Saturday, January 29, 2011


From Wikipedia:  "Dihedral angle is the upward angle from horizontal of the wings or tailplane of a fixed-wing aircraft.  Anhedral angle is the name given to negative dihedral angle, that is, when there is a downward angle from horizontal of the wings or tailplane of a fixed-wing aircraft.

"Dihedral angle (or anhedral angle) has a strong influence on dihedral effect, which is named after it. Dihedral effect is the amount of roll moment produced per degree (or radian) of sideslip.

"Longitudinal dihedral is a comparatively obscure term related to the pitch (flight) axis of an airplane. It is the angle between the zero lift axis of the wing and horizontal tail. Longitudinal dihedral can influence the nature of controllability about the pitch axis and the nature of an aircraft's phugoid-mode oscillation."

Northern Harrier (female).

A lot to keep in mind while hunting a tasty vole.


KaHolly said...

Hopefully, it comes naturally!

Kyna said...

I'm a pretty educated person. I don't believe I've ever seen the word 'phugoid' before. I'm impressed. :)

(nice pics!)

mainly mongoose (Lynda) said...

Fearing that I may be suffering from phugoid-mode oscillations, I rushed to the dictionary. It's not there. Is this a hoax to strike panic into the hearts of flying beasts?

Hugh said...

Phugoid is a very good word that I had never heard before either. Phugoid mode oscillation refers to the slowing and speeding of an aircraft as it alternately pitches up and down.

biobabbler said...

Uh, you're kinda freaking me out, 'cause this weekend I was looking at a series of silhouettes of birds either soaring or gliding. The series was designed to help you identify birds in flight. This post of yours is the PERFECT follow up. =) Now, if only I could remember it all. =) Thanks!

Heidi Van Impe said...

"Noom noomneenoom...dihedraling, dihedraling...ooohh vole..pitch axis, phugoiding, keep it steady and don't call me Shirley!"