Drone vs. aircraft wing testing

[laurens23]

If pilots can see with detail, at speeds, drones and birds approaching them from supposedly up to a mile away, why cant they use a little control input to evade it? A leading edge would only have to move a couple of inches above or below a hovering object to avoid puncture?
OR is it that they CANT see what they claim they see, and these events are more like the bugs on the windshield example. You cant have it both ways.

there are a multiple factors to consider here.

let see how much time we have in ideal conditions:
The collision took place at 383km/h (238mph). So one mile gives you 15 seconds. in that time you need to: Look at the area where the drone is, process and identify what you see, determine if it is a risk, determine what action to take, take action, evaluate if the action rescued the risk.

You have to deal with:
Empty_Field_Myopia
Visual_Scanning_Technique

Objects on a collision course are stationary in the field of view of the pilot (they just get larger), making them hard to spot. Moving objects are much easier to see compared to stationary objects, but they are not on a collision course.
Note: This is as seen from the pilots reference frame. In both cases the drone can be stationary or moving with respect to the operator.

With objects this small there is no way to determine if you will hit or miss with several feet, until just moment (1-2sec) before you hit/miss it.

Therefore you would need a significant course or altitude change to get from a high risk of collision to a low risk of collision. moving an inch to avoid a drone might just as well put you in the path of the drone.

Changing course and creating separation takes time (multiple seconds). You need to point the nose a different direction and then travel in that new direction to create distance from your original path.

I fly GA planes. When I see birds I usually have only 2-5 seconds from seeing the bird to passing it. That is not enough time to move enough to make sure I miss them. I will not make evasive manoeuvre. keeping my profile small and be predictable.

 

[Prmath]

there are a multiple factors to consider here.

let see how much time we have in ideal conditions:
The collision took place at 383km/h (238mph). So one mile gives you 15 seconds. in that time you need to: Look at the area where the drone is, process and identify what you see, determine if it is a risk, determine what action to take, take action, evaluate if the action rescued the risk.

You have to deal with:
Empty_Field_Myopia
Visual_Scanning_Technique

Objects on a collision course are stationary in the field of view of the pilot (they just get larger), making them hard to spot. Moving objects are much easier to see compared to stationary objects, but they are not on a collision course.
Note: This is as seen from the pilots reference frame. In both cases the drone can be stationary or moving with respect to the operator.

With objects this small there is no way to determine if you will hit or miss with several feet, until just moment (1-2sec) before you hit/miss it.

Therefore you would need a significant course or altitude change to get from a high risk of collision to a low risk of collision. moving an inch to avoid a drone might just as well put you in the path of the drone.

Changing course and creating separation takes time (multiple seconds). You need to point the nose a different direction and then travel in that new direction to create distance from your original path.

I fly GA planes. When I see birds I usually have only 2-5 seconds from seeing the bird to passing it. That is not enough time to move enough to make sure I miss them. I will not make evasive manoeuvre. keeping my profile small and be predictable.

Large birds hitting an aircraft is Nothing but Bad.........
Ask Sully

 

[FoxhallGH]

Basic Physics guys - opposite and equal actions/reactions. It makes no difference if the drone is hovering and the wing is doing 200 mph - or if the wing was stationery and the drone was fired at it at 200 mph. Impact force is exactly the same, and result is exactly the same. This is the reason why bird-strike tests on aircraft are done by sitting the plane on the tarmac and firing a chicken at it out of a giant BB gun (rather than hanging a chicken on a rope and flying a plane at it!).

 

[Cheech Wizard]

I hate to have to say this, but you are massacring basic physics. It doesn't matter which is moving and which is stationary, because those definitions only apply in the frame of reference of the observer. Imagine, as a simple thought experiment, that you were watching this collision while moving at the same speed as the drone. If all you could see was the drone and the wing then, from your perspective, the drone would be stationary and the wing would be moving. But it wouldn't change the dynamics of the impact.

Better stop now @ac0j , sar104 lives in Los Alamos, I think he might know what he's talking about.

 

[Cheech Wizard]

Large birds hitting an aircraft is Nothing but Bad.........
Ask Sully

ANYTHING hitting an airplane is bad!

 

[Cheech Wizard]

Hey, can we just agree that YOU SHOULD NOT FLY CLOSE TO MANNED AIRCRAFT? If you can't follow the rules get out of the hobby. Or we will have to start reporting you ourselves to save our hobby. Is that what you want? Just grow up and follow the rules.

 

[ac0j]

Basic Physics guys - opposite and equal actions/reactions. It makes no difference if the drone is hovering and the wing is doing 200 mph - or if the wing was stationery and the drone was fired at it at 200 mph. Impact force is exactly the same, and result is exactly the same. This is the reason why bird-strike tests on aircraft are done by sitting the plane on the tarmac and firing a chicken at it out of a giant BB gun (rather than hanging a chicken on a rope and flying a plane at it!).

Basic......
What is also typical, after firing drones at commercial wind screens, and light duty wings, precisely controlled and aimed. They STILL have just caused basically small to medium bird strike damage. BUT, the Physics guys have grant money, so they will keep trying different ways to kill a plane with a drone until they get the catastrophic damage they want us to believe is going to be common.

 

[Cheech Wizard]

Basic......
What is also typical, after firing drones at commercial wind screens, and light duty wings, precisely controlled and aimed. They STILL have just caused basically small to medium bird strike damage. BUT, the Physics guys have grant money, so they will keep trying different ways to kill a plane with a drone until they get the catastrophic damage they want us to believe is going to be common.

And firing laser beams into Pilots eyeballs.

 

[Chip]

Better stop now @ac0j , sar104 lives in Los Alamos, I think he might know what he's talking about.

 

[sar104]

View attachment 52122

Come on - at least get the quote correct: "Autoritätsdusel ist der größte Feind der Wahrheit.", which really means something rather different.

 

[Chip]

 

[Chip]

Come on - at least get the quote correct: "Autoritätsdusel ist der größte Feind der Wahrheit.", which really means something rather different.

I laughed hard when I read this and said to myself that I better stick with quoting Shakespeare or Chaucer from here on out because no way Sar had time to read those guys in school! But, having done a little research, I must respectfully raise a point of order.

I ran your quote through google translate and got "Exhilaration is the greatest enemy of truth." Now, I agree that "exhilaration" is different than "blind faith in authority."

But, I checked wikipedia and found this quote:

"Unthinking respect for authority is the greatest enemy of truth" with this citation:

Albert Einstein, in a letter to Jost Winteler, c.1901. Highfield, Roger; Carter, Paul (1994), "The Delicate Subject", The Private Lives of Albert Einstein (1st United States ed.), St. Martin's Press (Macmillan), pp. 78–79, ISBN 9780312302276, OCLC 29702990, retrieved on August 11, 2012.

So, maybe he said both?

 

[sar104]

I laughed hard when I read this and said to myself that I better stick with quoting Shakespeare or Chaucer from here on out because no way Sar had time to read those guys in school! But, having done a little research, I must respectfully raise a point of order.

I ran your quote through google translate and got "Exhilaration is the greatest enemy of truth." Now, I agree that "exhilaration" is different than "blind faith in authority."

But, I checked wikipedia and found this quote:

"Unthinking respect for authority is the greatest enemy of truth" with this citation:

Albert Einstein, in a letter to Jost Winteler, c.1901. Highfield, Roger; Carter, Paul (1994), "The Delicate Subject", The Private Lives of Albert Einstein (1st United States ed.), St. Martin's Press (Macmillan), pp. 78–79, ISBN 9780312302276, OCLC 29702990, retrieved on August 11, 2012.

So, maybe he said both?

View attachment 52150

It's a translation that's been debated for years. Your citation is correct but the letter was in German and it has been pointed out that the phrase doesn't translate especially easily. The context, from the book, is interesting:

Mileva's pregnancy held Einstein's attention only fleetingly over the following weeks. His main concern was his first direct challenge to the scientific establishment through an attack on Paul Drude, editor of Annalen der Physik. In a long letter, he sent Drude a series of objections to his electron theory of metals (in which thermal and electrical properties are explained in terms of an electron gas). Einstein proudly told Mileva that his points were too straightforward to be refuted. He had come up with a similar theory to Drude's himself, so he felt it quite proper to approach him as an equal and 'point out his mistakes'. Once again, these scientific matters took precedence over the personal. 'Do you still remember how awkward I was the last time?' he asked Mileva. 'But you can bet I didn't write Drude anything about that. How are your studies going, and the child, and your mood? I hope that all three are as well as is to be expected. I'm sending you kisses especially, so you'll never be lacking in good cheer. What the present leaves to be desired will be compensated for in the future — and how.'​

​

Einstein hoped that the brilliance of his letter to Drude might earn him the offer of a job: he made clear in it that he needed one. Instead, Drude's reply dismissed Einstein's objections out of hand. It was no more than a stand-in schoolmaster could expect after taking on one of the scientific giants of his day, but it came as a stinging rebuff to Einstein's pride. Three months earlier he had told Mileva that Drude was without doubt 'a brilliant man'; now he saw him as a 'sad specimen' whose response proved his wretchedness. More than ever he was convinced that the dunces of the world were in confederacy against him. 'It is no wonder that little by little one becomes a misanthrope,' he told Mileva. To Jost Winteler he wrote that he would `make it hot' for Drude by publishing his criticisms in a skilfully humiliating article. 'Unthinking respect for authority is the greatest enemy of truth,' he declared. Einstein's threats ultimately turned out to be empty: he never would publish an attack or cause Drude the least bit of discomfort. In his most revolutionary paper of 1905, on light quanta, Einstein would cite Drude's work in the very first reference without taking a single swipe at his methods. His threats were similar to the theatrical behaviour that Mileva had witnessed before, when he described his confrontations with his mother. However, there was one important consequence of Drude's snub: it threw Einstein into defiance, and he now vowed to marry his pregnant girlfriend at any cost. He told Mileva that he had made an 'irrevocable decision' to accept any job, however modest, and however much at odds with his 'personal vanity' end scientific goals. As soon as he found work, they would marry and set up home together secretly, presenting a fait accompli to their families. 'Then no one can cast a stone upon your dear head,' he told her, 'and woe unto him who dares to set himself against you.' Einstein would later claim that he had married Mileva only out of a sense of duty — but these comments suggest a more passionate commitment than he was ready to admit in old age. After suffering a humiliating reverse, he wanted Mileva at his side in his battle against the philistines.​

 

[Mad Mavic]

I was redirected here as a result from a sarcastic fellow Mississippian, but I suppose that's fodder for another thread.

There seems to be a lot of support for DJI in their attack on the university for the drone/wing impact video. I'm sure the wing of a Mooney was chose over others due in part to cost. For example, the wing cost of a Falcon 50, Hawker, Citation, Embraer, etc. would most likely exceed the universities budget, but probably not fit in the test chamber.

As a general aviation pilot, my take is that most drone pilots don't hold a civilian aviation licence, let alone a commercial, complex aircraft rating. Therefore the average drone pilot doesn't connect with the psychological effects on pilots regarding drone traffic; one of which is the thought of hitting a drone at Vso (stall speed in a landing configuration) at max weight.

Take the drone out of the equation and just consider the mass of a Mavic Pro battery hovering at an altitude that intersects the glide slope/path of an Cessna Citation on final approach; which by the way, at some point, intersects the 400 feet max AGL of drones. A 3 degree glide slope intersets 400 feet AGL approximately 7600 feet from the touchdown point, or beginning of the runway.

A Citation on final approach can be traveling up to but not more than 250 Kias, or 287 miles per hour. You are the PIC and the Mavic battery just pokes a hole in you wing, possibly rupturing the fuel tank, a hydraulic line, goes into one of the fans, or cracks the windshield. The stress load on a pilot increases by a factor of 10 when in the air, just under normal circumstances. Factor in a Mavic battery hitting your aircraft while you are communicating with ATC, scanning your instruments to ensure you are on glide slope ensuring you don't deviate from the runway, or fall below stall speed. Also throw in the other traffic, and a small drone strike suddenly becomes a massive concern.


For reference, aircraft speeds are referenced by their "V" designation. For example, Vne is the "not to exceed" speed of an aircraft if you wish to keep your control surfaces such as flaps, ailerons, and even wings. Vr is the speed at which an aircraft rotates at takeoff, and varies depending on the weight of the aircraft at time of takeoff. This weight is influenced by the amount of fuel in pounds, passengers, cargo, etc. V1 and V2 in particular, are a couple of interesting speeds worth looking up for anyone not familiar.

In summary, the letter from DJI seemed to be more concerned with dollars (yuan) than it did sense. I call bs on the entire article. The university in my view, shows concern for public safety, and wasn't in no way intended to inflict fear on the public.

If the author of the letter is so convinced that the video was ridiculously false, then let's all take our drones and position them in a hover inside the glide slope of his jet as he reevaluates the contents of his current letter. I'm sure he would choose his words more carefully, and his concern for yuan would be minuscule compared to his desire for a parachute.

I love flying my drone, but also acutely aware of potential aircraft in my area and know where they won't fly if at all possible, therefore allowing me on occasion, to fudge on the 400 feet AGl, but never at the expense of endangering an aircraft. But I would never side with the author who wrote the article supporting DJI. it's obvious he is only concerned about revenue, period.

Fly high and fly often

 

[pftarch]

...In summary, the letter from DJI seemed to be more concerned with dollars (yuan) than it did sense. I call bs on the entire article....

It is not a shock to me that DJI is trying to protect their business interests and I agree with most of their response. I do not feel that their response was "bs" at all.

My main issue with the URDI "study" is that it is taking a highly unlikely scenario (lightweight plane traveling at full speed hitting one of DJI's heavier consumer drones at EXACTLY the leading edge of the wing where it could do the most damage) and presenting it to the public without a slew of disclaimers.

DJI's response rightly indicates that at what the FAA considers the maximum legal operating height of drones the Mooney should be going MUCH slower. I'm not saying that it's impossible for either a Mooney to be flying too fast at low altitudes or for a Phantom 2 to be flying too high, I just wish the URDI study would have pointed out that for their test scenario to happen in real life, either the Mooney pilot or the drone operator, or both, would have to be flying recklessly AND be doing so at PRECISELY the right point for a catastrophic impact to have occurred.

As long as we can look at "possible" scenarios let's fire a 5 oz. baseball onto the leading edge of the Mooney at over 200 knots. Then we can title the video "MLB, Major Risk in the Sky?". The plane "could" be flying at 100' AGL at over 200 knots at EXACTLY the same time as a Red Sox slugger smacks the ball way up into the air. Sure, it's unlikely, but shouldn't we let the general public know about ALL the "possible" dangers to manned aviation.

The fact that URDI didn't release the video of what the bird strike did is also telling (and was rightfully pointed out by DJI). They reference it and say it did more (but different) damage, but they failed to show that video. In addition, they were using a fairly small bird, not a goose, or eagle, or vulture, etc. I feel that it is appropriate to show the heavier bird strike damage because it occurs to commercial AND light aircraft on a regular basis, whereas drone to aircraft collisions are EXTREMELY rare AND have, too date, not caused the level of damage indicated in the URDI video. I feel it is important to show the bird strike consequences because it put's the drone damage in perspective. Our hobby is under attack for a wealth of over hyped reasons, and I feel, that the URDI video just throws gas on that fire.

I think that new common sense restrictions on drone flight AND manned flight can reduce the likelihood of a drone to aircraft mid air collision to a near zero probability situation. Keep drones under 400' AGL or nearest structure and keep manned flight above 1000' AGL. Put reasonable restrictions on drone operations near airport approaches (and 3 or 5 mile radiuses are NOT what I consider reasonable restrictions.) It will mean that manned aviation will have to give up being able to fly under 1000' EXCEPT in an emergency or take/off landing scenario, but, it would all but eliminate aircraft drone conflicts.

 

[sar104]

It is not a shock to me that DJI is trying to protect their business interests and I agree with most of their response. I do not feel that their response was "bs" at all.

My main issue with the URDI "study" is that it is taking a highly unlikely scenario (lightweight plane traveling at full speed hitting one of DJI's heavier consumer drones at EXACTLY the leading edge of the wing where it could do the most damage) and presenting it to the public without a slew of disclaimers.

DJI's response rightly indicates that at what the FAA considers the maximum legal operating height of drones the Mooney should be going MUCH slower. I'm not saying that it's impossible for either a Mooney to be flying too fast at low altitudes or for a Phantom 2 to be flying too high, I just wish the URDI study would have pointed out that for their test scenario to happen in real life, either the Mooney pilot or the drone operator, or both, would have to be flying recklessly AND be doing so at PRECISELY the right point for a catastrophic impact to have occurred.

As long as we can look at "possible" scenarios let's fire a 5 oz. baseball onto the leading edge of the Mooney at over 200 knots. Then we can title the video "MLB, Major Risk in the Sky?". The plane "could" be flying at 100' AGL at over 200 knots at EXACTLY the same time as a Red Sox slugger smacks the ball way up into the air. Sure, it's unlikely, but shouldn't we let the general public know about ALL the "possible" dangers to manned aviation.

The fact that URDI didn't release the video of what the bird strike did is also telling (and was rightfully pointed out by DJI). They reference it and say it did more (but different) damage, but they failed to show that video. In addition, they were using a fairly small bird, not a goose, or eagle, or vulture, etc. I feel that it is appropriate to show the heavier bird strike damage because it occurs to commercial AND light aircraft on a regular basis, whereas drone to aircraft collisions are EXTREMELY rare AND have, too date, not caused the level of damage indicated in the URDI video. I feel it is important to show the bird strike consequences because it put's the drone damage in perspective. Our hobby is under attack for a wealth of over hyped reasons, and I feel, that the URDI video just throws gas on that fire.

I think that new common sense restrictions on drone flight AND manned flight can reduce the likelihood of a drone to aircraft mid air collision to a near zero probability situation. Keep drones under 400' AGL or nearest structure and keep manned flight above 1000' AGL. Put reasonable restrictions on drone operations near airport approaches (and 3 or 5 mile radiuses are NOT what I consider reasonable restrictions.) It will mean that manned aviation will have to give up being able to fly under 1000' EXCEPT in an emergency or take/off landing scenario, but, it would all but eliminate aircraft drone conflicts.

They did release the video of the bird strike.

The rest of your criticisms are non sequiturs. They are testing worst-case events, so why on earth would you expect them to test situations that everyone knows will be of less concern? And they are testing consequence, not probability.

Your hobby is not under attack but, if you expect to be allowed to fly wherever you like and get offended if anyone attempts to investigate the possible consequences, I can see why it might feel like that.

 

[pftarch]

They did release the video of the bird strike.........Your hobby is not under attack but, if you expect to be allowed to fly wherever you like and get offended if anyone attempts to investigate the possible consequences, I can see why it might feel like that.

A. They didn’t show the simulated bird strike in the OP, or, more importantly, in the article that DJI responded to. Here it is as still posted on the UDRI site:

Risk in the Sky? : University of Dayton, Ohio

B. Please reread my post and point out where I said anything even CLOSE to “... to be allowed to fly wherever you like .....”

I understand, and am more than willing to abide by, reasonable restrictions on UAS flight and even indicated some suggested restrictions on my post.

Peter T.

 

[ac0j]

They did release the video of the bird strike.

The rest of your criticisms are non sequiturs. They are testing worst-case events, so why on earth would you expect them to test situations that everyone knows will be of less concern? And they are testing consequence, not probability.

Your hobby is not under attack but, if you expect to be allowed to fly wherever you like and get offended if anyone attempts to investigate the possible consequences, I can see why it might feel like that.

AND, their findings were that a drone in a "worst case scenario" does ALMOST as much damage as a Pigeon. it is unfair to NOT make that statement.
If you are a general aviation pilot afraid of drone strikes, give up flying. You have bigger, more deadly and, more common dangers to worry about.
They have fired drones at windscreens, and planes many times. NEVER has it proved more deadly that a bird strike.

 

[sar104]

A. They didn’t show the simulated bird strike in the OP, or, more importantly, in the article that DJI responded to. Here it is as still posted on the UDRI site:

Risk in the Sky? : University of Dayton, Ohio

B. Please reread my post and point out where I said anything even CLOSE to “... to be allowed to fly wherever you like .....”

I understand, and am more than willing to abide by, reasonable restrictions on UAS flight and even indicated some suggested restrictions on my post.

Peter T.

That's pure sophistry. The published it, which you asserted that they did not. Just because someone else linked to an abbreviated video doesn't change it at all.

 

[sar104]

AND, their findings were that a drone in a "worst case scenario" does ALMOST as much damage as a Pigeon. it is unfair to NOT make that statement.
If you are a general aviation pilot afraid of drone strikes, give up flying. You have bigger, more deadly and, more common dangers to worry about.
They have fired drones at windscreens, and planes many times. NEVER has it proved more deadly that a bird strike.

No - they showed that in that scenario the drone caused significantly worse structural damage than the bird simulant.

Who has fired drones at windscreens and planes many times? I know of precisely one such test, and it involved a commercial airliner, not a GA aircraft. Citations please.