Lecture notes

Thermal structure

introduction - basic convection
Sun heats ground not air - density/ pressure / stability 
cellular convection / convergence and divergence / patterns
depth of convection / spacing of thermals / size of thermal

Thermal sources - heating
Sun angle /surface / crop / moisture / (evaporation takes energy and cools the surface ) / geology and wind

Thermal sources and trigger effects
Very hot spots / hot cold boundaries / cloud shadows, lakes, ridges, towns etc
Potential for convection that is focused by irregularities in the surface and the cellular patterns

Detailed movement of the air
Sticks to ground like surface tension but think of mass
wind around not through the thermal - wind shear
Breaking away and accelerating/size and shape and shear
fully developed thermal 

Horizontal movement of the air
Wind whear around thermal - inflow and outflow
T/E vario is confused by the wind shear
what happens in the bottom of thermals and the top of blue thermals

Formation of cloud 
latent heat and inflow

How to climb in thermals

Introduction
different techniques / mutually opposed ways to do it / why?

Size of thermal
60kts = 100 feet per second - measure your thermal
Size of the turn

Variometer problems
vario lag - different for gusts and lift - variable time lag!

How to tell the difference before the lift and the gusts

How to climb when you know where the thermal is
How to climb when you don't

Efficient circling
Constant pitch attitude and let the speed vary
Use extra speed to tighten the turn and flatten out to keep it flying when the speed goes - fits in with one way of thermalling
and works well with small thermals and modern gliders

Maintaining the concentration
How lond is a climb - example
Hard work and physical as well as mental
common mistake is allowing bank to reduce after some time
often need to re centre especially with shear
looking up to recentre also take a big turn allowing you to come back to same place (straighten up will lose you the lift)

Reading clouds

The physics
Latent heat / condensation / evaporation / dewpoint / droplet size with age

basic cloud shapes
good and bad shapes - cloud base is the bit that is working - avoid overhangs when planning route

Looking at the side and the top of clouds
depth of cu - life cycle - what is your height?

Look at cloud bases
domes / dips / dags / how they change with time

Look from underneath
Look up! Straight up!

Patterns in the sky

soaring depends on convection exhibiting patterns not chaos

Cellular convection
depth and spacing - inflow and outflow - size of thermals - how to cruise - thermal entry techniques

Streeting
Similar depth and spacing - inflow - trigger effect of cloud - energy lines - how to cruise in lift / cross between streets

Wave on top
Different shape of energy lines / areas / wind shear area

Blue streets
How to hunt thermals - follow blue streets and cross between them 
Can reach top of a blue thermal and therefore feel outflow region / laminar flow on top / wave effects on blue days

Speed to fly

the maths but simply
climb at 6 kts, cruise at 100 coming down at 6 what is the average? Half climbing half running - 50kts
climb at 6 kts run at 90 coming down at 3 what is average? Twice climbing than running - 30kts
do it graphically

Now what is missing from this diagram. Glider polar

Put in the polar curve and point out that speed you fly does not change average much - it is changing the rate of climb that makes the difference

Example - three gliders top of climb to top of climb - too fast (Dick Dastardly) just right (Peter Perfect) and too slow (Penelope Pitstop)
Show what happens and what it looks like and then refer back to graph
What happens when next thermal is not there
Can you keep accurately to speed to fly in changing air? No

Rules of thumb - block speed for cruising, up to theoretical maximum but never beyond
There is benefit in going slower than optimum - better thermals

Look at effect of staying in lift in the cruise

Lift strength - average 2kts save 50% of the time over average 1kt. Average 3kts is not such a time saving over average 2! Not an even ladder.

Cross country strategy

the game of x-c flying
You can hit the ball but are you going to play cricket, tennis, squash - all diferent games with a different nature.
Badge flying / distance / record and competition flying all different games with different rules, rewards and strategies.

Some common modes of thinking required - think ahead!

Typical mistakes you will see all the time
Running out to the edge of soarable conditions and leaving without topping up to top of convection
final glides down sind streets
Leaving thermal because gaggle goes overhead
use example of start on NZ wave day

Think!!

Techniques to help
observe - wind - weather - height band - lift strength and nature - other gliders - make a short term and a long term plan 
what will I do in 30n secs/3mins/30mins/3 hours?

The big thing
It's a statistical world out there - use strategies that give you best chance of success on average. Platy the numbers game.

Even applies to climbing in lift!

Final glides

the theory
use Dick, Pete and Penny to show too fast, too slow and just right - and use the graph

In practise
calculators / field elevation/ arrival height / safety margin / practise

Tactical stuff
working energy on route
dolphin up to glide
don't fall into the psychological trap of looking for the big climb for the big glide...

Rules of thumb
30-1 is 200' per nm or a faster glider is 100' per km