Jet-engine Bird Strike Protection

[drshi]

Every time I see news of a bird killing a jet engine I immediately wonder why some sort of screen cannot be placed over its inlet to either catch the bird or at least dice it into small pieces. Why is this not possible?

 

[SteamKing]

Because the screen would probably be sucked into the engine along with the bird after the strike, causing even more damage to the engine. Also, the presence of the screen would disrupt and reduce airflow into the compressor, making the engine less efficient.

 

[drshi]

Because the screen would probably be sucked into the engine along with the bird after the strike, causing even more damage to the engine. Also, the presence of the screen would disrupt and reduce airflow into the compressor, making the engine less efficient.

Surely a screen could be made to withstand the impact of a bird at the low altitude and reduced speed where such impacts occur, no? Also, the intake could be widened to compensate for the reduced air flow; or the front of the engine could be lengthened so a retractable screen could be used during takeoffs and landings. Seems to me that some such possibility would at least be the object of continuing research, but I can find no mention of this anywhere. The best they seem to come up with is akin to firing cannons to scare away nearby birds, which is 19th Century science. What aerospace engineer would be content with the knowledge that a BIRD can bring down a giant jetliner and kill hundreds of people? I'd dedicate my career to eliminating such a horrendous bug ... er ... fowl up.

 

[D H]

Surely a screen could be made to withstand the impact of a bird at the low altitude and reduced speed where such impacts occur, no?

No.

This suggestion naively comes up all the time from people outside the aviation industry. People who work in the aviation industry are not stupid. Don't you think someone would have already investigated this solution? That it isn't used doesn't mean they haven't thought of this. It means that they have thought of it and it can't work.

 

[drshi]

I, too, am not stupid. I have researched your claim and can find no indication that any such "investigation" has been conducted by the aviation industry or the FAA. Your certainty must mean that you are aware of such studies, so I would greatly appreciate any references you can offer to support this. Merely "thinking about" solutions does not constitute research. Were the Defense Department to insist that the industry solve this problem, how much do you want to bet that it would be solved?

 

[berkeman]

I, too, am not stupid. I have researched your claim and can find no indication that any such "investigation" has been conducted by the aviation industry or the FAA. Your certainty must mean that you are aware of such studies, so I would greatly appreciate any references you can offer to support this. Merely "thinking about" solutions does not constitute research. Were the Defense Department to insist that the industry solve this problem, how much do you want to bet that it would be solved?

Google is our friend. I googled Bird Strike Jet Engine Damage Prevention, and got lots of good hits. Here's the first one off the list, to a paper from Boeing:

http://www.boeing.com/commercial/aeromagazine/articles/2011_q3/4/

 

[drshi]

Thanks for the effort. Though the reference you've provided contains a great deal of information about this problem, there is no mention whatsoever of any effort to prevent such strikes. I have a research program that scans scores of Google-type sites, and I used this earlier; but I passed up one because it was merely a forum, and this time I looked at it and found a wealth of info even including a photo of an actual screen tested by Pratt and Whitney on an F-119 engine. This source alone turns out to reference everything that's been done in an attempt to solve this problem, so thanks for inspiring me to take another look at my research. Here's the site:

http://www.airliners.net/aviation-forums/tech_ops/read.main/331717/1/

Gratefully,
Rob

 

[AlephZero]

I have researched your claim and can find no indication that any such "investigation" has been conducted by the aviation industry or the FAA.

Without wanting to sound offensive, the reason is that the amount of "investigation" to show your idea is completely unworkable is so small it's not worth publishing.

To quote from the Boeing reference:

A 12-pound Canada goose struck by a 150-mph airplane at liftoff generates the kinetic energy of a 1,000-pound weight dropped from a height of 10 feet.

If you want to design a "screen" that would stop that, and sill let the air through, feel free to try. Engineers who work in the industry have better things to do with their time.

What aerospace engineer would be content with the knowledge that a BIRD can bring down a giant jetliner and kill hundreds of people?

That is hysteria, not engineering. As the Boeing link says, the number of people killed by birdstrike incidents is of the order of 10 a year. That's not exactly a large proportion of the total deaths in aviation accidents - about 1500 per year in the US alone, not counting the rest of the world. And in most years, all of those US deaths were "general aviation" accidents, not paying customers on commercial flights.

 

[AlephZero]

but I passed up one because it was merely a forum, and this time I looked at it and found a wealth of info even including a photo of an actual screen tested by Pratt and Whitney on an F-119 engine.

That sort of "screen" has nothing to do with birdstrike protection. It's just a bit of chicken wire (almost literally) to stop any bits of of light debris that come loose in the test cell from getting into the engine.

 

[SteamKing]

I don't get this prejudice against using technology because it might have come from the 19th century or whatever. We still use wheels, levers, gears, etc. How old are these technologies? I mean, they call a superfluous endeavor 're-inventing the wheel' for a reason.

 

[drshi]

I've had enough holier-than-thou condescension from you people. I'm switching over to the airlines.net forums where people are willing to actually discuss problems rather than make excuses why they won't. Hasta la vista, Babies.

 

[SteamKing]

Adios, muchacho!

 

[berkeman]

I've had enough holier-than-thou condescension from you people. I'm switching over to the airlines.net forums where people are willing to actually discuss problems rather than make excuses why they won't. Hasta la vista, Babies.

Hopefully a great invention will come out of that discussion.

 

[jarcentales1]

I wonder if the guy who thought of putting a screen in front of an engine inlet has ever been near an aircraft engine before or knows what 70,000 pounds of thrust can do on the inlet side.

And besides, bird strikes not only a problem to the engine itself but to other flight components like say, a wing or the empennage. And besides, if you lose one engine, you still have the other to depend on (or the other three on a 747 or an A380) even though your thrust output has significantly decreased. Much more dangerous to land, yes, but your odds of maintaining flight and landing are much more higher than if you lose a flight component.

Now, if you lose an aileron or any other flight component, that's a different story...

 

[SteamKing]

That's why they shoot frozen chicken carcasses at the cockpit windows to simulate a bird strike. If a strike were to seriously injure the pilots, that means big trouble for the plane.

 

[SteamKing]

Hopefully a great invention will come out of that discussion.

I can see it now. A flying Bird-o-Matic!. It slices up the bird as it goes into the engine, the compressor strips off the feathers, the carcass strips are lightly roasted as the bird passes thru the combustion section, and a scoop out the back delivers a hot, freshly prepared meal to the passengers in the cabin.

 

[jarcentales1]

That's why they shoot frozen chicken carcasses at the cockpit windows to simulate a bird strike. If a strike were to seriously injure the pilots, that means big trouble for the plane.

Uh, you do realize the cabin, including the cockpit, is pressurized, right? Opening that window is asking for major trouble.

And besides, the AFS is what's flying the plane and the ILS is what lands the plane.

 

[256bits]

Uh, you do realize the cabin, including the cockpit, is pressurized, right? Opening that window is asking for major trouble.

Are you certain about that.
Ask a pilot.

 

[SteamKing]

Uh, you do realize the cabin, including the cockpit, is pressurized, right? Opening that window is asking for major trouble.

And besides, the AFS is what's flying the plane and the ILS is what lands the plane.

Congratulations, or condolences, you are immune to sarcasm.