Resultados 1 al 5 de 5

Tema: POLAR CURVE

  1. #1
    Fecha de ingreso
    20 Oct, 06
    Mensajes
    1

    Predeterminado POLAR CURVE

    I have read somewhere that CompeGPS (6.2) can calculate polar curve from IGC file - tracklog Garmin eTrex VISTA. If not, do you know another SW?
    Thank you.

  2. #2
    Fecha de ingreso
    01 Mar, 05
    Ubicación
    En el medio del páramo
    Mensajes
    8,595

    Predeterminado

    I guess Guther could help you in this case. I've send him a PM for help.

    Best regards...
    Todo el día de arriba para abajo...

  3. #3
    Fecha de ingreso
    30 Nov, 04
    Ubicación
    Germany
    Mensajes
    189

    Predeterminado

    give me another day to respond as I am on vacation and dont have access to my pc.

    Typing this on a pda is a bit boring.

    cheers
    Gunther

  4. #4
    Fecha de ingreso
    02 Dec, 04
    Ubicación
    Perth West Australia
    Mensajes
    30

    Predeterminado

    CompeGPS will extract a polar plot from your tracklog but you need to record airspeed. So you need a vario/gps with an airspeed probe and calm still air to fly in to get a reasonable plot.
    Under the flights button you will find "polars" click on "create a new polar" load your IGC file and there you get a plot of airspeed versus sink.
    Since I haven't been able to get a flight in still air, it is impossible to extract a polar from the graph,ie I get about 6 different sink points for any given speed.
    So in the end I have used the edit polar function to come up with a polar that approximates my Aspen something like a sigma6 plot or comparable glider.
    If you get a chance to fly in still air with an airspeed probe vario/gps fly the glider through its entire speed range and select the best subtrack ie select a small portion of track with a right click on the track, select "subtrack" and a start and end point.
    Save that subtrack and then create a polar from it.
    Try a few diifferent subtracks and see how much variation you get in your polars.
    Hope this helps
    Have Fun

    Rod

  5. #5
    Fecha de ingreso
    30 Nov, 04
    Ubicación
    Germany
    Mensajes
    189

    Predeterminado

    Hi Rod, nice to hear from you again and thank you for this answer.

    The Garmin Vista has a barometric altimeter. However the data used for the track information are taken from the GPS. Due to this there might be some scatter in the data caused by the restricted accuracy of the GPS altitude data in comparison to the barometric data. As we are talking about an accuracy of 0.1 m/sec for the descend rates this might have some impact too.

    Another problem is the lack of an airspeed sensor. One possibility to compensate would be to fly in 2 opposite directions and level out the average windspeed. However I think this is more or less a theoretical attempt as it would double the necessary flight(s). My home resort would probably not be appropriate to do all this. On top of all this the slightest thermal will have a big impact on the data ...

    However opposite to Rod I have never tried it so I appreciate Rods posting very much.

    Cheers
    Gunther

Permisos de publicación

  • No puedes crear nuevos temas
  • No puedes responder temas
  • No puedes subir archivos adjuntos
  • No puedes editar tus mensajes
  •  


About us

    CompeGPS Team SL All rights reserved © 2012

Follow us on

Twitter Facebook youtube Google Plus Flickr