Here are a couple of pictures of our flights.
Early Morning Launch
Nice, clear sunlit balloon
Testing with transmitter + rolled up antenna elements.
So far, we have had 3 successful flights and plan a fourth soon. This will be our first with a prestreached balloon. Prestreaching consists of slowly inflating the balloon to about 4.5 kPa pressure and letting it sit fully expanded for awhile. This pricess steaches the material and smooths out any manufacturing wrinkles, dimples and creases. Performing this prior to a launch is supposed to hopefully expand the volume slightly and allow the balloon to reach higher altitudes without bursting. Our prestreacher consists of a couple of small aquarium pumps, flow measuring devices, and a pressure transducer. The control is provided by a sketch residing in a Seeeduino micro controller and a Seeeduino motor control. The speed of the pump motors can be adjusted 0 - 100% which adjusts flow and pressure of the air. A small OLED display presents data and status information to the operator. This prestreacher is manually operated without any automatic routines.
Hopefully, the process will allow our flights to achieve a few extra thousands of feet.
Seeeduino V4.2 and motor control unit.
Overview showing controller, pumps, flow meter, transducer and BOV.
Everything including the manometer used to calibrate.
