Insanely Fast: 105 miles per hour was good for what place?

Today, Day 7 of the 18m Nationals, was unbelievably fast. The task was once again an Assigned FAI Racing Task with with small 500m turn cylinders at Browns Peak, Bryce Woodlands, and Burnt Peak – then back to Nephi. Task distance 568 km.
At launch time, much of the start area was in shade and we were down to four tow planes, which led to a late start gate opening. I was worried that it would once again be a race against the end of the day and was determined to get going as soon as possible.
Fortunately the cloud cover moved east, and at 14:33 the gate opened, and everyone had to descend below 12,000 feet. Since we fly based on FAI rules we can then climb up to 17,500 feet before crossing the start line and going on course. Cloud bases were considerably higher than that so everyone had to watch their altimeters to avoid airspace penalties.
I found a good climb a bit removed from the mad hustle near the gate and was up above 17,000 within minutes and at 14:45 I was on my way.
The conditions out on course were exceptionally strong. We had good cumulus clouds throughout the entire task area, there was only minimal overdevelopment near the second turnpoint, winds were generally light, and thermal strength often exceeded 10 kts. Cloud depth was fairly modest which meant no risk of thunderstorms. Not even virga. Thermally induced convergence lines formed above the spine of practically all mountain ranges.
If you could design perfect weather conditions for soaring, you would be hard pressed to make any improvements over what we were handed today.
When conditions are this good, the focus must be on pushing forward at all times. Selecting the best lift lines along the clouds and stopping only for the strongest of thermals is what makes the winners stand out at the end of the day. Equipment is also important, especially glide performance at very high speeds. I found myself flying with A8, John Seaborn, on the first leg but my attempt to keep up with him quickly became futile when his dot disappeared in the distance on my Flarm screen not long after the first turnpoint.
There were some decisions to make as to which cloud street would provide the better line but the streets were all fairly well aligned with the task. It was a bit akin to deciding which interstate highway to pick when Google predicts similar arrival times for each option. I payed attention to the shapes of the clouds as well as to the shape of the terrain and the wind and the decisions came relatively easy. But the alternatives might have worked just as well in many cases.
I reached the southern-most turnpoint at 4:45PM with 250 km to go to the finish. After yesterday’s experience with the power switch (someone seemed to have turned off all lift at exactly 6pm) I was a bit worried about a repeat occurrence. I had had a good run south but I needed an equally good run north if I wanted to be on final glide by 6pm.
Fortunately we did not see much if any weakening of the conditions for the next hour. I got some good climbs south and north of the Tushar Mountains and then picked a line of still newly building clouds over the Pavani Range where I found a 9 knot climb at 5:50pm which took me to Final Glide altitude.
From there I flew all out at 130 kts toward the finish line. There was still strong lift even over the valley. Very different from yesterday. I attribute the difference mainly to the wind direction. Today we had south-westerly winds and temperatures on the ground were exceptionally hot at 103 degrees Fahrenheit. (Yesterday the northerly wind from Utah Lake brought early cooling and shut down all thermal activity.)
I finished with an average speed of 105 mph (170 kph). I was quite proud of myself until I found out that it was still only good for 24th place. John Seaborn won the day with a blistering performance at 118 mph (190 kph!). Almost the entire field flew faster than 100 mph today. There may have been equally fast soaring races before but I am not aware of any where such speeds have been achieved by so many. These were truly outstanding conditions.
Sean Fidler was 4th today and still leads overall with Andy Blackburn in 2nd (today 3rd), and John Seaborn in 3rd. Tomorrow is the last contest day and the top 5 pilots are within 200 points from one another.
My flight trace on WeGlide:
Contest Results:

Sudden Power Outage in Southern Utah

Yesterday late afternoon, on our rest day, someone must have flipped a switch because suddenly the power was out. Not just in Nephi but in the whole area. It stayed out all night and only came back after the sun had come out and was warming the ground.
Today, Day 6 of the 18m Nationals, was just like that. We were given a big assigned racing task to fly. More than 600 kilometers with small 500m FAI turn cylinders at Monroe Peak, Bryce Woodlands, Griffin Top, Browns Peak, and Big Baldy. Then back to Nephi.
Conditions were forecast to be strong. However, a northerly wind was blowing even in the morning bringing relatively cool air from Utah Lake and the Great Salt Lake to the launch area. (I say relatively because it was still quite hot.) This depressed thermal activity at the start and it took quite a while to get the fleet launched. And even then, thermals near the start were weak and topped out at about 13,000 feet.
When the gate opened everyone had to descend to 12,000 feet and then almost the entire fleet was flying in a single gaggle near the start line trying to get up but it wasn’t really working. We were just going in circles without gaining much altitude. It was already very late for our big task – almost 3PM – and I got impatient and went out on course. Since I am not one of the fast guys no-one gets on my heels which is just fine with me…
Three weeks of contest flying haven’t made me a gaggle person and I enjoy making my own decisions even though I know it’s usually not the fastest way to get around the course.
I crossed the valley to the east to join the clouds over the San Pitch Mountains, found a good climb at the south end, and then back west to the Pavani Range. Some others had gone direct through the blue – I don’t know if that made them faster. There was great lift just east of the Fire TFR, and from there I crossed to Monroe Peak, which worked well as usual. From there I followed the western edge of the Sevier Plateau in good air to the southern-most turnpoint.
The next leg took us over the Bryce Canyon area where I blundered by taking a too far northerly line which led into a heavy sink street. I deviated back to the south, more than 90 degrees off course to get into better air at the southern tip of the Escalante Mountains. The sink street and deviation cost me at least 10-15 minutes, which I really came to regret later. The entire area is quite spectacular. I previously knew it only at level ground from hiking and trail running trips to the National Parks at Bryce Canyon and Grand Staircase Escalante.
The western drop off of the Escalante Mountains produced an extremely powerful lift line and soon I was running again at 120 kts to the north. The Griffin Top turnpoint was perfectly aligned with the lift line and no stopping was needed anywhere. There was a blue hole to cross west of Wayne Wonderland but the convergence line extended through the blue, marked by some whispies along the way. Near Whiskey Knoll I got onto the Wasatch Plateau and the usual convergence on the plateau worked very well. Some pilots flew a bit further east and I was able to pass them along the western edge of the clouds. The convergence training in Boulder served me well locating the line of lift along the clouds.
Near Knob Mountain the convergence line curved strongly to the east and I had to get to Browns Peak, on the northwest side of the plateau. I decided to leave the wonderful line of clouds and fly the remaining 50km to the turnpoint in the blue along the western edge of the plateau. The air was reasonably good such that I achieved about a 50:1 glide ratio at about 80 kts. But as soon as I had left the clouds the convection shut down and thermal activity became minimal.
I turned Browns Peak about 2000 feet below final glide with another 100km to go to the finish. My flight computer showed some predicted convergence zones over the high terrain southwest of Mount Nebo and along the western edge of the San Pitch Mountains. I decided to detour to their western side and I was quite confident that I would be able to pick up the remaining 2000 feet along the way.
However, just like the day before, it was late afternoon and someone must have switched off the power. I followed the best looking terrain that had been in the sun all day long but there was simply no climb to be found. I worked my way south along the ridges towards the last turnpoint at Mount Baldy. Eyeballing it I wasn’t sure if I would be able to get there above the peak. It would be close.
I carefully examined the slope of the canyons to the west to ensure that I had a safe escape route into the valley and decided it was ok to give it a try. Fortunately the 500m turn radius was big enough to allow me to turn before the actual mountain for I did not have enough altitude to fly over the top.
Now back to Nephi. I was now 200 feet below final glide at MC0 and needed to find just one climb to make it back above minimum finish altitude.
The closer I got to Nephi the stronger the headwind became and the gap gradually became bigger. The north facing ridge lines worked just a little bit and I followed them religiously wherever I could to eke out a few feet of altitude gain. There was absolutely nothing to circle in and I don’t think that ridge soaring figure eights would have worked either. The little bit of lift was too close to the rocks and just too weak.
I knew there were some good hay fields south of the airport in case I did not make it back home so I kept going. 10km out it was evident that I would make the airport but that there was no way to finish above the 6500 ft minimum arrival altitude.
I monitored the radio for quite some time and fortunately no-one else was coming back at the same time. I eventually crossed the finish line at 5600 feet and decided to land straight in from the south on Runway 35. The landing was nice and smooth but I was clearly too low for a valid finish.
The 10-15 minutes that I wasted near Bryce Canyon airport made all the difference because the lift had ended just as abruptly as the power outage arrived the day before.
I’m a bit puzzled why the lift can end so abruptly. In Boulder it is almost always possible to find lift late in the day and I also had some great evening runs in lift along the San Pitch Mountains where the air was just dead today. I suspect it may have to do with the northerly wind that also messed up our start. Once the sun starts to go down, the north wind strengthens and brings more and more cool air into the valley. This then results in a fairly abrupt end of thermal activity. The problem on final glide from the south is compounded by the fact that the strengthening headwind is not anticipated by the flight computer which therefore delivers overly optimistic readings. That’s worth considering for the remaining two days.
What could I have done differently? Well, those who stuck together as a group had a better chance to find the last climb of the day in the blue. They may also have had a better chance of avoiding the sink street that cost me the crucial 10-15 minutes at the end. Maybe I need to learn to love gaggle flying and become a part of the herd… I don’t know. Something to contemplate.
Andy Blackburn won the day today ahead of Rick Indrebo and John Seaborn. Sean Fidler leads overall ahead of Rick Indrebo, Andy Blackburn, Jim Lee, and John Seaborn. The top 5 are less than 200 points apart.
Flight Trace on WeGlide:
Contest Results:

Every Conceivable Excitement

Day 5 at the 18m Nationals in Nephi had it all: 15 kt lift and 15 kt sink. Long glides across big blue holes over unlandable terrain with totally still air. We had heat, storms, rain, snow, and graupel showers. We were fighting against being pulled up into the clouds and minutes later we were fighting to stay airborne. We worked with dust devils and massive gust fronts. We were flying in huge gaggles and alone in the wilderness. We also had to avoid a wildfire TFR and a Restricted Area that occupied about a third of the second turn cylinder. The flight was spectacular and exhausting. Calling the day dynamic would be a total understatement. We had two landouts but everyone is safe and accounted for.
Our task was an Assigned Area Task (AAT) with turn areas at Whiskey Knoll (40km radius), Drum Mountains (20 km), and GB Intersection (40 km). Nominal distance was 540 km. Minimum task time was 3:30.
Getting up from tow was a challenge and some pilots had to come back for a relight. I was second on the grid and stayed in my weak climb off tow and saw its strength gradually improve until I was up at cloud base. Getting the entire fleet up took a long time and the start gate opening time had to be pushed back several times.
The weather forecast was for overdevelopment in several parts of the task area and when the gate opened there was already ample evidence of that to the south.
When the gate eventually opened everyone was keen to get going. I left as part of a large group that crossed the valley immediately after crossing the start line to get under a dark cloud line line that curved from the San Pitch Mountains into the first turn cylinder. The bulk when straight for the darkest clouds but by the looks of the line I was pretty sure that the strongest part would be on the western edge. I resisted the temptation to follow the crowd and was well rewarded with 5-10 kt climb rates in straight flight. By the time we reached the southern tip of the San Pitch Mountains I was up at 17,000 feet and looked down on a conga line of gliders a few miles further east and many thousand feet below. Now that felt good!
I upped my speed to 110 kts and kept racing along the convergence towards a dark wall that had built up further south: a massive, impenetrable storm front was moving in opposite direction, directly towards us. A look at the map suggested that the front was just about at the northern edge of the turn cylinder. It was a race against time and I hoped that I would get there before I would get into rain.
There was a big drop in cloud bases as I got near the front and I had to take out the spoilers to destroy several thousand feet of altitude to stay well below the clouds. But I figured whoever came after me would have an even harder time because the front was moving fast.
I got into the cylinder and turned just before the rain. A look at my Flarm screen showed that I was now well below the conga line that was coming towards me. The vertical separation eliminated any safety concerns and I rushed back towards the lift line that had carried me south. Once the bulk of gliders had passed I took a 10 kt climb to regain the altitude I had destroyed with the air brakes and I was back up and running, turning northwest towards the Drum Mountains.
The last clouds were just west of the Canyon Mountains, then came a gaping blue hole that stretched about 60 kilometers all the way to the Drum Mountains. I downshifted info flap position 1 and trimmed my Ventus to 80 kts to fly across the desert. The contrast was stark: minutes ago I was racing all out along a strong lift line, now I had to cross a big area of completely still air.
On the other side of the gap, a big black cloud was building over the Drum Mountains. It promised good lift but only if I got there before it would also overdevelop. I was wondering if I should speed up to get there faster but that would lower my arrival altitude and diminish my safety margin in case I had to turn back towards the airport of Delta. I decided the time gain from flying 90 kts instead of 80 wasn’t worth it and I stayed with the plan that would preserve altitude. Altitude always provides the most options and that’s what I like to have.
I reached the Drum Mountains and was surprised not to immediately find the strong lift that I had anticipated. I assumed it was probably on the west side, considering the light westerly wind and hoped that I would get there before the edge of the Restricted Airspace. Gosh, everything on this task is a close call! Fortunately the western edge of the clouds was about 2 miles away from the forbidden area and even better: there was the lift I had hoped for. I moved south along the edge of the clouds when I spotted a glider going up rapidly on the southern side of the cloud. I joined a 7-8 kt climb that got me back up to cloud base.
Off towards the third turn area further south! The sky ahead looked very complicated. To the left was a rapidly overdeveloping shelf that was off from the course line to the east. To my right was a dark line of clouds with heavy rain showers. Dust from a massive gust front on the ground marked the outflow from that storm. Don’t cross that gust front!
The Cricket Mountains directly to the south had a little bit of sun on them. The clouds overhead were dissipating, probably remnants of earlier overdevelopment in this area. I was hoping that the sun might start a new cycle of thermal development along the mountains and picked a line directly along the spine that would lead to the eastern edge of the third turn area.
I tuned my flight computer to Delta Muni, directly behind me, as this is the only safe place to land in this area. My flight computer showed that I was 4000 feet above arrival altitude at Delta at MC4. Would I be able to get into the turn cylinder before that number was down to 0?
There was only one way to find out. Once again I flew very conservatively at 80 kts to conserve altitude. There were some little bumps along the ridge that stretched my glide a bit, but I found absolutely nothing that I could have circled in.
When I got to the edge of the turn cylinder my arrival altitude at Delta had shrunk to 200 ft. Nick and turn! As soon as I heard the beep that I made it to the edge I changed course and headed back up to the north.
What difference 15 minutes can make! The cloud shelf to the east that I had hoped to fly along was now gone except that virga and rain was still falling in places. A line of dark clouds was now further north but I wasn’t sure if I would be able to reach it in time before it would blow up as well.
At least I was gaining on my arrival altitude at Delta so I had a safe place to go to if needed.
I made it around a rain shaft and saw a glider circling further east along a dark shelf, climbing at 6 kt,  7 km away. I had to cross some sink to get there and when I arrived 2000 ft below the lift was gone. But the shelf looked good and there had to be lift somewhere. Another gust front on the ground marked the way. I flew to the upwind side of the front and as expected the air was shooting up! 14 kt of lift in straight flight!
Soon I was up at 14,000 feet and had Nephi in glide. At the same time rain started to fall so I had to get out of there. I pushed northeast towards the Canyon Mountains which were in the sun with beautiful clouds on top. It looked like I could get there about 2000-3000 feet above, connect with the clouds and have an easy glide home.
Not so fast. As soon as this plan had formed in my mind I hit 12 kt of sustained sink and my altitude washed away in no time. What goes up must come down… When I reached the Canyon Mountains I was below the level of the highest peaks and in desperate need of a climb. Otherwise I would be landing out. Fortunately I had driven through this area two years ago and I knew that some of the fields below were landable. (Bruno Vassel ended up landing in one of these fields minutes later.)
But I wasn’t willing to give up so easily. There had to be some lift over the rocks. The air was quite turbulent but I found a 3 knot climb that improved with altitude. I was still far below minimum time so the strength of the lift was of no importance. As long as the air went up towards Final Glide I was willing to take it.
As I climbed I observed s new gust front rushing north from Gregs Beach towards Nephi. This could mean strong and gusty winds on the ground and I was eager to out-speed the gust front on the way home. When I was high enough to get even through heavy sink I was on my way and rushed back to the finish.
The wind on the ground was about 20 kts but blowing directly down the runway and the landing was easy and uneventful. I finished the task with more than 30 minutes undertime, which took my nominal task speed of 139 kph down to 117 kph.
It turns out that most of the fleet had to finish early today. In hindsight, one possibility would have been to continue further south in the last turn cylinder and focus my landing option on Milford instead of Delta. But I don’t know if this would have worked and how I would have come back from there. I’m happy with my decisions as they have kept me in safe gliding distance of good airports at all times.
Today’s winner was Joe Bostik (who like me also flies a Ventus 2), only 1 point ahead of Jim Lee (JS1) with Robin Clark (ASG 29) in third. Sean Fidler now leads overall ahead of Rick Indrebo and Jim Lee. John Seaborn did not have a good day and dropped down to 6th, but less than 200 points behind Sean.
My flight was good for 19th place today with 872 points which moved me up to 22nd or 23rd overall. I’m quite happy with this result, especially considering the caliber of pilots at this contest.
Contest Results:

The Race Against The End of the Day

Day 4 at the 18m Nationals in Nephi and Region 9 Sports Class in Nephi. The 18m pilots are not even half-way into the contest and it feels like we’ve already been here a long time.
Maybe that’s because today involved a lot of waiting – either on the ground or in the air. The Sports Class went up first and was sent on their merry way. They had a big 3 hour task to complete.
The plan for 18m was a 524 km Assigned Racing Task with fixed turnpoints at Table Mountain, Star Point, and Indian Ranch. After two thirds of the fleet was launched on Runway 17 the wind switched from south to north and that meant that those left on the ground had to move their gliders to the other end of the runway. Launching fully ballasted gliders with a tail wind at a mountain airport in the summer with density altitudes of 8000 feet or more is definitely not a good idea.
I was among those already up and flying. I escaped the gaggling crowds by taking a convergence line to the northeast where I could float along on my own. I knew the wait would be substantial and my plan was to conserve mental energy.
Eventually everyone was in the air but by then it was past 3pm and it was evident that starting out on a more than 500km task was likely to get pilots in trouble. Table Mountain was switched out for Monroe Peak, which shortened the task to about 440km. Still an ambitious plan, especially given that the cumulus clouds were projected to dissipate and give way to blue skies by about 5 to 5:30pm. Pilots had to confirm their understanding of the new task in a roll call and reprogram their flight computers in the air. I parked myself in a weak lonesome thermal so I could do the data entry without attracting the crowds.
The gate eventually opened at 15:27 and by 15:32 I had climbed back from our tag altitude of 12,000 to 17,000 feet in a 12 knot boomer and was out on course ahead of anybody else. I had had ample time to check the conditions out on course and knew where to fly. The first leg was blazing fast. I cruised at 100 kts and only stopped twice to climb back towards the clouds, being very careful to stay below 17,500 feet to avoid airspace penalties. The lift can get so strong in the west that keeping the glider down can be a real challenge. I even briefly opened my airbrakes as I was cruising through exceptionally strong lift to avoid getting sucked up to forbidden heights.
Getting in and out of turnpoint one was easy in soaring terms but a big challenge with respect to traffic. The best lift line in and out was the same and since I had started out ahead I had to avoid a lot of conflicting traffic. I deliberately flew a line that was far from ideal to stay clear of the gliders that were streaming towards Monroe Peak.
Leg two started out quite well also. My average task speed up to this point was 162 kph and the day was at its peak. Looking ahead I had to make a choice between two possible lines to TP 2. One was on the western edge of the Wasatch Plateau, the other was to the east of the plateau over the eastern desert. For a while I thought I would take the easterly line because it seemed much better defined and Skysight had predicted strong convergence east of the plateau.
However, it soon became evident that the easterly line was too far east. When a few additional clouds popped on the western edge of the plateau I decided to stay there. This had the added advantage of easy access to safe landing areas in the Manti-Ephraim valley whereas the eastern side of the plateau is a lot less hospitable.
Unfortunately the climbs along the western edge of the plateau were nowhere near as good as those along the first leg and there was also considerable sink in-between which quickly destroyed any hard-earned gains. I struggled to find a good line and my average task speed dropped below 150kph. Except for the western edge, the plateau itself was largely blue and I had to get high to safely cross. A mediocre climb near Mt Baldy got me back up to 17,000 feet and that’s where I started the transition towards Star Point.
The plateau is super scenic but from a soaring standpoint it was somewhat disappointing. As I got near Start Point I spotted a big gaggle and rushed towards it only to find that the lift averaged only 1-2 kts. Nothing kills your task speed faster than remaining stationary in a weak climb. I left to round the turnpoint and kept looking for better air. The wind was from the west and I wanted to have more altitude for the transition into the wind.
I found a line of good air that allowed me to progress westwards without dropping out of the sky. Back on the west side of the plateau the clouds were disappearing fast. I followed the ridge lines and tested the bowls but could only find 2-3 kt climbs at first. Things got a bit better as I moved further south where I found a good climb east of Manti-Ephraim. I tanked up for the next transition via the southern tip of the San Pitch Mountains which have worked for me before late in the afternoon.
Today there was not much there there, and I moved on towards the Pavani Range. Fortunately I was high enough to cross the ridges and fly on the sun-facing west side towards the last turnpoint. I was several thousand feet short of final glide and had to find another climb. I joined another glider but the lift died after the first turn. Onwards. I was getting low and the lift was getting weak so I began to dump water ballast.
Two minutes later I hooked a 6-7 kt climb south of Scipio. I quickly closed the water dump valves again and was able to climb a few thousand feet to get to final glide altitude at MC4.
I noticed other gliders taking a direct line towards Nephi but felt more comfortable taking a small detour via the foothills of the San Pitch Mountains that had been baking in the afternoon sun. I have had good success in the past stretching my final glide along the rocks.
The ridges weren’t as strong as hoped but they did enough to get me home. Which means I did win the race against the end of the day…
Once again I am astonished at the winners’ speeds of more than 100 mph (162 kph). Sean Fidler won the day ahead of John Seaborn. That is also the current standing overall. My speed of 130 kph (again!) put me in 24th place for the day and 25th overall. The stragglers among us have a private competition going where there are some exclusive prizes to win such as Strudel and Krautfleckerl. Feel free to ask me about that…
Contest Results:
The Region 9 Sports Class ended today. Congratulations to all participants and in particular to the winners.

115+ Mile Final Glide at 214 kph!

Day 3 at the 18m Nationals in Nephi. The weather forecast promised strong lift, increasing thermal heights, especially to the south, light winds, and nice cumulus clouds throughout the entire task area. The only question mark was the possibility of overdevelopment. But no thunderstorms.
The task committee gave us a lot to work with by declaring an AAT with 3 hour minimum time and two big turn areas at Delano Peak in the Tushar Mountains and Lamersdorf Peak in the Wah Wah Range.
The Region 9 Sports Class launched first today so the tow planes would have less fuel on board for towing the heavy 18m ships which are all laden to the legal brim with water ballast. If conditions are this good, you want your glider to be as heavy as allowed so it will glide further at high speeds.
When our turn came the day was fully developed and I caught a 9 kt climb off tow that took me all the way to cloud base in no time. Then I went to explore the clouds to find out if there was a pattern for lift and sink distribution below our puffy friends. As expected, the best lift tended to be on the south-west side, which was upwind and facing the sun.
I was itching to get going and when the gate opened I was among the first to cross the start line. I figured the fast guys would catch up to me sooner or later and I would get plenty of company soon enough. The first clouds were lined up well and I knew where I wanted to go and was able to enjoy my glide out in solitude.
The start went quite well but after maybe 30-40 km the clouds were not working nearly as well as they had before. I noticed a convergence line on the east side of the Canyon Mountains that was to the west of the clouds and that helped me along until I found a good climb south of Williams Peak.
From there I tried to stay high as I saw some of the Sport Class gliders struggling low along the Pavani Range. A small wildfire had just started above one of the ridges north of the Kanosh Canyon and that was one more reason to stay very high in case a TFR would be declared (this did in fact happen later in the afternoon). Far below were a few paragliders directly above the fire getting smoked.
I tried to leave the area as quickly as possible and flew to the east of the Tushar Mountains to get a bit deeper into the first turn area. These mountains are absolutely spectacular. Several years ago I participated in a trail marathon that went all the way to the top of Mt. Delano – one of my most demanding foot races. I always marvel how easy it is to climb these mountains in a glider by comparison.
This was also the section were I was being passed by the fast guys who had started later than me. They kindly marked two good thermals for me that took me all the way to 17,000 feet. Thank you! The fastest pilots kept going further south and I decided once again to fly my own race and took a promising line to the west towards the second turn area. My flight computer predicted 30 minutes overtime even if I would only scratch the second turn area so I figured I had gone far enough to the south anyway.
I got some great views crossing the Tushars from east to west, heading past Beaver towards Lamersdorf Peak. I found a good climb over the Mineral Mountains just west of Beaver and the clouds continued after a modest blue hole to the west.
I got into the second turn area and my flight computer still showed 28 minutes of overtime. A great looking line of clouds curved directly into the direction to the finish. The computer said I would need to fly 202 kph average for the rest of the task – the remaining 188 kilometers or 115+ miles – to arrive on time.
That speed seemed inconceivable to me so I turned north towards the finish.
At MC4 I was about 6000 feet below final glide path but the line of clouds ahead looked excellent and I was sure to find some good climbs along the way.
Well, the clouds were even better than expected. I remembered that the line was the result of two convergent winds: a southerly wind to my right, and a more westerly wind to my left. These two wind streams were coming together, pushing the air up along the way. The result was a lift band that stretched all the way from the second turn area to the finish more than a hundred miles to the north.
All I had to do was stay relatively high along the west side of the clouds and the convergence propelled me forward while the tail wind pushed me along. It was a spectacular part of the flight because it was so easy. I just continued straight, slowing down in the strongest parts of the lift and flying faster in the weaker parts.
I continuously gained on the final glide path and the predicted overtime got shorted and shorter. My ground speed started to exceed 200 kph and soon I started to wonder if it was in fact possible that I might come back below minimum time if the line were to continue.
Well, continue it did. By the time I was abeam Filmore my flight computer showed that I had reached final glide altitude at MC4 and when I reached the Canyon Mountain it was obvious that I would arrive too early and too high. I put the Ventus in speed flaps and pushed the trim all the way forward to run 130 kts and I just kept the nose pointed at the finish.
I eventually reached the finish cylinder about 800 feet high and arrived with almost 5 minutes below minimum time. That’s unfortunate because it means my average speed for the flight was only 142kph instead of the actual 146 kph. (This is because the flown distance is divided by the minimum time and not the actual time if one finishes early.) (My average speed for the entire 188km final glide was 214 kph.)
But it was great fun nonetheless. For the future, I just have to take the possibility into account that a great looking line might work even better and allow for an even greater time cushion. It would not have been hard to go a little deeper into either of the two turn cylinders.
Today’s winner was Rick Indrebo with a speed of 163 kph, closely followed by Sean Fidler and Bif Huss. Rick and Sean also took the lead overall closely followed by John Seaborn who is in third overall.
My daily score today was 872 points, a good improvement over the first two contest days.
Flight Trace on WeGlide:
Race Results on SSA Website:

About Rainshafts and Blue Holes

Day 2 was a day of contrasts at the 18m Nationals and Region 9 Sports Class Contest. The 18m class was sent off on a three hour minimum Assigned Area Task (AAT) with three 30 kilometer turn cylinders at Crispy, Drum Mountains, and White Pine Peak.
Skysight predicted very strong conditions along the airmass boundary separating the western desert from the ridge lines of the Rocky Mountains. The task looked like a triangle but one could almost turn it into an out and back race to take full advantage of the lift line along the Pavani Range. To do that one would have to go deep into the first turn cylinder near Mt Delano in the Tushar Mountains, then backtrack north, head west and nick the second turn area, only to return to the mountains and go deep again in the third turn cylinder before heading back north again towards Nephi along the same line.
This would minimize the time in the blue and maximize the time spent flying straight under the cloud shelf marking the convergence.
I suspect that many pilots had similar ideas for the day and one of my pre-take off concerns was the back and forth traffic along the same cloud street. The sky is a big place but all soaring pilots look for the best lines of lift as marked by the clouds and that can lead to high-speed head-on traffic along the same routes and at similar altitudes.
John Seaborn, the defending 18m Champion and yesterday’s winner confirmed my thoughts but added that the best laid plans usually go the way of the waste bin as soon as one gets a look at the sky in flight. How right he would be.
After some start delay with the usual intense pre-start gaggles the first leg looked just as promised. But this only held until Filmore, about two thirds towards TP1. The further south we went the darker the skies became and my plan to get almost to the Tushars went by the wayside as soon as a pilot ahead reported lightning strikes near Mt. Delano. Storm clouds can produce amazing lift but they are not my cup of tea. I watched the leaders head into the dark overcast, flying between rain shafts and decided that this wasn’t for me.  I only nicked the turn cylinder and instantly new what this meant: I had to alter my strategy and go much deeper into the western desert than I had intended – otherwise I would finish well below under minimum time.
Fortunately there were some good clouds along the first part of that third leg until the Big Blue Hole appeared that Skysight had forecast. The next clouds were perhaps 40-50 kilometers away, over a line of hills in the distance. I tanked up under the last cloud and then went out into the desert, dialing my speed back to 80 kts. By now the leaders who had flown deep into TP1 caught up to me and so I had some company. At this point this was quite welcome for I knew the pilots in front would mark any good lift ahead.
However, the air across much of the blue hole turned out to be completely still. I could have let go of all controls and the glider would have flown on its own. There was even time for contemplation. Flying a glider usually involves rapid decision making, with decisions often taken every few seconds. But now I flew over flat, largely featureless desert. I had pointed the glider to the next clouds and all I could watch was the variometer for any indication of lift or sink to make small adjustments to my glide path. For some time there was neither. My altitude slowly trickled away but the task setters had done us a huge favor by setting a course that would allow us to keep Delta Muni in glide.
By the time I reached the next clouds I had only used up a bit more than 3000 feet of altitude. It’s amazing how efficient our machines are in the air. Fortunately the clouds on the other side worked reasonably well. In hind-sight I was a bit too conservative accepting mediocre lift at first before I gained enough confidence that the sky ahead was indeed working. I passed the center of the Drum Mountain turn area and carefully paid attention to the restricted airspace, which is used by the air force for fighter training. I got to know a former F16 pilot who had been stationed in Utah – you definitely want to stay well clear of that area even when there are no contest points on the line!
Once my flight computer showed a good amount of overtime even when I would only nick the last turn area, I turned and largely back-tracked the path I had just taken, heading back south-east. More clouds had developed and the blue hole had shrunk considerably, making the transition a lot easier.
Going deep into the second cylinder turned out to be a good decision because heavy rain started to fall in the third cylinder just as I go there. I had to cross a virga line to get into the turn area but then I found strong lift just to the west of a rain shaft that I flew around once I decided that it was time to turn back to Nephi. You could see the gust front from the rain driving up dust on the ground – often a great indication of where to find lift.
A line of clouds across the Canyon Mountains marked a good line towards Nephi and I went on final glide even though my flight computer predicted that I would be 500 ft too low at MC4. The lift over-delivered and I kept increasing my speed to 125 kts and still arrived almost 1000 ft too high.
That turned out to be a blessing because dozens of gliders arrived within minutes of one another. It was hard to find two to three seconds of free radio time to announce my arrival among all the finish announcements and sorting out of the landing sequence. Amazing how this works without air traffic control. However, instead of diving right into the traffic jam I climbed back up to cooler temperatures and waited until the commotion on the ground had settled down.
Oh, results. I guess I’m in a competition and these things should be reported. My average speed for the day was 130 kph just like on Day 1. Not fast but a modest improvement in relative terms because today’s winner, Robin Clark, averaged 161 kph, which means I scored just a little over 800 points. Not great but not terrible either. I have realistic expectations and am here to learn and not to win.

Alone in the Desert or: 1st Contest Day of the 18m Nationals in Nephi

The weather forecast projected early over-development and thunderstorms over the Wasatch Plateau but good soaring conditions over the western desert. And a big storm cell was projected over Mt. Nebo for mid afternoon. The task committee did a good job trying to keep us out of bad weather and declared an Assigned Area Task with two big 30km turn areas at Kanosh Canyon and Pine Peak, followed by two smaller 10km ones at Drum Mountains and Delta Muni. Then back to Nephi. 2:30 hours minimum time. Task distance anywhere from 267 km to 492 km. Yes, kilometers. They seem to be an alien measuring concept for some but I grew up in Europe and find them quite intuitive.
After a somewhat challenging climb-out I hung out at cloud base until task opening time, then everyone was forced to descend to 12,000 feet before climbing back up as high as possible before crossing the start line. This rule tries to make the start fair to those who are late on the grid but it creates a lot of traffic at just below 12,000 feet right before gate opening time.
I escaped the traffic by finding my own clouds further afield but this turned out to be a mistake. I hopped from cloud to cloud not finding anything useful to climb in until most of the field had already gone out on task. I finally was able to cross the start line at 14:45, dead-last and a whopping 25 minutes after the leading (and winning) pack. I was at first angry at myself for taking so long to climb but then I told myself that I just had to fly my own race without any distractions. I felt much better once I put a positive spin on my situation. Mind games. Amazing how this works.
The first leg went blazing fast under a cloud shelf that separated the dryer desert air from the thunderstorm-prone airmass over the mountains. For quite some time my task speed indicator was above 170 kph and my mood was up. Maybe starting late was an advantage.
But when I got to the first turn area, a rain cell just south of Filmore blocked further progress and I had to turn west earlier than I wanted. The cloud line was suboptimal too as it forced me into a detour to the north to stay below the clouds and then cross a big blue hole to get into the second turn area.
Up until that point I had kept in close contact with the clouds but now that I had dropped below 13,000 ft the clouds were no longer working. That’s when I remembered my struggles in the start area. Today was a “get high, stay high” kind of day. I went from “race mode” to “stay up mode” and began to search for lift among all the usual suspects. The ground was still far below but it looked positively alien. I suspect all the Mars movies are made in Utah.  I scanned the ground for roads or any sign of civilization but none was in sight. Just sand and rocks as far as the eye could see.
Well, I wasn’t very selective with my next thermal. This is no place to get low and I was all alone in the desert with all the other gliders well ahead of me. I centered the next 3kt climb and slowly worked my way back up to cloud base. Once there, the air was buoyant again and things were easy until the next blue hole when they were not.
Turnpoint three brought me into the proximity of the Restricted Area and of course the best looking cloud was over forbidden terrain. Oh well. I took another detour line towards Delta and decided to approach it from the very south as I still had some time to kill so I would not finish under minimum time.
Once I got close to Delta a great looking cloud was right on course towards Nephi but I fell victim to the recency bias and took the next 4kt climb to climb to Final Glide Altitude instead of switching gears back into race mode.
The cloud past Delta delivered the strongest climb of the day, catapulting me up to 2500 feet above Final Glide altitude and from there it was nose down and 125 kts to the finish line, still arriving high.
I thought my task speed of 130kph was respectable but that only lasted until I got a glimpse at the score sheet. John Seaborn finished first with 173 kph, closely followed by four other pilots who also beat the 170 kph mark. Racing against the best in the Nation is a humbling experience as I knew it would be. But it’s a great way to learn and I know I can do at least a little bit better.
I should also mention that the landing was rather sporty with significant cross winds gusting to above 20 kts. Half an hour later it was blowing even harder. I hope everyone had safe landings without any damage.
Contest Results:

Declared Tasks and Badges – From Beginner to Diamond

At my club, the Soaring Society of Boulder, we are trying to help freshly minted glider pilots who are eager to develop their skills but are unsure how to go about it.  Stats show that a large percentage of recently-trained pilots exit our sport long before they have experienced what’s possible.  However, those who reach for the challenge, often find a passion that lasts a lifetime.

I believe that one key tool that can help a new pilot’s development is a set of standardized soaring tasks.  In the case of Boulder, we carefully designed them for our demanding mountain soaring environment. It’s paramount that pilots stay safe as they progress. This article introduces these tasks – from Beginner to Diamond.

You can find much more detailed information about these tasks here.

From Beginner to Silver

The first four tasks are supported by Proving Grounds: from Beginner to Silver.


Our first task is called “Boulder Dash.”  It is a ~45 km flight around the city of Boulder and takes the pilot never further than 12km (7.5 miles) away from the airport.  It is suitable for any licensed pilot who is able to stay airborne on a good soaring day.  In addition,  the pilot must have the mental bandwidth to maintain situational awareness.  E.g., they must pay close attention at all times to other traffic and airspace constraints.

The tasks build on one another and are getting progressively harder.  “Hill Rambler” introduces pilots to mountain flying over the foothills of the Rocky Mountains.  It also doubles the distance away from the airfield.  However, pilots can easily keep the takeoff airport within safe glide at all times.

Niwot’s Challenge” takes pilots close to the Continental Divide, the spine of the Rocky Mountains.  Pilots learn to carefully manage their altitude to ensure the safety of the flight at all times. The second turn point doubles again the distance away from Boulder. Pilots must consider other landing options should it become necessary.

Lookout for Silver” builds on everything pilots have learned in the prior three tasks.  Pilots can earn Silver Distance and Silver Altitude – two of the three components of the Silver Badge.  Total task distance is 170 km – a great preparation for earning their other badges.

Proving Grounds Support

These first four tasks will be supported by Proving Grounds.  Proving Grounds is a platform developed by a group of Canadian soaring pilots.  It is super easy to use and provides a low maintenance approach to member development. The Soaring Society of America supports its adoption in the US.  This may be a great opportunity for your club!

Pilots who complete any one of these four tasks can simply email the .igc trace to a “bot” which automatically scores their flight.  Pilots can then post their achievements on a stainless steel task board.  The board will be mounted at the airfield and lists the flights ranked by average speed achieved (adjusted for glider handicap).  The bot provides all the relevant information.

In addition to support by Proving Grounds, our club will provide individual task sheets.  These contain task-specific safety tips (e.g. suggested minimum altitudes, air traffic pointers, potential terrain traps) as well as tactical advice regarding weather, soaring conditions, and how to fly each task.  Pilots are also encouraged to become proficient in the use of a flight recorder – a key requirement for earning their badges.

Our support program does not end there.  The next step is for pilots to work on their Gold and Diamond flights.

Gold and Diamond

Gold in Glide” is aptly named because this task allows pilots to earn their Gold Distance requirement while staying in glide range of the home airport the entire time.  This is possible thanks to our topography, outstanding soaring conditions, and our club gliders.  During the summer, we can routinely soar to just below Class A airspace (which starts at 18,000 feet).  Our club’s two Discus CS gliders are ideally suited for accomplishing all badge tasks.

Front Range Diamond Goal” and “Front Range Diamond Distance” are task recommendations for pilots who have completed their Gold Badge and are ready to leave glide range for the first time.  However, other airports near the proposed routes help pilots stay safe.  These tasks are mere suggestions: pilots are encouraged to adjust their tasks based on the day’s specific weather conditions, e.g. taking advantage of particular energy lines (such as the typical Front Range Convergence).

Our club encourages flight instructors and experienced cross country pilots to support aspiring pilots with ground-based coaching.  Some may even fly some of the tasks with them in our club’s DG 505 or via lead-and-follow mentoring.

The goal is to give pilots a framework and support to embrace the challenge of developing from glider pilots to XC mountain soaring pilots without putting themselves in danger.  It may lead to more pilot engagement and long-term retention of valuable club members.

Here’s a link to download a presentation with detailed descriptions of all tasks.

If your club has also taken steps (similar or different) to help pilots cross the gap from freshly certificated glider pilot to safe cross-country pilot, I’d love to hear from you in the comments or via email at

This Brilliant Man Can Get You In Trouble – Misapply MacCready Theory At Your Own Peril

(Editorial Note: since initial publication, I have added a few thoughts suggested by readers.  Andy Blackburn’s input has been particularly valuable.  I also added a post scriptum at the end with additional tips.  Thank you to all who commented.)

Who has not heard of the MacCready Speed-To-Fly Theory?  It is the brilliant discovery of a brilliant man who was not only the first American to become a world soaring champion but who came up with a scientific way to demonstrate how fast we should be flying in-between thermals in order to maximize our cross-country speed.

Paul MacCready (1925-2007) – one of the most most influential individuals in soaring history. You can find his bio here.

Not long after MacCready published his theory, other pilots followed his example and began equipping their gliders with “MacCready Rings”.  These are simple devices mounted around a glider’s variometer telling  the pilot how fast they should be flying depending on the expected strength of the next lift.

With the onset of flight computers, MacCready’s Speed-To-Fly Theory (or STF for short) went digital.  Today, every flight computer requires the pilot to input their “MC value”,  and every STF vario will produce audio and visual signals. These tell the pilot whether to speed up, slow down, or maintain the current speed – based on the MC value they selected.

Over time the application of STF theory has evolved a bit.  E.g., pilots have learned that it is useful to slow down as they get closer to the ground to minimize the risk of a landout.  Others correctly pointed out that “chasing the needle” is not only distracting but that constant control inputs make it inefficient as well. Instead, most would recommend flying at “block speeds” that approximately correspond to the correct MC setting.  After all, flying a bit too slow or a bit too fast makes little difference in terms of the average speed achieved. Some have even come up with scientific ways to show when, how, and how much to deviate from MacCready’s theory. (E.g., see Daniel Sazhin’s and John Bird’s work about “Bounded Rationality and Risk Strategy in Thermal Soaring” or John Cochrane’s article, “MacCready Theory with Uncertain Lift and Limited Altitude“).  Instead of getting into more details here, I recommend that interested readers take a look at the article “Just a Little Faster, Please“, also by John Cochrane.

However, no-one doubts that MacCready theory at its core is mathematically correct and scientifically sound.  It remains the undisputed foundation of any theory about how fast we should fly in cruise.  Most importantly: every flight computer and every vario asks you to input an MC value.  So you better know what these devices are doing with the information you enter.

MacCready Theory in a Nutshell

Every soaring textbook has an explanation for how and why the theory works. In essence, it is quite simple: when the lift ahead promises to be strong you should fly faster.  When the lift ahead looks to be weaker, you should fly closer to your glider’s best L/D speed, i.e. the speed where it has its best glide ratio.  MC theory tells you exactly how fast you should fly based on the strength of lift you expect ahead.

The series of charts below illustrate a simple example.  They are based on the speed polar of a Discus CS (one of the most popular standard class gliders) without water ballast.  (The principles explained are the same for whatever glider you fly but the values will obviously differ. If you fly a similar glider, such as an LS4, a DG 300, or an ASW 24 they will be close. A DG 505’s polar is also similar.) The speed polar is the curved line in blue.  It illustrates the rate of sink at various speeds.  The speeds are on the horizontal axis (in kts), and the glider’s rate of sink at these speeds is shown on the vertical axis (also in kts).  Using the same units on both axes (in this case kts) is very helpful because you can calculate the glide ratio at any point along the curve simply by contrasting the speed to the sink rate.

Speed polar of a Discus CS. Horizontal and vertical speeds are in knots (nautical miles per hour).

The next graph below shows that the best glide performance of the Discus CS is at about 55 kts. You can find this best glide speed by placing a tangent (the red line) against the speed polar starting at the chart’s origin (the point 0,0).

The best L/D speed is at the point where a tangent originating at 0,0 touches the speed polar.

At 55 kts the Discus will sink at a rate of 1.3 kts.  55 divided by 1.3 equals 42.  55 kts is the best L/D speed for a Discus and its best glide ratio is 42:1.

The only time you would ever fly at the best glide speed is when you are desperate.  Let’s say the lift has died for the day, the air is completely still, and you are just high enough to safely make it to an airport.  That’s when you would fly at best L/D.  This speed is also called MC 0 speed:  the expected strength of the next lift is zero (because you know there is no more lift to be had) and all you are trying to do is to stretch your glide as far as possible.

Let’s look at a more frequent example.  It’s a pretty strong day.  You are high and there are several good-looking cumulus clouds ahead. During the last few climbs you achieved 4-5 knots on average from the bottom to the top of each thermal (including any centering delays, re-centering efforts, etc) and you expect the next lift will be just as strong.  In this case it makes sense to set your MC to 4.  You expect the next lift to be just as strong and you are not willing to stop for anything less than that – at least for now.  In this case you should fly at MC 4.  (MC 3 or MC4 are perhaps the most common MC settings that pilots use for Speed-to-Fly calculations.  Higher settings only make sense in exceptionally strong conditions. How often would you not take a climb that averages 4+ knots from bottom to top?)

You simply feed MC 4 into your vario and it will tell you to fly at MC 4 speed.  The chart below shows you how your vario calculates this speed:  it places a tangent (once again the red line) along the speed polar curve but this time it starts at a point 4 knots above the origin.  The tangent touches the speed polar at 83 kts and you can see that at this speed the glider will sink 2.9 kts per hour.  The glide ratio at this speed is 83/2.9 = 29.  I.e. you will glide 29 ft forward for every 1 ft of altitude you lose.  29:1.

At MC 4, a Discus will achieve the highest average speed if you fly at 83 kts in still air. At this speed your glider will descend by 2.9 kts and your effective glide ratio will be 29:1.

OK, so far, so good.  You already knew this anyway.  But what does this have to do with the headline?  Where’s the peril?  That’s what we’re getting to now.

The Other Use of the MacCready Value

The MC value that you enter is not only used by your vario to calculate your best Speed To Fly but it is also used by your flight computer to calculate whether you can safely reach a place to land.

I very much doubt that this was Paul MacCready’s idea.  But that’s how your flight computer works. And if you don’t know it, it can be a big problem!

In the example we just discussed above it is hard to see.  When you’re flying high and happy and are confident that the next thermal will deliver a 4 kt average climb you are probably not too concerned about reaching a safe place to land.  And if you glance at your flight computer it will use your MC 4 setting to calculate which airports (or landout fields) are in safe glide at MC 4.  I.e., it will do so based on a glide ratio of 29:1.

But let’s say the expected 4 kts of lift did not materialize.  In fact, the clouds that looked so good before are now dissolving and you’re getting lower and lower.  Far from being confident that the next lift will deliver 4 kts, you are gradually getting concerned.  And, as you should, you dial back your MC settings.  First to MC 3, then to MC 2, and, as you get lower and lower, you move it back to MC 1. Eventually you are getting desperate and dial it all the way back to MC 0.

This makes sense because you want your STF vario to tell you to fly more slowly so you better conserve altitude and have more options to find lift ahead, rather than driving hard down to the ground.

But what does your flight computer do with the same information?  As you reduce your MC settings to 3, 2, 1 and then to 0, your glide computer thinks you can glide farther and farther.  It basically removes your safety margin.  Remember: at MC 0 your flight computer believes you are able to consistently  fly at the very optimal glide speed – 55 kts in still air – and achieve a glide ratio of 42:1. Is this realistic? Probably not.

By reducing the MC value to 0 you just told the glide computer to lie to you.  It is now showing airports (or fields) in glide range that really aren’t.

But things are probably even worse.  Quite possibly much worse!

Unless the day has truly died and the air become completely still, chances are that the airmass you are flying through is actually going down.  Why?  Because as long as there are thermals and the air is going up somewhere, it must be going down elsewhere.  Completely still air hardly ever exists and it most definitely does not exist on a day when we expect to find enough lift to fly cross-country.

So let’s say the air you’re flying through is actually going down by 1 kt.  One knot is not much and definitely not unusual. What are the implications?

Well, first of all you should be flying a bit faster.  When the air is sinking at 1 kt, your STF vario will tell you to speed up even if you leave your MC setting at 0.  How does it do this?  Easy: 1 kt sink will simply shift the glide polar down by 1 kt because you have to add the sink rate of the airmass to the sink rate of the glider.  (The vario obviously knows you are in sink and it does this automatically. ) You can see the new polar on the chart below (in orange).  You can also see where the tangent touches the new polar curve.  This point is at 59 kts and your sink rate will now be 2.4 kts.  (In still air it would be 1.4 kts but since you’re in 1 kt sink, so you’re actually coming down at 2.4 kts.)

Sink will shift the speed polar down because the sink rate of the air must be aded to the sink rate of the glider at any given speed.

Now, look at what happened to the glide ratio!  At 59 kts and 2.4 kts sink, your glide ratio is now 59/2.4 = 24:1.   You’re still flying a high performance glider but just 1 kt of sink is enough to basically turn it into a Schweitzer 1-26!

What about the safety glide calculation?  Your glide computer does not know how long the sink will last so it does not take it into account at all!  (This makes sense because otherwise the safety glide calculation would jump around wildly each time you fly through a bit of lift or sink.) Remember this! The flight computer will account for wind (because wind doesn’t change from second to second) but it does not account for lift or sink when it calculates which airports (or fields) are in glide.

So what does it tell you?  Since you turned down the MC value to 0, it will calculate your safety glide with a 42:1 glide ratio even though you are only achieving 24:1!

It is easy to see why this is at best misleading, and at worst a major safety hazard.  A lot of beginning XC pilots tend to use what they think of as a “conservative”, i.e. low, MC setting.  As long as this is only applied to Speed-to-Fly calculations it makes sense because it helps them stay high (while obviously slowing them down).  But when applied to safety calculations a “low” MC setting is just the very opposite of conservative!

What Should You Do?

Now that you understand that your MC settings are used for two completely different purposes – calculating your speed to fly, and calculating your safety glides – what can you do about it?

The answer is simple: use two different MC settings, each appropriate for its purpose!

If your glider has an electronic Speed-to-Fly vario and you are also using a completely separate flight computer with a moving map, things are straightforward. For the vario use an MC setting that’s based on the minimum strength of the lift you are willing to accept.  For the flight computer use an MC setting that’s appropriate for safety glide calculations.

This describes the setup that I was flying with last year.  I had an STF vario in the panel and a stand-alone Oudie IGC flight computer with a moving map display.  I entered my STF MC setting into the vario, and kept a different (usually higher) MC setting on the Oudie.  This way the Oudie would only show me airports and fields that really were in safe glide range.

Things get problematic when your STF vario and your flight computer are connected with one another. Changes that you make to your MC settings on one device are probably automatically sent to the other device. The two devices are kept in synch.  This seems like a great convenience but in reality it is anything but!  In real life it is quite rare that you want to use the same MC value for your STF calculations and for your safety glide calculations. And whenever it is appropriate to use two different values than either of these two calculations will simply be wrong!

If you use a setup where your SFT vario and your flight computer are connected with one another (e.g. via cable or bluetooth), see if there is a setting that prevents the two devices from synchronizing MC values.  You want each of these devices to correctly calculate the thing it is supposed to calculate!

If you only use only one single device for both STF and safety glide calculations (or if you cannot prevent your STF vario and your flight computer from synchronizing MC values) you must remember to edit your MC setting based on what you want to focus on. If you are relatively new to cross country soaring I suggest that you set the MC value appropriately for safety calculations and simply ignore your vario’s speed-to-fly suggestions.  You’re probably not going to fly as fast anyway as the vario suggests you should.

And there’s one additional thing you should do:  make sure that you complement a safe glide calculation by also setting a safe arrival altitude.  After all, you don’t want to arrive at the airport (or field) at grass root level. You want to have enough time to do a proper landing check and fly a safe landing pattern.  What’s a safe arrival altitude?  That is a different question for another time.  In Boulder, I always plan to arrive no lower than 1500 AGL because we have a very busy airport, and I may be in line behind other gliders or even a bunch of skydivers that are floating above the field just when I get there. Extreme weather can create problems, too.  Here’s a scary experience from a few years ago.

What MC Value is Appropriate for Safety Glide Calculations?

We know from the MacCready theory how to set MC for Speed-to-Fly calculations:  enter the expected lift of the next thermal.  Better still (since you don’t really know how strong the lift ahead will be): enter the minimum strength of lift that you are willing to take right now.

But how to set MC for calculating safety glides?  Well, as always, it depends. Since this calculation is about safety, and only about safety, the key question you should ask:  given the looks of the conditions ahead, what is the “worst-case glide slope” with your glider in the direction you’re heading – at least until the next landable field or airport?  Whatever your estimate is, you can then enter an MC value that corresponds to that glide slope.

OK, so how do you estimate your worst-case glide slope?

We have seen above that sink has a very negative impact on the attainable glide slope.  Just 1 knot of sink will turn a 1:42 glider into a 1:24 glider.  What about 2 knots of sink?   Let’s take another look at the speed polar.

Discus glide polar in still air (blue) and glide polar in 2 kts of sink (orange). If the air descends at 2 knots the best attainable glide ratio is 18:1. To achieve it, the pilot must fly 67 kts.

Two knots of sink will shift the speed polar down by – you guessed it – 2 knots.  You’re in sink, so you must fly faster.  How fast? Place a tangent from the origin against the new (orange) speed polar.  67 knots is the speed to fly and your rate of sink will be 3.8 kts.  In the best case, this equates to a glide ratio of 18:1.  (I say best case because it is pretty difficult to fly exactly at the right speed to fly and if you fly a little faster or slower, your glide ratio will actually be worse than 18:1.)

Depending on where you fly, two knots of sink still isn’t all that bad.  Here in Colorado it is not uncommon to hit pockets of sink where the air goes down by 5 kts or even 10 kts.  In wave conditions it could be as much as 20 kts!  How would that affect your glide slope?

The chart shows the original polar curve (in blue), as well as three additional polar curves: one for 5 kts of sink (orange), one for 10 kts of sink (gray), and one for 20 kts of sink (yellow). Tangents from the origin against each of these polar curves determine the best achievable glide slope at the indicated flying speeds. The point where the tangent would touch the curve for 20 kts of sink is to the right of the chart. Va and VnE also set practical limits how fast you can fly to get out of such extreme sink.

The chart above shows that the impact of strong sink is downright frightening.  If you fly through 5 kts of sink your best glide ratio is 11:1 at a speed of 88 kts.  If you cross 10 kts of sink, your best glide ratio becomes 5:1 at a speed of 102 kts.  And at 20 kts of sink, the answer is literally off the chart. You’d fly somewhere between rough air speed and Vne and you’d be lucky to achieve much better than 2:1.

Scared? Well, you should be.  Big sink is scary.  If feels like you’re coming down like a brick.  Because you are. Well, almost.  Fortunately, strong sink tends to be short-lived.  And since it’s true that what goes up must come down, it’s also true that what comes down must go up.  Strong sink and strong lift tend to exist in close proximity to one another.  Wave flying is an extreme example where 10-20 kt lift and 10-20 kt sink can be within 1 or 2 miles from one another.  Try to get out of sink and back into lift as soon as possible! Hopefully you know what you’re doing!  Or, perhaps even better: think twice before you decide to fly in such extreme conditions to begin with.  The point is that such extreme scenarios are not really all that helpful when you decide how to program your flight computer.

In regular summer soaring conditions the more typical cases are that you’re getting low because the lift is weakening, that you fell out of the lift band, or that you crossed into a slowly descending airmass.  In Boulder, Colorado, a classic example for the latter is that you fell out of the convergence, can’t get back, and are struggling to find good lift in the eastern airmass. A divergence zone running parallel to the convergence may put you in sink.  In these cases you are unlikely to be confronted with sustained strong sink.  But even in relatively benign conditions, it is still quite possible that you experience an average of 1 kt of sink on your final glide home.

Lets revisit the chart for 1 knot sink.

As we saw before, at 1 kt sink we should fly 59 kts and our glider will sink at a rate of 2.4 kts.  Our glide ratio will be 24:1.

If this is the “worst-case glide-slope” that we are expecting, how can we instruct our flight computer to make the appropriate safety calculation?  The answer is: we have to find the MC setting that corresponds to a 24:1 glide slope in the absence of lift or sink.

The following chart shows how we can do this easily.

This chart is identical to the one above except that he additional intersection point of the 24:1 glide ratio line and the still-air polar curve is highlighted. Note that 90/3.7 obviously also equals 24:1.


We simply look for the point where the 24:1 glide slope line (i.e. the red tangent to the orange speed polar) intersects the original (blue) still-air speed polar.  We find that this point is at a speed of 90 kts and a sink rate of 3.7 kts.  Now we draw a new tangent (the dotted red line) that touches the blue polar at exactly this spot. Then we check where this new tangent intersects the vertical axis. You can see that for the Discus this point is at 6 kts.  In other words: if we expect a worst case glide slope of 24:1 all the way to the airport (i.e., conditions that reflect 1 kt of sink), we should set MC to 6.

You might be interested what MC setting I use.  Once again, it depends!  If there is a well-marked energy line ahead that I can follow, e.g. a cloud street or the typical Rocky Mountains convergence line, I am comfortable to base my safety glide ratio on an MC value as low as 3.  If the sky is blue and I don’t really know what to expect I tend to use MC 4 or 5.  And if the terrain is particularly hostile I bump it up to 6 or 7. Ultimately, it comes down to a judgement call.  The more doubt I have about the conditions ahead and the greater the probability of sink, especially prolonged sink, the higher I set my MC value.

If you’re flying in particularly challenging terrain or if you’re not yet experienced in avoiding areas of persistent sink, you may want to follow the advice of the French mountain soaring team and use a “worst-case glide ratio” that is 1/2 of your gliders best glide performance. For the Discus CS this glide ratio is 21:1.  The chart below shows that a Discus (without water ballast) will achieve 21:1 at a speed of 95 kts when the corresponding sink rate is 4.5 kts.  And the corresponding MC value is about 10.

At tangent placed against the point where the glide ratio line of 21:1 intersects the blue polar curve crosses the vertical axis at +10. In real life you will probably never expect the next climb to average 10 kts from bottom to top, but if you did, you would fly a dry Discus at 95 kts, i.e., MC 10.

Remember that estimating a “worst-case glide ratio” is by no means a guarantee that reality may not be harsher yet.  Perhaps even much harsher.  I have shown above how bad a glide ratio gets if you hit 5, 10, or even 20 knots of sink!


The purpose of this article was to make clear that your glider avionics use MC for two completely different purposes and that applying inappropriate values can have dangerous unintended consequences.

Your STF vario uses MC to calculate the best speed-to-fly based on your assessment of the strength of lift ahead.  If you’re conservative, you want this value to be lower, not higher.  This will make you stay relatively high albeit at the expense of a somewhat lower cross-country speed. Irrespective of your level of experience, the most appropriate MC value is, “what is the weakest lift that I would be willing to accept right now.” MC 2, 3 or 4 are fairly typical.  Only in exceptionally strong conditions will it be 5 or higher.

Your moving map flight computer uses MC to calculate which airports or fields are within safe gliding distance.  If you’re conservative, you want this value to be higher, not lower.  This will force you to stay high enough that you can safely reach your destination even if you should face less than favorable conditions ahead. Your skills, experience, the terrain, and the conditions of the day are all important factors to consider when you set this value.  On benign summer days a value of MC 5 or 6 may be appropriate.  If you’re inexperienced, flying over hostile terrain, or if you are unfamiliar with a particular soaring area, MC 10 will give you an extra safety margin. And always complement your glide slope calculation with a safe arrival altitude so you have the altitude you need for a safe landing pattern.

Importantly, set your MC values separately for  your STF vario and your flight computer.  Prevent these devices from synching their respective MC values if at all possible.  Be very careful if you only use one device (or one synchronized input) for both calculations.  The biggest trap exists when you dial back your MC setting for SFT purposes and your flight computer stretches your attainable glide unrealistically farther and farther.

Even the highest possible MC setting will not be appropriate to calculate safety glides when extreme sink, or strong sustained sink, is possible. When conditions are extreme, the best advice is to stay really high at all times.  And if that’s not possible, or if you’re not sure you can deal with the conditions at the time, you can always decide to fly on a different day instead.

Have fun and fly safe!


Post Scriptum

There has been a lot of interest in this article.  Within 48 hours of publication it has been read about 2,500 times and a lot of readers made excellent comments, either below or on social media.

First of all they confirm that the trap is real: entering a low MC value into your flight computer will result in wildly over-optimistic glide slope calculations and show fields or airports within glide range that really are not. However, there are multiple ways to avoid the trap and my suggestion in the article of using a different (and higher) MC value for safety glide slope calculations is only one of them.

Below I want to summarize a few comments that I found particularly helpful:

  • If the terrain in your soaring area is generally landable there is not all that much to be concerned about.  E.g., one pilot from the Netherlands commented that where he flies there are always several landable fields in glide even from as low as 1000 AGL.  If that describes your soaring terrain then this topic doesn’t really apply to you.  Your main challenge may be to resist the temptation to keep trying to find lift until you’re very close to the ground.  Delaying the decision to land until it is too late for a safe landing is the #1 reason why glider pilots get killed. This is a different topic. You can read more about it here.
  • As an alternative to using MC inputs for your final glide calculation you may be able to use “Required L/D”.  E.g., I have my Oudie set up to display two Nav boxes at the top of the screen: “Required L/D” and “Current L/D”.  As long as my “Current L/D” exceeds the “Required L/D” I am gaining relative to my required glide slope and my odds of making it to the target improve.  Conversely, if the “Current L/D” drops below the “Required L/D” I am losing against my required glide slope and may be in trouble.  This is a very useful method.  If you use it, it is critical that you also complement it with a safe arrival altitude. In this video, I show an example of a final glide back to Nephi, Utah where I needed a glide ratio of 25:1 to get back to Nephi but then my “Current L/D” temporarily dropped to 18:1.  (I was flying my 48:1 Ventus 2.)
  • A lot of excellent pilots don’t use a “Speed-to-Fly” vario to tell them how fast to go.  Instead they primarily rely on “block speeds.”  E.g., if they are high and feel “confident” of finding good lift they will fly at a speed that roughly corresponds to their gliders STF at an MC setting of 4 in still air.  If they are getting towards the bottom of the best lift band they become “conservative” and fly at a speed that corresponds to MC 2.  And when they get “desperate” and are really looking for lift, they slow down to a speed corresponding to MC 1. And if they are “feeling lucky” high under a strong cloud street they fly extra fast.  One of the commenters calls it “warp” speed.  For a dry Discus CS these speeds might be: desperate: 60 kts; conservative: 65 kts; confident: 75kts; warp: ~85-90 kts.  Add about 10 kts to each speed when flying with water ballast.  If you like this method there is no need to mess with your MC value at all.  Simply set an MC value on your flight computer that’s appropriate for your safety glides (combined with a safe arrival altitude) and leave it at that.
  • Similarly, if you like your STF vario set to “netto” instead of “Speed-to-Fly” you also don’t need to bother meddling with MC values during the flight, and can just use an appropriate MC setting for safety glides on the flight computer.
  • What MC value is appropriate for safety glides varies with the soaring terrain.  My article was written from a mountain flying perspective.  Where I fly in Colorado it is common that the next landable airport or field is 20, 30, 40, or even 50 miles away and soaring conditions tend to include strong lift as well as strong sink.  Talk to experienced pilots in your area to understand what safety glide ratio (and hence what MC value) may be appropriate for where you fly.

Keep the comments and insights coming.  Soaring is an unforgiving sport and our safety largely depends on our ability to learn from the mistakes others have made before us.  (Or on sheer luck – but only for as long as it lasts.)  By learning together we’ll become better and safer pilots.

My Soaring Goals for 2021

Soaring above Mount of the Holy Cross – one of the more intimidating 14ers in Colorado

Having reviewed my progress against the Soaring Goals that I had set for 2020, the last day of the year feels like a good time to publish new goals for 2021.

So here’s what I’m aiming for:

1. Stay Safe by always heeding my own advice.

2. Improve Specific Flying Skills, based on this analysis of a race day in Nephi, this analysis of the Speed League Season, and the advice from soaring GOAT Sebastian Kawa, who emphasized that we must learn to fly very precisely if we want to be fast.

      • Netto in cruise.  Sharpen focus on following energy lines, measured by consistently achieving above-average netto values in cruise flight, a much better metric than circling percentage and effective glide ratio.
      • Altitude band.  Use more of the available altitude band to become more selective in thermal acceptance.  This will require an adjustment of my flying style.
      • Precision thermalling. Focus on quick centering, maintaining optimal coordination, circling speed, and 45 degree bank angles.  As a result, achieve above average climb rates when compared to other pilots flying in the same area on the same day.

3. Speed Goals. Apply these skills to achieve the following:

      • When flying on Speed League Weekends aim to score among the top 3 Boulder pilots 66% of the time (up from 50% in 2020).
      • Try to break one of the Open Class Colorado Speed Records (stretch goal).

4. Distance Goals.  Weather permitting, I would like to achieve two of the following in 2021:

      • Reach one additional U.S. State flying from Boulder: New Mexico, Utah, or Nebraska.  An aspirational stretch goal is a “border to border” flight from Boulder to New Mexico, then to Wyoming, and back to Boulder.
      • Complete a 1000 km flight per OLC plus rules.
      • Complete a 750 km FAI triangle or a 1000 km Diplome.
      • Add to my 14er bag with a flight to the southern-most peaks of the Sangre de Cristo Range or a flight into the San Juan Mountains.

5. Contest Goals.  I plan to fly at least three or the following four contests:

      • Region 7 in Albert Lea, MN (May 17-22)
      • 20m 2-seater Nationals in Montague , CA (Jun 14-22)
      • Region 9 or 18m Nationals in Nephi, UT (Jun 29 – Jul 8)
      • Region 10 in Uvalde, TX (Aug 15-21)

Since these are my first contests, I want to focus mainly on skill development, flying consistently, and completing as many tasks as safely possible.  Stretch Goal: place in the top 33% at one of the Regional Contests or in the top 50% at a Nationals Contest.

6. Giving Back.  I will continue to put energy towards inspiring others worldwide to join our sport, to develop, excel, and stay safe.  I will do this through:

      • Writing – follow me on and on Facebook
      • Presentations and Podcast Contributions – to local, national, and international audiences
      • Videos – subscribe to my ChessInTheAir YouTubeChannel, and
      • Serving for soaring organizations such as the Soaring Society of Boulder

I wish everyone a Very Happy New Year!

Stay safe, and may your soaring goals come to fruition.