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 :)
Fly safe - Let's keep our copters flying!
DJI Inspire 1 / Skycat X55-CF parachute integration by www.remotevision.ch:
Other documentary videos:
Manufacturers contributed to this project:
Beautiful video. I've put at the top of the parachute wiki page (replacing one of your earlier videos).
Here are logs of four ejects; two manual and two automatic. Unarm seems to stop logging just when things becomes interesting.
This video is a ground view of the eject. Copter total weight was 3.4 kg. On this video whole process is fully seen including ground impact.
Youtube makes video very poor quality, here is downloadable original video 1st Pixhawk automatic parachute recovery - ground view (download it to PC for full resolution).
Thanks for the logs.
Yes, there's an item on the to-do list to keep logging if the disarm is caused by a parachute release.
The vehicle falls quite far before the parachute deploys. I wonder if we need to try and force that earlier in the software or is the delay mostly in the deployment mechanism?
When logging is available we could analyze better where delay is. Now we need to estimate delay based on video.
I made video analyze frame by frame and found overall delay to be 1.35 - 1.45 seconds from moment when copter is clearly flipped sideways to moment when parachute package is on the way to out. Unfortunately on that moment copter has good speed towards the ground and travels some meters before parachute is fully deployed.
Another video where we ejected using Pixhawk manual eject command delay was about 0.8 seconds from a moment when pilot said "now" to moment when parachute was visible out of the tube. This is very rough estimation, or almost a guess, but still consistent with automatic eject delay.
Eject delay with this setup is very low, 0.08 - 0.2 seconds from the moment when release is activated. This is the time which can be seen on oscilloscope. Here is minimum battery we have used; NanoTech 3S 350mAh 65-130C at rest voltage 11.96V and delay was 224ms.
After this delay parachute is on the way out of the tube and traveling takes some fractions of the second also. Here is one video where delay can be seen in air:
1.4 seconds is long time to fall and should be shorter but only in case when we don't increase the risk of false eject.
Feel free to make test code and we try it at our own risk. Even wilder test codes are ok for us and we have a methods to take copter down safely what ever it does.
It's a long time since last update. All kind of projects has kept us busy and some results of those are seen today publicly in our store. Those which are not allowed to publish flies commercially / on test phase at various locations around the Globe.
Latest addition to our portfolio is new launcher to smaller end; X48-CF. It is ideal for 2 - 3 kg multicopter and can be extended even higher weights. Video under is shot from our winter test session. This area is a lake near our workshop and it has 5 km free space to test parachutes without need of ladders for picking copter from tree :)
We also have few third party devices here at test and development. We'll publish more about them during spring 2016 period. If you have an idea or product you think we should know or have in our store and perhaps even participate R&D, do not hesitate to contact us!
Pixhawk has been in air several times with automatic eject enabled and so far not a single failures has occurred.
Here is a video of one ordinary test session. First one is X48-CF ejected from full speed and very low altitude. Basically it acted as brake parachute.
Another eject is XL84 installed on DSLR carrier hexarotor. Descent speed looks like unrealistic slow. Theoretically impact speed should be around 3.4 m/s but that looked even slower. Perhaps pilot chute gave some additional drag.
Hi Henri, that first video was wild!
On the second one because of the very cold air your effective Cd may be very high, approaching 3. I've seen this in my own testing on cold days. Also the smaller "pilot" chute can also slow it some. So you have a IFC-84-SR for the large main. What is the smaller chute model? That looks like one of our's as well. Is that a IFC-36-SL?
Smaller chute is IFC-48-S. It was standard package from store.
Temperature really affects quite a lot. Air mass density increases from 1.204 / +20°C to 1,395 / -20°C and it has linear effect to drag. We have used lower 1.204 for all values represented.
So, warm air might cause thermaling which has great effect for drag and cold air has higher density which also effects drag. Win - Win case.
Our closest test area on own yard is surrounded by trees from west-north-east and has open field to south. It causes sometimes very strong down flow (downdraft correct term?) and it seems that parachute has no drag at all. And suddenly close to trees parachute catches up flow and almost stops. We are playing with so slow descent speeds that even smallest change on climate has effect and especially thermal might slow descent speed easily to half.
Yup, all very good assumptions Henri!
Update for Pixhawk users and devs:
Today we did parachute function endurance testing for Pixhawk 3.3.3 firmware. We flew two batteries and aimed to get all out of the test copter. We performed long and deepest possible dives with minimum throttle, straight minimum throttle descent, shaking with max lean angles etc.
Result was that Pixhawk didn't eject parachute and all went as should. Based on today two flight test it looks like that with this very much shaking / vibrating copter it ain't possible to cause unwanted eject.
Videos follows once edited.
Here is the video of Pixhawk firmware 3.3.3. automatic eject (or manual) and some updated and more accurate data. Earlier reply is deleted as it contained inaccurate data and now after new analyze data is closer to reality.
Logs are attached. Scenario was simple throttle OFF at altitude 84 meters. Copter fell quite far until Pixhawk decided to eject. I hit also manual eject at some moment on the way down and parachute were out 0.4 seconds before it would have been too late. It was very close call. Fall speed at that point was 32 m/s and parachute were fully inflated at altitude 13 meters.
In the end I'm not fully sure if Pixhawk ejected at all or were mine manual eject request primary trigger for eject.
It seems that Pixhawk hesitates for a long time (35 meters in this case / or no eject at all) and when it decides to eject takes it some time until output gives signal. This delay can be seen on manual eject on table when eject is hit, first propels begins to shut down and then parachute is ejected.
- Pixhawk: 35 meters at ~2.5 seconds (or no automatic eject at all)
- Delay for I/O signal: ~0.5 s. This is estimated using video material and logs. Logging ended at altitude 48 m and parachute is out at altitude 26 m, speed 32 m/s. Travel time minus launcher delay is Pixhawk delay.
- Delay for Fuse blow: ~0.18 seconds (3S drive battery typically on our tests)
- Delay for parachute inflation: ~1.1 seconds. Deceleration begins immediately and after 1.1. seconds speed is approx. terminal velocity.
This is data we got, please feel free to make conclusion.