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Harald67 / c150

Flightgear Cessna 150
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Can not taxi in grass #35

Closed Harald67 closed 7 years ago

Harald67 commented 7 years ago

The aircraft slows down a lot, and sometimes get stuck in the grass. Check FDM friction of wheels perhaps.

Harald67 commented 7 years ago

Same problem with the c172p, impossible to taxi correctly on grass. The c172p is not always stuck because of it's engine power but it will break sometimes. Probably a too high rolling friction of the ground material.

gilbertohasnofb commented 7 years ago

I think the friction of the ground is defined in the xml files inside of FGDATA/Materials. Maybe we should ask for someone to review those values for the grass?

Harald67 commented 7 years ago

I had a quick look in material and in the property tree ; I found a jsbsim property for ground but there was a value of 5 for the rolling friction, I could not find that value in Materials/*. So this probably need to understand how that value is computed or add some nasal code to check the material name under the wheels to know what is the material that is 'bugged'.

gilbertohasnofb commented 7 years ago

If you are using ALS, check for instance FGDATA/Materials/regions/global-summer.xml. You will find a definition for the landclass Grassland, which has the following friction:

<friction-factor>0.7</friction-factor>

Note that there are more than one types of landclass for grass (I believe GrasCover and Greenspace are other ones), and it also depends on the region you are (since each of those xml files get activated in specific latitude x longitude values).