LX-4000, Ilec SB-8/ASR, or B-100 Flight Computer?

On Nov 6, 10:30 pm, Richard <r...@snowcrest.net> wrote:
> Software is what calculates the wind not the instrument.

More than 98% of the engineering content of a flight
computer is software. The instrument is in fact mostly
software. And the software is completely different
in the different instruments.

> Most instruments have pitot and temperature inputs
> and I beleive all use calculation of wind from circling drift in a
> theraml, course change, True Airspeed and GPS info.

Incorrect. ILEC SN10 certainly does not require circling
to calculate wind; you'll often get a wind indication on
tow.

> They all probably use slightly different combinations
> of the inputs and use a different formula.

Right. So, talk to experienced XC pilots who have
*really* flown with these instruments, and find out which
ones are considered to produce reliable wind info.
Your mileage will vary. A lot.

Hope that's helpful,
Best Regards, Dave "YO"

<drn@nadler.com> wrote in message
news:1194439463.031311.264950@y27g2000pre. o...
> On Nov 6, 10:30 pm, Richard <r...@snowcrest.net> wrote:
>> Software is what calculates the wind not the instrument.
>
> More than 98% of the engineering content of a flight
> computer is software. The instrument is in fact mostly
> software. And the software is completely different
> in the different instruments.
>
>> Most instruments have pitot and temperature inputs
>> and I beleive all use calculation of wind from circling drift in a
>> theraml, course change, True Airspeed and GPS info.
>
> Incorrect. ILEC SN10 certainly does not require circling
> to calculate wind; you'll often get a wind indication on
> tow.
>
>> They all probably use slightly different combinations
>> of the inputs and use a different formula.
>
> Right. So, talk to experienced XC pilots who have
> *really* flown with these instruments, and find out which
> ones are considered to produce reliable wind info.
> Your mileage will vary. A lot.
>
> Hope that's helpful,
> Best Regards, Dave "YO"


So how do you know for sure that a particular software produces accurate
wind data? It seems that any test would require accurate wind data
determined by some highly trusted independent method to compare with the
software output.

Bildan

Bill Daniels wrote:
> Well, having flown over the mountains and plains while listening to other
> pilots reporting wind from all points of the compass, I've jotted down their
> readings, my data and the time. Later I compared that to the data collected
> by a real-time NOAA wind profiler 16NM away. Using the wind profiler as a
> reference, all of our calculated winds aloft data were highly unreliable.
> No one was better than the others and all were way off. The only useful
> data was collected while circling and then only if the circles were perfect,
> otherwise it's is a rough approximation..
>
> To get accurate real-time wind data in flight you need four input variables,
> ground track, ground speed, trufe airspeed, and true heading. The last is
> because winds aloft data are referenced to true north. To date, all glide
> software omits heading input.
>
> Bill Daniels

Another local pilot and I have compared wind calculations when flying in
the same area. He has an L-NAV, and I use SeeYou. Both units are using
airspeed data. Often the wind speeds are within a knot or two of each
other, and wind direction often is the same within a few degrees.

Either both units have amazingly similar errors, or both are quite accurate.