August 12, Wednesday

Balloon construction took up 2 sessions and was only completed today. After filling the balloon up with helium, we calculated the lift of the balloon once again and it was significantly larger this time.

Measuring lift of the 3rd balloon

 

242 grams – more than 10x greater than the first

We achieved a lift of 2.374N (242g), which was more than 10 times greater than that of the previous balloon! As the estimated mass of our electrical components is 130 grams, the extra 112 grams of lift will allow us to be more generous with our tapes, blue tack, wires and possible electrical equipment or additional payloads that can enhance the functionality of the blimp.

 

Before attaching the dummy weights

After measuring the lift, we proceeded with calculating the moments about the CG by the electrical components. We classified the components into 3 main categories: Camera, propeller and bladder. We then measured the mass of each component from each category and then used dummy weights that correspond to the mass of each category.

 

3 dummy weights lined up on the long edge of the balloon

After measuring the length of the balloon, calculating the moments due to each category and identifying the centre line along the horizontal axis of the balloon (one of the long edges), we used blue tack to attach the 3 dummy weights on to the balloon. A rope is attached along the vertical axis (along the CG to prevent an additional moment) of the balloon to tether it down since there is an excess of 112 grams of lift.