PARACHUTE anyone ?

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:

http://cgi.ebay.com/NEW-40-SPEED-RUNNING-POWER-CHUTE-training-parachute-/220760637799?pt=LH_DefaultDomain_0&hash=item33665c0167

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...

The chute needs to get out into the relative wind in a hurry and deploy rapidly. This might mean a deployment system such as a ballistic charge but probably more likely spring loaded. I was a skydiver for almost thirteen years and my pilot chutes were all spring loaded. Pulling the ripcord separated the two halves of the container on my back which allowed the pilot chute to spring out and catch the wind.

If you were to deploy too soon (or by accident) on your copter rig, there might not be any relative wind to act upon the chute, if the copter wasn't falling, and the chute could possibly tangle around one of more of the props. If you were to deploy while the copter were falling and tumbling, this too could end in disaster. A parachute is not a 100% fail safe method. It would be interesting to have inflated air bags much like the Mars landers but of course not real practical in this hobby.

If you wish to look futher into parachutes, here are some links that will help you design, buy materials to make your own or purchase ready made products that might work.

http://www.pcprg.com/sptp.htm

http://www.madehow.com/Volume-5/Parachute.html?Comments%5Bdo%5D=mod...

http://www.aeraustral.com.au/parachute.php

http://www.strongparachutes.com/pages/pc_intro.php

http://www.paragear.com/templates/base_template.asp?group=27#P2550

http://www.paragear.com/templates/parachutes.asp?group=193&level=1

http://hienergy.tripod.com/Hang%20gliding/PC%20misconceptions.htm

http://www.aerosekur.com/parachutes/parachutes_index.html

http://www.olywa.net/yosemiteflash/parequip.htm

http://www.thirtythousandfeet.com/parachut.htm

http://www.apogeerockets.com/parachutes.asp

Best of luck

Gary

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Comments

Jerry Rodberg March 28, 2011 at 1:21pm

While you want to save the copter, your REAL concern is the DLSR. So, considering the issues with whole copter recovery, why don't you look at the other end? Build an impact resistant (plastic and styrofoam) shell around your DSLR. Mount that into your gimbal cradle. If something goes wrong, eject the whole module. Attach the parachute to the rear or whatever puts the most foam between the camera and its impact. A spring ejection would clear the camera from the chopper, provide velocity to inflate a parachute, and keep you clear of the rotors in one fell swoop. If the chopper is in flight, this may destabilize it, but the ejecting capsule could clear a second chute out of the frame. Flight gains could be adjusted to correct flight, too, if need be, to adapt to the change in center of gravity and weight. It'd also be actually testable without risking copter or DSLR.
ARHEXA March 28, 2011 at 1:18pm

Guys, i stick to the parachute, i know it's not a magical solution,

but as far it seems the best.

I have no idea how the quad might fall, but something makes me believe that the heavy DSLR at the bottom of the quad will keep it falling horizontally aligned (like the ground position), so hopefully the parachute will shoot vertical to sky....
Overwatch March 28, 2011 at 1:12pm

Deformation zones aren't very practical for aircraft without fuselage, or for aircraft that have huge booms sticking out of them, or for aircraft that can come down in any orientation. A quad passes for all three.
Ryan Fraser March 28, 2011 at 12:35pm

I have had a lot of thought regarding "Fail Safe" solutions.

Recently I've taken this route from NASA. The Daily Planet had a piece about these and I was amazed at how simple but effective it was.

They are called "deployable energy absorbers".

http://www.nasa.gov/topics/aeronautics/features/helo-droptest.html.

On the TV show they were able to bring the G down by more than half.

Cheers!
Gary Eldridge March 28, 2011 at 11:08am

The chute needs to get out into the relative wind in a hurry and deploy rapidly. This might mean a deployment system such as a ballistic charge but probably more likely spring loaded. I was a skydiver for almost thirteen years and my pilot chutes were all spring loaded. Pulling the ripcord separated the two halves of the container on my back which allowed the pilot chute to spring out and catch the wind.

If you were to deploy too soon (or by accident) on your copter rig, there might not be any relative wind to act upon the chute, if the copter wasn't falling, and the chute could possibly tangle around one of more of the props. If you were to deploy while the copter were falling and tumbling, this too could end in disaster. A parachute is not a 100% fail safe method. It would be interesting to have inflated air bags much like the Mars landers but of course not real practical in this hobby.

If you wish to look futher into parachutes, here are some links that will help you design, buy materials to make your own or purchase ready made products that might work.

http://www.pcprg.com/sptp.htm

http://www.madehow.com/Volume-5/Parachute.html?Comments%5Bdo%5D=mod...

http://www.aeraustral.com.au/parachute.php

http://www.strongparachutes.com/pages/pc_intro.php

http://www.paragear.com/templates/base_template.asp?group=27#P2550

http://www.paragear.com/templates/parachutes.asp?group=193&level=1

http://hienergy.tripod.com/Hang%20gliding/PC%20misconceptions.htm

http://www.aerosekur.com/parachutes/parachutes_index.html

http://www.olywa.net/yosemiteflash/parequip.htm

http://www.thirtythousandfeet.com/parachut.htm

http://www.apogeerockets.com/parachutes.asp

Best of luck

Gary

Toy Parachute - Science Projects with Toy Parachutes
ip9 March 28, 2011 at 10:56am

@Zak - slight off-topic, but they do have an airframe is thats something you've been looking for

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=...
Developer

Mark Colwell March 28, 2011 at 8:49am

I am re-purposing a large 50" Golf type umbrella $2 from Bargain Mart. It has 8 panels, 3 red, 2 white and 3 blue, weighs 74 grams bare . It's now off the frame waiting for sewing on 8 lines, I was planning on using mason's nylon line, but it might be to much, maybe 30# sailplane tow line. I will use a spring to eject chute upward, chute will have a coiled 1 mm fiberglass rod sewed in that will spring open right after ejection. I don't know how /when it will be triggered yet.
ARHEXA March 28, 2011 at 8:25am

or fatal to a DSLR ;)
I.S. March 28, 2011 at 8:22am

Someone can translate text on that vdo?

I don't believe a quad free falling from 700m not even bending one arm.

Anyway, even if the drone landed with no damage, could be fatal if it felt on people.

PS: I like the motor mounts
ARHEXA March 28, 2011 at 8:20am

but do we realy need parachutes ;)

YES.

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