G’day my name is Bruce and I am doing some research into parachute recovery systems for UAS. I’ve looked at various commercial systems with different deployment methods (mechanical projection, inert “cold” gas projection and pyrotechnic “hot” gas projection). However, while there is a wealth of information on the internet regarding commercial systems and their performance, I’m finding it difficult to find information regarding system failures. I would be interested in hearing from anyone who has experienced failures with UAS recovery systems to learn more about how / why the specific system failed.
I would be happy to correspond or speak with anyone who has experienced a UAS flight failure and a recovery system failure. If you have an experience you’re willing to share I can be contacted at firstname.lastname@example.org.
Usualy either Motors or ESCs fail.
G’day amilcarlucas, thanks for the response. I may not have worded my question that well - I was looking for information regarding the failure of the recovery system, not the UAS - (such as failure of the parachute to deploy, possibly slow deployment or entanglement etc)
My experience on chute recovery system failure:
- The speed of the UAV (a flying wing) was too fast when the chute was deploying. The cord was not strength enough to hold the energy so it broke. Fortunately, the UAV safely land manually. I think it is important to position the recovery system on accurate CG so the plane will not crash if such kind of failures happen.
- The cord was cutted by the propeller.
- Difficulties to land precisely on windy conditions.
Sorry for my bad English.
Bruce greeting to you
We all have failure we need to come from it .
Let me try to help you out.
- decided an altitude at which chute will open . my past experience suggest greater the all up weight of UAV more height is require because moment of energy is greater.
- design parachute with considering following points
a)shape of parachute
b) material of parachute used kevlar ropes with steel sleeves which cannot be cut by spinning of propeller.
c)decided speed rate at which uav will touch ground
d) adjust height of chord of parachute and point at which all chord are attach to UAV.
e) you can control the parachute trigger autonomously or manual trigger.
f) make to two three prototypes and check it with same weight of UAV attached to it and drop it from a reachable height as close as to the altitude to decided.
I hope this will definitely help you.
Thanks and let know
I have emailed you this same information.
I have been involved with several projects that have used parachutes, and have observed a few common failure modes.
- High winds two issues
A.I used to have a good video of a parachute test we did a few years back in high winds, the aircraft started to fall well, but got caught in an updraft and was carried a very long way away before finally descending into bushland. Aircraft survived, so technically not a failure.
B. Aircraft flying into the wind with a low ground speed, but after a failure, parachute was deployed causing the aircraft to be swept away with a ground speed that suddenly accelerated to over 60KPH, impact with a vehicle on the ground left both the aircraft and ground vehicle seriously damaged…
- Automatic parachute release system with no connection to onboard flight controller
A. Lack of coning correction… in sweeping turns, the parachute controller can be fooled into thinking that the vehicle is on an irrecoverable attitude, and can lead to false triggers
B. Lack of connection to the flight controller can leave the motors running, leading to entanglement of the parachute and propellers
- Weak parachute ejection systems
Failure to propel the parachute away from the vehicle and force correct spread, can lead to entanglement and failure to correctly open the canopy.
As a side note, I have tried many parachute launch systems, and the best by far has been the Parazero system from Israel.
There’ll be a few relevant entries in the issues list:
Good day, your topic is interesting…im doing and developping a small parachute system for my drones, do you mind advice me where i can purchase a good parachute for it?
You can buy on bangood.com and gearbeast.com even hobbyking.com also
G’day Omkar, thanks for the information and advice. I’m still in the researching mode but will reach out as things progress. Thanks again.