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  • Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.

    Post 16 Update

    Post 17 Warning

Does FSX model "grass" runways?

T

tracyq144

Charter Member
I.e., are the dynamics any different than asphalt/concrete runways, as far as takeoff and landing?

Thinking of the A2A Cub and Spitfire, mostly, and how they, in "real life", would probably be easier to set down on a grass runway (due to the more "slippery" texture of grass as compared to a hard runway).

Please excuse my poor phrasing, although English is my first, and only language, I am not too smart. :)
 
it goes farther than that in real life comparison...

heat rising off an asphalt runway vs grass can cause a lot of extra 'float' for a small lightweight plane...even packed bare dirt or gravel vs grass can make a difference.

the grass traction is different but really only wet grass makes a significant difference even vs wet pavement - or so I am told...I am sure others with first hand experience will be along shortly with more info for you

I do not believe any of this is replicated in FSX...but maybe fodder for the new "Flight" sim forums...?
 
In the real world, a dry grass runway adds about 15% to the total takeoff distance for most light aircraft, and landing distances increase somewhat more (around 30%), but as far as I can tell, FSX doesn't model either the increased takeoff/landing distances or the fact that grass tends to be more "forgiving" on landings due to the inherent flexibility of the surface.

As for the extra "float" caused by paved runways, I've never run into it as a flight instructor. If an aircraft has too high of an approach speed, it's going to float on landing, regardless of what the runway surface happens to be. While thermals present on warm days can make the descent towards the runway somewhat tricky, I've never had a situation where an on-speed approach resulted in floating just because it happened to a hot day.
 
As far as I know it does not accurately model any of those aspects but maybe going outside of the SDK which you can do with FSX that could be done...I don't know what the reference point would be for coding under those differing conditions unless you could do it from the WX coding itself.
Ted
 
Thanks Heywood. I've bookmarked that page for later. it looks like a while bunch of good reading..
Pam
 
About the original question of the topic, I don't know if FSX really models grass runways, and in any case it certainly doesn't model the "thermic" difference with asphalt runways described above.
However, FSX takes into consideration the type of ground to determine the adherence of the tires. Try to land on a snowy slope, and your aircraft will not be able to stop. When it comes to grass however, in the best case I suppose it will consider it as dirt...
 
FSX does model Grass to the extent that it does reduce the coefficent of friction, ie they are different than asphalt. Such demonic aircraft as the default cub are much more forgiving on the"grass". In actuality real taildraggers such as Supercubs and 180-185's are much easier to land on gravel and grass with some degree of grace. The heat issue is not modeled, and in fact not applicable in some parts of the world.... such as Alaska, and in some seasons.

T
 
fliger747 said:
The heat issue is not modeled, and in fact not applicable in some parts of the world.... such as Alaska, and in some seasons.
Click to expand...

Which heat issue? It takes very little sun to produce extra lift on approach. Merrill field has a strip mall on short final for runway 25 that produces noticeable lift during the summer. None of this is experience in FSX in my experience.
 
Ummm, never considered Anchorage as part of Alaska..... (Though I hear it's not too far distant). Just never liked the goofy winds much, even in the Whale.

Don't get that in Fairbanks particularly, or much of anywhere in the interior, though those summer cumulus days can be as rough as the ones in the midwest (East).

Nothing like flying at 2AM with that gentle pale north light and super smooth air... and glassy water! Won't be too long till the floats go on again.... T
 
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