On May 17, 2015 Paul and Chris flew a test flight with a different type of payload. Walking through Walmart one day, Paul saw a display for a $10, four foot styrofoam glider. It stated that it "Flies Over 150 Feet". Well, that sounded like it needed to be tested out.  This was the result. The glider had an AP510 APRS transmitter/logger and a 808 #16-lens-A camera installed for a total of 320g.   On the rear, a piece of plastic coat hanger was cut to create a tail hook for attaching to the balloon. The lateral/longitudinal center of gravity was extremely close to that of the original glider, but it now weighed 120g more. The center of gravity was also moved up the vertical axis a bit.   Since there were a lot of unknowns to test on this flight, it was decided to go with a small (350g-ish) chloroprene balloon for a quick test. The balloon was loaded it with over 2 kg of lift gas for a fast ascent and quick burst.    The poor glider, being hauled up at 8m/s, BACKWARDS, spun and darted around like crazy.       The flight carried it up over Raleigh to almost 60,000 feet when the balloon burst. Sadly, the on-board camera ran into an error (counterfeit microSD) and shut down just two minutes before burst. After burst, the plane detached from the balloon remnants and fell fast. Chris and Paul positioned themselves at the landing zone and waited for the glider to land. It "landed", nose first, about 300m from them on a country road at just under 7m/s.  The fuselage lay in pieces in the road while the wings bounced to the grass nearby. The front 5 cm of the glider's nose snapped off as well. But all of the gear survived and the AP510 continued to operate. A fun, quick flight. Chris and Paul both agreed that it was pretty nice to be looking over the flight video a mere 1.5 hours after launch.   This was one of our fastest ascending flights to date.  The AP510 and its battery were not as thermally protected as in most flights. On-board temperatures dropped to -36 C and voltage decreases were noted on the LiPo battery. A new firmware load on the AP510 appears to have fixed the strange altitude bugs that were seen in previous flights. So without a video record after burst, how did it perform? The hook seemed to work as designed. There was no balloon, string, or evidence of any sort of tangle on the glider. The tail of the glider looked as pristine as it was at launch. But did it act like a glider?   Using Google Earth to zoom in on the descent, a zigzag pattern appears in the on-board recorded flight data (point every 10 seconds). If we then zoom to the landing site and look upwards, you can see the path the glider made on the way down. The data points are 200-500 feet apart horizontally. One could envision a descent in a spiral, but nose down and falling at 15 mph. Less gliding -- more falling with style. Oh, on the way home Paul and Chris stopped at a Walmart and purchased two more gliders. |
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