Flying Early Part 2

Mitigating Risk by Course Selection

One of the biggest impediments to an early start on a good day is the risk that we will start too early, land out in the first hour or so, and ruin what would otherwise be a great soaring day. Fortunately, there is a technique of task layout that manages this risk very well. It involves planning a task with a short run opposite the main direction and then reversing and passing back over the takeoff point. If I am planning a long task with an early start I will usually lay out a task with a first turn point about 20-35 km in the opposite direction from my main task area. For example, if I am planning a 500 km triangle to the northwest and northeast of my home airfield, I might select an initial turn point about 20-35 km south of my launch point. I use a start line over the home airfield and if I cross it (heading south) at only 1000m (3300' AGL) I only need one thermal about halfway to the south turn point to get there confident that I can glide back over my home field on my way to the north. If I start too early and don’t find a thermal I can cut back early and return to the home airport for a restart or a relight. When this technique works (and it usually does if there are any morning cumulus) by the point where I leave the local area to the north I will have managed 50 to 75 km of my task with little or no time at risk of being away from a relaunch. This type of task layout is called a “start on leg” and it is fully acceptable for use in flying FAI triangle records. It can also be used for other types of tasks or OLC flights to add relatively low-risk early morning kilometers to your flying. I always use declared tasks with fixed turn points and a start line, but even if you don’t you can still use this technique of starting in the opposite direction and doubling back over your launch point to manage the risk of a too-early start. It’s a great confidence builder and helps you to learn how to fly early in the day.

Course selection in the morning should avoid wet or swampy areas as they are always late to kick off thermals. If lightning strike information is available from your weather service this can tell you where there was rain overnight or the day before so you can avoid those areas. Agricultural and cultivated areas drain well and heat up early as do surface mines, sand quarries, and urban infrastructure. Another course layout consideration for early flying is to avoid rising terrain. You are going to have a shallow height band to work with at the beginning of the day so a course into even a few hundred feet of rising terrain pinches your height band and reduces your time and space to find thermals. The exception to this rule is if you are lucky enough to have a ridge or hillside perpendicular to the morning sun. These will generate stronger thermals earlier than flat terrain and are worth diverting to - especially if the sunlight side is also the upwind side. Morning mountain flying is a wonderful experience but few of us are so blessed as to do it regularly.

What about water ballast?

Morning flying requires frequent thermaling, a good quick centering technique, and a nimble lightly wing-loaded glider in the first hour or two. So, there is a trade-off between early starting in a lightly loaded glider and later starting in a ballasted glider. In my experience, we tend to overestimate the effect of water ballast on distance achieved in a day. Ballast only helps performance in the peak 4-5 hours of the afternoon and for most of us adds at best between 6 and 10 kph during that time frame. However, if flying early and light for an extra 1.5 hours in the morning nets us only 75km (and you usually do better) you are better off for the day’s maximum distance by skipping water ballast and starting very early. If you do carry moderate ballast and launch too early, it is not a big problem to land back at your airfield without dumping the ballast so you can quickly relaunch. Consider that self-launch gliders land with comparable extra weight all the time. Just fly a normal pattern with disciplined airspeed control, and expect a longer rollout and the wheel braking to be poor. Get out quickly and get the wings level if you have wingtip ballast tank vents. Then take another launch.

Shifting gears

Once on course in the morning our strategy is to stay as close to the top of our height band as possible. Height gives you time and options. You will still be lower than normal mid-day cruise altitudes but you will usually find that the high thermal density (closer distance between the thermals), slower cruise speeds (this is not the time for high-speed cruising) with liberal lateral deviations following good clouds, all allow for extended cruising without circling. When you do stop to circle, take each thermal right up to cloud base (keeping required cloud clearance, of course) but before you get there note a reference point on the ground to set your exit line to the next cloud. As you get close to cloud base you can’t see the next cloud so it’s helpful to have a ground reference to aim for. Further along, as the morning and flight progress, expect the thermals to increase in height and strength and the thermal/cloud density to thin out. As this occurs you will begin to “shift gears” to flying a bit more aggressively with higher inter thermal speed settings, more discriminating thermal selection, negative flap settings, and the other aspects of normal mid-day soaring. As your thermal height and confidence increase, you can relax and congratulate yourself on the early kilometers you have accomplished.

Banner photo by John Sullivan

 Roy Bourgeois is a well-known US and South African glider pilot who serves as the Chief Pilot for the Greater Boston Soaring Club. He has held several US national records, competed in many US and Canadian Nationals, and has flown over a quarter million XC kilometers in his 4200 hours of gliding. He can be reached at royb@bw.legal