Is a bird substantial enough to break turbine blades?

[Ricky]

Bertie!

(Or anyone who may want to speculate)

I'm in the last stages of A&P training (already a "P") but I can't
figure out if a big bird would be substantial enough to break
conpressor blades, or interior compressor or turbine blades for that
matter.
I'm guessing the first stage blades would turn the bird into soup. I
also know that first (and second & sometimes later stage) blades are
usually made of much harder material to absorb fod.
I'm also aware that sometimes an abrasive grit is used in turbine &
compressor washes so the blades are understandably very, very tough,
especially with the extreme temps of interior turbine blades.
So, after watching the 757 bird ingestion my college-A&P mind is
trying to figure out exactly what happened, why the turbofan spit fire
and such.
I asked an instructor today & he said the first stage blades likely
will break with a large bird and, of course, cause chaos the rest of
the way through the engine. He also said that small birds can pass
through without even being noticed.
So I'm guessing that exactly what happened is likely up to a wide
range of speculation until you could get into the engine and see but
I'm still curious of ya'll's speculation, too (ya'll's; that's Texan!)

Ricky

[Bertie the Bunyip[_19_]]

Ricky > wrote in news:8e1e5bc2-64ba-4c74-921c-
:

>
> Bertie!
>
> (Or anyone who may want to speculate)
>
> I'm in the last stages of A&P training (already a "P") but I can't
> figure out if a big bird would be substantial enough to break
> conpressor blades, or interior compressor or turbine blades for that
> matter.
> I'm guessing the first stage blades would turn the bird into soup. I
> also know that first (and second & sometimes later stage) blades are
> usually made of much harder material to absorb fod.
> I'm also aware that sometimes an abrasive grit is used in turbine &
> compressor washes so the blades are understandably very, very tough,
> especially with the extreme temps of interior turbine blades.
> So, after watching the 757 bird ingestion my college-A&P mind is
> trying to figure out exactly what happened, why the turbofan spit fire
> and such.
> I asked an instructor today & he said the first stage blades likely
> will break with a large bird and, of course, cause chaos the rest of
> the way through the engine. He also said that small birds can pass
> through without even being noticed.
> So I'm guessing that exactly what happened is likely up to a wide
> range of speculation until you could get into the engine and see but
> I'm still curious of ya'll's speculation, too (ya'll's; that's Texan!)

Yes, he's right. Small ones often go right through. If they go through
the core, you can smell them, in fact. You usually get a small
"whumpfh" as they go through.
I know of a large flock of starlings that stopped a JT8 instantly and
broke it;'s mounts.
A large-ish bird will definitely wreck blades. Probably the first
compressor stages will go and the debris from those will take out th
erest of the compresser and the turbine. I've seen an engine you could
see right through with only shards of the blades left on the spools like
an eaten cob of corn. Actually I've seen a few of these, all JT8s.
I'd say that 757's engine was in the same shape after eating that heron.
the fire spitting is due to an uneven flow through the engine. Since th
ecompresser section was screwed, it would be providing air to the burner
cans erratically and instead of a nice smooth fow, you get a series of
pulses. We usually call them compresser stalls.
The grit they clean the engines with is usually something like walnut
shells, AFAIK, but I'm not an engineer! Your insturctor would know
infinitely more about this stuff than I do.

Bertie

[BT]

dependent on the size or quantity of bird(s)
the first impact can substantially damage the first or second stages.. and
the inlet guide vanes..
damaged blades and vans can then be ingested into the rest of the engine
causing catastrophic failure

ask a few military pilots who have survived it..
and a few you cannot ask because they did not..
BT

"Ricky" > wrote in message
...
>
> Bertie!
>
> (Or anyone who may want to speculate)
>
> I'm in the last stages of A&P training (already a "P") but I can't
> figure out if a big bird would be substantial enough to break
> conpressor blades, or interior compressor or turbine blades for that
> matter.
> I'm guessing the first stage blades would turn the bird into soup. I
> also know that first (and second & sometimes later stage) blades are
> usually made of much harder material to absorb fod.
> I'm also aware that sometimes an abrasive grit is used in turbine &
> compressor washes so the blades are understandably very, very tough,
> especially with the extreme temps of interior turbine blades.
> So, after watching the 757 bird ingestion my college-A&P mind is
> trying to figure out exactly what happened, why the turbofan spit fire
> and such.
> I asked an instructor today & he said the first stage blades likely
> will break with a large bird and, of course, cause chaos the rest of
> the way through the engine. He also said that small birds can pass
> through without even being noticed.
> So I'm guessing that exactly what happened is likely up to a wide
> range of speculation until you could get into the engine and see but
> I'm still curious of ya'll's speculation, too (ya'll's; that's Texan!)
>
> Ricky

[Jim Stewart]

Bertie the Bunyip wrote:
> Ricky > wrote in news:8e1e5bc2-64ba-4c74-921c-
> :
>
>> Bertie!
>>
>> (Or anyone who may want to speculate)
>>
>> I'm in the last stages of A&P training (already a "P") but I can't
>> figure out if a big bird would be substantial enough to break
>> conpressor blades, or interior compressor or turbine blades for that
>> matter.
>> I'm guessing the first stage blades would turn the bird into soup. I
>> also know that first (and second & sometimes later stage) blades are
>> usually made of much harder material to absorb fod.
>> I'm also aware that sometimes an abrasive grit is used in turbine &
>> compressor washes so the blades are understandably very, very tough,
>> especially with the extreme temps of interior turbine blades.
>> So, after watching the 757 bird ingestion my college-A&P mind is
>> trying to figure out exactly what happened, why the turbofan spit fire
>> and such.
>> I asked an instructor today & he said the first stage blades likely
>> will break with a large bird and, of course, cause chaos the rest of
>> the way through the engine. He also said that small birds can pass
>> through without even being noticed.
>> So I'm guessing that exactly what happened is likely up to a wide
>> range of speculation until you could get into the engine and see but
>> I'm still curious of ya'll's speculation, too (ya'll's; that's Texan!)
>
> Yes, he's right. Small ones often go right through. If they go through
> the core, you can smell them,

Wow. Gives a new meaning to "bleed air".

[Bertie the Bunyip[_19_]]

Jim Stewart > wrote in
:

> Bertie the Bunyip wrote:
>> Ricky > wrote in news:8e1e5bc2-64ba-4c74-
921c-
>> :
>>
>>> Bertie!
>>>
>>> (Or anyone who may want to speculate)
>>>
>>> I'm in the last stages of A&P training (already a "P") but I can't
>>> figure out if a big bird would be substantial enough to break
>>> conpressor blades, or interior compressor or turbine blades for that
>>> matter.
>>> I'm guessing the first stage blades would turn the bird into soup. I
>>> also know that first (and second & sometimes later stage) blades are
>>> usually made of much harder material to absorb fod.
>>> I'm also aware that sometimes an abrasive grit is used in turbine &
>>> compressor washes so the blades are understandably very, very tough,
>>> especially with the extreme temps of interior turbine blades.
>>> So, after watching the 757 bird ingestion my college-A&P mind is
>>> trying to figure out exactly what happened, why the turbofan spit
fire
>>> and such.
>>> I asked an instructor today & he said the first stage blades likely
>>> will break with a large bird and, of course, cause chaos the rest of
>>> the way through the engine. He also said that small birds can pass
>>> through without even being noticed.
>>> So I'm guessing that exactly what happened is likely up to a wide
>>> range of speculation until you could get into the engine and see but
>>> I'm still curious of ya'll's speculation, too (ya'll's; that's
Texan!)
>>
>> Yes, he's right. Small ones often go right through. If they go
through
>> the core, you can smell them,
>
> Wow. Gives a new meaning to "bleed air".
>

Yeah, if you passenger a lot it might happen to you at some stage.
you'll hear a whump from the engine and then you'll smell it. It doesn't
smell like christmas turkey, BTW!
99 times out of a hundred, there's no damage whatsoever. a boroscope is
required, though. had one a few weeks ago. We never knew until we did
the walkaround for the next flight and saw blood on the cowling. It went
down the outside ) only through the fan) but we had to have a boroscope
done anyway.
I lost one when I was an FO to a turkey buzzard. The skipper was flying,
the vis was less than 1/8th the temp was about 90, feild elevation was
1500', we had a tailwind, we were at max weight for the runway and we
hit the bird at just below V1 which was about 147knots IIRC. The skip
abandoned and we stopped, right on the end of the runway. The fuse plugs
all went on the taxi in. The engine was wrecked. Another one of our
airplanes lost the same engine under similar conditions on the same
runway a couple of years earlier, and they went, no problem.


Bertie

[Kingfish]

On Jan 8, 2:06*pm, Bertie the Bunyip > wrote:

> I lost one when I was an FO to a turkey buzzard. <snip>
> The skip abandoned and we stopped, right on the end of the runway. The fuse plugs
> all went on the taxi in.

What aircraft was this? How does one taxi with a bunch o' flat tires?

[Bertie the Bunyip[_19_]]

Kingfish > wrote in
:

> On Jan 8, 2:06*pm, Bertie the Bunyip > wrote:
>
>> I lost one when I was an FO to a turkey buzzard. <snip>
>> The skip abandoned and we stopped, right on the end of the runway.
>> The fus
> e plugs
>> all went on the taxi in.
>
> What aircraft was this? How does one taxi with a bunch o' flat tires?
>

737-200 and you don't. Though I have seen it done with a Caravelle and a
looooooot of power.

Bertie

[Ricky]

On Jan 7, 11:20*pm, Bertie the Bunyip > wrote:
> Ricky > wrote in news:8e1e5bc2-64ba-4c74-921c-
> :
>
>
>
>
>
>
>
> > Bertie!
>
> > (Or anyone who may want to speculate)
>
> > I'm in the last stages of A&P training (already a "P") but I can't
> > figure out if a big bird would be substantial enough to break
> > conpressor blades, or interior compressor or turbine blades for that
> > matter.
> > I'm guessing the first stage blades would turn the bird into soup. I
> > also know that first (and second & sometimes later stage) blades are
> > usually made of much harder material to absorb fod.
> > I'm also aware that sometimes an abrasive grit is used in turbine &
> > compressor washes so the blades are understandably very, very tough,
> > especially with the extreme temps of interior turbine blades.
> > So, after watching the 757 bird ingestion my college-A&P mind is
> > trying to figure out exactly what happened, why the turbofan spit fire
> > and such.
> > I asked an instructor today & he said the first stage blades likely
> > will break with a large bird and, of course, cause chaos the rest of
> > the way through the engine. He also said that small birds can pass
> > through without even being noticed.
> > So I'm guessing that exactly what happened is likely up to a wide
> > range of speculation until you could get into the engine and see but
> > I'm still curious of ya'll's speculation, too (ya'll's; that's Texan!)
>
> Yes, he's right. Small ones often go right through. If they go through
> the core, you can smell them, in fact. You usually get a small
> "whumpfh" as they go through.
> I know of a large flock of starlings that stopped a JT8 instantly and
> broke it;'s mounts.
> A large-ish bird will definitely wreck blades. Probably the first
> compressor stages will go and the debris from those will take out th
> erest of the compresser and the turbine. I've seen an engine you could
> see right through with only shards of the blades left on the spools like
> an eaten cob of corn. Actually I've seen a few of these, all JT8s.
> I'd say that 757's engine was in the same shape after eating that heron.
> the fire spitting is due to an uneven flow through the engine. Since th
> ecompresser section was screwed, it would be providing air to the burner
> cans erratically and instead of a nice smooth fow, you get a series of
> pulses. We usually call them compresser stalls.
> The grit they clean the engines with is usually something like walnut
> shells, AFAIK, but I'm not an engineer! Your insturctor would know
> infinitely more about this stuff than I do.
>
> Bertie *- Hide quoted text -
>
> - Show quoted text -

That's it, compressor stall, I shoud've remembered. That explains
(probably) the pulsing thrust & fire, not having a smooth, even
airflow to the burner section (cans). I wonder how much, if any,
thrust was being produced.

Yeah, it's often walnut shells used for the compressor & turbine
washes.

We didn't get to work on any large turbine or turbofan engines in
powerplant training. We overhauled some ancient PT-6s and did a hot
section on a small Allison.

Today (start of new semester & start of airframe training) we began
learning how to drill out rivets. Choosing the right bit for rivet
size, learning the air drill, keeping the bit straight & smooth to not
screw up the hole, the tough part for me was popping the head off! I
kinda got it after about 20 rivets but it's gonna take practice.

I also passed my long-overdue medical Monday, paving the way to get
back in the cockpit soon as I can afford it. Dang, I forgot my wallet
got stolen last year including my certificate. Gotta get with FAA to
get a replacement.

Ricky

[Bertie the Bunyip[_19_]]

Ricky > wrote in news:4653615f-ba61-4373-b7ee-
:
=


>
> That's it, compressor stall, I shoud've remembered. That explains
> (probably) the pulsing thrust & fire, not having a smooth, even
> airflow to the burner section (cans). I wonder how much, if any,
> thrust was being produced.

Probably quite a lot. Doesn't look like they had a lot of rudder in. and
the airplane isn't yawing back and forth with the pulses, so they
probably weren't that fierce.

>
> Yeah, it's often walnut shells used for the compressor & turbine
> washes.
>
> We didn't get to work on any large turbine or turbofan engines in
> powerplant training. We overhauled some ancient PT-6s and did a hot
> section on a small Allison.
>
> Today (start of new semester & start of airframe training) we began
> learning how to drill out rivets. Choosing the right bit for rivet
> size, learning the air drill, keeping the bit straight & smooth to not
> screw up the hole, the tough part for me was popping the head off! I
> kinda got it after about 20 rivets but it's gonna take practice.

Cool. I only make smileys when I try and rivet!
>
> I also passed my long-overdue medical Monday, paving the way to get
> back in the cockpit soon as I can afford it. Dang, I forgot my wallet
> got stolen last year including my certificate. Gotta get with FAA to
> get a replacement.


Yes, you'll need that.

Bertie

[Robert Dorsey]

I have seen many turbofans torn down for bird ingestion but have never
seen a single one with "broken" compressor blades (assume you are
talking axial). They get pretty nicked up on the leading and trailing
edges and a little bent but that Ti is very tough against fracture.
The fan blades can get pretty knicked up also. Those little brittle
bones carry a lot of energy at high velocity. By the time they get to
the turbine wheels there isn't much left to cause damage.
A human ingestion is a different story. That will cause even the very
heavy fan blades to fracture.
Robert



On Mon, 7 Jan 2008 21:11:18 -0800 (PST), Ricky
> wrote:

>
>Bertie!
>
>(Or anyone who may want to speculate)
>
>I'm in the last stages of A&P training (already a "P") but I can't
>figure out if a big bird would be substantial enough to break
>conpressor blades, or interior compressor or turbine blades for that
>matter.
>I'm guessing the first stage blades would turn the bird into soup. I
>also know that first (and second & sometimes later stage) blades are
>usually made of much harder material to absorb fod.
>I'm also aware that sometimes an abrasive grit is used in turbine &
>compressor washes so the blades are understandably very, very tough,
>especially with the extreme temps of interior turbine blades.
>So, after watching the 757 bird ingestion my college-A&P mind is
>trying to figure out exactly what happened, why the turbofan spit fire
>and such.
>I asked an instructor today & he said the first stage blades likely
>will break with a large bird and, of course, cause chaos the rest of
>the way through the engine. He also said that small birds can pass
>through without even being noticed.
>So I'm guessing that exactly what happened is likely up to a wide
>range of speculation until you could get into the engine and see but
>I'm still curious of ya'll's speculation, too (ya'll's; that's Texan!)
>
>Ricky

[Sully]

The crew from the E-8 AWACS that crashed on take off in at Elmendorf
AFB, Anchorage AK had a flock of geese take out their engines killing
the entire crew. Up until then for some reason Elemdorf was
considered a wildlife sanctuary for the most part. After that they
decided to start trying to get rid of the birds on the airfield. I've
also seen some pretty rough looking C-5 engines after getting into
some seagulls but for the most part it depends on the size of the bird
and where it hits on the fan and how much goes through the compressor.

Gary


On Mon, 7 Jan 2008 21:38:54 -0800, "BT" > wrote:

>dependent on the size or quantity of bird(s)
>the first impact can substantially damage the first or second stages.. and
>the inlet guide vanes..
>damaged blades and vans can then be ingested into the rest of the engine
>causing catastrophic failure
>
>ask a few military pilots who have survived it..
>and a few you cannot ask because they did not..
>BT
>
>"Ricky" > wrote in message
...
>>
>> Bertie!
>>
>> (Or anyone who may want to speculate)
>>
>> I'm in the last stages of A&P training (already a "P") but I can't
>> figure out if a big bird would be substantial enough to break
>> conpressor blades, or interior compressor or turbine blades for that
>> matter.
>> I'm guessing the first stage blades would turn the bird into soup. I
>> also know that first (and second & sometimes later stage) blades are
>> usually made of much harder material to absorb fod.
>> I'm also aware that sometimes an abrasive grit is used in turbine &
>> compressor washes so the blades are understandably very, very tough,
>> especially with the extreme temps of interior turbine blades.
>> So, after watching the 757 bird ingestion my college-A&P mind is
>> trying to figure out exactly what happened, why the turbofan spit fire
>> and such.
>> I asked an instructor today & he said the first stage blades likely
>> will break with a large bird and, of course, cause chaos the rest of
>> the way through the engine. He also said that small birds can pass
>> through without even being noticed.
>> So I'm guessing that exactly what happened is likely up to a wide
>> range of speculation until you could get into the engine and see but
>> I'm still curious of ya'll's speculation, too (ya'll's; that's Texan!)
>>
>> Ricky
>