Transcript THERMALLING BASICS - SAC - Soaring Association of Canada

Canadian Advanced
Soaring
Finding and centering thermals
THERMALLING
(and how to avoid landing out)
• Other possible titles:
“How I landed out over 50 times.”
“50 Farming families I’ve met.”
“ S.W. Ontario walking tours.”
Purpose
• Improve your soaring skills.
• By learning from the mistakes of
others.
• Reach the point where you enjoy cross
country soaring.
• Give you some insights into current
thinking about cross country.
• Pass along your new skills and insights
to fellow pilots.
KEY MESSAGES
• Safety, safety, safety! Don’t just talk about it
– strive to be a shining example of a good
pilot.
• Club policy on out landings versus straight
in approaches.
• Train on weak days.
• Turn tightly – wimpy 27 degree turns
guarantee failure.
• Read the sky.
• Know your instruments
A WORD OF CAUTION
• When we talk about actual thermal
strength, we should be talking about
ACHIEVED climb rate and not indicated
climb rate.
• A 4 knot (indicated) thermal will
translate into an achieved climb of 2
knots if you are a superior pilot.
What does a thermal look like?
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A tree – long trunk with bushy top?
A column of warm air?
Multiple cells (cores) feeding a large Cu?
Impact of wind shear?
Which thermal model?
• Whatever works for you.
• No theory will ever beat practical
experience.
HOW TO READ CLOUDS
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Depth of cloud – vertical development.
Shape, Texture, Curl over.
Solid, dark base.
Firm profile – not fuzzy.
Cloud shadow. (Overdevelopment?)
Growing clouds, Mature clouds and dissipating
clouds.
• Learn to recognize the differences!
• Beware of towering Cu.
How to Read Clouds
• Rule of thumb – 1 in 3 clouds working.
• Thermal height is proportional to
distance between thermals.
• 8,000’ cloud base – thermals far apart,
lots of sink.
• 3,000’ cloud base – thermals close
together, not much sink.
• Thermal cycles - try to get in phase
with growing clouds.
HOW ABOUT CLOUD STREETS?
• Multiple cores roughly aligned with the
wind.
• Start low and run hard when high.
• When high – use cloud shadows.
• Think about this:
If there are cloud streets operating then
there must be sink streets!!!
Note cloud shadow!
SINK STREETS
• Trust me – they exist!
• Turn 90 degrees and get out of Dodge.
• Remember – you can get streets of lift
and sink on Blue days.
Thermalling Rules
• First glider in thermal establishes direction
of turn.
• When joining a thermal do NOT interfere with
other gliders.
• Keep yourself visible to other pilots in the
thermal.
• If you are climbing faster than other gliders –
you must not impede other pilots
• Maintain a good lookout at all times.
THERMALLING RULES
• Do not reverse your turn in a thermal –
another glider could be on your tail.
• Suggestion – give way to less
experienced students/pilots.
• Suggestion # 2 - in competitive flying –
do not impede the climb of a better
pilot.
• Your generosity will be rewarded!!!!
FINDING THERMALS??
Thermal Indicators
• WHEN HIGH …..
Use clouds or haze domes.
• WHEN LOW…..
Use terrain features.
On overcast (overdeveloped) days fly to
areas of sunshine.
GROUND FEATURES
Slopes/hills
Sand pits/quarries – Ingersoll!
Dark fields
Villages/towns
Mfg. Plants/car parks
Fires
Forests? Lakes?
Thermal Indicators
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Other gliders – most times.
Birds – hawks and seagulls.
Dust “devils” – ploughed fields.
Debris – plastic bags, hay, small cars.
Slopes, ridges, hills, towns, factories
etc.
• Fires – often quite small but powerful.
• Remember the rule ……
READING THE SKY
• Overcast days (overdevelopment or
spread out)
• Fly from sunlit area to new sunlit spot.
• Cirrus rapidly approaching? Don’t give
up – slow down and seek ground
sources of lift.
• Look for other gliders.
• Spread out if you are gaggle flying.
THERMALING SKILLS
• Constant airspeed – fly attitude!
• Constant angle of bank!
• Tight turns – our comfort zone is a
mere 27 degrees – pilots consistently
over estimate the actual angle of bank.
• We need to turn at 45 degree angle of
bank.
• How about stalling?
Calculate my bank angle?
• Airspeed – you know.
• # seconds to complete 360°
turn – you know.
• Gives you approximate angle of
bank.
• Virtually all new pilots
overestimate their bank angle.
Circling Time in Thermals
Bank
angle
30°
35°
40°
45°
40 knots
45 knots
50 knots
55 knots
23 sec.
26 sec.
29 sec.
31 sec.
19 sec.
21 sec.
24 sec.
26 sec.
16 sec.
18 sec.
20 sec.
22 sec.
13 sec.
15 sec.
16 sec.
18 sec.
Circling Time in thermals
• Better pilots typically fly at 45 to 55
knots @ 19 – 23 seconds per turn.
• If you are wandering around at 20
degree angle of bank – you cannot
thermal efficiently.
• Good training – Blanik @ 42 knots –
around 19 to 20 seconds.
• Caution – remember laminar flow …
you can also thermal too slowly.
While you are thermalling…..
• Read the sky ahead.
• Pick out growing cloud(s) – have more
than one option!
• Avoid blue holes!
• Select best course line based on cloud
layout.
• If you deviate – try to deviate upwind.
Common Thermalling Errors
• Look outside – keep your head out of
the cockpit!
• Use the audio function.
• Use ALL your senses.
• Speed control – fly attitude – fear of
stalling?
• Angle of bank – fear of stalling?
• How do I calculate my bank angle?
Common Thermalling Errors
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Taking every thermal.
Thermal “love in” – the last to leave?
Follow the mob or lead?
Team flying – single file or spread out?
On blue days it is essential that all
gliders on a task spread out.
Common Thermalling Errors
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Turning too soon when you enter a thermal.
Banking at high speed : 60 knots + +.
Chasing the vario – remember vario lag.
Ignoring the yaw string.
Rough control movements once established
in the thermal.
• Entering thermals at high speed.
• Leaving thermals at high speed.
KEY POINT
• IT TAKES TIME TO CENTER THERMALS!
• A “good” pilot will take FOUR turns to core a
thermal. That is 70+ seconds, over a minute –
a long, long time, going nowhere!
• A really superior pilot will center the thermal
in two turns. Time saved during a 20 thermal
flight?
• At least 10 minutes!!
• An “average” pilot may NEVER center the
thermal.
KEY POINTS
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Read clouds carefully.
Enter and leave thermals correctly.
Turn tightly.
Be selective with thermals you take.
Use conservative MacCready settings.
Speed up by slowing down between
thermals.
• Be flexible!
MOST IMPORTANT POINT OF
ALL!
• STOP WAITING FOR THE PERFECT
DAY !
• Train when the weather is weak.
Cruising between Thermals
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This should be a very busy time for you.
How fast to fly?
How slowly?
Go left?
Go right?
Fly through the blue hole or go around it?
Avoid the overcast ahead on course line?
Catch up with that LS 8 ?
Between Thermals
• Lake effect.
• Turn point in blue air – what to do?
• First – decide how far you have to fly in
blue air.
• Second – climb as high as possible.
• Slow down and be patient.
• Work weak lift in blue air – particularly
after turn point- wind at your back.
Psychological Factors
• The importance of flexibility - learn to adjust
your pace.
• At 7,000 feet ignore weak lift.
• At 2,000 feet take anything!
• High = Fast
• Low = Slow
• Be patient – a 1.5 knot thermal at 1,200 feet
may be a 4 knot thermal at 3,000 feet
Psychological Factors
• The need for companionship – follow
the leader often puts your brain in
neutral.
• Think for yourself – avoid the herd
mentality.
• The other guy is just a dumb as you
are.
(Most of the time, anyway!)
The Tortoise and the Hare
• The Hare:
20% fewer thermals.
Average thermal taken 30% better
• Yet the Tortoise won!
• Why???
• The Hare needs to work on cruising
between thermals.
PLANNING
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Check lists.
Weather forecast?
Declaration.
Water*, Food.
Pee system.
Map preparation – do not
rely on GPS.
• Course line?
• Key radio frequencies.
* Top priority for safety!
• Know how to operate
your instruments –
vario, computer, radio
etc.
• Can you reach
everything?
• Weather shaping up per
forecast?
• Take your time – let the
day develop.
• Get input from qualified
pilots.
• Be positive – don’t get
psyched out!
PERSONAL AWARENESS
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Fitness – both physical and mental.
Hydration – very important!!!
Food - nourish the body.
Relaxed awareness while flying.
Look.
Listen.
Feel.
Summary
• Develop thermalling skills – particularly on weak
days.
• Constant angle of bank, constant airspeed.
• Tight turns !
• CONSERVATIVE ring setting.
• Make haste slowly and steadily.
• Read the sky ahead.
• Avoid blue holes.
• Work on long inter thermal glides – 15 to 20km.
• Lead – don’t follow.
• Have fun!
Airport Hopping
(Airport hoping?)
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Seductive for the low time pilot.
Pros and cons. Silver distance – o.k.
Dangerous for longer flights?
Your energy and concentration is on the next
airport and NOT on weather reading.
• Actually slows your speed dramatically.
• Many airstrips are very narrow!
• Target fixation – final glides…. The mind stops
working!
Recommended Reading List
• A comprehensive reading list will be
e-mailed along with a copy of this
presentation.
E-mail address:
[email protected]
Recommended reading list
• Soaring Cross Country
• New Soaring Pilot
Irving
• Winning 11
• The Platypus Papers
• Meteorology for glider pilots
• Transition to gliders
Reichmann
Welch &
Moffat
Bird
Wallington
Knauff
QUESTIONS?
• Thank you for supporting our National
Team!
• Enjoy a terrific soaring season and set
your sights high.
• Fly safely and with joy!