So my plastics man and I made some prototype sled and avbay parts for initial testing and playing with. And we did quite a review of the parts and minor things do need to be changed before they could be regarded as flightworthy, but nothing major. Going to be doing some talking with my GPS guy at Dairy Aire about some mounting and insulating logistics... I thought I'd share this minor progress with everyone and also pose a pre-build question.
Per some lengthy conversations with Curt Von Delius regarding high altitude environments and batteries, I am beginning to change some ideas about my avbay, slightly.
After looking at some timescale line graphs of temperature recordings from various high altitude balloon projects I think I may be able to safely build an avionics bay that is not air-tight for my 200K flight.
The key point we brought to light is the overall short amount of time my rocket will spend in these drastic environments. While the temperature drops in the graphs from balloon data is indeed extreme, it is not quick. Take a look at this graph i pulled from
https://www.societyofrobots.com/space_balloon_temperature.shtml
It describes some sensor plots from a few iterative balloon proects, doccumenting both exterior and interior avbay temperatures over time and altitude. Very useful for my project, even without having much detail on their avbay insulation work. Based on this graph and others like it, I think it is safe to say that my rocket wont be up there long enough to freeze batteries or overheat chipsets.
The lack of atmosphere to serve as a thermal reservoir shouldnt be as much of a problem for my batteries as will be the ice-cold air re-entering the avionics bay as the rocket descends..
To counter this, I plan to wrap the batteries themselves in an insulating wool, of sorts, and pack the rest of the empty space of the avbay full of simple foam. This should help retain some of the original thermal energy and protect against that cold air.
Major major benefits to doing it this way. I now may use barometric detection for pyro events as well. THIS MEANS THAT I DRASTICALLY IMPROVE THE OVERALL SAFETY OF THE PROJECT by allowing for a deployment based on a failed staging.
I was pretty sure I could do this via accelerometer/timer setting with both the Raven and the Telemega, but I hadnt had a chance yet to contact Adrian or Altus to confirm this. But I am almost positive that I can do it with baro.
Example
In the event that Time < 100 seconds, yet baro altitude decreasing, fire pyro lines. ( which would be a surgical charge)
THIS WILL PREVENT MY SUSTAINER FROM COMING IN HOT in the event of a failed light for whatever reason.
But... Am I understanding the criteria correctly?
I will try to get a chance to send some emails out tomorrow, as well as update the writeup to reflect these avionics bay changes... But I'd like to hear feedback from here and TRA (emailed) first...
As for the funding and advertising, Im looking at maybe setting that up next week.
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