I'm not all that sure an RC plane will necessarily do anything that
an accelerometer will detect when the battery voltage fails.
I would think a battery monitor would be good enough.
What would you expect to happen if you wanted to do
inverted flight? or a roll?
Also, a properly build plane that still has servo control and
only loses motor power should still be controlled.
A transmitter signal to release the parachute should be
It's not for a plane, although some winged aircraft should have uses for it. It's for multirotors. Specifically for craft carrying photographic equipment or specialized payloads. These types of drones are not often required to bank very hard or fly in such a manner that they exhibit very large g-forces. They are mellow flyers capable of shooting extremely steady jitter free video.
I have full telemetry equipment in most of my craft including voltage monitors. In the case of my hexacopter, even if one motor fails, the other five can compensate to a degree.
The parachute is, for lack of a better phrase, a murphy's law prevention. If a flight controller fails or perhaps a catastrophic shortage of electrical components occurs, a battery monitor does little good.
regardless of how many failsafe's there are or how confident we are of our solder jobs' or connection points, the risks are still present.
In the case of a $10K unit carrying payload you would rather not see damaged, A parachute system can arguably prevent or even minimize damage to our equipment or damage to any property it's about to impact.
Now, having said that, I build and fly FPV racing machines that are subject to high g-forces and perform acrobatic maneuvers. They are write offs and a parachute system is irrelevant/useless to that application.
My intent is to hopefully design or add to someone's existing design a system that can be easily built and programed, 3D printed or constructed by other means, openly shared and open to improvements or customization, and also cost effective for all to enjoy much like the open source RepRap 3D printers and such.
The values/parameters for deployment do not need to be absolute. I would imagine that you do not want the parachute to deploy if the craft banks(any axis) at a 45 degree angle, but once it has exceeded 80 degrees for a filming platform it is to be considered unstable and out of operator control to the parachute system.
Oh, and yes I could trigger parachute deployment via a spare channel. That would certainly work but my reaction time vs. a processors' is somewhat slow when you consider a pilot concentrating on moving the craft, looking down at a screen to frame video and monitor telemetry...bla bla bla..and there is also the shock factor when a pilot is caught off guard in the case of catastrophic failure. Maybe at 30,000ft an actual airplane pilot has some time to deal with certain issues but at 400ft and below in a craft with no wings, it's a matter of split seconds. Is it doable? yes. would I rather a system to do it for me....absolutely.
I'm not afraid of this project failing, my fear is not trying it in the first place which prevents it from succeeding.