XC tips

TIP: HELMET VARIO

"If your only objective is local thermalling a helmet vario is fully adequate. I have one as a reserve on my helmet; if the main one should fa    il I can always continue with the backup. I also use it for travelling and for tandem flying. The available helmet varios are small and reliable, and come in both battery and solar powered versions"

TIP: SPEED BAR SET UP

"I have my speed bar set up so that my legs are always resting on the first step of the ladder. This way all I need to do is stretch my legs to accelerate. Having to fiddle around to find it first is inefficiënt."

TIP: WHEN YOU FALL OUT

Photo: Martin Scheel

"When flying XC you need to have a good understanding of the maximum available altitude on the day, regardless of it being a blue or cloudy one. This knowledge will help you decide if it pays to spend time searching for that thermal you just lost, or if you should rather be heading along. If you loose it close to the max. altitude and you're not just about to go on a big transition, by all means just continue instead of wasting any more time searching."

TIP: FINDING THE BEST LIFT

• Climb rate decreasing > turn tighter
• Climb rate increasing > open up the turn
• Climb rate remains constant > circle radius should also remain constant

Tip:
When I encounter lift while flying straight I always keep flying straight until the lift begins to decrease again, then I turn into the wind for my first circle.

TIP: SOARING IN CLOSE

"Soaring uncomfortably close is normally not beneficial. Besides, keeping a bit more distance will be good for the nerves."

TIP: ROUTE PLANNING WHEN TAKING VALLEY WINDS INTO ACCOUNT

"The direct route to the bowl (red arrow) is good if we have plenty of altitude. However if our altitude is low enough that we're likely to pass over the flatter section marked A at low altitude, it is better to take a detour (yellow arrow) to avoid the lee rotor from the valley wind (blue arrow)."

TIP: SEARCHING FOR FLATLAND THERMALS WHEN LOW

Photo: Jerome Maupoint, Gin Gliders

• Where's the wind coming from? Flatland flying means less leeside worries, but even a small hill may cause serious rotor.
• Is there anywhere where the landscape is oriented better against the sun?
• Where is the best soil for heating?
• Where will the thermal be triggered?

"This brief checklist can be summarized into an even briefer sentence: First look for easily heated soil, then try to visualize where the thermal will release!"

TIP: THE VENTURI EFFECT

"Whenever a flow is forced through a constriction we can observe venturi effects. The flow speed in the constriction increases and the pressure drops. In the photo above we see the narrow gorge just west of the launch at Bassano, Italy. Time and again this gorge eats pilots who underestimate the venturi effect and blunder too far in, only to find that they cannot get back out against the wind. There are some small landing options but they are far from ideal."

TIP: INVERTED VALLEY BREEZES

"Free flyers should always acquire updated weather forecasts before going to launch. These will tell if adjacent regions have substantially different weather patterns that may influence valley winds locally. Thus, unusual situations are less surprising."

Photo: The flying arena around Landeck, Inn Valley, Austria. If the western Alps are covered in cloud, the centre of the heat low will be displaced towards the east and the valley winds here may be inverted.

TIP: ARRIVING AT BASE

"The nearer you get to cloud base the further out towards the edge of the cloud you should fly, preferably on the upwind side if there are no obstacles around. In the mountains on days where cloud base is beneath the peaks, you should aim for the valley side of the cloud, where a brief visit inside has less consequences."

TIP: THERMAL LIFESPAN

"Observe the surroundings continuously whilst flying. Only by doing so can you build a picture of which of the cu's around you are building and which are decaying. Track their lifetime to get an idea of the life span of the thermals, and which ones have already been active so long that flying to them doesn't make sense."

Fig: Six images showing the lifespan of a cumulus cloud. In the first frame the cloud is just beginning to form, from frame four it is decaying again. It only pays to head for developing cu's as decaying clouds indicate nothing but increased sink. The sequence was taken over a period of approximately ten minutes.

TIP: WING TIP VORTICES

"Wingtip vortices can cause your wing to shudder when you fly through the wake behind another glider. The closer you get the more dramatic the shuddering becomes. Tandem gliders are carrying more weight and trail stronger vortices"

TIP: SMOKE AS A THERMAL MARKER

"Two smoke trails drifting towards each other. Where they meet - red area - there's a good chance that a thermal is releasing. The hang glider has noticed it and is aiming right for the thermal. Low down the lateral drift is stronger. This means that two pilots thermalling at different altitudes in the same thermal column will experience differentiated drift, with the lower pilot drifting more!"

TIP: THERMAL DRIFT OVER CRESTS

"The same slope may produce both weak and strong thermals. To avoid the risk of getting blown back into the lee it is best to only concentrate on the stronger ones. When thermalling in strong winds it is important to always remain near the windward edge, as dropping out here only causes us to sink back into the thermal, whereas dropping out on the lee side could mean sliding down the backside unable to re-penetrate due to lack of groundspeed. In the diagram the pilot on the right is thermalling near the windward side of the thermal whereas the pilot on the left tried to push back to the high relief too early and now has to cope with a landing in turbulent conditions."

TIP: FINDING THE CORE

"Finding the core is very important. The core of a thermal is the place where the thermal is lifting the strongest. If there is wind then most often the core is to be found up-wind. This is because weaker thermals drift more with the wind than stronger ones. So if you are already in a weak thermal then as part of your 360 you should straighten out as you turn into wind and start to search upwind to try to check if there is stronger lift. Try to continue to search upwind until you find that the lift decreases, then just go back to the strongest lift you found and use that."

TIP: ALWAYS CHECK FOR OBSTACLES

"Practicing your ground-handling skills should be done in places where there are no obstacles around. Failing to stick to this most basic rule may quickly put you in dire straits. And when the above happens just remember to keep smiling"

TIP: THERMAL GENERATION

"Thermals may come from any surface that is readily heated by the sun. For your mental picture try to imagine walking over the ground where you are flying. Wherever you feel the air getting warmer you can expect thermals to originate. But, cool, shady and wet areas always hinder thermal development. The rocky SE slopes in the picture are perfect for generating early thermals, knowing this the Atos pilot flies straight to them."

TIP: TO 360 OR NOT

"In weak soaring conditions I may opt to do full circles in the embedded thermals even low down. If the thermal is just 70m across or more I find that I can climb better by doing 360s than by flying figure-8s. Hang gliders will need somewhat more than that.
If the wind is strong I just soar normally - strong wind and steep slopes means good climb rates anyway."

TIP: CLOUD SPOTTING

"Never stop observing clouds; sunbathing, working in the office, driving (!), whenever! It is interesting and will make you a better pilot. When you are earth bound you generally have more time to follow the life cycle of the clouds you are observing - once airborne this is much harder.
How long does the cloud last from the moment you notice it till it has disappeared again? And equally important; how long till the same area produces the next cloud?"

TIP: CLOUD STREETS OVER FLATLANDS

"Two things to consider when utilizing cloud streets to fly in flatlands:

•  If the gap between two clouds in a street is greater than the distance to the next parallel street it is probably wise to change streets.
• If your bearing is at an angle to the cloud street it pays to go as far as possible along the streets and change street when a gap in your current street appears."

TIP: BLUE THERMAL DAYS

"It is obviously harder to locate thermals on blue days when no cu's show us where they are. On such days we must base our route decisions on the relief and simply aim for likely thermal sources and triggers, or we must watch for other hints. Birds, dust, grass, butterflies or even pollen are good markers, as are other pilots."

TIP: FLYING CONVERGENCE

"Convergences are great to fly when we're high, but nearer the ground we may encounter strong turbulence."

Photo: Convergence in the upper Rhone Valley, Valais, Switzerland. The valley breeze coming over the Grimsel Pass is so strong that it pushes the convergence line ever further into the main valley.

TIP: INVERSION BOUNCES

"As a thermal rises up and meets an inversion, it’ll get turbulent. On some days, a strong thermal might push through the inversion and with persistence you can go with it through the bouncy part and enjoy the clear air and spectacular views above the inversion layer."

TIP: KEEP LOOKING

"When circling in a weak thermal, be very aware of everything around you. Look round for other pilots, birds, leaves, dust, spider webs – anything really. As soon as something looks like its going faster than you, get over there. If you see a pilot climbing faster than an express elevator within gliding distance below you, jump on it!"

TIP: APPROACHING BASE

"The closer you get to cloud base, the further out towards the edge of the cloud you should fly, preferably on the upwind side if there are no obstacles around. In the mountains, on days where base is beneath the peaks, aim for the valley side of the cloud, where a brief visit inside is less consequential."

TIP: OPEN UP YOUR CIRCLE

‘Whenever I see a developing cumulus cloud above me I know there’s a way to get there. So when I find myself in a ‘dead end’ and have lost the core, I simply increase my turning radius until I re-encounter the core. I like flying alone a lot but there’s no arguing that exploiting difficult thermals is much easier with a gaggle.’