Hang Gliding and Paragliding Volume 44 / Issue 12:December 2014 | Page 57

enough to perform a more normal,
steady thermal 360.
Figure 2 provides a picture of this
procedure. Note that because of the
presence of the hill the thermal is not
drifting much downwind, so the center
of my turn needs to be essentially
stationary. This practice is similar to
making a turn to stay over a point on
the ground in wind. You can’t make a
360 evenly banked all the way around
or you will drift with the wind. So we
have to make a steeper bank on our
downwind leg to remain in front of the
hill.
It should be clear that a safe thermal
turn low in front of takeoff is not a
steady, uniform process. The obvious
reason is that you need more control
to handle the unexpected near the terrain. Another reason is that thermals
bulling up a steep face are not generally
uniform. The presence of the ground
tilts them and also turbulates their
downwind border as shown in figure
3. The upwind portion of your turn
tends to take place in lift that is getting
stronger, while the downwind portion is usually in diminishing lift. We
should all recognize that it is easier to
turn a hang glider in building lift than
in steady air, while it is harder (slower
to react, heavier forces) when the lift is
diminishing. This is another reason for
gaining airspeed when you pass into the
downwind portion of the 360.
To be sure, using this turning
technique is not apt to result in as much
height gain as a turn that is at minimum speed all the way around. But,
the severe (as severe as you can imagine)
consequence of hitting the ground
going downwind in the back side of
your turn trumps performance any day.
I have never come close to hitting the
ground with this technique, although I
know I have come closer to the hill with
comfort than some pilots who aren’t
aware of the benefit of carrying extra

maneuvering speed.
As with all our learning, all pilots
should learn this variable-turn technique well away from the terrain. You
can try it in a thermal up high. Simply
determine the upwind direction and go
slow upwind and faster with a steeper
bank downwind. Practice until you
have the timing down and are intimately familiar with your glider’s response.
The first time you try it nearer the
hill, use a wide thermal so you can be
well clear. Eventually you will be able
to make a safe decision when to turn
in the first thermal with ample safety
margin. Remember, you are judging a
dynamic situation in three dimensions
with a bit of unknown—the sink and
turbulence at the downwind points
are not necessarily the same every time
around.
Of course, if you boat out off launch
and the lift is gentle and widespread,
much to your joy, your 360 may be a
normal leisurely circle. In this case, you
will probably be above launch by the
time you are on the back side of the
turn anyway. Go in peace. But when
the lift is weak or broken or small or
turbulent or any combo of these characteristics, you need to use the variedcircle trick.
Sometimes I find that I can get two
or three 360s in a weak thermal that I
may have latched onto below launch,
but the drift takes me too close to the
hill to keep circling. In this case I make
^H\