Note Sept 16 2006: this page is no longer being kept current. The URL for the current version of this page is now www.aeroexperiments.org/AEP.shtml

Welcome to the Aerophysics Exploration Pages!

 

 

This section is still under construction...

This page was last modified September 16, 2006

 

These pages will be heavily based on graphics and photos rather than text, and will present many of the ideas covered elsewhere on the Aeroexperiments website in a much more concise format.

 

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.

 

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.

 

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--though many more diagrams and photos will be added to most of the articles in the future.

 

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 tutorial pages. This will change as construction continues.

 

 

Outline for the "Aerophysics Exploration Pages":

 

* a) 2 paths

 

* b) An "unconventional" approach?

 

* c) What is a turn?

 

* d) Definition of the relative wind

 

* e) 2 kinds of yaw (under construction)

 

* f) Oblique and side views of aircraft with dihedral (under construction)

 

* g) A definition of dihedral

 

* h) Oblique and side views of aircraft with anhedral (under construction)

 

* i) A definition of anhedral

 

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

 

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

 

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

 

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

 

* n) "Conventional" use of the rudder (under construction)

 

* o) Definition of a "coordinated" turn (under construction)

 

* p) Definition of a "slipping" turn (under construction)

 

* q) Definition of a "skidding" turn (under construction)

 

* r) Roll torque created by dihedral during slips and skids (under construction)

 

* s) Roll torque created by anhedral during slips and skids (under construction)

 

* t) Oblique and side views of "W"-shaped wings (under construction)

 

* u) Oblique and side views of "M" shaped wings (under construction)

 

* v) The flexible hang-glider wing: how billow contributes to anhedral (under construction)

 

* "Conventional" measurements of dihedral or anhedral can be inadequate (under construction)

 

* w) Looking at anhedral in flex-wing hang gliders: VG off versus VG on (under construction)

 

* x) Sweep creates a dihedral-like effect

 

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

 

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

 

* aa) Competing effects of sweep and anhedral

 

* ab) Interesting experiments: Zagi RC glider with variable anhedral/dihedral geometry, and rudder (under construction)

 

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

 

* ad) 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

 

* ae) 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?

 

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

 

* Other causes of adverse yaw (under construction)

 

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

 

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

 

* 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" (under construction)

 

* 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 (under construction)

 

* Curvature in the relative wind during yawing motions: the airflow follows the path of the turn (under construction)

 

da) More detailed definitions of "slips" and "skids" (under construction)

 

* db) Aerodynamic sideforce during slips and skids (under construction)

 

dc) Sideslips and forward slips (under construction)

 

dd) "Kicking out the crab"

 

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

 

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

 

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

 

Unusual cases: "drifting" in the upwind direction! (under construction)

 

* Misconceptions: the quest for the "flat turn" (under construction)

 

* Misconceptions: ideas about "slipping turns" in hang gliders and trikes (under construction)

 

* ya) Pool of images for the Aerophysics Exploration Pages (under construction)

 

* 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

 

 

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