May 13, 2008

Soar Minden
Glider Flying Information

Glider Thermaling

 

Minden's thermal season got off to an early start this year, with several pilots making 500 km flights in late March.  It is continuing nicely in June and should really get rolling as the last of the wave moves out.  Come fly those long cross country badge flights! 

Thermal season normally runs May through August, although we find some soarable conditions every month of the year. The secret of good thermals is large temperature change from night to day and uneven heating of terrain. Minden has both in abundance during the summer.

The beginning of a good soaring day at Minden is indicated by the formation of wispy cumulus clouds over the Pine Nut range. This starts the early bird tows to Mineral Peak and a head start to the White and Inyo ranges 250 K to the south.

Visiting pilots often ask for tips on finding thermal lift on blue days; as a general rule we tell them to look for high ground facing the early morning sun. Eastward facing slopes and ravines will form chimneys of rising hot air to climb on. The object is to get on top of ridges and run on weak lift in the general direction desired. As the trip progresses south or east lift will improve over time to the point one is running level at the bottom of the class A airspace and covering ground at speeds well in excess of 100kph.

The Sierra mountains to the west might appear to be the best place to start looking for lift as they face the morning sun. Don't forget, however, that there are miles of high ground to the west that is cooling the prevailing winds. In addition Lake Tahoe further cools the air before it rises over the Western slope of the Sierras and then drops down into the Carson Valley.

Our general experience is that the Sierra side of the valley is not the place to look for lift with the west systemic wind. All bets are off when the wind is from the east, as then these mountains to our west will produce ridge lift that is workable as well as strong thermals up the steep sides of the canyons rising to our west.

The house thermals just to the east of the field are generated by the barren sagebrush between the circular fields. There are numerous active and inactive sand and gravel pits that could be described as hot spots also.

As you're working your way to the high ground you'll see several shallow ponds about 5 miles east that frequently generate lift and will help you work your way to the Pine Nuts and ridge running. The bare ground surrounding these ponds generates the thermals. You'll also find similar bare ground adjacent to Thermal Hill (Hot Springs Mountain) just on the other side of the Johnson Lane subdivision, and that bare ground will frequently act as a source of thermal lift. Beware the valley in which Sunrise airstrip is located; the valley lies just east of the low range of hills at the end of Johnson Lane. The downwash over these low hills makes for strong sink much of the day.

Desert thermals are, as a general rule, smaller in diameter but stronger than mid-western or eastern US thermals. This fact demands tighter circles along with accurate speed control. Flying in a circle at various speeds results in ovals, making it difficult to stay in a thermal.

Practice the steepest bank you can, too. This makes your turn radius smaller and keeps you in the strongest part of the lift.

Additional practice is advised with slow flight; consider that a slower speed and a reduced bank angle might just as likely result in the same tight circle and a faster rate of climb. The basic premise is to practice with the ship and fly it as best you are able.

We highly recommend two books, one entitled "Thermals", by Rolf Hertenstein, the other entitled "Soaring Cross Country", by Helmut Reichmann. These two books have the whole world of gliding cross country knowledge in them.

Soar Minden will be happy to send you off with an experienced instructor to help you polish your thermaling skills. We firmly believe a two or three hour flight with an instructor will pay enormous dividends when you're off on your own trying to figure out how to center lift and where to look for the next source of lift.

And if you're planning to use your newly acquired skills for a long cross country flight, talk to us too about taking some dual instruction in cross country flight. We have several SSA Master Instructors with contest experience who will sharpen your skills as you break the apron strings ("Breaking the Apron Strings" is the title of another text for sale on our shelves, and one that you'll find useful as you plan to fly away from the immediate area.). Our cross country instruction will recommend standard courses and turn points for badge flights and work with you to declare the flight in advance and then file the badge claim afterward.

Remember when mountain flying; Lift is where you find it and always have a place picked out to drop in to if the lift gods decide you must land!

(Add links to Skew-T, Thermal Index & Trigger temp)