Answers to various comments:
The CO2 cartridge gets pierced when it gets installed in the holder. The
holder has an o-ring that maintains the seal after that. So everything is
pressurized up to the valve once the cartridge is installed.
The safety advantage of the burst disk is in ground handling. I hadn't
thought about the safety problem of the burst disk disabling the recovery
system in flight. I will have to give that some thought. Leaky plumbing
could do the same thing. I have started to think about the fact that
recovery deployment is a single-string loss-of-vehicle critical system, and
losing the CO2 isn't the only way it can fail.
Yes, I could probably use a gearmotor and a ball valve instead of the
solenoid. I'm not sure there would be much weight advantage with the motor
and valve combined, but it would certainly be easier on the electrical
system. The primary reason I'm using the solenoid is that I already had it
on hand.
On Tue, Dec 1, 2015 at 6:23 AM, Robert Watzlavick <rocket@xxxxxxxxxxxxxx>
wrote:
Not commenting on the specific design, but I'd rather not have a chance
for a pressure vessel to burst when I'm working on it. Seems to me that it
would be better to lose the vehicle due to the deployment system not
working than take a chance on getting injured.
-Bob
On 11/30/2015 06:38 PM, Lars Osborne wrote:
If I am reading this correctly, you have a burst-disk to ambient between
the source and the valve.
By adding this you are choosing that in the case of an overpressure during
flight, rather than leaking through the valve or causing a small explosion,
the deployment system will disarm itself and the rocket will become a
ballistic, energetic impactor.
I am guessing that all components have large margin against rupture due to
over-pressure, so unless you have severe concerns about safety during
ground operations, why include it? I would lean on the side of "blow it
out or blow it up" if it were my project. But I may be missing something
important.
Thanks,
Lars Osborne
On Mon, Nov 30, 2015 at 3:12 PM, Robert Steinke <robert.steinke@xxxxxxxxx>
wrote:
Because of Thanksgiving I'm a little late getting the SpeedUp update out
this week.
http://speedupworld.com/news_11_30_15.html
One benefit of this weekly blogging is that it requires me to get
something done at least once a week.
Bob