Thermal Parameters Test

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mrstells
Posts: 6
Joined: Sat Mar 13, 2021 2:08 am

Thermal Parameters Test

Post by mrstells » Fri Jun 11, 2021 9:18 pm

I have seen some people ask about thermal parameters here (strength, diameter), myself included. I have done two tests, one on thermal diameter, and the other on thermal strength (netto). Both tests were conducted with zero variation in every weather parameter that is adjustable. I used XCSoar to make the measurements.

For the thermal diameter test, the diameter shown is the maximum diameter one can fly while still staying within, or close to, the core. Plane flown for this test was Libelle.

Very Narrow - <120m
Narrow - <150m
Normal - <200m
Wide - <280-300m
Very Wide - <400-500m

Thermal strength is measured in NETTO, and test was flown with Discus 2a. The thermal width was held constant at very wide. Thermals were centered to the best of my ability.

Very Weak - 2m/s
Weak - 3.3m/s
Moderate - 4.5m/s
Strong - 5.7-6m/s
Very Strong - 7m/s

Lenticular
Posts: 140
Joined: Tue Aug 01, 2017 7:29 am

Re: Thermal Parameters Test

Post by Lenticular » Sat Jun 12, 2021 12:07 am

Interesting - thanks!

I have been doing some reading of various pilot reports from the US in the Rockies, and it seems that on "good" days they see what Condor would consider "Strong" to "Very Strong" thermals as standard, with some thermals apparently being beyond what we can even achieve in Condor?

I have achieved great climb rates in Condor by setting wind against ridges. This yields some wild rides. :D :twisted: 8)

I edited my reply in the other thread, so I hope someone sees it and can comment.

It would appear our best options are to use low values for variation (Very Low or Low), and then set the next-strongest thermal type we want, so that the strongest we get isn't too strong vs. what we want.
G-ZULU /// LTN
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