======================================================
= ASW 20                                             =
= 15-meter class sailplane                           =
= for FlightGear with LaRCsim and the UIUC Aeromodel =
=                                                    =
= Flight model by:                                   =
= Michael Selig, et al. (m-selig@uiuc.edu)           =
= http://www.aae.uiuc.edu/m-selig/apasim.html     =
=                                                    =
= External model by:                                 =
= Roland Stuck (rstuck@evc.net)                      =
======================================================

To run, try:

fgfs --aircraft=asw20-v1-nl-uiuc

Files and directory structure required in $FG_ROOT/Aircraft/ to fly the
model:

asw20-v1-nl-uiuc-set.xml
asw20/Models/uiuc/asw20-stuck/asw20-stuck-model.xml
asw20/Models/uiuc/asw20-stuck/asw20.mdl
asw20/Models/uiuc/asw20-stuck/asw20mp_.0af
asw20/Models/uiuc/asw20-stuck/asw20mp_.1af
asw20/Models/uiuc/asw20-stuck/asw20mp_.2af
asw20/Models/uiuc/asw20-stuck/asw20mp_.3af
asw20/Models/uiuc/asw20-stuck/asw20mp_.4af
asw20/Models/uiuc/asw20-stuck/asw20mp_.5af
asw20/Models/uiuc/asw20-stuck/asw20mp_.6af
asw20/Models/uiuc/asw20-stuck/asw20mp_.7af
asw20/Models/uiuc/asw20-stuck/asw20mp_.8af
asw20/Models/uiuc/asw20-stuck/asw20mp_.9af
asw20/Models/uiuc/asw20-stuck/asw20mp_.aaf
asw20/Models/uiuc/asw20-stuck/asw20mp_.baf
asw20/Models/uiuc/asw20-stuck/asw20mp_.caf
asw20/Models/uiuc/asw20-stuck/asw20mp_.daf
asw20/Models/uiuc/asw20-stuck/asw20mp_.eaf
asw20/Sounds/uiuc/asw20-sound.xml
UIUC/asw20-v1-nl/CDfa-01.dat
UIUC/asw20-v1-nl/CLfa-01.dat
UIUC/asw20-v1-nl/Cmfa-01.dat
UIUC/asw20-v1-nl/Cmfade-01.dat
UIUC/asw20-v1-nl/aircraft.dat

These files above come with the FlightGear base package.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Model description and updates:

6/8/03: - Update: 

* Added spoilers using j/k keys to close/open spoilers.
  Added flaps    using [/] keys to raise/drop flaps

* Set control deflections to be like ASW 27 for now.  Still looking
  for ASW 20 manual.
       
12/25/02 - Update: 
       
* Elevator deflections up/down were swapped. Fixed w/ this one.

* Add wind noises to sound file.

11/8/2002 - First release: v1-nl

* Roland Struck (rstuck@evc.net) has granted FlightGear permission to
  use and release the external model files with FlightGear under the
  GNU GPL.

* This flight dynamics model simulates an ASW 20 15-meter sailplane.  

* A weights and balance was performed to arrive at an allowable
  c.g. location and from that data, mass moments of inertia were
  calculated.

* Lift, drag and pitching moment data is modeled from -180 to +180
  deg.  In general, the aerodynamics are modeled using various sources
  too numerous to mention here.

* Apparent mass effects are modeled.

* The simulation starts on the ground.  To simulate being tow, the
  throttle can be used.  The "thrust" was tuned to simulate a
  reasonable line tension and max rate of climb while on tow.
  Alternatively, Ctrl-U can be used to jump up in 1000-ft increments.

* Interesting flight characteristics to note:

  - When starting out, quickly change views to see the external
    aircraft.  The wings will start out level, and then one side will
    drop.  For whatever reason, the left wing drops first even though
    the data in the model is symmetrical.

  - Taking off requires careful control of the rudder and ailerons.
    Use rudder to line up with the runway and ailerons to level the
    wings.  It is easy to over correct (especially without a
    headwind), and the consequences should be reminiscent of being
    towed in a real sailplane.  [I am speaking from experience, being
    a sailplane pilot and having part owned a Pegasus (~ASW 19)].

  - The max lift-to-drag ratio is approx 42:1.  This means that from a
    height of 1 mile, the gliding distance is 42 miles.  This
    efficiency is most readily apparent when flying and landing.
    Adding spoilers is a high priority for the next update.

  - The long wings produce an over banking tendency when circling as
    would be done in thermals.  "Top aileron" is required to keep the
    wings from over-banking.  In addition extra rudder is then
    required to stay coordinated.

  - Tail slides and hammer heads appear to be quite realistic.  This
    is one bonus that comes from modeling key aerodynamic data from
    +-180 deg.

* What is not yet simulated: water ballast, flaps, spoilers.

* Drag due to rudder deflection, aileron deflection, and side slip are
  not yet added.  When these are added, slipping on landing will be
  more realistic.
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~




**************************************************
 Prof. Michael S. Selig
 Dept. of Aerospace Engineering
 University of Illinois at Urbana-Champaign
 306 Talbot Laboratory
 104 South Wright Street
 Urbana, IL 61801-2935
 (217) 244-5757 (o), (509) 691-1373 (fax)
 m-selig@uiuc.edu
 http://www.aae.uiuc.edu/m-selig
**************************************************