Simulation of 8 lb drone being ingested by a jet engine

Suffice to say it doesn't end well, for drone or engine. Why did the researchers use an 8-lb drone, when the typical drone weighs less than half that?  The researcher responded:

"This is the drone size that one European country has sanctioned for their postal services to deliver packages to high altitudes. The work is not based on any organization’s request. We are able to model a variety of different drone sizes and models. We chose this model as a demonstrator, because it was one of the larger size commercial drones available that is capable of carrying large weights and reaching higher ceilings."

Excerpt from the full story:

...The smart folks at Virginia Tech’s CRASH (Crashworthiness for Aerospace Structures and Hybrids) lab have been working hard to answer these questions. Founded and directed by Professor Javid Bayandor, the team at the CRASH lab’s latest endeavor has been to build simulation models for turbofan engines, drone components, and basically smash them into each other to see what happens. From a Virginia Tech press release,

An 8-pound quadcopter drone can rip apart the fan blades of a 9-foot diameter turbofan engine during take-off in less than 1/200th of a second. The speed of drone debris thrashing about inside the engine could reach speeds 715 miles per hour. Broken blades also would create more fragments as the fan crumbles and warps the engine block housing, contributing to catastrophic engine failure.

So there is little doubt that a drone of this large size would cause catastrophic engine failure. This sort of damage would be consistent with the type of damage that occurs regularly with a ingestion of a large bird. However thanks to FAA standards for aircraft engine design, the failure and detachment of a rotor blade is anticipated, and must be contained within the engine. Failure to contain a blade could obviously lead to other damages, from structural parts, to fuel tanks, electrical controls, or even death or injury. It has happened on older designs, such as Delta 1288, a MD-88 that failed and engine parts entered the passenger compartment, killing 2 (this was a 1963 designed engine).

...

An 8 lb drone is not the type that one would get for Christmas and be used by a younger, less responsible person however. Without crunching the numbers, I suspect a smaller DJI Phantom sized drone at 13″ and 2.6 lbs would be more likely to be the first to actually get ingested into an engine. The Phantom seems to be the ‘go to’ drone for people first entering the hobby, and is most likely to be operated by those without any real knowledge of airspace or air safety.

Our plans are to study a full array of drone sizes, with different materials, weights, and  configurations.

adds Professor Bayandor. Materials is also one of the topics that the CRASH team is studying. Currently, “The drone is composite, but the core is made of denser metal alloys.”. As we know, drones built from carbon fiber and alloys are not the only type we will see. Google has previously demonstrated a delivery drone in a wing form, made primarily from foam.

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However, he adds, “In this early stage of the study, it seems that battery packs and on-board cameras can cause most damage. ”

I posed the question of what materials are likely to cause the most damage to the turbofan engine? Carbon Fiber tubes and plates, aluminum parts such as motor shells, circuit boards, LiPo battery packs? Professor Bayandor reports, “At this point, we are still formalizing our material modeling matrix, but the materials mentioned are among the general candidates considered.”

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Comment by Eric Coronel on April 11, 2016 at 6:36pm

Why not report simulations of the damage caused by UAVs in incremental weights (1, 2, 3, 4, 5 lbs.)? These people have no curiosity.

Comment by Mark Omo on April 11, 2016 at 8:16pm

Eric depending on the accuracy of the simulation it takes significant computing resources, possibly they only got enough supercomputer time for one simulation?

Comment by Monroe King on April 11, 2016 at 9:53pm

When I was in the Navy we learned all about FOD (foreign object damage) a jet can suck up a bolt or nut off the deck of an aircraft carrier and that might be all she wrote for that engine.

It does depend sometimes it might go right threw sometimes well the passage way has a row of rotating vanes and then a row of static blades (stator vanes) and they alternate one after another. There are typically 14-16 give or take rows increasingly smaller (the disk get larger and the blades get shorter in the center forming a cone shape leading into the combustor) the height of the last row is about an inch to 2 inches or so at the end of the compressor stage. It then opens up into the combustor in between the compressor and the power turbine. At that point it goes back down to the inch or 2 and enters the hot power turbine which normally has 2 or more stages of blades and stators. The blades are hollow and the air from the compressor stage is forced threw the power turbine blades for cooling. 

A bird is not that big a deal usually. (flesh and bone) But just one motor from a regular size quadcopter could easily wipe out a jet engine. So the real question is what are those odds? 

The only way to really prove it is to ingest a few quadcopters and quantify the results.

Comment by Monroe King on April 11, 2016 at 10:36pm

Just on the off chance you might watch these video's I'm going to post them. Most people know little or nothing about what really goes on in the aircraft industry and what people have to do every day to insure safe operations of aircraft. It is amazing the work they do to make flying safe for everyone.

If you don't believe a drone can take out an aircraft in a heartbeat watch these 2 videos. Even if a drone strike did not take out an aircraft there would be costly damage to the engine.

I know these are boring to watch but if you care at all about the safety of others or possibly your own family, friends or loved ones you need to know.

Look at the damage one 1/4 inch nut did in one of the videos and how much it cost to repair that damage. In one of the videos a lens flue off a small marker lamp and was ingested. See what that can do.

One of each military and civilian. There are a bunch of FOD videos out there you can check out if you know what your looking for.

 


Developer
Comment by John Arne Birkeland on April 12, 2016 at 6:09am

Nobody in their right mind would argue that ramming a copter trough a turbine is harmless.

On the other hand, what many people get upset about. Is the danger inflation done by media. Making UAV's out to be some kind of heat seeking missile that that will make airplanes crash at any time. But the reality is that on average the danger of bird strike is much, much, much higher. How many birds do you think there are there in the sky, compared to UAV's at any given time? And even so, bird strikes are seen as an acceptable risk.

The real problem are a handful of people INTENTIONALLY ENTERING RESTRICTED AIRSPACE to get footage, in some cases even intentionally placing the UAV in the path of airplanes. But this is a case of criminal behavior done by selfish pricks, and no amount of regulations will prevent stupid from doing stupid things.

Comment by David Drysdale on April 12, 2016 at 7:22am

@John Well put their are lots of things that will take out a plain the real question are what are the odds a drone and plane will occupy the same space at the same time. It has been poste on diy drones before but the number is around 1 in 35 million to 1 and 135 million. There are one death per 10,000 bird strike a year in the USA if I remember correctly and around 10,000 strikes per year. So we have a long time to go yet for the done plane strike death.

Comment by Tony K on April 12, 2016 at 10:06am

oh i miss Darius JAck.... NOT 

Comment by Cala on April 12, 2016 at 10:14am

Irresponsable people are not going to stop with any law, responsable Rc pilots are the only complicated :(

TONYYYY!!!!!!! ........lol

Comment by Mike on April 12, 2016 at 10:34am

Having looked at some of Dr. Byandor's work in some detail, it is apparent that these simulations leave a great deal to be desired. First, the materials being used to represent multicopters have a great deal more steel and non-flexible plastic in them than what is really the case. In addition, the batteries were assumed to be very rigid objects, which Li-Polys are not. In some of his simulations the collision geometry used was physically impossible. In others, he was using over 700mph as the collision speed, failing to indicate that the only time a commercial airliner can get anywhere close to that speed (most can never go that fast) is at altitudes of around 40k ft. Finally, it needs to be said that precisely NONE of the simulations run have, in any way, been validated with real test data of any kind.

I recall one of GE's commercials/ads were touting that a GE-90 swallowed a step ladder whole and kept running. (I suspect while it may have kept running, it was damaged enough to take it out of service until stuff got replaced.) I think the notion that a predominately foam and/or plastic airframe, whether fixed-wing or multicopter, really doing significant damage to a large commercial airliner is laughable. That having been said, what the community as a whole needs actual, physical, testing of sUAS vs. various airplane parts. Problem is, particularly with large commercial airliner engines, is that it would be really, really expensive, particularly if you do end up breaking something.

Unfortunately, pseudo-science like this feeds into the media-hyped "danger of drones" nonsense.

Comment by Tony K on April 12, 2016 at 10:39am

@  Mike i do agree.

I know early days (70's) pratt and whitney engines kept running for 24 hrs on full power with rock and ash thrown at them. I have a very hard time believing that my quad is going to disable a commercial jet engine.. 

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