Just how dangerous is a Drone

[Willie14228]

So I just saw a post that really got a good bit of smoke coming out of my ears,
It was along the lines of how could a little 1.5/ 2 pound drone be dangerous
Here is a great little calculater that can help you find out just how hard your drone can impact an object
ENERGY CALCULATOR
Select the energy button then on the right side of the entry fields you can select the unit type.
To give you a reference point a baseball traveling at 95 MPH will impact an object at about 80 foot pounds of energy,
A 2 pound drone traveling at 30mph will impact an object with 60 foot pounds of energy keep in mind a baseball doesn't have sharp edges, extended legs, whirling props and so on. And that is controlled flight.
What about free fall terminal velocity is 122 MPH now I'm not saying the drone will reach those speeds at a free fall (dead stick) but let's say it can reach 75 mph on a dead stick free fall that means it will impact with over 350 foot pounds of energy (378 fpe)
A 357 caliber pistol shooting a 200 grain slug at 900fps produces 350 foot pounds of energy
Please I beg you NEVER underestimate the power and danger of these devices

 

[pross]

Where are you getting 122kph for terminal velocity from?

Found a calculator online here Free fall with air resistance (time and velocity) Calculator a 2 lb weight dropped at 2000m only reaches 21kph

 

[Willie14228]

If an object was able to free fall with no type or form of drag, resistance it would do so at 122 miles per hour, that being said nothing in the atmosphere can fall without drag/resistance and depending on the height, and shape of the object along with it's orientation those variables will change and therefore the speed will change, as to the rate of the fall of a drone I estimated. With a price sticker of around a grand I will be glad to allow another the honer of testing the math in real life

 

[pross]

Well if you set the air resistance to zero in that equation you get 710kph

 

[Willie14228]

Well if you set the air resistance to zero in that equation you get 710kph

I'm in the U.S so I used MPH not KPH

 

[FormerMember07122019_2]

The rate of fall may be even less if you consider that the center of gravity may be below the propellers and the aircraft would autorotate like a regular helicopter. Now then, If it fell sideways that would be a different story. Of course, I am not going to do any experiments on my drone but if someone had a defective one their willing to donate to science it would be a good experiment to try dropping one.

 

[AMann]

I love the physics of this thread, I copied it and will present it to my 8th grade science students asking them to evaluate it.

 

[Oneball 1971]

Maybe DJI could donate a unit in the name of science.

 

[old man mavic]

anything up in the air from a bird to a large aircraft has the potential to kill or injure someone if it hits them its the laws of physics at play they are all great when they are flying. but if they develop a problem and stop flying gravity takes over. its about managing risk and managing the airspace unfortunately birds are out of our control

 

[Willie14228]

Actually I'm sure they have already done some tests of their own
I don't know but when it comes to free fall I would say the phantom would fall with the most stabilized manner due to it's bottom gimble and shape. The Mavic platform is square and has no real airfoil to speak of I would say it's rate of fall would be greater than the phantoms and like airframe

 

[old man mavic]

So I just saw a post that really got a good bit of smoke coming out of my ears,
It was along the lines of how could a little 1.5/ 2 pound drone be dangerous
Here is a great little calculater that can help you find out just how hard your drone can impact an object
ENERGY CALCULATOR
Select the energy button then on the right side of the entry fields you can select the unit type.
To give you a reference point a baseball traveling at 95 MPH will impact an object at about 80 foot pounds of energy,
A 2 pound drone traveling at 30mph will impact an object with 60 foot pounds of energy keep in mind a baseball doesn't have sharp edges, extended legs, whirling props and so on. And that is controlled flight.
What about free fall terminal velocity is 122 MPH now I'm not saying the drone will reach those speeds at a free fall (dead stick) but let's say it can reach 75 mph on a dead stick free fall that means it will impact with over 350 foot pounds of energy (378 fpe)
A 357 caliber pistol shooting a 200 grain slug at 900fps produces 350 foot pounds of energy
Please I beg you NEVER underestimate the power and danger of these devices

i get the gist of your post they can cause injury or worse if they drop from the sky but they are only as dangerous as the person flying them by the same analogy a baseball bat is not dangerous when used to play baseball but is if used to hit someone with

 

[Willie14228]

i get the gist of your post they can cause injury or worse if they drop from the sky but they are only as dangerous as the person flying them by the same analogy a baseball bat is not dangerous when used to play baseball but is if used to hit someone with

You are absolutely correct it isn't the object but how the object is used (misused) that poses/increases the risk of injury. As an R/C flier I have seen some examples of nasty injuries

 

[Point Zero]

I'm sure there is a website somewhere that lists the greatest killers of human beings on earth and even though I have never seen such a list I would bet my life savings that drones would be somewhere at the very bottom! (well civil and commercial drones that is). I know this assertion will upset a few people on these forums, but thankfully mathematical facts and statistics are undeterred, unaffected and uninterested by cheap unprofessional journalism and those that choose to respond to these reports as if they came from the mouth of God.

DJI Drones are very safe

 

[old man mavic]

I'm sure there is a website somewhere that lists the greatest killers of human beings on earth and even though I have never seen such a list I would bet my life savings that drones would be somewhere at the very bottom! (well civil and commercial drones that is). I know this assertion will upset a few people on these forums, but thankfully mathematical facts and statistics are undeterred, unaffected and uninterested by cheap unprofessional journalism and those that choose to respond to these reports as if they came from the mouth of God.

DJI Drones are very safe

exactly the point i was trying to make the drone itself is not the problem its how its used the media is biased in there reporting we all know that

 

[Point Zero]

We are in complete and utter agreement sir! @old man mavic

 

[Willie14228]

I'm sure there is a website somewhere that lists the greatest killers of human beings on earth and even though I have never seen such a list I would bet my life savings that drones would be somewhere at the very bottom! (well civil and commercial drones that is). I know this assertion will upset a few people on these forums, but thankfully mathematical facts and statistics are undeterred, unaffected and uninterested by cheap unprofessional journalism and those that choose to respond to these reports as if they came from the mouth of God.

DJI Drones are very safe

I don't care what brand or airframe if misused or abused it can become dangerous.
This has NOTHING TO DO WITH journalism but with self regulation if responsible pilots take the time to coach and mentor (as many do here) then there is less risk. Just because media might see a post like this one and try to use it out of context or blow it out of proportion doesn't mean it isn't true.
Yes when properly flown and when properly maintained DJI drones are up in the top ranking in safety. But it is still just a tool at the end of a hand using it what and how that hand uses it is what counts

 

[duhs10]

You are forgetting a major point in your comparison of a drone to a .357 bullet.... and that is the amount of surface area that the force will be spread upon. I'm not arguing that a free falling drone wouldn't cause energy, but your comparison is misleading.

 

[Willie14228]

You are forgetting a major point in your comparison of a drone to a .357 bullet.... and that is the amount of surface area that the force will be spread upon. I'm not arguing that a free falling drone wouldn't cause energy, but your comparison is misleading.

A legit point (pun not intended) I wasn't trying to say a drone was going to shoot a hole in someone though I wouldn't discount the possibility of a shattered arm or some other extension piercing the skin or something.
Most of the trauma would be blunt force and chances are in favor of injury instead of fatility. Those chances move further right if we look at a strike into the windshield of a moving vehicle or worse yet skier and or boat (how many vids have you seen with over water shots) Add the fact that as we all know the sensors REALLY do not like over water flight and for some odd reason we don't breath very well under water the danger slider moves even more to the right
My point of this post is before you try something ask yourself the "what if questions", know and understand the risks and don't let the small size of these drones fool you into thinking they will not hurt someone.
I have over 3 million miles with no accidents or recordable violations as a commercial truck driver. Because every trip every day with every weather condition possible I weighed my options and actions using the "what if" preparation senerio.
The simple fact is it does not matter what a manual or manufacturers statement or a federal guidelines say you and craft can or cannot do. As the Pilot in command you are the final responsible party of that craft. That means that even if a governing body says that this or that can be done it is up to you to decide that it is safely done

 

[kadras]

The FAA has proposed changing the rules for flying over people. The actual Notice of Proposed Rulemaking (NPRM) has not been issued, but they have released a draft, which includes an assessment of the dangers of UAVs hitting people. Here is the link to the proposal. https://www.faa.gov/uas/programs_pa..._NPRM_Operations_of_Small_UAS_Over_People.pdf

The discussion starts on page 56. This statement is from page 73:
The FAA seeks comment on whether establishing an impact kinetic energy threshold and using kinetic energy transferred upon impact is the appropriate method to measure the potential injury a small unmanned aircraft could cause upon impact with a person.

From page 86: Next, the manufacturer would determine the ground impact speed resulting from an unpowered free-fall from the highest altitude the small UAS is capable of attaining at full power.
The FAA formula is shown on page 88.

 

[Slim.slamma]

http://www.assureuas.org/projects/d..._UAS_Ground_Collision_Severity_Evaluation.pdf
Two impact kinetic energy methodologies are presented to provide a risk and scenario based approach to determining kinetic energy thresholds for safe UAS operations. Parachute mitigations and the application of area weighted kinetic energy methodology for two scenarios are presented to outline thresholds for a broader range of vehicle weights to conduct flight over people than is currently possible with the unmitigated vehicle designs currently available. An initial investigation of energy transfer based on crash testing and dynamic modeling was conducted along with finite element analysis for human head and torso impacts. The crash test results and subsequent analysis strongly suggest that RCC-based thresholds are overly conservative because they do not accurately represent the collision dynamics of elastically-deformable sUAS with larger contact areas in comparison to the metallic debris analysis methods for high speed missiles on the national test ranges. Dynamic modeling is necessary to improve the assessment of UAS failure modes and associated impact energy, to establish appropriate standoff distances, to model impact footprints for severity analysis and to conduct probability assessments as part of an applicant’s submission for waiver or certification.


FAA Issues Study on UAS Human Collision Hazards
When the studies were complete, personnel from NASA, the Department of Defense, FAA chief scientists, and other subject matter experts conducted a strenuous peer review of the findings.


Researchers Release Report on Drone Airborne Collisions

http://www.assureuas.org/projects/deliverables/a4/sUAS_vs_Steel_Crash_Test_Dummy_Video.mp4

List of Figures
Figure 1 Gadd Severity Index ................................................................................................................. 25 Figure 2 - Ground Collision Severity Taxonomy Defined for the A4 Task................................................. 31 Figure 3 - Model Outputs Detailing the Collision of a 3 lbs Object with a 6 lbs Object............................. 36 Figure 4 -Model Outputs Detailing a Collision Between a 3 lbs Object and a 200 lbs Object ................... 37 Figure 5 - Low Order Modeling of Impact KE Transfer Based on Vehicle and Body CG Offset.................. 38 Figure 6 - Comparison of Estimated Terminal Velocity for Several Manned Aircraft and UAS Departing Controlled Flight from 400 ft AGL , ......................................................................................................... 47 Figure 7 - Comparison of Estimated Kinetic Energy for Several Manned Aircraft, UAS and UAS Payloads Departing Controlled Flight from 400 ft AGL, ......................................................................................... 48 Figure 8 - Estimated Terminal KE for UAS and Manned Aircraft, ............................................................. 49 Figure 9 - Comparison Between Rotor Rotational KE for UAS and Manned Aircraft Classes., .................. 50 Figure 10 - Injury/Fatality Thresholds from Various Studies ................................................................... 52 Figure 11 - Janser KE Thresholds............................................................................................................ 53 Figure 12 - Example Kill Probability Chart and Feinstein Single-Point KE Values46 ................................... 54 Figure 13 - Probability of Fatality from Debris Impacts for Various Body Parts ....................................... 55 Figure 14 - Probability of Fatality from Debris Impacts for Various Body Positions ................................. 56 Figure 15 - Average Probability of Fatality from Debris Impacts ............................................................. 57 Figure 16 - Janser Standard Man Dimensions and Calculated Projected Areas ....................................... 58 Figure 17 - Top View of Sled Setup for UAS Drop ................................................................................... 70 Figure 18 - Front Left View of Sled Setup (upper left), Vertical Drop Position of Dummy and UAS (upper right), Pendulum Setup for Horizontal Impact Test (lower left), and Dummy and UAS Setup for Angle Impact Test (lower right) ....................................................................................................................... 70 Figure 19 - Example NIAR Test Summary for an Individual Test .............................................................. 72 Figure 20 - Example NIAR Time History for an Individual Test ................................................................ 72 Figure 21 - Analysis of Phantom 3 Resultant Force for Skull Fractures versus Impact KE......................... 80 Figure 22 - Probability of Neck Injury Trends from NIAR Test Data ......................................................... 81 Figure 23 - Resultant Force versus Impact KE for Steel, Wood and Phantom 3 ....................................... 83 Figure 24 - Potential Collisions between UAVs and a Human Head......................................................... 85 Figure 25 - Rotor Speed vs. Rotor Diameter for Multi-Rotor UAS, Compared with APC RPM Curve......... 90 Figure 26 - Rotor Speed vs. Rotor Diameter for Multi-Rotor UAS, Compared with APC RPM Curve......... 91 Figure 27 - Notional injury severity index vs. rotor diameter for reported incidents,,, ............................. 93 Figure 28 – Laceration Testing Setup ..................................................................................................... 94 Figure 29 – Example of Deep Laceration from Propeller Strike............................................................... 94 Figure 30 – Injury Severity vs. Tip Velocity ............................................................................................. 95 Figure 31 - Lacerations on Syndaver Artificial Skin from Multiple Blade Impacts, Both with and without Blade Guards. ........................................................................................................................................ 96 Figure 32 - Laceration length vs impact velocity with and without blade guards .................................... 97 Figure 33 - Rotor Enclosures in Existing Micro UAS, ................................................................................ 98 Figure 34 - Suggested Safety Feature for Toy Rotors .............................................................................. 99 Figure 35 - Probes for determination of IP Code ratings....................................................................... 100 Figure 36 - Example Ballistic Modeling of a Falling Multi-Rotor Aircraft................................................ 101 Figure 37 - Diagram of sUAS Operating in Vicinity of People (Baseball Stadium Example)..................... 102 Figure 38 - Penetration Effects on Type A Roof Structure (per Table 40 definition of roofing types) ..... 109

No need to speculate
KISS