What a great week!
I managed to finish the basic seating structure completely, now only awaiting ergonomic foam build up and coating. But, even better Claus Nørregaard and I managed to perform the first two tests of the drogue separation system for space capsule Tycho Deep Space.
If you have no idea what the drogue separation system is, you better read this previous blog post before proceeding. http://slim-weight.info/wiredscience/2012/01/top-dome-and-drogue-chute-jettison-system/%3C/a%3E%3C/p%3E%3Cdiv%3E%3C/div%3E%3Cdiv%3E%3C/div%3E%3Cp class="paywall">This system was designed one late night after work by myself and Claus after a couple of old nasty beers and was based on previous wonderful experiences with thin alu-sheets which hold the parachutes of the old spacecraft Tycho Brahe-1. In general, the idea is to have 3 fragile points holding the lid of the new space capsule, containing the drogue, which will break during induced pressure. So, no matter the amount of fragile alu-plates holding the lid or the amount of nitrocellulose, providing the pressure, the system should work. Bang. Lid off. Drogue out.
Preparing the test. Image: Claus Mejling
Ready to rock´n´roll approved by Claus Mejling. Image: Kristian von Bengtson
Alu-plates holding the lid
Underneath the top-lid we placed nitrocellulose and the actual drogue. In each of the 3 openings where the lid will be bolted to the spacecraft we placed alu-plated. 2 plates in each opening for test 1 and 3 for test 2.
The bolts where tightened using a regular Copenhagen Suborbitals method. This time it was: until your fingers give up and then a little more with a wrench before the alu-plates became deformed. I do not want to rely on accurate measurement on such adjustments. If it works the “sloppy” way it will always work. As long as your design are made for this you are GO.
The test can be seen in the video below.
After performing a couple of tests like these you always get back home from work a little high. Somehow it is the climax of any development period. You have worked hard for a long time preparing for this, building the hardware really not knowing if it is a good idea or not. The minutes before the test everyone is very excited. Will you blow up the entire space capsule? Will you create a hole in the ceiling or get knocked out yourself by a flying top dome from a space capsule. Many questions which can only be answered by letting someone push the button… KABOOM..
Test 1 was really right on the spot. More than we expected. The lid was lifted off the space capsule with an even pressure and the 3 attachments point using alu-plated where beautifully deformed the way we predicted. The second test was less great but would still work. The main difference was that the nitrocellulose was formed as a ball which always becomes a joker. If you do this the explosion and pressure has a tendency to move to one certain direction instead of 360 degrees which is pretty clear in the test2-part of the video.
Coming test will include: adding more alu-plates and identify by brute force (crowbar) how much the lid is actually attached the top of the space capsule. More lid detonations using more nitro preferably placed above the drogue chute instead of underneath.
I have a great feeling about this system and it is only a matter of fine tuning and small adjustments. I will bet one beer with all the readers that the drogue will be deployed from the capsule. Whatever happens after deployment is not for betting yet..
Ad Astra Kristian von Bengtson
