Dear reader,

We are now live at The development project continues, and updates are added to this blog in random intervals.

We have parachutes launchers available in many weight ranges; optimal 1 - 6 kg and these could be extended with higher impact level up to 11 kg. For larger up to 23 kg multicopters we have XL - series with pilot chute principle.

For those who wants to digest all information available of products, we have left this blog as it is. This blog follows closely main steps we have gone through while developing parachute launcher. Blog might feel like Do It Yourself kind and to be honest, in the beginning it was.

After hundreds of hours thinking, designing, prototyping and testing our patent pending launcher turned to be the most reliable parachute launcher for professional use. We have searched all possible boundaries of technology and from this blog you'll find results of these successful tests but also not so successful tests.

You never know where The final limit of technology is without experiencing it. That's the reason why we have done tests for scenarios which might not be even realistic on flight.

For production versions of Skycat we could proudly to say that we have experienced zero mishaps, never failed a single eject and parachute has deployed every time. This includes rescue scenarios with every imaginable scenario copter could face in air. Check this out as one sample of our test sessions! 

Skycat parachute launcher has been tested beyond all imaginable abuses copter possibly could experience in flight. We have sink it to water, it has been heated hours to 90°C and exposed to extensive moisture, we have frosted, defrosted and frosted it again, it has been in mud and snow and still it has worked. Same overshooting tests we have done also for electronics. This is not promise you can use our products outside of submarine but we have tested it so :)

This blog will still be updated as well our Facebook pages and Twitter at

Fly safe - Let's keep our copters flying!



DJI Inspire 1 / Skycat X55-CF parachute integration by

Other documentary videos:

Skycat Twin test session

OPENTX for parachute eject and 6POS switch

DUAL spring loaded switches - single RC channel for parachute eject...

Brake enabled SimonK firmware

Ground eject demonstration in slow motion 

Water test

Aerial test No 2 for Opale Paramodels 2.5m^2 parachute 

Aerial test No 1 Opale Paramodels 1.8m^2 parachute 

A moment of deploy

Tower test 3

Tower test 2


Manufacturers contributed to this project:




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     I have the slightly larger 2.5m^2 parachute from Opale Paramodels.  From looking at their website it looks like they've recently added an deployment mechanism for the large DJI hexacopter.

     Yes, I'm happy to modify the AC code so it deploys the parachute automatically when it notices something going wrong.  I'm not sure if we can trust the copter to put itself into a good orientation...because if it could control it's orientation it probably wouldn't crash.


Opale paramodel guy might be reading this project also. I mentioned my project when we had email discussion but discussion ended shortly after I gave link to this project. I think this is good marketing for them also and not competitor at all if he thought so. If someone has room on copter for that 59€ ejection tray he should go for it. I thought that tray takes too much footprint if it had to be installed above copter like I have to. It is difficult to say without mockup or real model does it fit or not.

I add one another link for commercial rescue solution. This seems to have quite large footprint also but for sure is very reliable and tested:

I had email discussion with these guys also and got information that this Mars-120 has room for future electronics. Electronics is one reason for large footprint. We could only guess what electronic does but I bet for killswitch for flight controller and automated deploy.

Automated deploy is very good alone and if there is also external kill switch for light controller, changes for fly away or crash will be much lower.

I think it this way now before real experience with APM:

1, APM notices that something is going wrong soon and deploys a parachute.

2, APM thinks everything is going ok and continues mission as usual. But, operator sees something going wrong and makes decision to deploy chute. This manual deploy is done as default using APM or with external killswitch board which cuts power from APM and drives deploy servo based on receiver orders.

I'll receive training quad from Jdrones in any day (now 2 weeks DHL transport). That copter is one I planned to sacrifice for science. If you Randy do some code changes, I might be able to test it at winter. Last winters has been very snowy and if this next is similar we will have half meter snow here in southern Finland. Snow is very good damper.

Bernardo, this spring maximum force fully compressed is more than 10kg. 90mm tube is way too big for pilot chute I think it would come out just by opening a hatch. Thickness of this spring assembly including piston plates is about 15-20mm. So it doesn't need too much space in tube.

But never knows what happens before try it.

I have never looked inside mattress, it was interesting idea. Next time I will look when I get old one.

Hi.  I see no mention of a pyrotechnic initiator - that approach is very common in model rocketry and real air vehicles.  CO2 and springs are nice but a pyro is simpler, quicker, and more elegant to me.  I am working on this problem from that angle.  your inputs would be appreciated.


Hi Timmy,

Welcome to project! It's good to have real experience on board.

Pyrotechnic initiator was an idea in mind but it was so distant technology for me that I didn't write anything about it.

May I add you to foreword as lead developer of pyrotechnic branch of this project? We have now three main branches:

1. Eject system which contains mechanics of all kind

1.1 Spring deploy, Henri

1.2 Pyrotechnic initiator, Hopefully Timmy

2. APM automatic deploy, Randy

3. External watchdog, more about this later. Yesterday I got one name for this but I haven't got his confirmation yet. He builds embedded systems for some industrial purpose and is skilled programmer.

put me in for external watchdog if the other candidate doesn't work out.  my whole career was in flight test and i think that's where you are going to end up.


Some updates:

Yesterday I tested once pilot chute deploy spring by throwing a container from rooftop. Hatch was secured with a pin which ripped of when a rope attached to ladders tightened. Chute opened immediately. Servo mechanism is under design.

Today I found from local hardware store an air ventilation component which fits perfectly to my test copter. Parachute in it is smallest Opale parachute which I'm going to use as pilot chute for larger copter. This is very similar size as Mars58.

This cable mess photo represents relative installation position for small chute tube container and its hatch.

Still pretty big but looking good!


A friend of mine told me that you're developing a parachute deployment system and asked me if I could help you with the electronics.

I don't have any experience with the DIY Drones but I've been working as an electronics designer since 2007 and I've also been an electronics hobbyist since i was a kid.

I'd like to get some information/specs what kind of system are you looking for.

1. Is it just a killswitch which can be activated from the radio transmitter?

2. or Is there some other event which should launch the parachute:

maybe -radio signal lost?, -main controller software crash?, something else?

I made a simplified block diagram which is just based on my assumption about this project. Please feel free to comment and modify it because I'm trying to figure out what are you looking for :).


hmm a 1/a to b sized model rocket engine mounted to a cardboard/balsa disk and use that to push out the chute?

depends on the specific impulse needed to get that chute moving.. lubing the chute tube ahead of time with teflon spray would also be helpful... could also use towline with a small rocket and drag/pull the chute out of the tube..depends..



Welcome on project Antti!
Your diagram was just like how I have understood Watchdog/Killswitch function. Two independent circuits side by side and both of them are able to drive motors down and deploy a chute.

Randy is perhaps one of the best here to tell us if this is possible to do and how it is made possible.

What I am aiming for with this function:

- Jesper's flyaway case was something where were at least two IF's combined and result was flyaway. One if circumstance only wouldn't cause it. One if was GPS glitch and another was a parameter problem set by user. Killswitch would have helped here.

- Case in USA this year where copter crashed to audience might have been avoided by APM automatic deploy. It was flying low in that particular case but in general.

- Cameracopter crash in this summer at music festival in Hungary would have been avoided by APM automatic deploy as well as with killswitch. Depends which one was faster. It was flying high and lost one prop (Octocopter).

- My own plane experience where I was flying in purpose a plane as high as possible for capturing perfect landscape photo. I saw only a black dot in sky but it was very stable trainer and flew almost itself. In one moment after an eyeblink I just didn't see plane anymore. APM + killswitch would have helped here. Similar scenario is very possible with copter if battery is draining faster as it should.

- one copter case this summer in France where battery exploded mid air. Result was black copter or what was left of it. Would killswitch done trick there, maybe.

In general: killswitch/(watchdog?) is an optional independent extra chip for adding one extra layer of safety for cases where APM is unable to make correct decision for any reason. It is optional and APM should work without as default.

There is also one extra function where killswitch board could be used. When testing APM automatic deploy a killswitch could cause some troubles mid air for checking how APM automatic deploy works. This could be done so that APM doesn't need any code for testing.

I could use my copter for testing. It is test copter anyway for searching boundaries of multicopter. (I have found one in first week of flying, don't land in althold mode...).



We did new tower tests last weekend. This time we tried how spring assembly kicks pilot chute out and how main chute is pulled from tube. This part worked just like it should but opening height variation was quite high. I guess packing of pilot chute plays big role here as well as overall length of ropes.

Video link is on the foreword of this discussion.

I ordered Teflon tape inspired by one commenter in this discussion. I think it helps to reduce diameter of tube and also length of the tube. Tube is already perhaps 2-4cm too long. Currently chute packing has been very loose. 

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