How to stop an expensive crash

[Peter Schaming]

So, a year ago I decided to put a thermal imaging camera aboard, a FLIR Tau, in addition to the other equipment. I became obsessed with preventing an expensive crash, so went on to develop a parachute rescue and recovery system. The smaller sized unit weighs about 160 grams, stands under 3 inches high, and prevents crashes. A larger unit weighs about 270 grams, as the parachute and case are larger.

There are limitations. It is not for sport flying, and there is a dead zone near ground level where it just wont open fast enough, but overall for photography up in the air, it works great. I am going to put it on the market shortly.

On three occasions, the cords got tangled somewhat in the props. The cording is kevlar, so they held up fine. The parachute and the quad never sustained any damage from the entanglement. Once when doing a flip, and another couple times when a fly away occurred, and/or it quite was windy. The motors are either shut down or in the process of shutting down, so no damage occurred, and the landings were not that much different from normal. I will get some videos posted shortly on youtube.
I found that a number covers for quadcopters that are in the 3 inch range, so kept the profile low. It can be mounted directly on the quadcopter, or mounted on a piece of carbon fiber plate (with standoffs), to also act as a shield.

The electronics are connected between the battery and main feeds for the quad. In the event of failure, the motors shut down, and a parachute ejects. As stated before, there are limitations. To get the microprocessor, sensors, and software to understand the difference between normal flying, and crashing, took some time, and of course, it can always be improved. I have become an expert in crashes. I have purposely crashed a test quadcopter hundreds of times, and of course, initially with a parachute that didnt always open, at first. Usually from a height of 75 feet or more. I just realized that the parachute I used was getting old, having been used well over 75 times, and thought, its time for a new one. The material is 1.1 oz nylon, very strong, durable, and as I said, will withstand a lot of openings, bad conditions, etc.. When tweaking parts, I would sit and release the parachute into a fan system for hours on end. They really hold up well from repeated being abused.
The tubing is carbon fiber, the hardware custom made, and I, or someone I have trained, will solder the electronics.
So I decided to call the company PRARIX. Parachute Rescue And Recovery Innovations for multirotors. (The X is shaped like a quadcopter).

It will save the quadcopter, and expensive cameras, and other equipment. Now thats, peace of mind.

 

[Gary Seven]

Well that's all well and good, but really. Your "Join date" is today and the first thing you do in "New Member Introductions" is SPAM the forum? Really??

 

[Carapau]

I would t say it isnt spam- it's no different to DJI posting yet this thread is already more personal. Welcome to the forums.

So, more importantly what weights can your chutes handle and what is the descent rate once deployed?


Sent from my iPhone using Tapatalk

 

[Av8Chuck]

To be fair, he had mentioned this in another thread, I think a lot of people here might be interested in this sort of solution so I suggested that he post it in its own thread. I guess I should have specified where I though he might want to start it.

Don't you think as this site grows in popularity that new comers with good [and bad] ideas will want to post them here. Not sure that constitutes SPAM?

 

[Bartman]

Welcome to the site Peter and good luck with your product launch. We've had more than a few people come through and post their announcements never to be heard from again so that leaves us a little cynical at times. We hope you'll do well with your business and participate when you have time.

Bart

 

[Peter Schaming]

Well, I didnt consider it spam, but maybe it is to some. I have been reading this site and others for a long time, I just havent posted anything, it seems there is so much to read just by searching. I generally just read the searches with my tablet in bed at night. Yea, I know what the next response is, but this is not about that.
Anyway, to answer the question of rate of decline after the chute is deployed and weights. If you look at how this is calculated, its not a simple thing, and it seems no one agrees on descent rate or even how to calculate it.
Today, the wind definitely made a difference, yesterday it was calmer. Supposedly the temperature also makes a difference. The height also makes a difference.

Honestly, I havent done so, but intend to measure in real time in the field. The rocket guys do use parachutes a lot, but it seems they are quite a bit higher than we generally fly, it has a lot farther to fall, and speed picks up, to a point, with height. This is generalizing. Maybe the rocketguy, who hates us parachute multirotor jerk spamers, knows a bit more about rocket chutes, behavior, etc..and could contribute on that end. I am just kind of glad its a bit of a boat ride between us, it seems like he is ready to pull the trigger. But I have been shot at before, just 45 years ago. Cant run between trees that quick anymore.

I have a number of videos, obviously, and figure I can calculate that way also.

I use a DJI 450 , landing gear, sometimes a GOPRO, 10 inch blades, a DJI disco, and a Disco clone with carbon fiber body with the 42 inch 8 sided chute. I also have been testing an elliptical chute on the same machines. The elliptical chute is supposed to be almost twice as slow, but I havent seen that. I dont generally go to much over an estimated 100 to 150 feet. With wind, it can travel a bit. Occasionally, it finds a tree, and I dont know why or how. It seems to be a tree magnet, some days, and not others. I have had it drop between trees where I wouldnt fly it, because they are so close. I have started going out into larger open areas, like football fields.
I use a roof rake to get it down, sometimes in addition to a ladder, extension or step. I will be back out tomorrow before a storm arrives, and see what exactly I can measure, with what we have.
Well, I might as well start posting, until everyone gets real sick and tired of my dark sense of humor, that will emerge.
Thanks for the greetings. I shall return.

 

[dazzab]

Well, you have my interest. I'm interested in anything that adds to safety and preventing damage to my equipment is great as well. I've been considering using two MARS chutes for some time now but couldn't figure out how to kill the power when they deploy. I'm also interested in having the system controlling the chutes totally independent from the flight systems. I really don't think it's a good idea to have the flight systems controlling the safety systems. In the case that the flight controller is doing something stupid, like a fly away, I don't think it's a good idea to count on it to control the logic of when to deploy the chutes. Not sure, just thinking out loud.

I have a friend who has a kill switch on his S1000 that is independent. Now that it's been proven how sensitive DJI flight controllers are to radio interference I think that's the only way to go. Copter refuses input from pilot, pilot trips kill switch as soon as copter is over a safe area to ditch. Die copter die.

 

[Gary Seven]

@Peter Schaming WRT "spam" postings, I simply call them as I see them. However, given that all the other posters in this thread don't seem to have a problem with your post and in fact are generally interested in the subject, it would appear I stand corrected here. Sorry for the negative vibes, man.

I'm a little bummed at the "hates multi rotor jerk spammers" quip. I LOVE MR folk...just hate spammers and am ultra-sensitive to them. I tend to shoot first and ask questions later in this respect. Again, my bad here. I apologize.

Yeah, I did a lot of rocketry some years back (actually got started with Estes kits when I was a kid, but went kinda "rogue" in the 90's and 2000's). Then I got into homemade rocket fuels, which sort of led me to pyrotechnics....I like to watch rockets explode.. That activity however, has been curtailed somewhat by the fact that I now have kids, complaining neighbors, and local law enforcement. I still get in a rocket or two once a year or so when I can.

Yes, back in the day when I was actually interested in retrieval of my (non-exploding) rocket, I (we) used parachute systems. But the "how's and why" WRT MR's would be totally different than with SRM vehicles.

What is it you would like to know?

 

[Peter Schaming]

The closest I have come to rocketry, is being involved using a driveshaft to launch a beercan with an explosive cemented inside, for a bicentenial cellebration. Went thru 30 half kegs of beer, in 24 hours, under 100 people, and no one got hurt from any antics.
Anyway, the way I see it is with rockets the height where the parachute ejects is far higher than where it ejects with a multirotor, in general.
First a device peaks or fails, starts to drop, and a parachute is ejected. The device is picking up speed before the chute opens, causing the device to almost come to a standstill. Then the descent starts again. The device begins to pick up speed, until it stabilizes. When the device is several hundred to several thousand feet high, and average rate of descent becomes apparent. In 75 to 150 feet, it seems it is much less so. Obviously, the higher I fly, the better numbers I would get, measuring rate of descent and see large differences between different style parachutes.
At what height would the average rocket start to peak and have you seen or calculated differences between parachutes and/or under different conditions?

 

[Peter Schaming]

I posted a typical drop test on you tube

 

[Peter Schaming]

The GOPRO for movie making is attached to a hat with a cable tie. The depth perception with GOPRO is unlike watching in person. In person, the quadcopter is plainly visible, on film it becomes a dot. The ground is frozen, littered with goose ****, and after many drops, I lost one cable tie attached to a piece of carbon fiber tubing. I use the carbon fiber legs to keep the quad higher than the DJI legs allow. I have found this is especially important when geese share the same field.

 

[Gary Seven]

I posted a typical drop test on you tube

How are you deploying the chute? Are you using a "LaunchPad" with an accelerometer? http://www.ti.com/ww/en/launchpad/launchpad.html

Is your deployment controlled automatically or are you linked via your Tx and a servo?

Up close photos would be better. It seems there are some in this thread who would like a peek at this.

 

[Gary Seven]

The closest I have come to rocketry, is being involved using a driveshaft to launch a beercan with an explosive cemented inside, for a bicentenial cellebration. Went thru 30 half kegs of beer, in 24 hours, under 100 people, and no one got hurt from any antics.
Anyway, the way I see it is with rockets the height where the parachute ejects is far higher than where it ejects with a multirotor, in general.
First a device peaks or fails, starts to drop, and a parachute is ejected. The device is picking up speed before the chute opens, causing the device to almost come to a standstill. Then the descent starts again. The device begins to pick up speed, until it stabilizes. When the device is several hundred to several thousand feet high, and average rate of descent becomes apparent. In 75 to 150 feet, it seems it is much less so. Obviously, the higher I fly, the better numbers I would get, measuring rate of descent and see large differences between different style parachutes.
At what height would the average rocket start to peak and have you seen or calculated differences between parachutes and/or under different conditions?

There's no one way to answer that last question. It depends. First, with rocketry you want your deployment system coming on line when the rocket hits it's apogee. But depending on rocket weight and altitude at apogee, timing of deployment as well as parachute size and type will vary greatly. Also, for "standard" model rocketry using BP (black powder) rocket motors, there is a set time when the deployment charge will fire after initial burn. This of course will pop the nose cone and deploy the chute. With larger, heavier, and high altitude rockets, altimeters and servos are use to initiate deployment...but the timing of this varies greatly depending on weight and projected altitude.

Google or search YouTube for LDRS rocketry and you'll see what I mean. But the advantage rockets have over MR's (or any RC vehicle for the matter) is altitude. Seems to me with a MR you're only going to have a second or so for a deployment to unfold and be successful. Because you typically will be at very low altitude compared to even a simple, basic model rocket, deployment speed and accuracy is paramount.

That's why I'm wondering in my reply to your post #10 how you are deploying your chute.

 

[Peter Schaming]

Without software recording the actual fall, I can only time with a stop watch. It doesnt work for the olympics anymore, so, I will need to use a computer. Without a computer, it appears to take between 2.2 to 3 seconds for the machine to stop, start falling, eject the parachute, and the parachute to fully open. What that distance is, is less than I originally thought. Many, many times, I can hear the blades spinning with the motors off. This slows the fall. Occasionally, the machine falls perfectly horizontal, and that was a total surprise to me. Even when I purposely made sure the machine was well off balance. I can put a 5000mah 4 cell in a disco clone, and its so far away from being balanced at COG, its impossible. Yet, it has repeatedly fallen perfectly horizontally, and I can hear the blades spinning. I check it over and over, and its not balanced at all. It really threw me off. I really have become almost an expert in crashes. I could go on and on about what happens during a crash. It is expensive though.
Anyway, I believe the dead zone is approximately 40 feet. I have killed the machine at 50, and the chute is open when it lands. Thats being conservative. Anything above that should be protected. If it means you are almost 100 percent protected above 40 feet, why fly lower unless it is necessary. And 40 feet really isnt that high. So without the system you are ALWAYS with ZERO protection. But, like everything in the world, it has pro and cons, its not for sport flying. You cant do flips, etc, etc, etc. Its for protection if you have expensive cameras. Thats it. I am also working on kit using compressed air to eject the parachute. Initial testing has worked very, very well. I do that in my "spare" time.

 

[dtw]

The only problem I have with these types of solutions - including MARS system, is that 99% of my crashes have happened while I was 30 feet or less from the ground. Either my battery was too low (my fault, didn't follow my flight plan), or fat fingered the throttle, or got too close to a tree. While I've been 60+ feet in the air, I've never had an incident. Not that it couldn't happen, but just sayin'...

 

[sledge57]

Interesting video, part of me thinks that MR needs a larger chute, looked like a slightly hard hit to me and part of me thinks that quick descent is good since it will cut down on the amount of drift.