Fall 2018 - Spring 2019
Fall 2018 - Spring 2019
Fall 2018 - Spring 2019
spring 2018
Precision hot air balloon
in collaboration with alexandra marcus & alfa lopez
The hot air balloon is the oldest vessel for successful human flight, relying on basic physical principles such as convection and buoyancy. This project sought to create a MATLAB model for the trajectory of a Mylar film balloon filled with heated air, for some arbitrary geometry, size, fill temperature, ambient condition, and payload. The model was then put the test: when prescribed the desired height and flight time, the team reverse engineered flight conditions and launched a physical prototype with an altitude deviation of 1.43% and a time deviation of 0.00%.
Buoyancy drives the balloon upwards, but it depletes as the enclosed air cools and its density increases. Drag plays a significant factor during both ascent and descent due to the shape of the balloon. Height and flight duration can be decoupled using fixed or linear payloads.
Conduction leads to heat transfer through the thin Mylar film. Convection is the most significant transfer mechanism at play, with losses to the environment due to the temperature on each side of the film. Radiation for our purposes was nearly negligible but may play a role in precision calculations for large-scale balloons.
The team was prescribed a max height of 7 m and a flight duration of 30 seconds. The team achieved the precise duration and missed the height by just 10 cm.
Buoyancy drives the balloon upwards, but it depletes as the enclosed air cools and its density increases. Drag plays a significant factor during both ascent and descent due to the shape of the balloon. Height and flight duration can be decoupled using fixed or linear payloads.
A video of the physical demonstration is shown below. The teaching staff asked the team to achieve a max height of 7 m with a flight duration of 30 seconds. For reference, the horizontal beam in the building is stationed about 6.5 m above the ground.
