Redundancy

[ninja]

Hi all,

I have been contemplating the lack of redundancy built into the DJI Phantom range. In the case of a motor failure mid-flight that aircraft is coming down no question. There are other manufacturers building hexcopters and I am wondering if anyone has any experience of those and whether they are able to suffer a motor failure during flight and still be able to perform a safe landing or fly safely home?

There are in fact of course many single points of failure that could cause a crash on the Phantom range i.e. motors, props, speed controllers, battery, flight controller, IMU etc. (Don't get me wrong I think the Phantom is a fantastic machine!) I am just thinking that for the CAA/FAA etc to consider relaxing their rules about flying over people, animals, vehicles etc then the manufacturers should be taking steps to consider this a little more and bring them in line with other commercial aircraft. I am guessing that the technology is there.....it's just a case of finances.

 

[bbfpv]

Most hex's can still fly with single motor failure.

Helicopters fly over people all the time, and they only have a single engine.

 

[N017RW]

The Phantom is an 'every man's' flying camera. Nothing more.
The capability you describe is available on higher-end equipment.
Bear in mind the P3s, with all their capabilities sell for at or less than DJI's top-tier flight controller alone.

 

[ianwood]

Designing a fully redundant system is very costly and time consuming. All critical systems would need to be doubled or tripled. All of which translates into weight. Which means more battery to maintain flight time. Which means more weight. Which means more battery. And so on.

Then you need to develop the logic that detects and corrects failures. That needs to be bulletproof which will require many months if not years of development and QA. And a company like DJI is not set up to develop mission critical software.

 

[happydays]

Helicopters have flywheels (or something similar) to enable them to continue for a while if the engine stops.

 

[N017RW]

Not a flywheel per se other than the mass of the rotor assembly.

They have collective pitch and can 'reverse' the pitch to perform 'auto-rotation'.

 

[ianwood]

Helicopters are death traps and should be banned!

 

[Man.Of.Kent]

Helicopters are death traps and should be banned!

Good luck with that one! [emoji576]

 

[Chuck Young]

Helicopters cause my permasmile!

 

[Joao Carlos]

Put a parachute, some water floaters and problem fixed. If there was a good parachute kit for the P3 I would buy, mostly for the fun of it.

 

[SteveMann]

My hex lost a prop at 100 ft and I was able to make a safe landing.

 

[malibusteve70]

parachute

 

[wordsmith]

The perfectly safe, 100% failure-free, totally dependable Phantom 3 already exists. It sits on your shelf and never sees the light of day. (mind you, it's pretty boring too)

 

[Quadcopter102]

Helicopters are death traps and should be banned!

I love flying.... but I would not like to be in something that cannot glide when the fan stops!

 

[reddy]

DJI can improve the Phantom with a algorithm, it is only software based and doesnt need additional Hardware.
It is possible to fly the Quad after 1 Motor is stoppt.

See: https://www.ethz.ch/de/news-und-ver...-algorithmus-macht-quadrocopter-sicherer.html

I think it is a nice feature.

 

[SteveMann]

I love flying.... but I would not like to be in something that cannot glide when the fan stops!

The you don't understand how helicopters fly.

 

[N017RW]

DJI can improve the Phantom with a algorithm, it is only software based and doesnt need additional Hardware.
It is possible to fly the Quad after 1 Motor is stoppt.

See: https://www.ethz.ch/de/news-und-ver...-algorithmus-macht-quadrocopter-sicherer.html

I think it is a nice feature.

This has been demonstrated by other before as well.

People think just 'add' an algorithm and you're all set.

Well the Phantom is a flying camera with just enough CPU to get the job done.

Notice how symmetrical the videoed quad's assembly was? The Phantom's CG is not down the center of the vertical axis. It is eccentric with a camera and gimbal hanging down below.

Enabling the Phantom to perform what a stripped down quad did in the video would mean much more than software.

 

[ianwood]

Being able to maintain stability with a dead motor will take a lot more than just an algorithm.

As for parachutes, not exactly easy to retrofit to a closed system. No one will like the reduced flight times due to the added weight. It would also need to be manually triggered otherwise it might not deploy at the right time. I would be highly suspicous of any claims to automatically deploy. Manual trigger requires wireless connection.

 

[Chuck Young]

I love flying.... but I would not like to be in something that cannot glide when the fan stops!

Used to work on airplanes, none of them glide when the fan stops, that's why we called them lawndarts.

Helicopters on the other-hand can glide, it is called auto-rotation. smile

 

[Quadcopter102]

The you don't understand how helicopters fly.

I do sir, 1 big fan on top and a tiny one at the back to stop it becoming a spinning top.
I recall a newsreport video on TV some years back - about a chopper over NYC - the tail rotor ( I forget which) was either hit by another news chopper or building...but one thing for sure was ...it lost the tail rotor and became a spinning top all the way down.
I respect your views on Choppers... but as my dear old granny used to say..... "each to his own"