Aerocene Cut Down Mechanism


#1

There is already a brilliant explanation on how it works over here:


Maybe we can compile more info, such as pictures, plans, code, for the electronic cut-down.
As well as some pictures of the icy mechanic cut-down :slight_smile:


#2

I copy a description and a couple pics of the mechanic cut down mechanism by Grace Pappas, which was tried on the september Munchenberg free flight:

Two seperate pieces of string are connected to eachother using an ice cube. At low altitudes, the ice will melt, allowing the two pieces of string to seperate.
Now each string could be attached to different stuff, depending on desired function. In the example of releasing a payload, one string can be attached to the aerocene and the other one to the payload so when the cube melts the payload gets released to the ground.
Note: the higher altitude, the lower the temperature so mechanism will only work bellow a certain height.


#3

Results of ice cube experiment:

  • Payload approximate weight: 500 grams
  • Ice cube time to melt: 24 minutes / 1440 seconds
  • External temperature: 19 Celsius
  • Aerocene climb rate: 1,5 meter per second
  • Estimated burst altitude with ice cube cut-down: 1,5 m/s x 1440s = 2160m

Experiment footage: https://www.dropbox.com/s/87ak8kke5q78zfc/IMG_3543.mov


#4

Hi Joaquin,

Great work with the ice cut down experiments!

Firstly, to introduce myself, I´m Gwilym from the Aerocene studio here in Berlin. Thank you for all the super work you are doing and helping to make this forum happen!

To give yourself and the Aerocene community some more information on how the cutdowns can work, please see the documents below, created by Alexander Bouchner for his cutdown designs.

The Ice cutdown method initiated by Grace Pappas and that you have been exprimenting with could be used with the rotation cutdown model.
Essentially, once the ice melts it will cause the payload to fall, and in doing so flip the entire sculpture thanks to the second rope attached to the top.
Once the sculpture is rotated, the hot air will escape through the opening that is now at the top of the sculpture.
Please see the helpful images in the document created by Alex!

If you have any questions regarding this, post them here and I will do my best to provide the answers :slight_smile:

Rotation cutdown

Aerocene fleet


#5

@Gwilym Thanks so much! I’ve downloaded both documents and I’m studying them carefully. They will come in super handy for flight permissions. I do have a question regarding ice-cube melt + rotation cutdown model:
How does the air escape through the opening after rotation if it was previously closed? Or do you keep the opening at the bottom open for all the flight duration? Doesn’t the hot air escape?
Thanks indeed! Keep rocking :guitar: :punch:


#6

Hi Joaquin!
That´s right, for this kind of flight the opening at the bottom of the sculpture would be open for the whole duration of the flight. Your question regarding the heat loss is a good one! But so far this technique has worked in past free flights.
With enough hot air at the top of the sculpture, the amount of loss at the bottom is not enough to effect the lift significantly.
Keep up the great work! :clap: