Cal Valley is over and man what an adventure! I am proud to say the event was a great success! You’ll have to read on to find out the results ;-)
Friday started with a scenic drive to the Call Valley Lodge and unpacking the plane after its cross-country shipping. There was no damage and we were able to assemble it with only one complication: somehow during packing, I missed my 0.050” ball driver that is required to take off two panels to install the battery. Fortunately, Jim Thomas had a spare to loan and proceeded to pick on me the entire weekend for “borrowing all his stuff.” Once assembled, the plane checked out just dandy. We also were able to sneak in two quick flights in the stiff northern breeze that was blowing through the valley. Nothing major going on during the flights, just checking that the hardware was still content being tossed back into the sky.
Friday night brought some amazing chicken on the grill cooked by Rich Beardsley and company. Boy, this food and group surely can’t be beat! Rich was the stand-in CD for John Ellias and explained the task for Saturday; a distance run to turn point K was pretty much in everyone’s future. For reference, turn point K was slightly over 40 road miles south-east of the launch area. With winds typically from the north-north-west, this first leg was a downwind run. It would be the upwind leg that claimed most.
Saturday morning was more or less a hurry-up-and-wait time for me. Still slightly on east-coast time, I was up at 6am and ready to start flying. Slowly, everyone emerged from their rooms at the Lodge and we all were treated to another wonderful meal by the chefs of the group. Hash-browns, eggs, sausage, bacon, and more filled everyone’s stomachs. Over breakfast, everyone was strategizing how on earth to make a huge run to K and also have enough lift to get back. Some said to look for an area of convergence where the coastal marine air coming east met the warmer desert air coming west, creating a ridge of rising air. Others said to just stay over the road and find what you could in the open flats. Still others said to tank altitude early and make a long glide over “The Valley of Death” about 10 miles in. The game was afoot!
Around 10:30am, everyone walked their planes to the winches and set up vehicles for the road trek. Team ALOFT was one of the first to the launch point to go through our relatively lengthy checklist procedure (compared to “switch is on, wiggle surfaces, launch!”). I believe we were third to launch just about 11:19am. Adam quickly found the house thermal that breaks just upwind from the launch over the one-story hotel. We transitioned to auto-soaring mode and proceeded to climb up to altitude. Once during the initial climb, Adam took over manual control to avoid a gaggle of sailplanes climbing in the same thermal and we decided to move on course to get some separation from the group. Four other teams had already moved on course and were out of sight down range.
On course, ALOFT is an easy beast to fly. Once you “click the green button,” she’s on her own and heads down the road until she feels a thermal. Matt and I sat in the back seat of our rented Jeep Wrangler and simply monitored the progress. Thermal strengths were coming up as ALOFT climbed to cruising altitude. Seeing 3000ft slip past with no signs of stopping, Adam in the front seat was able to relax a bit and settle into a rhythm keeping his eyes trained skyward. Chris kept a steady driver’s foot on the gas and matched pace with the plane, also meanwhile playing team sanity check and keeping things safe.
The run south was rather eventful. The Valley of Death was a droopy several miles between thermals. Teams Atomic Fireball and Dust Devils were having similar rough luck ahead. With ALOFT nearing only 1200ft of altitude remaining, Adam was perked up ready to take over at our newly raised 1000ft manual takeover safety limit altitude. Finally, the vario started to blip and we eased up toward the other two planes now having better luck. Wafting through 2500ft, the other guys took off down the road in search of something better. Somewhat of a sudden, the air let go and ALOFT started gaining real altitude. Climb rates were starting to really go nuts, showing short peaks of +10m/s and over 6m/s sustained. I started calling altitudes to the car in 50ft increments and barely had time to say “3750 feet” before having to say “3800 feet and climbing” and shortly thereafter “5000 ft and still strong.” At this point Adam said enough and we should get moving. I intervened in the ALOFT code and sent her back on track, watching another 400ft of free altitude as we worked out of the massive thermal. Adam still had eyes (thank goodness for 20/15 vision!) as we started down the road with the plane holding steady at our prescribed max speed of 40kt indicated airspeed heading down course.
We soon overtook the remaining few teams and were simply cruising down the road burning off our altitude. Minutes and hours and miles flew by quickly at these speeds. Thermals were generally widely spaced, but well defined and strong when we found them. Staying over 3000ft was possible and ALOFT dutifully tracked several thermals downwind along the course.
At the southern end of the valley, the two mountain ranges came together and meet, choking out the flat grassland and gave way to rolling hills that never seemed to produce lift that would stay together. Our altitude cushion was being eaten away by both the crummy lift and the ground altitude that climbed toward the plane by nearly 1000ft. The trip to turn point K became a real challenge, with all of us trying to will the vario to signal steady lift. As altitude gets lower, the plane gets more conservative and stops for lighter lift, so even too seemed the code to be clinging to any organized lift it could find. Finally, we made the jump across the humpy hills, around turn point K twice for good measure, and a darted back over the mountains to better air. Now back down to 1500ft above ground and fighting the wind, we figured the harder challenge had begun.
The road north was much slower, but still in relatively good air for the first part. Any thermals we caught would drift back counter-productively toward the south, so forward progress took some work. We passed two teams still going south, one which had just landed. This far south in the valley was tough work for all. Slowly but surely, we ticked back the miles from turn point K with increasing north winds making an increasingly more difficult run. Finally, some 70.5 miles on course, the wind was up to 10kts and the plane was down to 1000ft with no hopes of making the run over the Valley of Death again. Adam took over manual control and did his best to find some air. At 4:45pm, ALOFT quietly met terra firma just 11 miles short of completing the full course.
We heard that several teams had made most of the flight down to K! Greg Norsworthy even made the turn and tried to fight north. It was a tough but fun downwind leg for everyone.
Saturday evening was a great time of swapping stories from the day and once again filled with terrific food, this time tri-tips and pasta salad. Yummy! The chatting went on into the evening and the ancient pool table in the closed restaurant saw some more use too.
Sunday morning was not quite the same flurry of activity. Everyone pretty much had settled in with their hardware, except for a few scrapes and dings here and there. Greg Norsworthy and company went out searching for a plane lost on Friday afternoon, bringing back aerial video that several of us combed through on laptops trying to spy his flyaway. Breakfast of champions greeted the pilots again with awesome pancakes, eggs, and sausage. I felt honestly quite spoiled to have home-cooked food on a flying weekend. Thanks to all who cooked! Sunday also brought some different weather conditions. It was rather apparent at the winches that nobody was hooking up with a real boomer. Rich Beardsley worked the first reasonable lift and took off down the road toward the turnaround at turn point F, which was ~12mi downwind. The winds stayed up and tore the thermals to pieces. Most folks attempted the course and disappeared from our vision. Team ALOFT wanted to stay conservative and wait to leave until we had at least 2000ft, but after several launches, this just was not happening. It seemed the crews that left early weren’t returning, so we could only imagine we somehow missed the boat. Once, we made a very meager 3.9mi just trying to get some points on the board and see how ALOFT stayed with the weak downwind thermals, but hopes looked rather bleak for a better run.
The winches were scheduled to close at 2pm and everyone had to be back at the hotel with plane in hand by 3pm. Team ALOFT was launching even up until 1:30. Finally, we made a choice to launch and immediately start the course time by moving to and flying over the start line, then try catching something that would let us climb while drifting downwind while on course. This tactic seemed to work, letting us keep working with a very light 2m/s updraft for probably about 30 minutes while creeping along the road with it. Gradually, very gradually, the plane worked its way almost to 3000ft and we knew at least we beat our own 3.9mi from earlier. After losing this steady thermal, we pushed ahead down the course again.
Along the south run again, the Valley of Death struck and we were scooting quickly through sink and burning our minor altitude reserves. With the terrain wide open and landing opportunities all around, we let the soaring code stay on even down to 400ft above ground level. Adam kept a watchful eye out and Chris kept us close to the plane to have Adam in good position for a quick landing. Quite happily, we rounded the half-way mark of turn point F and then just could not find any workable lift. The rather stiff wind from the north consumed quickly any altitude we could bank while circling in lift downwind. Just 0.2mi north of turn point F, we made a ceremonious landing in soft grass next to the road. We completed 12.03 miles of the 23.66 mile course.
With the airplane on the ground and the winches closed, this wrapped up our flying for Cal Valley. However, we were still on the clock to get back to the Lodge to turn in a score sheet! We quickly took a few team photos and packed up the plane. It was a 15 minute drive back north to the Lodge and we had 15 minutes to spare. Whew!
In the end, ALOFT was in the air 7 hours this weekend, covering some 82 course miles. Over 94% of the flight time was completely hands-off autonomous and the soaring software was in command. The course times for the two day’s flights were 4hr 28mins and 45.8 minutes, respectively. Matt’s new unscented Kalman filter thermal identification algorithm worked beautifully both days and he has 127 minutes of auto-soaring test data to use for making improvements.
As for competition results, on Saturday ALOFT flew farther by over 15 miles than any other plane for a total distance of 70.47 miles. Sunday was much more difficult, ALOFT making only 12.3 miles compared to the 17.53 miles of the day’s winner. However, in overall standings ALOFT had a commanding lead from Saturday’s distance event and took first place overall! I feel somewhat guilty taking home a trophy because this is research and not really meant to be in competition. However, everyone seemed happy and I am encouraged by some overheard comments: “Look at the straight lines the robot flies … I need to work on my flying.” I am happy that folks are taking on the robot as a challenge; Sunday’s flying proves that the XC pilot guys really still can whip the robot. It is from this healthy showdown that all our skills are sharpened.
As a side-note, the Cal Valley event was really a research adventure for me, not just a fun time. Team ALOFT was able to sponsor the event with a SkyTrace GPS logger for every team in return for collecting the group’s flight information. This data is invaluable to collect tangible evidence of the day’s thermal activity and how teams were able to utilize it. There is not a lot of data in the micro-weather scale below where most manned sailplanes fly and I am certain that every participant has helped contribute to the body of knowledge more than they can realize. I will be posting the flight data from all teams on the results page soon and I encourage other researchers to use and reference it. If you have specific questions about the data, I would be happy to answer them via email as best I can. I will be doing my own analysis of the data and finishing up a paper I am writing about a thermal updraft model.
To wrap up this flight report, I would like to thank all my Cal Valley friends and flying buddies. Rich Beardsley did a great job standing in as CD for John Ellias who coordinated a wonderful event in an amazing venue. I don’t have room to name all the participants, but thanks to everyone for making this a fun weekend for all. More than any other soaring event I know of, Cross-Country is a team sport and takes all parties working together to pull off a successful flight. Thanks especially to Adam, Chris, and Matt as ALOFT teammates and a major reason why the auto-soaring was so successful! Last, thanks to you, internet reader; I get so much encouragement every single time someone meets me and says “I’ve been reading online and your stuff sounds neat.” It is fun that you too can share this adventure with me.
Montague is in three weeks, the summer is not over yet :-)
More Cal Valley pictures.
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