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Old Jul 31, 2011, 12:27 PM
It flew...nearly!
Norway
Joined Apr 2006
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Ballistic Recovery System for Multirotors

Hi!
I thought i'd start a thread for a project that I have a need for in the hope that talented people out there can contribute to something that will work. I am in the prosess of learning myself to fly tri/quads with the hope of finally sticking a camera on one and actually doing some AP. One of the challenges is that multirotors are much less easily controlled than planes (for me, at least), meaning more crashes. This is because they are less self stabilising than a plane, much easier to lose orientation with, contain more electronics that can go wrong and when they do, things go pear shaped quickly.

Although self levelling flight controllers have entered the arena, making them more stable even when momentarily disoriented, the problem with, say, a motor out still remains. I know one can build hexa's, Y6 and octocopters with some redundancy, but I'd like to stay with a tri or quad to keep costs down. I want the minimum cost platform that can do the job, with as little risk of damaging people/property as possible. Peace of mind is of value as well

We need two things as far as I can see, a device for deceleration, example, parachute and a means of deploying said device into the airstream.

I have seen a couple of novel ideas, but have yet to see anything actually be tested and utilised. If anyone has links to projects of interest, please post and I'll put them in the first post, so it's easy to follow.

I know this will probably end up panning out into absolutely nothing, but I reckon more work could be done here, and it would be fun if something came of it. There are examples of projects starting of as fun and ending up as commercially viable products and with so much interest in multirotor AP, those cameras are going to be worth protecting, not to mention the people/property aspect.

Cheers,
Matthew
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Old Jul 31, 2011, 12:39 PM
It flew...nearly!
Norway
Joined Apr 2006
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Some considerations regarding parachutes:
I would suggest using a round one. We tried a couple of drops with a steerable hk paraglider in a different project, but forward speed isn't desirable. Low speed will generally means less energy to expend on hitting cars/people etc. Also, presumably you have been flying in a reasonably safe place. When a multirotor stops flying my experience is that it falls out of the sky directly, we don't want it flying off under canopy to somewhere less safe or unretrievable.

So for the deceleration device: As little vertical and horisontal speed as possible, including any pendulum effect.

As far as deployment is concered I really think this has to be some kind of active system, really jettisoning the deceleration device out into the airstream. Time may be of the essence and just unpopping the lid on a container and hoping gravity will do the rest, won't work very well. We need to get the device out there, untangled, without fouling any props/motors and deploying as quickly and as reliably as possible.

Well people, it's up to you

Matthew
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Old Jul 31, 2011, 06:15 PM
Design and fly
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Set tight it's coming in a low cost solution for beginners wanting to fly higher without the worries of losing control. It won't be ballistic we have designed chutes from 5sq.ft. to 450sq.ft. for the last 14 years. We're actually releasing a soft wing for beginners to fly FPV with using the GoPro in the next 10 days. We have done test launches from fixed wing over the years and designed the full line of Q-T copter to accept the recovery upgrade. We have designed a full spectrum over the years from rocket assisted chutes to CO2 blown chutes to small DF to inflate the chute instantly.

We use elliptical shoots instead of a round chutes that are completely cross ventilated. ( any part that opens will inflate the rest of the chute through the risers instantly)

We did this as a win/ win for us. For beginners that can't fly but want in the air shooting we can make that happen on low wind days in the morning or evening in clean air. The same chute was redesigned to fit the T-Copter, the Q-Copter. The 500 and 600 have already been tested. Will get a video posted in action in the next 7 days. We have to get pending customers orders out first.

Just a heads up.

John
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Old Jul 31, 2011, 06:41 PM
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Quote:
Originally Posted by skycam4 View Post
Set tight it's coming in a low cost solution for beginners wanting to fly higher without the worries of losing control. It won't be ballistic we have designed chutes from 5sq.ft. to 450sq.ft. for the last 14 years. We're actually releasing a soft wing for beginners to fly FPV with using the GoPro in the next 10 days. We have done test launches from fixed wing over the years and designed the full line of Q-T copter to accept the recovery upgrade. We have designed a full spectrum over the years from rocket assisted chutes to CO2 blown chutes to small DF to inflate the chute instantly.

We use elliptical shoots instead of a round chutes that are completely cross ventilated. ( any part that opens will inflate the rest of the chute through the risers instantly)

We did this as a win/ win for us. For beginners that can't fly but want in the air shooting we can make that happen on low wind days in the morning or evening in clean air. The same chute was redesigned to fit the T-Copter, the Q-Copter. The 500 and 600 have already been tested. Will get a video posted in action in the next 7 days. We have to get pending customers orders out first.

Just a heads up.

John
Interesting, what does the system weigh? Do you have a website?
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Old Jul 31, 2011, 08:04 PM
Design and fly
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Not for the parachutes anymore. We manufactured the chutes in 5 sizes for 10 years from 1998 -2008. We're brining one parachute back just for use with the GoPro will be launched in a couple of weeks. Helicopter aerial systems for all types of uses took over in 2003 with the T-Copter line being added last year. AirFoil Site is the basic site. The recover chute will be added as soon as time allows.

John
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Old Aug 01, 2011, 02:16 PM
SX_
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Zambia, Lusaka, Lusaka
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Ok ive writen on quad and plane:
I did some high powered rocketry so have some clue as to how the chute works, and the potential problems I could imagine:

1, the quad is too low.. That would result in the chute not having enough time to open obviously this “minimum altitude” will also differ with the momentum of the quad if it is already falling the time to open chute will be less than a quad only starting the decent. This is as the required force (wind) to actually open the chute needs to be reached when the velocity of the falling quad builds enough air resistance. So higher is better and obviously forward momentum will also assist but quads hover most of the time so……

2, Tangling of the strings on the quad… there is not much that can be done and if it happens well the quad was falling anyway so just sit and watch . The means of parachute ejection will also play a role, rubber bands wont eject the chute very far and I think would tangle easier. Charged ejection would be my choice this would ensure the chute is ejected far enough away from the quad to increase its survivability substantially.
Also I would try to use some sort of spring wire (like a CB radio antenna) connected to the quad and the chute string this would unwrap off the quad easier than just string or atleast a long string..

3, Coding, and/or switch.. It would be beneficial if there would be some failsafe code activated by gyro and accelerometer sensing control is lost as well as a switch directly from the RX that can activate the chute. The reasoning behind the switch from the Rx is if there is a PCB failure then the chute could be manually activated still saving the craft. And another point on the coding one of the largest points of discussion I’ve seen is the right orientation to actually eject the chute, the only problem is that even with an electronic ignited discharge the delay could be substantial (milliseconds) thus the orientation will have changed significantly (I dint know the rate at which the quad spins but on the vids it looks FAST!!) obviously there could be a nice little(or large ) algorithm to estimate a near horizontal (going towards the sky not ground) trigger giving the quad 180 deg before it crosses the horizontal plane again where after it would not be such a good idea to discharge the chute as the chances of entanglement increases. But I don’t know if the processing time would be too long and thus not eject the chute before the quad meets terra firma. Again height would help But would rather have the chute out there tangled than tucked away safe in its tube when the quad hits the deck.

(does anyone notice that I’m bored?)


Maybe with height a drogue chute/streamer could be deployed to stabilize the craft before the main chute is deployed? Obviously this requires substantial height and I don’t really think most quads are flown that high..

oh and for added safety the chute should either switch throttles off or only armed one throttle is 0....?

and a plane:

1, the Plane is too low and slow.. chute deployment would also differ with the momentum of the plane if it is already falling the time to open chute will be less than a Plane only starting the decent or stalled. The required force (wind) to actually open the chute needs to be reached when the velocity (of the falling Plane) builds enough air resistance. So higher/faster is better and obviously forward momentum also helps. The Charged ejection will also assist in the opening of the chute as the unrolling of the chute does not rely on wind force alone…

2, tangling of the strings on the Prop/plane… The means of parachute ejection will also play a role, rubber bands wont eject the chute very far and I think would tangle easier (dependant on aircraft orentation). Charged ejection would be my choice this would ensure the chute is ejected far enough away from the Plane to increase its survivability substantially in any orentation. This will also be the most predictable and repeatable ejection system.
Also I would try to use some sort of spring wire or stainless cable (very thin) connected to the Plane(this is just to ensure the prop(or anything else) doesn’t cut the line.
a piece of bungee cord between plane(cable) and chute string will be important the bungee will absorb some of the impact of the chute opening at higher velocities..

3, the ejection can be triggered easily by 5v but obviously having 12v will again increase reliability I would have a small pcb with like 2 555timers watching 2 channels for failsafe and would trigger an ejection when throttle is at 0(or even soemthing like-20 when setting Tx failsafe) and the failsafe channel(chute) is activated you can even build in a .5 or 1 second delay.. charge can be ignited by a small piece of nicrome wire submerged in black powder (you can make some yourself ) if you have a shop that sells model rockets your fine

The chute material is also quite important thin nylon non rip material, heavy material is bad as the weight can actually overcome the wind and it falls the same velocity as the plane so it doesn’t open!! Again the ejection system has to eject the chute far enough from the plane to ensure “semi clean air” so the wind force can open the chute otherwise the chute can become trapped in the air bubble on top of the plane( when the plane is in a spin) and tangle the lines. so the chute needs a longish cord

The size of the chute varies depending on needs for a model plane I would like the velocity to be slow enough to minimize damage but not too large so it takes up to much room and weight on the plane. the whole chute system must not hamper the planes performance much!

so you could make a universal ejection system that could be used on a quad or plane.. pretty cheap, the simplest would be a rc switch that just turns smoe nicrome wire "on" and activating a charge to propel the chute out

One of the best chute ejection powders can be made with VitaC tablets takes long but what a POP!

I will impelement something in my quad/FPV plane sometime, just need to spend some time in my lab


Hope this helps a little

Cheers

Willie
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Old Aug 01, 2011, 03:20 PM
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Been thinking about this, could the chute fired from a co2 gas can?
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Old Aug 01, 2011, 08:12 PM
Gress Aero
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Old Aug 01, 2011, 10:35 PM
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How about something along these lines:
snakes in a can prank (0 min 29 sec)


Could a 'chute be spring loaded for ejection?

Rob D
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Old Aug 02, 2011, 01:32 AM
It flew...nearly!
Norway
Joined Apr 2006
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Here are some reasonably priced parachutes that may be useable:
http://aeroconsystems.com/cart/catal...utes-65-1.html

Seems to me the pilot chute with mesh might be a good candidate since line entanglement during deployment might be less of an issue.

Askild, one of the active flyers at our club, has a quad capable of lifting a "dummy" frame aloft. Once he returns from holiday I will try and get a drop done. It will likely be predeployed, just a drop to see what kind of speed we are talking about. I have a 36" white parachute destined to be tested in this way.

One method of deployment I have been pondering is a sort of "crossbow". The "arrow" is attached to the apex of the canopy, which is stored loosely in a canister. When deployed, the bow would shoot the "arrow" (it will be securely tied off to limit distance and keep it joined to the canopy), pulling the canopy out of the canister. You could use rubber bands or a theraband, arming before take off, and a servo trigger (could be linked to failsafe operation).

Matthew
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Old Aug 02, 2011, 09:42 AM
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Quote:
Originally Posted by nocontrol1 View Post
How about something along these lines:


Could a 'chute be spring loaded for ejection?

Rob D

I've seen this type of method mentioned before somewhere on RC groups and to me its probably one of the simplest and safest.

The chute is held in a small container over a compressed spring, held down by a pin connected to a high speed servo. Once the pin is pulled a 'Jack-in-the-box' action throws the chute out. Whether it would be powerful enough to clear a tumbling mulitrotor is another question.
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Old Aug 02, 2011, 12:56 PM
It flew...nearly!
Norway
Joined Apr 2006
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Definately worth a go. Does anyone have one lying around? How much force do they generate?
Matthew
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Old Aug 02, 2011, 02:35 PM
SX_
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Zambia, Lusaka, Lusaka
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The main problem with a spring/rubber band is that it just doesn’t give you deployment with enough energy to ensure that you have the chute at maximum distance from the quad, now b4 u shout at me, with the line "unrolled" the chute only has to open i.e. only needs enough "resistance" (force) to open. not to unroll etc. this is very beneficial if you are cruzing slow, it takes time for the quad to develop enough downward speed "force/air resistance" to unroll the line and open the chute.

Also if the chute is launched with minimal airspeed you want the chute FAR from the quad, the reason is as the quad (falling) builds momentum so does the un opened chute, and the air void close to the quad will also contribute to a much later deployment.
So if u decide to use a spring or rubber band, just remember they will only really be effective when u are fast or high. Not to say a charge much more effective but it should increase the deployment envelope. Especially in the speed ranges/heights we fly quads.

As usual just my opinion
Willie
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Old Aug 02, 2011, 09:47 PM View Post
skycam4
A moderator felt this post violated the following rule: Cross-posting. It is temporarily hidden while skycam4 edits it. Show it to me anyway.
Old Aug 03, 2011, 04:42 AM
Real Time Recon
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BRS chutes have been available for full sized ultralight for many years now.Video. of one being deployed on the ground.This one needs 100 feet to fully deploy .If this system could be 'shrunk' down in size you would be in like Flynn... The 'launcher' part, could be based around a small Estes model rocket motor.
BRS Chute Deployment Demo (1 min 9 sec)
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