan of a high aspect ratio model airplane?

I've heard of people talking of wingspan and effective wingspan. Considering: L = Lift Coefficient . 1/2 Rho . Velocity ^ 2 . Surface Area, I understand that tip ...
2
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2answers
2k views

What are the effects of camber location in an airfoil?

Am I correct to assume that for a low speed aircraft, the location of the camber in the MAC's airfoil will correspond with the aerodynamic center? Also, does that affect the moment coefficient? And ...
1
vote
3answers
463 views

What is the relationship between centre of gravity, centre of pressure and pitch?

Ok so I've got a couple of questions regarding CG, CP and pitch 1) When the aircraft is taking off, is the tail down force required to pitch up the aircraft high? Because the aircraft always has a ...
0
votes
1answer
1k views

Which moments are acting on a flying airplane?

I would like to ask some clarifying questions regarding the moments acting on a flying airplane. My understanding is that there are following force: Weight (pointing down and applied to the CG of ...

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