Off Topic, but hardware related.
It's been all over the news about the plane that crashed into a river
in (I think) New York. They said it was caused by birds flying into
the engine. Then they showed a report of the number of bird caused
plane accidents and deaths each year. From 1990 to 2007 there were
almost 80,000 accidents caused by birds. There have been numerous
deaths and millions of dollars of damages.
OK, looking at the engines they showed on tv, I immediately thought
***Why dont they put some sort of screening over the engine***
It would only seem like a couple hundred dollars worth of hardware
cloth would solve the problem. Why dont they think of simple
solutions like this?
I have to imagine it has been thought of. I also have to imagine it has to
be a problem. Air flow over the screen at 600 mph can be a problem.
Resistance and the support needed for the screen would be too. Not to
mention that some stuff that is normally sucked through the engine could
block the screen and cause even bigger problems.
They were also worried about icing and deicing. You'd have to almost put
the deicer directly into the engine itself and that can't be a good
thing. Also, when you look at the forces involved in hitting a large
goose at take off speeds or higher, you run out of materials that make
any sense very quickly.
the incredible vacuum pull of such an engine would require something a LOT
stronger than hardware cloth,and it wuold restrict airflow.
some Soviet fighter jets use doors that close over the normal intakes to
prevent ingesting debris on the runway,and have auxiliary intake doors on
the top of the engine cowling. Mig-29 does this,IIRC.
Except this still would not have worked in this incident,as the geese were
ingested at higher altitudes when the doors would have been open.
When I worked with flight engines at Pratt and Whitney, all flight
engines had anti-icing features built into the blades (some of the
compressor blades were hollow and hot air circulated through them). This
solved the engine icing problem. The icing problem is with the aircraft
We would NEVER put any "thing" in front of the engine for fear of
ingesting the "thing" and destroying the engine. A structure like a
screen and its supports has the potential for completely destroying any
Bird strikes are a very common event, particularly around airports.
Engines are designed to absorb bird strikes and tested against bird
strikes. At Pratt we had a steam powered catapult "chicken gun" which
was used to fire chickens into the inlet of a jet in a test stand. The
chicken was shot in at about 300 mph, and the engine was expected to
keep on running at power. For the design to be certified the engine
model had to pass this test.
I do not recall any requirement for tests with multiple chickens.
In the very early days (say around 1955) the chicken was alive. After
the SPCA etc. threw a hissy fit the test was changed so that the chicken
was killed before being shot into the engine. No one wanted us to scare
the chicken to death.
EJ in NJ
Kurt Ullman wrote:
At Pratt we had a steam powered catapult "chicken gun" which
I believe the do now. Back in the 50's it was as easy to get a live
chicken as a plucked and cleaned one. The live chicken is closer to a
real bird strike than a cleaned one, however, I doubt that the missing
viscera and feathers affects the effects on the engine.
BTW there is a "spec" chicken. IIRC the spec says that the chicken must
be thoroughly thawed, it must hit the engine inlet at or above a certain
velocity, and it must be heavier than a stated minimum weight.
EJ in NJ
The airflow into the intake on a jet engine is significantly higher
than the airspeed of the plane - and when, not if, the metal screen
fractured and went through the jet it will do a LOT more damage than
It doesn't work. When you get metal thick enough and hefty enough to
withstand that mph of wind, it restricts air intake. And then, a full sized
Canadian honker, which I believe these were, could go right through there at
that speed anyway.
I'm sure that they've studied it to death. They have studied much lesser
problems and spent much more on them.
As an aside, propane cannons were being used to scare birds in airports and
berry farms until the tree huggers (and nearby residents) stopped it.
To some poor deluded individuals, geese are more important than humans. And
in many sad cases, they are.
That statement makes no sense at all. Scaring them is far less
inhumane than sucking them into a jet engine. I did not mention this
in my original message but the thought did come to mind about
harming/killing birds in addition to the plane damage and human lives
lost. It's a bad situation all the way, and with all the technology
we have these days, you'd think they would have developed something by
now to keep these birds from getting sucked into the engines.
They sell these whistle devices to put on cars to scare deer away,
isn't there some way to do something like that to get the birds away
from the planes?
I know what propane cannons are, I heard them once, and they are sort
of annoying, but why not just fire them before a plane takes off, and
not all day long.
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