Maybe someone has encountered a small scale parachute ?
I'd like to add a safety parachute to the Arducopter !! help me decide....
As part of the project is to use an expensive DSLR on the copter,
My GF said i must have some kind of emergency parachute... after joking at it, i thought deeper -
I'd rather feel much safer having a parachute as backup to all electronics (even though i plan on 6 or 8 motors)
Just imagine an emergency button that will immediately turn off all motors and shoot a parachute.
questions:
as parachute takes some time to open (=some free fall height), the benefits are sure and obvious for a 100m fall.
but if i'm around 5m above ground, (which can still be nasty to the DSLR) - would i have enough "falling time" to open the parachute and having enough braking force ?
think i better make one by myself ? is it rather simple as cutting and connecting wires to a cloth,
or it is more complex design that i could hardly achieve and i better get a ready one ?
i came across this as the only parachute i could find:
It looks sturdy and well balanced & stuff... it's totally affordable !
they say the 40" version has 7KG resistance. i'm safe on this side, i dont want a much bigger one.
how about the opening technique ?
i could stuff it in a small plastic tube attached to the top of the dome, using a small solenoid or servo to kick it out...
how do i ensure it opens reliably ? i guess it depends on the folding inside the storage tube...
Comments
Oh I forgot the description log
http://myresearch.lt/blog/parachute/parachute.phtml
Ecilop 2 SteadyCam Quadcopter with pyro chutes
https://www.youtube.com/watch?v=6RHfUvHkCVU
An umbrella comes to mind, and ....
..I'm wondering if small graphite rods could be fastened in the same manner, if they could be somehow curled up when packing the chute. And they would force or at least encourage the canopy to open quickly.
Perhaps a light weight plastic with lots of 'memory' could be used. Music wire might work.
Next time I'm at the hobby shop I will see if there is anything that I can find to do a simple test.
A spring, as Gary mentioned, for ejecting the parachute may be the simplest way to get clear of the copter.
The toys (guns) that shoot those darts with suction cups can get some range....they also have a trigger mechanism that may also be useful.
i can understand that,
just tested a 80A 100mm EDF yesterday !
My Turnigy Plush, when disconnected, revs up to full throttle for about a second, then shuts down. It almost ended ugly when I first tried it.
I see,
breaking is an option. i hope it won't affect with very high torque resulting in yaw or flip over... (remember one motor is probably gonna be dead)
Yesterday i tested what happens when you disconnect the ESC while motor is running:
it was a generic ESC (not arducopter), when i disconnected the signal it started to jump between 0 throttle and the throttle it was left on, randomly.
though maybe connecting the signal line directly to ground might tell the ESC to stop also - have to check.
so for active breaking i have to put relays on the ESC's signal lines that will take the signal away from the APM, and connect all together to a servo tester outputting "0" throttle.
that's not too hard.
Chutes used in High Power rocketry might be an option, I'd also look at a mesh parachute (mesh on the bottom instead of lines), just to avoid tangling issues with all the rotors. As for deployment speed, without a forceful deployment you will have drop before it opens, you could use a power deployment with a cardboard tube (which then helps clear props too) ala HP Rocketry (usually a small BP charge). But I wouldn't do that without looking at the potential regulartory issues. A spring/piston might be a better choice....
Perhaps you can also reduce reaction time with a deadman switch stick that you just drop if things go bad. Probably faster than fumbling for a toggle anyway. You'd need to enable aggressive and active breaking on your ESC's to stop the props in time, not sure that's worth it.
mmm, this might be a bit too far...
the camera mount and landing gear around it will be made of thick aluminum tubes, i think it's a good protection, even if they bent a little, there still will be room before hitting the camera. and yes i can add foam....
anyways, i'm not aiming to save only the copter,
why not saving BOTH at once with a single parachute...?
after all the copter costs like 1/2 the DSLR....
what i've got to keep is an option to disable it totally - even if it's 100% manual.
if i'm flying near the sea or a lake, i'd prefer it smashed on the ground rather than drown in the water....
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