August 25, Tuesday

In our hopes to reduce the tendency of the blimp veering sideways when directing it in a straight line, we decided that we were going to incorporate two counter-rotating propellers to cancel each other’s torque on the blimp. As our ESC had another outlet for connection, the plan was to solder another set of wires to this second connection to power our second coreless motor to be used for the second propeller.

However, we encountered an issue as after we had soldered the second set of wires to the ESC, the coreless motors that connected to first set of wires failed to work when we tried to power both coreless motors. Even when the second set of wires was disconnected from the coreless motor, the coreless motor connected to the first set of wires still failed to work. We later learnt that, despite there being two outlets for connection on the ESC, it is actually not recommended to use one ESC to power two coreless motors. There was a possibility that we had fried one of the outlets on the ESC.

To move on from this, we decided to connect both our coreless motors in parallel to the ESC, using the first set of wires. This would still work just as well for us since we did not require differential thrust (i.e. we needed identical thrust from each propeller). Fortunately, both coreless motors could be powered though the current supplied is slightly lesser in each motor as compared to a single motor connected to the esc.

 

August 26, Wednesday

A propeller holder is needed in order for the propellers to be placed apart.  The distance between the propeller and the balloon also had to be taken into account. Hence, we settled on a design with a large separation between the propellers to ensure that when the propeller pitches up, the tip of the blades would not nick the balloon.