September 27, Monday

After consulting with Kanesh the past week, we tackled his suggestions one by one.

Here is an overview of Kanesh’s critics and suggestions:

1. Unable to achieve straight flight – not much suggestions apart from realigning the propellers
2. Unstable propeller holder (wobbling and vibrating) due to abrupt, jerky servo motions – redesign a more sturdy propeller holder
3. Loose servo arms and prone to falling off – screw the arms to the servo motor
4. Servos were connected weakly to the propeller holder with tape – redesign 3D connection parts to accommodate the servos

Firstly, point 3 was tackled. We secured the arms using screws provided with the servos we bought and this reduced vibrations in the arms as well.

 

Next, the propeller holder was redesigned to solve point 2. Instead of having such a long, structurally weak holder, we measured the distance between the holder and how far we can move it up before the propeller tips nick the blimp. Based on this measurement, the propeller design was reimagined. After testing it out, vibrations were reduced to almost none as compared to our previous holder thanks to its shorter length and sturdier structure.

 

 

For point 4, the connection parts were also redesigned. We made use of the screws just like in point 3 and screwed the servo motors onto the new connection parts. A simple ‘housing’ structure was utilised to secure the motor.

 

 

Combining all these gave our propulsion system much more structural integrity and stability, which definitely helps in the flight performance and steering aspects.

 

 

After revamping our propulsion system, we were ready to give our blimp another try. Although our propulsion system was improved, we still faced the same issue of path deviation without moving the joystick. Since it was suspected that improper positioning out our propeller is causing this issue, we commenced a lengthy trial and error process, where we fly the blimp twice and manually made small adjustments to the propeller. When our blimp deviated to the right, this was interpreted as the propeller holder not being perpendicular to the blimp length-wise, and the connection part was rotated in small increments to correct this deviation. Immediately, the effects were observed as we obtained straight flight for ~2m before deviation starts again. We continued this process and managed to obtain straight flight for ~6m before something extremely unfortunate happened.

 

Just as we were moving our blimp around SPMS to repeat testings, the Michelson-Morley experiment set-up tore our blimp with its sharp corner. Devastated, we were forced to stop work, though our flight performance has improved.

October 2, Friday

To patch up a large hole required some thought. It would be risky to apply contact adhesive around the hole directly and on the patching piece for fear that the patching piece might stick to open areas of the unaligned hole  and onto the other side of the blimp, which was highly undesirable. We opted to stretch the Mylar and layer clear tape over the hole before sealing the area with a patching piece using contact adhesive.

 

Since there were still issues with pitching, we broke apart the speaker to see what we could remove. Since the speaker has its own 1s LiPo battery (9g), it was removed and new wires were soldered such that it is able to connect externally to the 1s LiPo that we are already using for our camera. This meant that we will be using one 1S LiPo to power the camera and speaker, and another one 1S LiPo to power the propulsion system. However, as this only reduced the speaker’s mass slightly, we decided to remove it and shift our focus to the camera. Our current camera only has 600TVL resolution. After browsing several online shops, we managed to find another camera that has a 1200TVL resolution with a mass of 18g. Although it is heavier than our current camera, we thought this was a worthwhile upgrade since removing the speaker gives us more mass for us to work with. Along with the new camera, we also ordered 2 new ESCs for backup.

We also soldered all the connections within the propulsion system after finalising its design and position on the balloon.