Presentation on theme: "THERMALLING (and how to avoid landing out) Other possible titles: How I landed out over 50 times. 50 Farming families Ive met. S.W. Ontario walking tours."— Presentation transcript:
THERMALLING (and how to avoid landing out) Other possible titles: How I landed out over 50 times. 50 Farming families Ive 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.
The Need for Speed All cross country flights are a race against time. Essential to understand the importance of a superior climb rate as compared to high inter- thermal speed. (Any fool can fly fast!) Thermal activity – weak in morning and late afternoon – requires tactical adjustments. Late in the day – STAY HIGH!
First Cross Country The 50 km. task is easy – in a modern glider – assuming decent weather conditions.. 6,000 feet msl. at SOSA – York Soaring is in the bag. The biggest barrier you face is the psychological fear of cutting the apron strings.
YOUR OBJECTIVE Badge flying is NOT a competition. Your purpose is to COMPLETE THE TASK. Who cares if you complete a 300km. flight in 4 hours or 6 hours? You should ! Higher speed requires mental discipline and courage. Yet, enjoy the experience – the journey is just as important as the achievement.
The Big One – 300km. Junior glide ratio is 34:1 at fairly high airspeed. Most modern fiberglass gliders are in the 33:1 to 37:1 range. Astir, Libelle, Junior, Std. Cirrus. Even a 1-23, 1-34 or a 1-35 are capable of 300 km. + + The key – good thermalling skills and adequate planning. Conclusion – 300 km. flight is possible on many average soaring days in S.W. Ont.
PLANNING 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 – dont get psyched out!
The Big Day Once airborne, get a feeling for the day. How do actual conditions compare to the forecast? Thermal strength and ease of connecting. Wind shear – at what height? Operating band*– thermals consistent above 2,500 feet or higher? Resist the pressure to start too early! *Note – operating band will change as the day develops.
Thermal Indicators 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 ……
Thermal Indicators WHEN HIGH ….. Use clouds or haze domes. WHEN LOW….. Use terrain features. On overcast (overdeveloped) days fly to areas of sunshine.
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?
Calculate my bank angle? Airspeed – you know. # seconds to complete 360° turn – you know. Gives you approximate angle of bank.
Circling Time in Thermals Bank angle 30°35°40°45° 40 knots 45 knots 23 sec. 26 sec. 19 sec. 21 sec. 16 sec. 18 sec. 13 sec. 15 sec. 50 knots 55 knots 29 sec. 31 sec. 24 sec. 26 sec. 20 sec. 22 sec. 16 sec. 18 sec.
Circling Time in thermals Better pilots typically fly at 45 to – 23 seconds per turn. If you are wandering around at 20 degree angle of bank – you cannot thermal efficiently. Good training – 42 knots – around 19 to 20 seconds. Caution – remember laminar flow … you can also thermal too slowly.
Common Thermalling Errors 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.
Common Thermalling Errors 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.
Average thermal strength Typical flight computer – average thermal strength based on: –Start of climb? –Last 10 seconds? –Last 20 seconds? –Last minute? –Duration of flight? –Computers have given us greater insight into achieved speeds.
Average thermal strength Typically based on the past 20 to 30 seconds. That is why a 4 knot day really turns out to be a 1.7 to 2.0 knot day when you analyze the data. Beware of optimistic radio calls – 5 knots here.
Thermal strength* in knots * (Assuming 4 turns to center) Height gained 1 knot climb 2 knots climb 4 knots climb 6 knots climb 1,000 ft ,000 ft ,000 ft
Cruising between Thermals This should be a very busy time for you. How fast to fly? How slow? Go left? Go right? Fly through the blue hole ahead? Avoid the overcast on course line? Catch up with that LS 8 ahead?
Cruising between thermals How FAST should I fly? If I fly too fast, what happens? If I fly too slowly, what happens? The good old days of pure MacCready ring settings.
Impact of Conservative Ring settings If you set the MacCready ring at 0 How much performance/time do you lose? Answer – 20% Leading to a high probability of an out-landing! Why? Reduces your thermal search area. Limited amount of thermal activity during the day – you run out of time.
Thermal Probability S.W. Ontario* 1 mile5 miles10 miles 1 knot knot knot knot * Standard class glider.
KEY LESSON IT TAKES TIME TO CENTER THERMALS! A good pilot will take FOUR turns to core a thermal. That is 120 seconds, 2 minutes – a long, long time, going nowhere! A really superior pilot will center the thermal in two turns. Time saved during a 20 thermal flight? 10 minutes!! An average pilot may NEVER center the thermal.
How to read Clouds 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.
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.
Between Thermals Blue holes - course line deviations. How far ? Remember your objective! Upwind or downwind? Cloud shadow. Overdevelopment – how to handle? Cloud streets – visible and not so visible. Sink streets – be decisive – act quickly. Blue days – sunglasses.
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.
Course deviations Remember your mission ! A 30° course deviation causes you to fly 15% further. At 80 knots, 3 miles and 30° deviation costs you 20 seconds. If you gain a mere 100 feet, you are better off than the blue hole puncher.
Course Deviations (The Tortoise and the Hare) High personal confidence in my thermalling ability. Shortest distance (best speed) between two points? Straight line ? Flying with others showed that the most effective way to fly between two points is frequently made by deviating under wimpy lift.
Fly with purpose! Dont let the thermals push you around Effective Inter-thermal Flying
When you feel lift always slow down and turn into it Anytime you can climb while flying straight on course is advantageous
Turn point Tactics Take upwind turn point……….. LOW.* Take downwind turn point…… HIGH. *( Within reason, of course!) Bartell – a 2 knot thermal going downwind is as good as an 8 knot thermal going upwind.
Key Points 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!
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.
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 Develop stamina – both physical and mental. Fight the urge to do something. Be patient! Avoid follow the leader – fly your own flight. Fight the urge to catch up – the need for companionship. Remember your objective – finish the task safely.
Psychological Factors 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!)
Psychological Factors Dont get sucked in by higher performance gliders. Be realistic about your gliders performance: Astir versus Ventus Hornet versus LS 6 LS 6 versus Nimbus 3 McMaster strategy – optimize your gliders performance envelope.
Airport Hopping (Airport hoping?) 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!
PRACTICAL STEPS The importance of weak days. Use 1 knot thermals around the field. Work on low saves around your Club. (Just brief the Duty Instructor!) Work on stamina. Release early. The Tow pilot creed – if he fails to release in lift, he must want sink.
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 – dont follow. Have fun!
Recommended reading list Soaring Cross CountryReichmann New Soaring PilotWelch & Irving Winning 11Moffat The Platypus PapersBird Meteorology for glider pilotsWallington Transition to glidersKnauff
Recommended Reading List A comprehensive reading list will be ed along with a copy of this presentation. address: