krasw wrote, On 5/17/2013 11:30 PM:
On Saturday, 18 May 2013 02:33:22 UTC+3, Eric Greenwell wrote:
krasw wrote, On 5/17/2013 10:33 AM:


I really curious about what an "accurate" speed-to-fly command is.
What

is the command based on that makes it more accurate than the usual

variometer, like a 302?


Speed-to-fly is essentially function of vertical airmass movement.
When you get inertial-based netto, which is very fast and accurate,
your speed-of-command accuracy goes up order of magnitude. With
normal TE-based speed-to-fly you normally try to filter out gusts
with longer time constant. With inertial netto this gust-induced
noise transforms into data that you can use for calculating optimum
STF.

With Butterfly I have actually started experimenting with extremely
short time constant for inertial netto. It can be set so short that
netto becames essentially a quantitative indicator of your
seat-of-the-pants feeling. There seems to be no reason to filter or
average this data so heavily.

Does it give the correct STF for 1 second from now? I can't possibly
change the speed of the glider that fast.

Or does it give me the STF for 10 seconds from now, which I might be
able to achieve with abrupt control movements?

And then, 10 seconds later, when I'm going the speed I was given, but
now I'm in air going down faster/slower, does it give me another STF
that will be wrong by the time I achieve that speed?

I'm trying get an idea of what you mean by "accurate" STF commands. The
top contest pilots I've followed seem to fly pretty steadily - will it
give me the STF that a top contest pilot will cruise at? That's what I
would call "accurate"!


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl