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Quadcopter
- Thread starter Crispin
- Start date
Olazz
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Whats quite surprising is that rotor wash is something you learn about very early when flying rotary wing, and as the rotors turn counter-clockwise, the vortex created on the stb side of the aircraft is always forward of nose of the fuselage, whereas the vortex on the port side is slightly aft of the nose, as the counter rotating vortex is contained somewhat by the fuselage on that side.
The cable was clearly on stb side of fuselage and hence the vortex (which is counterclockwise) & being ahead of the fuselage pulled the cable to the blades.
The pilot no doubt had completed this manoeuvre countless times and had to be "rated" to do that job, so not an idiot or incapable.
I'd guess he was concentrating on the tower, masts, buildings, the people below & tail rotor position... rotor wash consideration probably wasn't tops and a split second misjudgement...
The cable was clearly on stb side of fuselage and hence the vortex (which is counterclockwise) & being ahead of the fuselage pulled the cable to the blades.
The pilot no doubt had completed this manoeuvre countless times and had to be "rated" to do that job, so not an idiot or incapable.
I'd guess he was concentrating on the tower, masts, buildings, the people below & tail rotor position... rotor wash consideration probably wasn't tops and a split second misjudgement...
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TonyP said:If you look closley one of the ground crew grabs the cable as is sags in a loop thereby pulling it into the blades!Ouch! Brown pants moment indeed!
Well spotted.
You can see the guy hiding in front of the middle of the trio. You can see his arm come out and grab the cable. A good idea gone really bad.
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Rob said:
I had a prop come off mid flight the day before. This, as you would expect, severely hampers flight. A bad crash caused the motor shaft to bend. Once a new prop was put on, you could see the prop travelling in two planes when hovering. Regardless, it flew. I had another motor on order in any case.
It was clear the motor was having a tough time because whenever there was a low battery, that prop would drop first as the battery could not keep the motor happy.
I am guessing it started failing either from overheating (though I have never felt them get warm in this weather) or bearings started failing. The lack of torque on that prop caused the whole thing to go out of balance.
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What about those Hexacopters. Can they, with six rotors/motors, keep the balance and fly if one dies?Crispin said:
Very interesting technology. This will be the next gadget. I've seen them put to good use professionaly as well.
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Hex actually offers no redundancy. Each arm has to have a counter to it. If you loose one, you'll still start spinning.
The only "safe" option is an octa which has 8 motors. The loss of a single motor, if detected by the computer (command not obeyed) it can shut down the opposing motor as well as one of the other sets affectively giving you a very heavy quad. You could still land, might be a bit hard but...
The tech in them is pretty amazing. Because the hardwork is done, i,.e. the computer and the hardware, everything else is up to the imagination of the guys writing the code. That is the "easy" part.
I found a nice feature today which would have been handy: Failsafe auto land.
It would have attempted to fly itself home (the place it took off from) and land. While mine might not have made it home, it would have made it closer to me rather than heading off into the sunset, even though it was struggling. It _might_ even have made it because once I got disorientated and then lost sight of it, I was screwed. I gave it stick in the hopes it would pop back up into the sky but alas...
The more I play and the more I remember that it is just an RC toy, the more amazed I get.
The only "safe" option is an octa which has 8 motors. The loss of a single motor, if detected by the computer (command not obeyed) it can shut down the opposing motor as well as one of the other sets affectively giving you a very heavy quad. You could still land, might be a bit hard but...
The tech in them is pretty amazing. Because the hardwork is done, i,.e. the computer and the hardware, everything else is up to the imagination of the guys writing the code. That is the "easy" part.
I found a nice feature today which would have been handy: Failsafe auto land.
It would have attempted to fly itself home (the place it took off from) and land. While mine might not have made it home, it would have made it closer to me rather than heading off into the sunset, even though it was struggling. It _might_ even have made it because once I got disorientated and then lost sight of it, I was screwed. I gave it stick in the hopes it would pop back up into the sky but alas...
The more I play and the more I remember that it is just an RC toy, the more amazed I get.
Rob
Well-Known Member
Crispin, have you though about wiring up a thermocouple onto the windings of each motor to monitor them? You could easily set up an alarm to sound or activate failsafe auto land if say one motor was 20 deg c hotter or colder than any other motor. As you have 4 motors you do not need to do any testing to find out what the temperatures are during normal operation because you can safely assume that at least one motor will be working correctly hence giving you an accurate temperature reading for the trip limits.
You could fine tune the value you set the trip at by changing it until you don't get any nuisance tripping, and they increase it slightly. Obviously you would need to try this with different payloads. Almost all brushless motor failures will affect the windings temperature, especially if its a model aircraft motor which is designed to run with lots of cooling airflow.
You could fine tune the value you set the trip at by changing it until you don't get any nuisance tripping, and they increase it slightly. Obviously you would need to try this with different payloads. Almost all brushless motor failures will affect the windings temperature, especially if its a model aircraft motor which is designed to run with lots of cooling airflow.
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That is an interesting idea. It would be pretty simple to do measure each motor and, as you say, raise an alarm when one exceeds a threshold for a period. If I used 1-wire sensors, good to 125c, then life is peachy as I don’t waste any inputs.
Added to list – thanks
Added to list – thanks
Matt Wright
Well-Known Member
Verrrrrryy coooollll... 
Navraj Singh
Well-Known Member
COOOLLLL!!!!!!! 
chadr
Well-Known Member
Crispin, looks like you and Tony need to practice a bit more with your choppers..... 
Check this out
http://www.wimp.com/futurehere/
Check this out
http://www.wimp.com/futurehere/
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Those guys are king. One day, we will all be killed by them.
More from them:
http://www.youtube.com/watch?v=E7X0_6o9J10
http://www.youtube.com/watch?v=geqip_0Vjec
There is a another robot swarm project on the go for farming. I'll try find the link but basically, it is a bunch of rovers planting seeds. They work as a team and planting and fertilising the individual seeds. When not much fertiliser is needed, the break apart and do other things. As conditions deteriorate across the field, they change roles and fertilise more.
Still very much a concept and not nearly as productive as Bob driving a tractor but the day is coming when these things will work as massive teams.
Pretty cool but can someone say Skynet?
More from them:
http://www.youtube.com/watch?v=E7X0_6o9J10
http://www.youtube.com/watch?v=geqip_0Vjec
There is a another robot swarm project on the go for farming. I'll try find the link but basically, it is a bunch of rovers planting seeds. They work as a team and planting and fertilising the individual seeds. When not much fertiliser is needed, the break apart and do other things. As conditions deteriorate across the field, they change roles and fertilise more.
Still very much a concept and not nearly as productive as Bob driving a tractor but the day is coming when these things will work as massive teams.
Pretty cool but can someone say Skynet?
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That is amazing . . But . .Crispin said:
How much intelligence is in the 'copter ??
I suspect there is a University 'Cray II' super computer behind it all.
I guess it won't be long before these things can see what's around them and make their own decisions.
Having one fly through a hoop thrown into the air is awesome - but what is tracking the hoop ??
Bob.
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These, AFAIK, were following pre determined routes but....
The onboard computer has a bunch of gutso and certainly can do a lot. As they (mine) stand, it can do lateral object avoidance, sonar for height (below 10m, otherwise gps) etc. Alongside all that, it also has a quick radio link which, on mine is a middle of the range, has a distance of about a mile. Using that, you can have a semi decent computer, for now, doing all the hard work.
They, the open source version available, are already planning the next-of-next version which has a shed load more processing power. Sure, they not about to fly to the moon but it's a pretty slippery slope in what they are able to do
[youtube:3b5bs3xx]A3FyJZbtSBk[/youtube:3b5bs3xx]
The onboard computer has a bunch of gutso and certainly can do a lot. As they (mine) stand, it can do lateral object avoidance, sonar for height (below 10m, otherwise gps) etc. Alongside all that, it also has a quick radio link which, on mine is a middle of the range, has a distance of about a mile. Using that, you can have a semi decent computer, for now, doing all the hard work.
They, the open source version available, are already planning the next-of-next version which has a shed load more processing power. Sure, they not about to fly to the moon but it's a pretty slippery slope in what they are able to do
[youtube:3b5bs3xx]A3FyJZbtSBk[/youtube:3b5bs3xx]
