On 5/4/2021 1:22 AM, 2G wrote:
On Sunday, May 2, 2021 at 10:53:58 PM UTC-7, krasw wrote:
On Sunday, 2 May 2021 at 08:58:35 UTC+3, Matthew Scutter wrote:
Would you expect it to function meaningfully differently in the flatlands? Circling wind should work just fine in a homogenous atmosphere, so functioning the same would be ideal.
Matthew, this is what we thought of wind for last 100 years. Now that we can measure it accurately with 1Hz sampling rate, it has proven to anything but homogenous. Thermal does not move with wind (because lower momentum of mass flow of air from surface, millions of kg/minute). Thermal creates plume of rising air, but also a plume of slower moving air. When you measure wind while thermalling, you are measuring this. When leaving thermal, you will fly into stronger wind. Ever had that feeling on headwind final glide that glider just does not want to stay on glide path unless you find lift? You flew into stronger headwind without knowing it. When arriving under cloud, you will most likely fly into lower wind area before flying into thermal. This can be used to your advantage. No need to make those searching turns yet unless the wind calmed down first.
Similarly I would be surprised if there was improvement in variometer function from an existing well-compensated setup. All I would wish for additionally from my existing variometer is that it would read accurately in the first second of the pullup into a thermal.
Inertial variometer does exactly this, gives a quantitative reading of the gust you feel in your seat. You need to get a used Air GlideS someday.

If this were the case then I would immediately see a stronger wind, as measured by the difference between true airspeed and GPS ground speed, upon leaving the thermal. I do not see this, ever. And I am monitoring it on virtually every thermal. This way of measuring wind does only give me the headwind component, but I get it in real time. If I want to check the direction I can turn until the difference is maximized. This only takes a few seconds. Most of the time I don't need to do this.

I intend to try out Hawk for a trial and see what difference it makes.

Tom


Not quite about Hawk Wind, but the same is possible with XCsoar or
Tophat: there is an infobox available that shows IAS, but it is hidden:
it is not included in the short list that appears when you tap the
settings icon for an infobox. You need to get several levels deep
inside the system settings designing the screen(s) to get the full list.
Now that I found it, I added it to my display. This allows me to
double-check the "component wind" (head or tail) by comparing the IAS
displayed there with what is displayed on my ASI. Note: yes, I wrote
IAS not TAS. This is a flight computer with no connection to the pitot
system. The estimated IAS displayed in that infobox is computed based
on the GPS ground speed, the estimated wind (resulting in TAS), and the
air density (approximated based on the altitude). If it differs from
the ASI reading, that shows that the true wind differs from the
estimated wind. E.g., if the infobox says 60 knots and the ASI says 65
knots that means there are 5 more knots of headwind (or less tailwind)
than the computer's estimate of the wind.