Archived from groups: alt.games.microsoft.flight-sim (
More info?)
"Dallas" <Cybnorm@spam_me_not.Hotmail.Com> wrote in message
news:6swde.4055$GQ5.2873@newsread1.news.pas.earthlink.net...
>
> "Dudley Henriques"
>> In this case, with a TAS of 157kts, the GROUND SPEED of
>> the airplane with a 40Kt headwind would be 117kts.
>
> Ok.. perhaps my question should have been how do you accurately determine
> the wind speed and direction aloft, because without that factor TAS could
> be
> dangerously deceptive?
Depends. It can be determined with instruments, or visually using points of
reference along a known course line. Visually, wind is estimated, then
corrected to produce a new point of reference down the line affirming the
correction's effect. Basically, in light airplanes, you are starting out
with an estimated correction based on forcast winds aloft at your cruising
altitude, then correcting for drift as you progress along your course line.
The difference between your desired course and the heading you have to
maintain to realize that course is your wind correction angle.
Modern navigation devices can produce this for you electronically.
Same with airspeed. You begin with an estimated TAS based on your IAS at
cruise corrected for temp and density. Then you time between two known
points to obtain enroute data. Then you adjust for any time difference shown
on your estimate and get your ground speed. Then you use the ground speed to
determine your arrival time at the next point or destination.
Basically, all flying is is starting with an estimate based on known data,
then adjusting that estimate (on the fly so to speak) to reflect any
changes. Finally, using this process of constant correction, you should
arrive at some hard data that will produce an accurate result for your final
figures for the trip.
Simple!! Sort of a "check" and re-check thing gets it done for you.
)
Dudley
Dudley
>
> I was thinking that one use of TAS would be to determine wind speed by
> timing the distance between two points and subtracting ground speed from
> TAS. But at that point.. so what? What we really wanted here was
> groundspeed anyway.
>
>
> Dallas
>
>