XC Secrets: Thermal Drift

XC Secrets: Thermal Drift


Holding onto a drifting thermal can be very
challenging but improving this skill can yield big gains in airtime. We go into much more detail on our website. For a good challenge, let’s make it overcast,
make the ground damp and green, throw in a downhill slope and begin on a small hill with
no pilots to help. A technique that works here should work anywhere. OK that is just rubbish. That thermal has got a lot of drift, it’s
being affected by the venturi at the top of the hill, and it’s got a sharp spike of lift
at the front which is very hard to work because you swing around with such a high bank angle
and end up in the sink at the back. So I think I’m going to go and have a look
for something better. I’m just using the weight transfer in my harness
now to feel out the lift. I’m going to follow this lift line a little
bit into wind. I’m keeping my hands high so I can gain some
ground while I’m pushing into wind. I’m trying to position myself in a better
place to aim to the place where I want a thermal to release from. OK that’s much better, so it’s not drifting
me over the ridge nearly as fast. Much better place. Rounder thermal. So in this position I’ve got much more freedom
to work the thermal, it’s not getting pushed over the ridge so quickly which means I can
centre much better on the lift, I can actually work around the core and get my circles to
line up with the centre of the strongest lift. OK it’s only 1m/s but it’s all the way around,
it’ll probably just scoop everything up off this hill. That’s going up pretty high, it’s got a pileus
on the top a bird climbing with me
Swindon out there So I’ve just hit an asymmetric spike of lift
on that side so I’m going to explore off to the South East a little bit to try and see
if I can find a better part of the core. There doesn’t seem to be anything useable
there, so I’m returning back to my original drift. So I’m totally ignoring the hill now, I’m
just trying to drift with it and I’m watching the bird in front of me, he’s gliding down
so he’s out the front there Hello! Nice bit of climb there
So I’m just responding to the strongest lift all the time and trying to adjust my circle
to capture that I’m not really thinking about the drift much
but you can see at this point I’m just about to start drifting with a different line, more
North East, and that’s the prevailing wind for the day. OK you’re coming back on the bus, baby! I am using a steadying hand on the outside
riser here, I don’t do this all the time, but some gliders like the Omega Xalps, don’t
respond at all to outside brake control, and the harness (Skywalk Xalps) is very wallowy,
so I’m trying to stabilize myself, mainly for your benefit on the GoPro camera so it’s
a little bit more stable. It also provides a very steady turn, I’m only
adjusting with weightshift and a little bit of inside brake, and this helps me map the
thermal when it’s so light. This climb takes me all the way up to cloudbase
where the enthusiastic clouds give us a bit more reliable lift. But if I drop out I now know the drift pattern
so I can apply it to the next thermal source to visualize the climb curtain and come into
the lift on the best line. For much more about thermal drift, read the
full article on our website.

13 thoughts on “XC Secrets: Thermal Drift

  1. Thanks! It's been too long since the last vid. We love it when we get to the point in thermalling where we ignore the ground and fly the sky, wish every human could experience that joy.

  2. Excellent video , but much better the article, just as a new guy with only 110 flights this helps a lot, but it will take me over 20 or more flights to apply all the tips. thanks for the help and your time to help us the new pilots. regards.

  3. my new experience in thermal drift was very good end practice. …I think that condition is not for little pilots. .😃

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