Dear reader,

We are now live at www.skycat.pro. 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 www.facebook.com/skycat.pro and Twitter at https://twitter.com/skycatpro

Fly safe - Let's keep our copters flying!

Henri

Skycat.pro

 

DJI Inspire 1 / Skycat X55-CF parachute integration by www.remotevision.ch:

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:

- http://www.opale-paramodels.com/

http://www.fruitychutes.com

- www.vectorheli.com

- www.3drobotics.com

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Bernardo,
You are right. With this method we will lose an advantage of very quick deployment. On opale paramodels video chute opened from altitude of 6m. With pilot chute that's not possible.

My old physics book "fundamentals of physics - fifth edition" has good graph at page 23. Lets say that start altitude is zero and velocity is zero as well. At timeline one second vertical velocity is -9.8 m/s and vertical distance is -4.9m. This equals quite close a situation I had here. From that point at latest will main chute start open. Pilot chute will also keep falling but slower. In some point pilot chute and copter speed difference has caused full rope to be pulled out. Referring graph in book, at point of two second copter has falled -19.6 meters and its velocity is -19.6 m/s. I will go to work soon so I can't calculate this exactly now but I guess that main chute is opened before point of two second.

This is something I could test later when spring actuated pilot chute kicker is done. It could be done in air or on the ground with high speed camera and blower. I'm not sure if my copter flies on that time yet but ground test is good option.

In this game every meter counts. So all good ideas for saving fraction of seconds are appreciated.
Latest updates. Bernardos doubts about opening altitude made me to do worry what opening distance would be. I made some calculations based on estimated values of pilot chute drag and speed and got result around 16 meters from deploy.

Then we went to local observation tower for test this. I dropped 9kg paint canister filled of sand from two different towers; 14 meters and 17 meters high. 14m was enough but canister ripped of from chute. It was attached only with tape. 17 meter tower drop was quite good replica of first drop. It takes about ten meters before pilot chute has enough drag and then rest happens very fast. Tests also demonstrated worst case scenario once. Everything is on video: http://www.youtube.com/watch?v=GfYjDrItW2o

First video is deleted as useless now.

Henri, great tests! very interesting!

The secret is to fly at high altitudes because if you stay at medium heights the parachute won't open and it will cause damage ;)

By the way, how are you going to eject the drogue? Spring?

With trashbag drogue it took more than ten meters but lets see what bigger real chute does. 36 and 60 inch chutes should arrive at this week.

I planned to eject drogue using a spring at least as a first try. Tube materials arrived on monday so only limit now is free time for hobbies (housepainting weather is perfect now and takes all early evenings after work).
Springs I try first are from Lesjöfors Sweden. I attached an image of them. Bigger weighs 17 grams and smaller 6 grams. Bigger is stronger than I can fully compress by hand.
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Parachutes for pilot chute use arrived today. Those seems to be old military chutes (bigger M94) and it is really done for tough military use. 60 inch chute weighs 370 grams and ropes are capable to hang perhaps some hundreds of kilograms. And smaller is like a 45 gram toy chute.

Anyway I'll try with these and meanwhile keep eyes open for lighter chute. At least ropes needs to be changed to be lighter type.
Updates: 60 inch chute weights without ropes 170grams which is too much. So I'll test first with 36inch toy chute. Better option should be found.

Prototype No2 tube is now almost done, two photos attached. It is huge in height but footprint is only 10x10 cm. Perhaps chute could be packed better and then fit it to smaller tube. This is very loose packing.
Tube itself seems now to be too strong. It has 5 layers of plywood which means 15 cross laminated layers of wood. I think 2-3 layers of plywood would be enough. Carbon fiber would be better but so far I haven't find any that big in diameter. Cfparts on Ebay thought manufacturing it but in the end they couldn't, too big in diameter. Polycarbonate with wall thicknes 1mm is also an option if I find it from somewhere. Problem with plastic is glueing which is not so reliable.

Now there is one decision to make; hatch. Should it be one with spring accelerated opening and hinge or two hatches with some sort of mouse trap release or one hatch whing has open hinge and allows full hatch fly away (hanging freely after deploy) or something else?
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Another image. Ipad Chrome upload system uploads only last selected image.
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That really is tall, probably too tall.

I could provide 3cm carbon fibre tubing and perhaps larger although it would probably be easier to just get a sample for $25 from these guys and they seem to have up to 4cm diameter.

@Randy: Thanks for your offer! Problem is that my chute is so big but 4cm would work well with smaller chutes. Now main chute tube is 25cm long and 9cm in internal diameter. Parachute is folded three times and free length without squeezing is about 25cm. First prototype was few millimeters larger in diameter but chute was folded five times. So far I'm not sure how it is packed optimally. Five folds and 9+cm tube required about 1.5kg force to pull out. With three folds it should need significantly lower force but requires more space.

We'll see what is optimal lenght and pull out force during testing. Tube is easy to cut shorter from bottom.

This 2.8m chute is quite big. I'll try to post packing photos perhaps today.

updates: Here is series of images as pdf of packing the main chute. Today I ordered one possible pilot chute more. Hopefully this third version is suitable. This is 1.8m2 chute from Opale Paramodels. Main chute feels good and therefore I trust this also.

I think one biggest risk we have is that pilot chute tangles before it opens the main chute. I believe pilot chute has good change to open because it is pushed out. Opening is only matter of luck if copter is spinning or is upside down. Anyway, this pilot chute is so big that it has good change to even turn copter and pull main chute out. If only pilot chute opens will speed be for 10kg copter according to descent rate calculator about 10.5 meters/s. It is way better than free fall.

@Randy: Is it possible to have automated deploy for high risk copter mode so that APM does decisions before operator sees something going wrong? Or does it have capability to wait and try to turn copter to best possible deploy orientation until last possible deploy altitude? 

 

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For all viewers: We must be proactive in safety of these heavy flying machines. Yesterday accident caused death of a pilot is again one sample what might happen if everything goes wrong. In this case pilot was flying 3D and none safety system couldn't prevent hit but same result is very possible with any large camera copter. 

It's very good Randy that you have understood safety importance and are involved in this one minor project for safety. You as all developers understanding insight of APM have best influence for developing safety systems.

It's sad to see cool 10k€ camera copters flying without any parachute even parachute is possible to buy from store today.

Anyway I will and hopefully many of you continue developing a chute which anyone can build if commercial version is unsuitable or too expensive. So far here is only three of us involved.

Keep it coming, very interesting! ;)

Has this spring enough force to eject the parachute from the tube? I good spring too would be the ones that are used in mattress because they aren't too stiff and have a long range of compression. Unfortunatelly i have never seen being sold in stores, just already in the mattress hhehehe

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