Linked Questions

16
votes
4answers
2k views

Do any airplane designs exist that don't involve a flight surface that provides downforce?

Most aircraft maintain longitudinal stability by balancing three forces: The down force acting through the center of gravity (CG) The lifting force acting through the center of lift The down force ...
12
votes
2answers
1k views

Is the differential between the forward and aft CG limits indicative of the overall stability of an airplane?

Studying up on the Cessna 162 Skycatcher POH to take my checkride in soon and I noticed the differential between the maximum and minimum CG's is a mere 2.5 inches from one to another. I got curious ...
5
votes
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 ...
11
votes
4answers
922 views

Why does the aerodynamic center exist?

I am a glider pilot and instructor with a master’s degree in actuarial mathematics. I teach aerodynamics every winter for upcoming glider pilots. As you surely know, the aerodynamic center is the ...
4
votes
1answer
8k views

How to find the location of the Aerodynamic centre?

Everywhere I look I'm only able to find information about airfoils. How do I find out the location of the Aerodynamic centre of an arbitrary aircraft irrespective of its type or shape?
3
votes
3answers
1k views

Why can't Centre of pressure and Centre of Gravity coincide?

I understand that normally CG is placed ahead of COP so that a tail down force can make the aircraft stable. But why can't the COP and CG be placed in the same position so that there needn't be a tail ...
0
votes
3answers
3k views

How can I find the CG of a model aircraft based on its dimensions? [closed]

Given the dimensions and gross weight of an RC model aircraft, how can I find the center of gravity? Can I calculate it, or perhaps there's some way to approximate it?
9
votes
1answer
2k views

Why do some turbofan blade have forward swept tips?

I notice that in Trent700 engine fan blade there is no curve extension at the tip unlike in other engine's fan blades such as the GE90 ,T900 etc. What are the purpose of it? Trent 700 without ...
3
votes
5answers
1k views

Is the aircraft neutral point a function of the tail incidence angle?

While using XFLR v5 for a basic analysis I am facing this issue. For a fixed configuration I varied the tail incidence angle and XFLR is displaying a change in the Neutral point location. But as per ...
0
votes
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 ...
1
vote
2answers
469 views

Are there any airplanes with the Centre of Gravity behind the Centre of Pressure? [duplicate]

We are used to seeing a forward CG in all airplanes, from a small Cessna to a large Boeing. I wonder whether any airplane with CG behind wing CP exists in production? Is it even possible? If so, what ...
0
votes
2answers
914 views

if center of pressure moves forward with angle of attack, then does it move forward of center of gravity also at a particular angle?

Consider an aircraft where- Center of gravity lies forward of Center of Pressure in CRUISE. Now as angle of attack increases, CP moves forward, then for particular angle, it must move forward of ...
1
vote
2answers
700 views

Confusion about Aerodynamic center

suppose, i assume Aerodynamic Center lies at Center of gravity. Then apparently moment by lift will be zero about CoG. But in reality Centre of Pressure may be behind aerodynamic center and still be ...
2
votes
2answers
257 views

Why is the center of pressure of a rocket at its centroid?

From thin airfoil theory, at subsonic speeds, the center of pressure of any uncambered airfoil is at quarter chord. For sounding rockets, however, the center of pressure is generally assumed to be ...
2
votes
4answers
190 views

How much torque can a Boeing 747 apply when pitching?

I know this is a weird way of thinking about / quantifying this, but I'm trying to figure out how much torque a 747 can apply to itself when it pitches upwards (turning about an axis from wing to wing,...

15 30 50 per page