Aerophysics Exploration Pages

Welcome to the Aerophysics Exploration Pages!

 

 

This page was last modified November 4, 2006

 

This feature will present many of the ideas explored elsewhere on the Aeroexperiments website in a more integrated manner.

 

Unlike the articles found in the "Practical" section of the Aeroexperiments website, these tutorial pages are aimed at exploring some interesting aspects of the theory of flight.

 

Each of the "Aerophysics Exploration Pages" is currently still under construction. More text, and many more photos and diagrams and links, will be added to many of the the existing sections in the future. Many new sections will also be added. Nonetheless the "Aerophysics Exploration Pages" are intended to be fully operational--every active link is meant to be of some interest or benefit to the reader.

 

Note to readers interested primarily in the dynamics of flex-wing hang gliders and trikes : all the articles marked with " * " on this index page will be of special interest. Some of these articles may appear to pertain mainly to "conventional" 3-axis aircraft, but actually lay the groundwork for understanding what follows. At present the asterisk coding system only appears on this index page.

 

Note to readers interested primarily in the dynamics of non-weight-shift aircraft: all the articles pertaining primarily to "flex-wing" aircraft (i.e. weight-shift aircraft without aerodynamic controls) are clearly identified as such, and can be skipped over without compromising the articles that follow. However, you might learn some interesting and unexpected things by reading these articles!

 

Note: please don't use the letters in this outline for long-term reference, as new pages will be inserted from time to time as the tutorial expands.

These links now open as new windows.

 

At present, there are many concepts that are explored briefly with both images and text on the page entitled "Pool of images for the Aerophysics Exploration Pages", that are not yet explored anywhere else in the Aerophysics Exploration Pages. This will change as construction continues.

 

 

Outline for the "Aerophysics Exploration Pages":

 

* a) 2 paths

 

* b) An "unconventional" approach?

 

* c) Your thoughts are welcome...

 

* d) What is a turn?

 

* e) Definition of the relative wind

 

* f) 2 kinds of yaw

 

* g) Oblique and side views of aircraft with dihedral

 

* h) A definition of dihedral

 

* i) Oblique and side views of aircraft with anhedral

 

* j) A definition of anhedral

 

k) The rudder as a roll control: aircraft with dihedral

 

l) The rudder as a roll control: aircraft with anhedral

 

* m) Definition of a "positive coupling between yaw (slip) and roll"

 

* n) Definition of a "negative coupling between yaw (slip) and roll"

 

* o) "Conventional" use of the rudder

 

* p) Definition of a "coordinated" turn

 

* q) Definition of a "slipping" turn

 

* r) Definition of a "skidding" turn

 

* s) Roll torque created by dihedral during slips and skids

 

* t) Roll torque created by anhedral during slips and skids

 

* u) Oblique and side views of "W"-shaped wings

 

* v) Oblique and side views of "M" shaped wings

 

* w) The flexible hang-glider wing: how billow contributes to anhedral

 

* "Conventional" measurements of dihedral or anhedral can be inadequate

 

* x) Looking at anhedral in flex-wing hang gliders: VG off versus VG on

 

* y) Sweep creates a dihedral-like effect

 

* z) The dihedral-like effect of sweep depends strongly upon angle-of-attack

 

* aa) The roll torque created by dihedral or anhedral is not strongly dependent on the angle-of-attack of the wing as a whole

 

* ab) Competing effects of sweep and anhedral

 

* ac) Interesting experiments: Zagi RC glider with variable anhedral/dihedral geometry, and rudder

 

* ad) Interesting experiments: adding a controllable rudder and other yaw devices to 4 flex-wing hang gliders

 

* ae) Interpreting in-flight observations: roll torque created by the combined effects of anhedral and sweep in flex-wing hang gliders, VG off versus VG on, high airspeed versus low airspeed

 

* af) A more "complete" consideration of adverse yaw in flex-wing hang gliders, with notes on fixed vertical fins: does adverse yaw create a helpful roll torque or an unfavorable roll torque?

 

* ag) In-flight observations supporting the idea that a flex-wing hang glider has more anhedral with the VG off than with the VG on, with notes on yaw-roll oscillations, tow dynamics, and spiral instability

 

* ba) The main cause of adverse yaw during rolling motions: the "twist" in the relative wind

 

* bb) Roll and yaw torques due to the difference in the airspeed of the left and right wingtips

 

* bc) Curvature in the relative wind about the yaw axis

 

* bd) A constant-banked climbing or descending turn involves a continual rolling motion

 

* Other causes of adverse yaw

 

* ca) Misconceptions: The "simple" view of how dihedral contributes to roll stability

 

* cb) Misconceptions: the "sideways gravity" and "missing lift" explanations of how dihedral contributes to roll stability

 

* cc) A "holistic" view of how dihedral contributes to roll stability and anhedral contributes to roll instability

 

* cd) Seeking pilot input on the effect of a vertical fin on flex-wing hang gliders

 

* Other factors that contribute to spiral instability: "effective span"

 

* ce) Spiral instability in flex-wing hang gliders: VG on versus VG off

 

* cf) The "parasol" or "pendulum" effect: location of the wing above or below the aircraft CG: influence on yaw (slip) roll coupling and spiral stability or instability, with notes on flex-wing hang gliders and paragliders

 

The "cabin" effect: blocking the airflow around the wing: influence on yaw (slip) roll coupling and roll stability or instability

 

da) More detailed definitions of "slips" and "skids"

 

* db) Aerodynamic sideforce during slips and skids

 

dc) Sideslips and forward slips

 

dd) "Kicking out the crab"

 

* de) The aerodynamic sideforce generated by a slip depends on the shape of the aircraft

 

The rudder makes a "wrong-way" sideforce (under construction)

 

Notes on using the rudder in a twin-engined aircraft with one "dead" engine

 

Unusual cases: "drifting" in the upwind direction!

 

* Misconceptions: the quest for the "flat turn"

 

* Misconceptions: ideas about "slipping turns" in hang gliders and trikes

 

* A fundamental reason for our pitch "coordination" inputs: keeping the vertical forces nearly balanced

 

* A fundamental reason for our pitch "coordination" inputs: curvature of the relative wind about the pitch axis during turning flight

 

* ya) Pool of images for the Aerophysics Exploration Pages

 

* za) Selected links from remainder of Aeroexperiments website: "You can't 'feel' gravity!"

 

* zb) Selected links from remainder of Aeroexperiments website: Complete analysis of forces: fully balanced turn, turn with inadequate lift or G-load, slipping turn, non-turning slip, and skidding turn

 

* zc) Selected links from remainder of Aeroexperiments website: Brain teasers for those who believe that downwind turns are "different"--i.e. that an aircraft can "feel" the wind direction in flight

 

* zd) Selected links from remainder of Aeroexperiments website: Downwind turns ARE "different"!

 

ze) Selected links from remainder of Aeroexperiments website: Notes on dynamic soaring

 

zf) Selected links from remainder of Aeroexperiments website: The never-ending myth of the "dangerous downwind turn"

 

 

Up to Aeroexperiments site map

Copyright © 2004 aeroexperiments.org