A multirotor flight is very critical: if it happens an ESC, motor, propeller, RX failure or even if you get a lot of vibrations in the flight controller, the multirotor will crash. That's why I created a parachute and attached it to the quadcopter. This was the first test I've done with a parachute for quadcopter:

It had a stick so it kept the parachute away from the propellers. The problem is that the CG is difficult to keep in the center of the quadcopter and also because if the quadcopter hits the stick on the ground when it lands it's going to break the stick.

Therefore, I positioned the parachute on the back of the quadcopter without a stick. I've done a "wind tunnel" test (lol ;D) to check if the parachute would open:

As you can see, it seems to work, so I tried it in field:

Although it didn't land well, nothing was broken because the quadcopter arms are foldable and the ground was soft (grass).

The parachute is activated with a receiver channel and a servo. So when I get in trouble I press a button in my transmitter and it will release the parachute.

Currently i'm projecting a parachute launcher with springs, so it will  be launch vertically and thus it will open faster. Another option would be using a small rocket/gunpowder to pull the parachute, but i'm still thinking on the positioning to avoid unwanted burn to the parachute and the multirotor

Cheers!

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Comment by robincfey on May 6, 2013 at 2:37pm

great start dude , im unsure about the hanging cords though , work on a pod system where its all neatly packed in and instead of using a spring or gunpowder (as fun as that sounds) try a smaller draw chute to pull the bigger one out 

Comment by Muhammad Al-Rawi on May 6, 2013 at 4:14pm

Wish I had this when I was learning to fly :) Well done!

I'm sure there's a way to reliably fit it in a capsule. I'm thinking something like the way those model rockets backfire their chutes out. I'll have to try that one of these days. 

Comment by Bernardo M. A. on May 6, 2013 at 4:57pm

thanks robincfey, a drogue would be a solution but it may take a lot to open the main parachute. What do you think?

thank you Muhammad hehhe updates us about the model rocket chute when you test them ;)

Comment by Gary McCray on May 6, 2013 at 5:10pm

The problem with a drogue on a multirotor is the ease of entanglement, you have no guarantee of the attitude of the multirotor and the chute can easily be upside down when it deploys, some sort of spring thing is probably best.

The simplest powered deployment would probably be ESTES model rocket motor chute deployment charge, but those take a while and it might be on the ground before it launches the chute. - Embarrassing!

Some sort of mechanical means to get the chute clear of the copter is probably best, possibly servo release of bent over light thin fiberglass rod (flyrod tip?)

Comment by Muhammad Al-Rawi on May 6, 2013 at 5:17pm

Good point, Gary. Now that I think back to it, those things did take awhile to light...

Maybe pack the chute in a tube with a loaded spring in the back? Some sort of servo latch mechanism to let the spring go. To an extent kind of like what's going on inside one of those cheap airsoft guns. 

Comment by Muhammad Al-Rawi on May 6, 2013 at 5:20pm

I would imagine, if you had the cord long enough to mostly clear the frame (considering it will be tumbling around in its descent) you could avoid most tangling. 

Comment by Bernardo M. A. on May 6, 2013 at 5:37pm

Gary, i think that the main problem with deployment charge is the heat that can burn the parachute. You can do a rocket with blackpowder that's ignited really fast.

Muhammad, i tried to use a spring but's now so easy to launch it since the parachute is soft and absorves some energy.

I've thought about using a CO2 refill, for chantilly, but i don't know how much pressure does it have

Comment by Muhammad Al-Rawi on May 6, 2013 at 5:40pm

usually you'd use some tissue-like material between the rocket and parachute to prevent burning it. 

Haha, don't know if I'd use a CO2 cartridge. Those things pack quite a punch. 

Comment by Bernardo M. A. on May 6, 2013 at 5:47pm

Thanks for the tip Muhammad! ;)

I was thinking about getting a CO2 cartridge pierce by something sharp so it will free the stored gas hhehe

Comment by FD on May 7, 2013 at 4:22am

Hi all, following the discussion, I am imagining a very lightweight / thin carbon fiber rod (thanks Gary) pulling out the parachute upon releasing it (thanks Muhammad). Considering a quad for the sake of the argument, could the rod be mounted on a motor arm pointing outward and then bent over to pull out a small, neatly packed parachute from a neighboring arm (or a tube mounted alongside it?

This would eliminate the problem of soft fabric compression that Bernardo mentioned using a spring and at the same time hold the center of the chute in a defined area away from entanglement. Just an idea.

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