Saskatoon Amateur Radio Club
High Altitude Balloon
    SABRE-2   

Strawberries anyone?

June 15, 2008
SARC Home Station
Alvin Buckwold School
715 East Drive

Once in a while you get a day that's just about prefect for flying a balloon.  Sunday, June 15 was one of those days.  Our "ground crew" arrived on site at around 6:30 to prepare for the 8:00 AM flight.  After several days of near constant rain, it was great to see a nearly clear, sunny sky and virtually no wind.  We had a good feeling about this flight.

Shortly after arrival, we began to set up for the flight.  Leigh, VE5LEE, our official photographer and videographer looked for good vantage points to set up the two video cameras.  Meanwhile, Gus and I laid out the tarps, blankets and other gear.  We still had almost one full tank of helium from our first flight and a completely full spare tank. 

Because we were launching so close to the city and to the airport, we were given permission with the stipulation that the balloon could not fly over the city or towards the airport.  To test the winds, Gus filled a little Winnie the Pooh balloon with helium and let it go.  Although it looked like it flew toward the airport, it had only traveled a few blocks before we lost site of it.  We were a bit nervous about the test balloon but the weather prediction called for light north west winds, so we continued with our preparations.  As our launch time approached we filled a second, larger balloon and released it.  This time it drifted almost straight up and we lost sight of it at about 3000 feet.  We were confident that our balloon would either travel almost straight up before catching the north west upper winds.

After our last near miss, we revised our check lists and included a second, redundant tracker.  The camera package has a 15 minute delay before the video camera starts.  We powered the trackers and cameras up at 8:45.  Within a couple of minutes we were receiving position packets from both VE5AA-11 and VE5AA-12.  As 8:00 approached, we checked our lift using a jug of water that simulated weight of the payload, desired free lift plus the weight of our fuller valve.  It wasn't until after the flight that we discovered that our calculations were wrong, but I'll talk more about that later.

At roughly 8:02 we slowly let the balloon and payload out on a tether line.  With at the end of the tether we again confirmed that both VE5AA-11 and VE5AA-12 were working correctly.  With that, we released the free end of the tether and the balloon and payload rose rapidly into the sky.  Although we didn't realize it at the time, we should have subtracted the filler valve instead of adding it in our calculations.  As a result, we had over-filled the balloon and we ended up with just over a 1000 foot per minute ascent rate.

Unlike our first flight, the winds were almost completely calm.  As the balloon rose, the roughly 20 people that came out had the opportunity to watch as the balloon rose directly over their heads until it finally disappeared from sight.  Amazingly, it was still visible to the naked eye at over 30,000 feet.  At about 35,000 feet it entered the upper winds and began to drift south east, just as predicted.  This was also when the VE5AA-11 tracker stopped reporting.  The chase was on, but not for long.  The chase team consisted of Gus, VE5SPI with his wife Laurie driving, me and with my wife VE5LEE driving and Richard VE5RH and Herb VE5HE in another vehicle.  As we headed out on Highway 16, that paralleled the balloon's trajectory, it was obvious that we wouldn't have to hurry as the balloon's speed varied from under 100 kph to as low as 10 kph.  After about 20 minutes the balloon was over 60,000 feet and was barely moving.  We decided to pull over and wait for things to play out.  As we sat, we finished off the package of cinnamon buns and, you guessed it, strawberries.  As the balloon rose past 80,000 feet a cheer went up because we knew we had exceeded our altitude of SABRE-1.  The next packet showed that the balloon had burst and it was on it's way back down.  At about this time, VE5AA-11 came back to life.

Since the winds were still quite light, we estimated that the landing point would be about 5 to 10 km north west of our location.  At about 15,000 feet we headed off to try to get as close the landing site as we could.  the predicted landing site lead us north down a grid road and then west of a very muddy dirt road.  The other two groups were in 4x4s but they assumed it was safe enough once they saw our Taurus sedan maneuvers through the mud.  As we drove, I could tell that the payload was almost directly ahead of us and only a 3000 feet up.  Next it was directly ahead and only 2000 feet up.  The last position I received showed it just 500 feet north west of our position.  I looked up and there it was, drifting back to earth.  As you can see, a large part of the balloon was still attached, but it didn't seem to cause and problems.

    

Although we SABRE-2 was a huge success, we still learned may things.  First, the failure of the tracker was caused by a loose connection on the fuse between the battery pack and the radio.  To avoid this, we will now solder all of our internal connections including those on things like fuse holder clips.  For future launches will will also be adding a dedicated power supply for the cameras, since the this power problem also affected the camera systems.  We also found that getting an accurate lift measurement was very difficult with the hose still connected to our filler valve.  To improve this, we added a quick disconnect to our fill hose and accurately measured the weight of the filler valve.

73, Bruce - VE5BNC

Final Path

Flight Path from Google

Google Earth KML

SABRE-2 Launch Pictures

SABRE-2 Payload Pictures

Payload Video