The bird-strike problem

Looking at the story of the downed plane in New York due to bird-strikes, why haven't the aircraft makers come up with a way of stopping solid things from entering the engines yet? Even putting a wire mesh over the front of the engine would be better than nothing surely? A better method maybe to have a elongated air duct section with a sloping mesh just before the engine. When something has been detected to enter the engine and is hanging on the mesh, the main air-duct is shutoff to the engine and a seperate air intake is opened to keep the engine running. Meanwhile, the original intake, now shut off to the engine has a flap which opens sucking everything out the bottom (with the sloping mesh helping everything escape), and once cleared will open back up again and normal operation which contninue.

The only reason I can think of why they don't do this is that the mesh may affect the amount of air that can be taken in by the engine, and have an adverse impact upon aircraft performance. Other than that, I am clueless why they haven't done more to stop things like this happening... Anyone know the real reason?

[edit on 16-1-2009 by tronied]

reply to post by tronied


well they have studied this a lot and i think the current design trend is meant to somewhat prevent this. However i don't buy the official story anyway. It's interesting that you posted your thread at the same moment i did mine where i propose that this incident was a false flag. to many funny things here.

I was thinking this EXACT same thing this morning. A mesh well ahead of the engines to divert birds or other objects from being sucked in. I came to the conclusion that the suction is so great that even if a bird hit the mesh, it would still be sucked into the engine or the mesh itself would create too much drag. But it seems like they could attach something to the sides of the plane to divert the geese and such.

Interesting to read this when I had exactly the same thoughts.

Check it out

[edit on 16-1-2009 by Benevolent Heretic]

I think it might be because a bird hitting the mesh at 500mph (Superbird! ) would just take that into the engine with it, perhaps? After all, if they can smash a thich windscreen, a bit of mesh is going to be no problem.

IMO

1. What will a mesh do? Stop the bird? It'll need to be a damn heavy mesh to stop a 2kg bird travelling at a "net" 200+ mph. Look at these fan blades... they are half wrecked - how heavy do you think a mesh will have to be to stop a bird?




Some Su-27 and MiG-29 variants had wire mesh across the front of the engines, mainly for runway FOD to enable rough field capability, and they retracted in flight IIRC.


2. The mesh will reduce peak engine performance, but may improve performance at angles of attack. It would also probably result in more noise through the wakes impinging on the rotor blades.


3. Having a 2nd inlet is utterly impractical. At take-off, the inlets are too small for optimum performance as it is. The early MiG-29s had a 2nd inlet... it was later scrapped.




Birdstrikes are by-and-by large one off events - airlines are unwilling to sacrifice performance for 99.99999% of the time to guard against the thing that occurs 0.00001% of the time.

I agree with it. Do you make run flat tyres mandatory on all cars to guard against the one in a million time that a blow-out will cause a real risk?

Originally posted by Enigma Publius
However i don't buy the official story anyway. It's interesting that you posted your thread at the same moment i did mine where i propose that this incident was a false flag. to many funny things here.

What?


You don't believe it was a double birdstrike? Despite witnesses clearly indicating that they seen the aircraft fly through a flock of birds?

False Flag? No likely

The engine will show signs of damage. That being said, having had a few birdstikes in the chopter but they involved small birds (pigeons) and the main rotor we still had to land and assess.

These things have a huge amount of kinetic energy on impact.

Mesh would not likely work in these cases as the bird would simply brute force its way through. Any structure robust enough to survive the birdstrike might may the aerodynamics unworkable as well.

Its really easy, kill off the birds around airports.

[edit on 1/16/09 by FredT]

Originally posted by FredT
Its really easy, kill off the birds around airports.

Or more likely, scare them off...


Find out what scares the sh!t out of them (like natural predator noises/scents) and plant artificial versions of it around airports.

If what I've read is right then the jet engines are already built to take a small impact? one quote i read was that they were build to take a strike from a bird weighing 8lb or so? and I'm sure i saw a video a while back showing Roll's Royce testing one of their engines (it had carbon blades iirc?) by firing frozen chickens into it. The problem seems to be when they struck by multiple birds and I'm not sure how you can really keep them away 24/7?

reply to post by solidshot


Great point defending against one bird is one thing but a flock? and I saw that video they also shot it into the windsceeen and when that thing hit it went off like a bomb.

Regarding your avatar, your pet the hairy one in the back wearing the black shirt whats it's name? I dont keep human pets they are nasty smelly moody animals IMHO


[edit on 16-1-2009 by SLAYER69]

There have been tests done with bird impact on the turbine blades. They can withstand a few impacts, but if your talking about a flock of them, well thats another story. And when you get so much crap going into an engine, its gonna flame-out.

Bird vs Jet Engine Super Slow Motion

VIDEO

A mesh would only cause splattered bird to get stuck on the mesh, and then you got a problem with huge chunks possibly getting sucked into the engine along with mesh pieces. Its better to have the turbine blades chop the bird up.


Cheers!!!!

[edit on 16-1-2009 by RFBurns]

What if the mesh comes loose in some way, you'll have planes dropping all over the place. Short of a deflector shield (hurry up Chewie!!), it's just one of the calculated risks involved in flying.

I guess you could strap a mannequin dressed like a drunken hunter on top of all planes, that might work.

Peace

To me it is strange that both engines were out. At least that is what I heard. One bird/engine? Multiple birds? Who knows.

reply to post by FredT


Killing the birds is not an option. Then you will get every animal rights activist group yelling and screaming.

Plus its not a workable idea either 1 or 2 miles away from the airport.

There really isnt any alternative to what airports are already doing to try to keep birds out of the way. This incident with the flock is rare, but it can happen.

What really needs to be done is set up bird watch in and around the airport and coordiante landings and take offs so that the birds are treated just like any other air traffic. It might sound silly, but if there is a flock of birds nearby, having a "hold for flight Geese 45" just may save from an occurance that happend yesterday.



Cheers!!!!

[edit on 16-1-2009 by RFBurns]

I think one of the reasons a mesh-like system is out is ice. In cold weather, they have major issues with planes icing up. Imagine if there was a mesh surface right in front of the engine that could get iced up. You either gets chunks of ice flying into the engine regularly or it freezes over completely and kills the engine.

Originally posted by BlackProjects
To me it is strange that both engines were out. At least that is what I heard. One bird/engine? Multiple birds? Who knows.

Its not strange at all - from various reports I have read, it was thought to be a flock of geese, which could be as many as 30 or 40 birds. Big, heavy birds.

Well done to the pilot!

Ah, ok... I see why some mesh would be a bad idea now. Its also probably worth keeping in mind that on most occasions, a single birdstrike to a single engine wouldn't prove as problematic, as they can fly and land on a single engine, it was just bad luck that it happened to them both.

They have directed sound weapons now right??? so why not create a beam of sound inforunt of the airplane or out to the side in a spectrum.

These sound beams may deture bird from a path directly into the engine... or it would just keep them away from the airports...

When I heard about this, and the news said they hit a flock of geese, I for one felt bad for the geese. Canadian geese for example are very emotional, tightly bonded creatures. They take family ties seriously. That must have caused some serious grief for some survivors of the flock that got hit.

Originally posted by Wertdagf
They have directed sound weapons now right??? so why not create a beam of sound inforunt of the airplane or out to the side in a spectrum.

These sound beams may deture bird from a path directly into the engine... or it would just keep them away from the airports...

Are you familiar with the typical dB level of a jet engine at idle much less one that is at near 100 percent throttle after take off??

A sound beam wont do any good in this case. It would have to be at a decible level so high, that it would end up killing the birds rather than scare them out of the way, and would be in the ultrasonic range, again causing far more worse to happen than help. Certian decible levels of ultrasonic sound can kill animals and birds, even human beings.



Cheers!!!!