Sharing a thermal

At 8000' 50kts IAS = 58kts TAS, so 27 seconds would
correspond to a 40 degree bank angle. Wing loading
is only relegant to the degree that it affects stall
speed. The only relevant variables for turn radius
are ture airspeed and bank angle - assuming you are
flying in an unaccelerated condition.

Of course you can make a real fast circle if you spin
it...

9B


At 23:30 18 October 2004, F.L. Whiteley wrote:

'Eric Greenwell' wrote in message
...
Bill Daniels wrote:


Most vario's have a time constant of about 2-3 seconds
or more. I put a
bunch of different varios on a test bench last winter
and found some
were as
bad as 11 seconds. The average 45 degree bank thermalling
turn takes
about
13 - 14 seconds

Yikes! I don't know what you are flying, but it takes
my ASH 26 about 27
seconds to make one turn (50 kts IAS, 8000' msl, 8.2
lb/sq ft wing
loading). That's measured from a flight trace. My
ASW 20 was a little
quicker, flying at 7.5 lb/sq ft, but nothing like
14 seconds.

Should be 17secs.

Try your flavor.
http://www.soarcsa.org/thinking_page...adius/turn_rad
ius_calculator.htm

Frank Whiteley

Wow, I really appreciate all the comments on thermalling. It is
amazing how much thought and calculations go into this sport although
not all agree on the solution. Reminds me of all the advice I got on
take-off. It was all good but also different.

It would seem logical if you are in a close circle with another glider
that reducing the bank angle is the safer technique. That said if you
are not in danger of conflict then increasing the bank angle seems to
follow what I was taught and what I have read.

The last flight of this year I tried water and that brought out a lot
of flaws in my termalling technique. Controlling speed and flying
through thermals were a problem. It was like learning all over again,
although when I looked at the trace after the flight I was impressed
with my average speed. I think using smoother and less abrupt changes
is something I need to work on and some of the techniques mentioned
here seem to enforce that.