Kawasaki Concours Forum
Mish mash => Open Forum => Topic started by: B.D.F. on September 29, 2017, 11:56:25 AM
-
But now they can carry people:
https://www.youtube.com/watch?time_continue=64&v=V3pi4HfQ0Gc (https://www.youtube.com/watch?time_continue=64&v=V3pi4HfQ0Gc)
I betcha' that thing does not autorotate worth a damn, making a 'loss of power' event really exciting.
Brian
-
I can't see any real advantage over a "standard" small helicopter but hey ho :)
Now this on the other hand is well cool ;)
! No longer available (http://www.youtube.com/watch?v=KLgR3Ipo-Ng#)
-
There are some big advantages over a helicopter. One is all the 'ruckus', noise, vibration and the general calamity one is in when flying in a helicopter. Like the old joke goes: helicopters do not fly, they just beat the air into submission and that is more than 1/2 true IMO. Another big advantage is control, multi- rotor but fixed lifting devices are very easy and extremely precise to control. A large rotor and anti- torque (tail) rotor are not.
Of course the other thing is that this vehicle is autonomous. Again, not really feasible with a helicopter but downright easy with a drone (in that configuration).
But I still have my original question: what does that thing do with a partial or more importantly, full loss- of- power? A helicopter auto- rotates all the way back to terra firma, provided the pilot is skilled enough (many are not unfortunately, auto- rotation is an extremely anti- intuitive situation). But those rotors (are they rotors on a drone? Props? Not sure which is right) are not large enough to auto- rotate so either that thing is going to need a ballistic parachute, and that would be problematic what with all those rotors in all directions, or have some kind of plan for bouncing on impact like that Mars probe had.
The last question is one of endurance, as that thing is electric, I just cannot see it having any practical value regarding how far / long it could carry and adult human, never mind cargo. The energy - density of electric powered devices is just not great enough yet and powering 8 or more rotors with an I/C engine is not practical, at least not IMO.
Brian
I can't see any real advantage over a "standard" small helicopter but hey ho :)
Now this on the other hand is well cool ;)
! No longer available (http://www.youtube.com/watch?v=KLgR3Ipo-Ng#)
-
fair points :)
Staying on the electric front, the Airbus E-Fan, 1-1.5 hour flight time
! No longer available (http://www.youtube.com/watch?v=Uoy3Efsxp3o#)
-
This is not really a drone because it carries people.
* An unmanned aircraft or ship that can navigate autonomously, without human control or beyond line of sight.
* Any unmanned aircraft or ship that is guided remotely.
This is just a helicopter with autopilot. Of course, if you omit the people and control it remotely, then it becomes a drone.... but somehow I don't see that as being very useful/practical :)
And that thing, without autogyration, and without lift surfaces for gliding, and without rocket-propelled parachutes, is more of a flying death-trap!
-
I can't see any real advantage over a "standard" small helicopter but hey ho :)
Now this on the other hand is well cool ;)
! No longer available (http://www.youtube.com/watch?v=KLgR3Ipo-Ng#)
BD-5J I once saw a BD-5 (not J) crash because his canopy unlatched on a high speed flyby.
As to reliability of a electric drone vs conventional helicopter. If I were the one certifying it I would want to see the software/lift capability safely land with any 2 motors/props out of action. If it could do that I would say probably more reliable than a conventional helicopter assuming weather in limits. All the complexity is in the software, not so much in the mechanics.
-
Here's a Scottish Drone :D
! No longer available (http://www.youtube.com/watch?v=hGYbnLosrBY#)
-
Like the old joke goes: helicopters do not fly, they just beat the air into submission and that is more than 1/2 true IMO.
Brian
I am pretty sure that the reality of rotary wing flight is that the apparatus is so ugly that the earth repels it. Least ways, that's the way I heard it ... many times.
-
Here's a Scottish Drone :D
! No longer available (http://www.youtube.com/watch?v=hGYbnLosrBY#)
Someone mention, Scotch?
-
Well, I would need a bit more than that, such as 'what happens when all propulsion is lost'. If the answer is 'die', then I think I would pass on the ride. Notice how the gentleman in the test- fly did not get more than about 8 ft. from the ground? That would be a good level I think. :-)
Because thrust is low and weight is critical, I doubt there could be enough redundancy built in to comfort me (and I suspect the FAA); there would have to be at least two, and preferably three or more, redundant power systems, control chains, etc., all of which would put far too much weight into the base aircraft system.
Again, not sure how it all works but I do not believe those 'rotors' can be used in any way without being powered. And in the end, that is the condition that the craft really has to operated w/in IMO, a total power loss situation. But hey, I am ascairt' of gravity so maybe not the best person to comment..... ;D
Brian
BD-5J I once saw a BD-5 (not J) crash because his canopy unlatched on a high speed flyby.
As to reliability of a electric drone vs conventional helicopter. If I were the one certifying it I would want to see the software/lift capability safely land with any 2 motors/props out of action. If it could do that I would say probably more reliable than a conventional helicopter assuming weather in limits. All the complexity is in the software, not so much in the mechanics.
-
This is not really a drone because it carries people.
* An unmanned aircraft or ship that can navigate autonomously, without human control or beyond line of sight.
* Any unmanned aircraft or ship that is guided remotely.
This is just a helicopter with autopilot. Of course, if you omit the people and control it remotely, then it becomes a drone.... but somehow I don't see that as being very useful/practical :)
And that thing, without autogyration, and without lift surfaces for gliding, and without rocket-propelled parachutes, is more of a flying death-trap!
Yeah, I hate the way that people call almost everything that flies a "drone", without knowing what the term really means. Blame this on the "newscasters" who have no clue what they are talking about and only read what some illiterate moron has typed into the Teleprompter. That's why we now say "impact" when we mean "effect", think that any rifle with a pistol grip is an "assault weapon" and anything flying is a "drone" when actually most are human-controlled and therefore an RPV "Remotely Piloted Vehicle".
IF A PRESON IS IN IT AND CONTROLLING IT, IT IS NOT A DRONE.
Oh, and I wouldn't get into that death-trap for all the Oreos in Nebraska.
-
Well, I would need a bit more than that, such as 'what happens when all propulsion is lost'. If the answer is 'die', then I think I would pass on the ride. Notice how the gentleman in the test- fly did not get more than about 8 ft. from the ground? That would be a good level I think. :-)
Because thrust is low and weight is critical, I doubt there could be enough redundancy built in to comfort me (and I suspect the FAA); there would have to be at least two, and preferably three or more, redundant power systems, control chains, etc., all of which would put far too much weight into the base aircraft system.
Again, not sure how it all works but I do not believe those 'rotors' can be used in any way without being powered. And in the end, that is the condition that the craft really has to operated w/in IMO, a total power loss situation. But hey, I am ascairt' of gravity so maybe not the best person to comment..... ;D
Brian
What if (big IF I know) statistics show that chance of total power failure in an electric drone is still less than some other fatal mechanical failure of a conventional helicopter? No doubt a LOT more research and testing needs to be done but I think some day these will be more reliable statistically than a helicopter.
-
What if (big IF I know) statistics show that chance of total power failure in an electric drone is still less than some other fatal mechanical failure of a conventional helicopter? No doubt a LOT more research and testing needs to be done but I think some day these will be more reliable statistically than a helicopter.
If my understanding is correct, "conventional" [long, adjustable prop] helicopters can auto-gyrate and land with power failure because they still have a certain amount of lift, especially if power was lost while moving forward. It might be a rough landing, but not just "fall out of the sky to certain death" like most multi-small-prop drones.
https://en.wikipedia.org/wiki/Autorotation
-
Yes, of course you are right I think, and it is entirely possible that a well designed drone flight system could be statistically less likely to cause a loss- of- life crash than the average helicopter suffering a power loss. While the idea is simple and mechanically it all works fine, statistically helicopters have a nasty crash rate after suffering a loss of power (again, pilot skill and immediate and correct reaction is absolutely critical for a successful, safe landing using auto rotation).
But the emotional response remains; a helicopter has a perfectly sound way of landing without any power at all while a drone in the same state is going to do its impression of a rock. This does not make what you say any less true or correct but it does tug at the ole' fear strings. At least mine. :-) Supposedly, the fear of falling is the only fear a human is born with, all the rest are learned. And I am happy to report my own fear of falling is intact and working great, exactly as my designer intended (whoever or whatever one believes is the 'designer'). :rotflmao:
All of which reminds me of a joke. OFFTOPIC: Two guys, Sam and Larry, run into each other and get to talking. They grew up together and are friends but had not seen each other for a long time, so of course the question of what each of them was doing comes up:
Larry: I am training to be a lion tamer.
Sam: Isn't that really dangerous?
Larry: Na. They give me a chair and a whip to handle the lion.
Sam: What if the lion gets mad and breaks that chair and is not afraid of the whip?
Larry: No problem: they give me a pistol just in case that happens.
Sam: What if that piston don't fire? What then?
Larry: Well, I will just reach down, pick up some $h!t and throw it in the lion's eyes and run out of the training ring.
Sam: What if there ain't no $h!t?
Larry: Oh, there will be $h!t, lordy yes, there will be $h!t!
So maybe that would be how a drone crash with a human inside it would work: there might just be enough $h!t to cushion the landing?
Brian
What if (big IF I know) statistics show that chance of total power failure in an electric drone is still less than some other fatal mechanical failure of a conventional helicopter? No doubt a LOT more research and testing needs to be done but I think some day these will be more reliable statistically than a helicopter.
-
Helicopters can only autorotate within a specific flight envelope. Too low and too slow, nope. And like you pointed out, how good is the pilot at performing that maneuver? You could use a ballistic recovery system (such as the one in a Cirrus SR22) on a multi rotor drone. Much harder to do with one large rotor. You would have to position the entire system above the shaft. But with multi rotor, a parachute system can be positioned between the rotors.
After seeing the degree of control and autonomy for pennies worth of electronics in my DJI Phantom 3 drone, I believe it is just a matter of time before we see people in electric, multi rotor aircraft.
-
Good point about the parachute not working well, if at all, on a conventional helicopter.
As I said, I am quite sure my reservations are emotionally based rather than logically based. Modern jet engines and their control are now so reliable that twin engine aircraft are free to fly over large bodies of water, something that was simply not done earlier. I believe the plane that started this new method was the 777, a relatively new airframe, and it is extremely reliable even with only two engines.
And yep, I too believe we will be seeing drones flying people around soon enough.
Brian
Helicopters can only autorotate within a specific flight envelope. Too low and too slow, nope. And like you pointed out, how good is the pilot at performing that maneuver? You could use a ballistic recovery system (such as the one in a Cirrus SR22) on a multi rotor drone. Much harder to do with one large rotor. You would have to position the entire system above the shaft. But with multi rotor, a parachute system can be positioned between the rotors.
After seeing the degree of control and autonomy for pennies worth of electronics in my DJI Phantom 3 drone, I believe it is just a matter of time before we see people in electric, multi rotor aircraft.
-
Modern jet engines and their control are now so reliable that twin engine aircraft are free to fly over large bodies of water, something that was simply not done earlier. I believe the plane that started this new method was the 777, a relatively new airframe, and it is extremely reliable even with only two engines.
I think part of what makes it possible is first really good engineering to make sure nothing does fail and a huge amount of redundancy (usually triple redundant) to make sure if anything does fail, it can still operate, AND if one engine does fail, it can still perform with only one. It is amazing- they have multiple redundant wiring, optical cables, fuel lines, tanks, batteries, computers, hydraulic lines, pumps, sensors, radios, etc. The real question is would they ever allow a SINGLE engine commercial passenger jet fly like that?
-
To directly answer your question, I sincerely doubt it.
But beyond that, I think it is very doubtful that any aircraft manufacturer and any airline would even entertain such a thing, never mind actually attempt to get it approved and certified.
As I said, it is only quite recently that twin engine aircraft have even been allowed to serve on routes that have substantial amounts of 'no emergency runway available' situations, mostly over water. The Boeing 777 has been the single aircraft that has moved that standard because it is the only large, long distance aircraft with two engines in the first place. They maintain careful records and must maintain a very high percentage of success rate with both engines performing correctly for the entire flight and should that average drop, they could lose certification for that type of flying with that particular aircraft; it is called ETOPS if you want to look it up.
And even then, the aircraft must perform sufficiently with one engine out. This means that while a 747 must perform adequately, when loaded to its max. take- off weight with one engine failing, it must do so with the three remaining engines producing full thrust, or 75% of nominal full power. But the 777 must perform adequately, also when fully loaded, with only one engine or 50% of its nominal full thrust as it only has two engines in the first place so removing one removes a full one- half potential power. A tough situation. Again, look at the engines on a triple- seven, they are the largest jet engines in the world because of that 'engine out' requirement. All other aircraft of a similar or larger size (gross weight) have four engines so removing one does not have nearly the same affect on the plane's performance.
The most reliable device in the world is almost always two devices. Seriously. Nothing even comes close to the reliability of being able to have one of a given device fail and the entire machine continues on safely. This is usually a terrible idea with very small, private twin engine aircraft because they are very underpowered with only one operational engine, and most private pilots do not have the training or <perhaps> as much skill or the reactions as well honed as commercial pilots, but once the air-frame is large enough that it will fly easily with any single engine un-powered, the odds of survival skyrocket. And of course this is not limited to just aircraft: the safest parachute known is two parachutes, the best way to ensure the success of a road vehicle with four wheels is to carry five wheels (and tires of course) and so on. Redundancy is the cornerstone of success whenever it is possible to have it.
Brian
I think part of what makes it possible is first really good engineering to make sure nothing does fail and a huge amount of redundancy (usually triple redundant) to make sure if anything does fail, it can still operate, AND if one engine does fail, it can still perform with only one. It is amazing- they have multiple redundant wiring, optical cables, fuel lines, tanks, batteries, computers, hydraulic lines, pumps, sensors, radios, etc. The real question is would they ever allow a SINGLE engine commercial passenger jet fly like that?
-
Airbus A350
To directly answer your question, I sincerely doubt it.
But beyond that, I think it is very doubtful that any aircraft manufacturer and any airline would even entertain such a thing, never mind actually attempt to get it approved and certified.
As I said, it is only quite recently that twin engine aircraft have even been allowed to serve on routes that have substantial amounts of 'no emergency runway available' situations, mostly over water. The Boeing 777 has been the single aircraft that has moved that standard because it is the only large, long distance aircraft with two engines in the first place. They maintain careful records and must maintain a very high percentage of success rate with both engines performing correctly for the entire flight and should that average drop, they could lose certification for that type of flying with that particular aircraft; it is called ETOPS if you want to look it up.
And even then, the aircraft must perform sufficiently with one engine out. This means that while a 747 must perform adequately, when loaded to its max. take- off weight with one engine failing, it must do so with the three remaining engines producing full thrust, or 75% of nominal full power. But the 777 must perform adequately, also when fully loaded, with only one engine or 50% of its nominal full thrust as it only has two engines in the first place so removing one removes a full one- half potential power. A tough situation. Again, look at the engines on a triple- seven, they are the largest jet engines in the world because of that 'engine out' requirement. All other aircraft of a similar or larger size (gross weight) have four engines so removing one does not have nearly the same affect on the plane's performance.
The most reliable device in the world is almost always two devices. Seriously. Nothing even comes close to the reliability of being able to have one of a given device fail and the entire machine continues on safely. This is usually a terrible idea with very small, private twin engine aircraft because they are very underpowered with only one operational engine, and most private pilots do not have the training or <perhaps> as much skill or the reactions as well honed as commercial pilots, but once the air-frame is large enough that it will fly easily with any single engine un-powered, the odds of survival skyrocket. And of course this is not limited to just aircraft: the safest parachute known is two parachutes, the best way to ensure the success of a road vehicle with four wheels is to carry five wheels (and tires of course) and so on. Redundancy is the cornerstone of success whenever it is possible to have it.
Brian
-
Is not a single engine aircraft, as Max had mentioned.
Or am I not understanding your post??
Brian
Airbus A350
-
Sorry I was picking up on the comments about the Boeing :)
Is not a single engine aircraft, as Max had mentioned.
Or am I not understanding your post??
Brian
-
Well, not sure which one(s) but Boeing is the Co. that produced the first long- range, wide bodied jet. And got approval for ETOPS using a twin engine aircraft. The Scarebus was not operational until much later than the triple- seven. And I believe the 777 is still larger and has the larger engines compared with an A 350.
"If it ain't Boeing, I ain't going!"
;D
Brian
Sorry I was picking up on the comments about the Boeing :)
-
Can I be more specific (it was late last night)
I was specifically correcting this section
"because it is the only large, long distance aircraft with two engines in the first place. "
Panto time
Oh no it isn't :D
Well, not sure which one(s) but Boeing is the Co. that produced the first long- range, wide bodied jet. And got approval for ETOPS using a twin engine aircraft. The Scarebus was not operational until much later than the triple- seven. And I believe the 777 is still larger and has the larger engines compared with an A 350.
"If it ain't Boeing, I ain't going!"
;D
Brian
-
OK, I gotcha'.
What I meant was that the 777 pioneered the big change in ETOPS because it was the only aircraft specifically designed for long distance flights and so when introduced, it was the one used to generate the data and have the rules altered because it was the only one. Now that the rules have been changed, other twin engine aircraft have joined it in long- distance travel when an emergency landing is not possible, including the A 350 you mentioned.
ETOPS is an acronym and it stands for Engines Turn Or Passengers Swim. Or something like that. ;D
And I had to look up 'Panto time'. :o :)
Brian
Can I be more specific (it was late last night)
I was specifically correcting this section
"because it is the only large, long distance aircraft with two engines in the first place. "
Panto time
Oh no it isn't :D
-
Another new one to drop into conversation.
he's behind you !!!
And I had to look up 'Panto time'. :o :)