Flight Recordings of Contests

Flight Recordings of Outstanding Flights: 2001

A good soaring day in the great basin and elsewhere
Multi-Place Motor Glider 750 km Triangle US National Record

by Carl Herold

On the morning of Thursday 26 July 2001, I declared a multi-place motor-glider 750 Km triangle speed task from the Douglas County Airport Home-base in Minden, Nevada, USA. I would fly my Nimbus 3DM, N73AB, CN # 1V. The flight was to be logged on my Cambridge Model 10 Flight Recorder. My attentive Official Observer was Nevada State Record keeper, Douglas J. Donohue from Gardnerville, NV.

My “Honorable Ballast” and Co-Pilot was ASH-25 glider pilot, Milton Hare from Redwood City, California. Milton was looking forward to bombing around the course in “My Barge” at high cruising speeds.

The morning soaring forecast indicated a freezing level at 15,000 feet in the Great Basin. Little did I realize how beneficial this would be as the soaring day unfolded. This was a weather condition to fly the weather and not the forecast. The previous day produced good soaring for others, but I had obligations that day. The lift forecast for today was 1,517 fpm (?), the same as for yesterday (?). The Reno NOAA Office Soaring Forecast indicated winds aloft of 280 degrees and 11 Knots at all soaring levels. The NOAA weather synopsis was: “A flat level ridge of high pressure is building in the soaring area. The air mass will become marginally unstable but moisture remains pretty limited so there will be some cumulous but probably no convection.” The K index was moved up from 3 yesterday to 4 today.

The 7:30 PST high resolution imagery provided few cloud clues to influence task setting. There were some clouds in the North Western quadrant of Nevada. The water vapor showed moisture thinning down the White and Inyo Mountains. The soundings for Reno, Desert Rock and Elko showed about a 10 Degree C dew point additional drop (dryer) above 500 mb (18,000 feet) inhibiting over-development. The surface moisture was also dryer below 750 mb. This looked like a virga day over much of the area well East of the Sierras from Minden to Lone Pine. If the cloud base were less than 14,000 feet, rain virga would mark the streets for cruising in lift and possible rain OD obstacles for the day. As the day warmed, pushing cloud base above 15,000 feet, then light rain virga turned to snow virga.

I would have to wait until the weather began to develop along the declared course to find out. With snow virga it looked like lightning and heavy over development weren’t likely, but mother nature will insert unplanned soaring pot holes. For this reason, I decided to declare my favorite and 41st 750 Km triangle instead of the 1000 Km triangle.

I declared a 759.63 Km speed triangle with the Windmill remote Start/Finish Gate 7.5 miles South East of Minden Home base. The first turn point would be the Cerro Gordo Peak near Lone Pine and the second turn point would be Mahogany Turn Point 14 miles West of the Round Mountain Gold Mine. The third and shortest leg was 26.4% of the course distance. The total distance flown from Minden to/from the remote Start/finish gate and the triangle was 783.6 Km (486.76 miles) I self launched into good lift and made a poor start at the Windmill Gate, 22 minutes after self launch. I did not connect into good lift by Lone Pine Canyon below adequate looking cumulous clouds. I made a second start 18 minutes later and still only achieved 400 to 600 fpm climb. I decided to not dally here and flopped over Bald Mountain at 11,500 feet looking for lift. There were lots of good looking clouds, but the weak lift was better for cruising 11,000 to 12,000 feet over the Pine Grove Mountains looking for stronger lift cells. I did not connect with much good lift, but kept cruising through scraps of delayed sink under clouds until about 15 miles South of Lucky Boy Pass when I finally found my second climbing thermal, a 10 knot climb to over 14,000 feet, with cloud base of 15,000 feet. I averaged 95 mph the next 126 miles to Cerro Gordo Peak. I could tell we needed to keep moving as the virga was growing fast East of the Sierras and appeared to be a likely blocking pot hole on returning North from Cerro Gordo Peak on the way to the second turn point. I averaged 89.78 mph on the first 193.86 Mile leg.

After turning the first turn-point, the misty virga was now snow. The small snowballs ranged from 1/8 to 1/4 inch in diameter and didn’t stick. When we reached East of the Tinnimaha Reservoir, I decided to enter under the cloud cover surrounded by snow virga and there was delayed sink and lots of lift streets for cruising everywhere and no lightning. I left the virga and meandered off course towards the town of Silver Peak East of the Fish Lake Valley and ran the next virga snow streets the same way just keeping the glider moving at 14,000 to 16,000 feet, indicating 75 to 85 knots. The true ground speeds were 90 to 110 knots, with a 10 Knot tailwind component. On the second 153.6 Mile leg, I averaged 85.69 mph. My meandering path along lift streets from the course line was increasing my average speed, and I was not wasting time thermalling. This is always a trade off to make.

On my approach to the second turn point, I moved towards a cloud in the blue west of the turn point. It evaporated with negligible lift and I turned East to 5 miles from my Mahogany turn point and then made a long southwesterly glide to the snow virga lined along the Gillis Mountain range (NE of Hawthorne) just cruising without much turning to get home against an increasing headwind, maintaining 14,000 to 15,000 feet. This extra 10 miles at the second turn point cost me about 8 minutes, I don’t consider this a mistake, just that every decision doesn’t always work out.

On the last leg home from the Mahogany turn-point, we (Milton flew about 50% of this leg home) only averaged 79.35 mph. I finished by gliding over Mt Siegel against an 18 Knot head wind with much turbulence at about 11,500 feet to dive to the finish gate at 8,500 feet with spoilers out above 100 knots to finish. Against the headwind, I allowed an extra 1500 feet margin to be above the Pine Nut Mountain leeward sink. It could have been a wasted energy margin, but we needed it. I should have set the remote gate at 10,000 feet instead of 8,500 feet. This would have saved me some more time, but at task setting time, I was initially concerned with a possible low and slow speed last leg.

The SSA Certified distance and speed were 472.00 sm (759.63 km) course was 84.62 mph (136.18 km/h). By thermalling seldom and staying at 14,000 to 16,000 feet cruising most of the flight along snow virga streets, we produced a 750 Km U.S. National and Nevada State multi-place motor glider speed record, exceeding the existing National record of 123.72 kph (76.61 mph) by 8 mph. After an hour on course, I knew I should have started at 10,000 feet instead of 8,500 feet...This would have increased the task speed to about 87.78 mph, producing a 3.14 mph increase. Hind sight is always 20-20.

We thermalled 33 minutes out of the 5 Hour and 34.6 Minutes (9.9 %) of the task time. Long meandering streets of snow virga lift provided continuous lines of cruising lift influencing the key tactical soaring strategy. A climb and glide strategy was not the best XC strategy today. We were soaring in average lift of -1 to 2 knots while cruising at 70 to 85 knots for long periods of time. Occasionally we would stop and thermal climb a few turns at 8 to 10 knots, if there was blue hole long glide ahead. We made (unproductive wasted) turns about 2% of the task time. More than 50% of the time we were cruising under virga cloud. We avoided the blue most of the time, except for gliding to and from the second turn-point.

The estimates above were produced by hand analysis. SeeYou and other flight analysis software tend to over-state the statistics by up to a factor of two. I have found the current computer modeling techniques tend to provide statistics to compare against other pilots, but the absolute accuracy is poor, ergo, I manually smooth the gps data in a series of many selected segments, performing total energy calculations along the whole flight. This is a better (for me) labor-intensive process, and is still not very accurate.

Our minimum and maximum altitudes around the course were from 11,500 feet to 17,700 feet msl, with an average cruising altitude of 14,700 feet.

Milton knew the flight was going well when he got to share the cruise and climb the “Big Barge” on the second and third legs of the flight. It wasn’t as exciting as climb and high-speed glide flying, but when the cruising streets are along your course, you cover the ground making less tactical mistakes. Further, by cruising at constant lower cruising speeds, I avoided those wasted dolphin pull-ups. We tended to stay under and close to the streets of virga and small roll clouds close to the virga. Streets of lift usually last longer and are less deceiving lasting than searching for a conventional convective plume.

The Record was homologated by the SSA and is waiting approval by the NAA. At that time it will also become a Nevada State Record.

This was the most efficient long cruising flight I have accomplished. On 30 May 1986, I flew close to the same course in my Nimbus 3T producing a National and Nevada Open single Place Speed Record of 83.35 mph.

On this same day of above described flight on 26 July 2001, four other pilots were also making long flights:

This was a good soaring day over a large area, especially in “The Great Basin”. The Great Basin is defined as the land where the rivers run inward instead of to the Ocean.

Hosted by Dr. Günther Eichhorn