What does a negative moment tell us about the characterisics of the airfoil?

Click For Summary
Increasing the angle of attack on the NACA-0012 airfoil results in a more negative pitching moment, indicating that the lift is concentrated towards the front of the airfoil. This negative moment is crucial for maintaining the longitudinal stability of an aircraft, particularly with cambered wings, which generate lift even in level flight. When the angle of attack is increased and the control stick is released, the negative pitching moment helps return the aircraft to a straight and level position. The discussion also touches on the importance of understanding coordinate systems in analyzing moments and stability. Overall, the negative pitching moment is a key factor in aircraft design and stability analysis.
  • #31
Right... both of those are named specifically as subheadings because they aren't treated the same.

Another list of books...
In fluids:
"Principles of Ideal-Fluid Aerodynamics" by Karamcheti - Moment has its own entry in the sense I use it.

"Viscous Fluid Flow" by White - Moment is used as I have described it.

"Fundamentals of Aerodynamics" by Anderson - Moment is used in several contexts as I have described it.

"Fundamentals of Fluid Mechanics" by Munson, Young and Okiishi - Separate entries for moment of inertia and moment of momentum as I have described.

"Theory of Wing Sections" by Abbott and Von Doenhoff - Moment is used as I have described; has a lot of stuff about pitching moments in particular.

"Low-Speed Aerodynamics" by Katz and Plotkin - Index doesn't refer to "moment" specifically, but points to moment coefficient. That section uses it as I have described it in relation to the pitching moment.

Other areas of mechanics:
"Dynamic Systems: Modeling and Analysis" by Vu and Esfandiari - Moment is used as I have described it and has a separate entry for moment of inertia.

"Classical Mechanics" by Taylor - Only refers specifically to moment of inertia

Those are the only books in arm's reach for me that talk about moments. All of them support me. I don't know how much more plain I can make it for you. In common engineering practice, the term moment refers to the first force moment. All other moments that are important are referred to by name.
 
Last edited:
Physics news on Phys.org
  • #32
boneh3ad said:
Right... both of those are named specifically as subheadings because they aren't treated the same.

Another list of books...
In fluids:
"Principles of Ideal-Fluid Aerodynamics" by Karamcheti - Moment has its own entry in the sense I use it.

"Viscous Fluid Flow" by White - Moment is used as I have described it.

"Fundamentals of Aerodynamics" by Anderson - Moment is used in several contexts as I have described it.

"Fundamentals of Fluid Mechanics" by Munson, Young and Okiishi - Separate entries for moment of inertia and moment of momentum as I have described.

"Theory of Wing Sections" by Abbott and Von Doenhoff - Moment is used as I have described; has a lot of stuff about pitching moments in particular.

"Low-Speed Aerodynamics" by Katz and Plotkin - Index doesn't refer to "moment" specifically, but points to moment coefficient. That section uses it as I have described it in relation to the pitching moment.

Other areas of mechanics:
"Dynamic Systems: Modeling and Analysis" by Vu and Esfandiari - Moment is used as I have described it and has a separate entry for moment of inertia.

"Classical Mechanics" by Taylor - Only refers specifically to moment of inertia

Those are the only books in arm's reach for me that talk about moments. All of them support me. I don't know how much more plain I can make it for you. In common engineering practice, the term moment refers to the first force moment. All other moments that are important are referred to by name.

I've already said 'moment' commonly refers to the first moment of force by convention.
 
  • #33
Then what are you arguing about? That has been my point all along yet you keep telling me I am wrong.
 
  • #34
boneh3ad said:
Then what are you arguing about? That has been my point all along yet you keep telling me I am wrong.

No it hasn't been your point all along. I made it first, and seem to have missed it. So what are you arguing about?
 
  • #35
Phrak said:
No it hasn't been your point all along. I made it first, and seem to have missed it. So what are you arguing about?

Claim what you want, that was not your point. I am done with this as it is going nowhere and serves no purpose.
 
  • #36
boneh3ad said:
Claim what you want, that was not your point.
It was.
I am done with this as it is going nowhere and serves no purpose.
See you later.
 
  • #37
Phrak said:
No, and this is the point. There is also the angular inertia, center of mass and total mass, and the moments involved in Euler buckling and torsional rigidity to obtain the radius or gyration.

None of which has anything to do with the question asked in the OP.
 
  • #38
mugaliens said:
None of which has anything to do with the question asked in the OP.

No. Indirectly, it does.
 

Similar threads

How does the pressure difference over a NACA 0012 affects its characteristics?
  • · Replies 1 ·
Replies
1
Views
3K
Airfoil moment performance details
  • · Replies 1 ·
Replies
1
Views
7K
How does the Enthelpy change tell us about the stability of the product?
  • · Replies 3 ·
Replies
3
Views
3K
A Bernoulli, lift and cause & effect
  • · Replies 30 ·
2
Replies
30
Views
4K
I Negative Mass and Hawking Radiation
  • · Replies 6 ·
Replies
6
Views
3K
What does negative voltage mean for MOSFET?
  • · Replies 18 ·
Replies
18
Views
9K
Torque/Moment of a bent wrench question
  • · Replies 4 ·
Replies
4
Views
3K
Job Skills Astronomer to Med Physicist or Dosimetrist - UK or US
  • · Replies 5 ·
Replies
5
Views
3K
What simple concept am I missing about moments?
  • · Replies 7 ·
Replies
7
Views
2K
B Learn About Moments & Equilibriums: What Does a Moment Mean?
  • · Replies 3 ·
Replies
3
Views
1K