Robin Hamilton writes of his sixth 300 km FAI triangle attempt in Texas in his
Swift:

Aug 27 flight highlights


Hearne (the launch point) conditions: Zapata-like cloud streets at c. 10.00 am.
10-15mph SW drift. Good day for going far but maybe not a triangle. Game plan
was to take advantage of the early strong drift and bet for reduction in wind
speed later in the day as the cloud base rose and the thermal activity might
offer more "blocking" of the wind.


Three attempts to get away - my release accidentally opened low on the first, we
broke a weak link after hitting a punchy thermal low on the second and I went on
the third leaving the airfield at 12.30. Thanks for your patience Mike Degtoff.


Fast run down wind with cloud streets and strong lift (average 500 fpm, a couple
of 800 fpm+) to first turn point at Oakwood by 2.00 pm. Cross wind leg also
averaging 50km/h (30mph) with even stronger lift and higher base (7,000' agl) -
it looks very dry down there. I found that it was best to run into wind along
the streets as the headwind speed was less (< 10 mph at height) and then run
across the streets at the shortest crossing points. Came round the second turn
point, Mount Calm, on the NE side of Waco airspace at around 4 pm - basically on
schedule for getting back to Hearne by 6 pm.


The final into wind leg started out well with no weakening in the thermal
strength and also base was getting spectacular (7,500' agl). It was all looking
very good till I got level with Marlin at 5 pm, having now only 50 km (30 miles)
and familiar terrain to cover in getting home. Climbed in a 700 fpm to 8,100 agl
just E of Marlin and surveyed the scene down the course. It was bluing out fast
on both sides of the Brazos valley, Hearne was well in the blue and there was
now (cu-nimb - related) cirrus coming in from the S.


I've seen this before at Hearne. It's like a pseudo-sea breeze that forms
regionally later in the day resulting in a strong, stable blow coming in from
the S and funneling up the Brazos valley. The previously good fat high clouds
that were along a line running to Hammond were melting even as I was taking that
last climb E of Marlin. I then glided way out to the W some 25 km to try to stay
connected with better sky, but it was basically being undercut and dissipating
faster than I could get to it.


I got a weak climb in some broken lift under a cloud remnant near Rosebud but by
then I was in a solid 35 km/h (20 mph) SE flow. I landed some 22 km (13 miles)
short of Hearne in a gusty 18-20 mph SE wind. Satellite shots later showed
extensive cu-nimb activity on a line S of Lake Somerville that had probably
caused the high surface wind up the Brazos Valley either as distant collective
gust front effects or as the bigger clouds collapsed.


It's difficult to get a large patch of Texas weather to keep itself in order
around a 300km triangle course but it was a fun day flying - the strong lift and
high cloud bases were a real pleasure. The ground is very dry up there and I
would encourage anyone to go out and get a piece of it - it's basically prime
time Central Texas flying and about as good as you'll get for flat soaring
anywhere in the world.

The flight track logs:
http://ozreport.com/pub/images/Aug20Columbus1.ppt and 
http://ozreport.com/pub/images/Aug27300ktriangle1.ppt.