Is this FOD bad?
08-26-2012, 03:11 PM
#1
Is this FOD bad?
Here are the pics, my new rabbit. Decided to check it out and noticed it has some small nicks, and there is some slight scoring around the compressor. Is this normal or is something else going on? I recently sent in another turbine that had way more fod due to grass and dirt getting sucked up in it over 40 flights during this drought we have over here. So decided to check out the rabbit to see how it looked after 3 runs and almost cried when I saw the nicks and rubs.
Is it normal to get some nicks, have some rub marks, some scoring etc.. if flying off grass or using jets that have a low intake on ashpalt?
I flew this one on asphalt but its a newer runway and is very "gritty".
Let me know if I should send this in
Also, is fllying off dirt/grass runways bad? Normally we have nice grass runways but due to the rought lots of stuff getting sucked up, dead grass flakes, dirt. Seems these things are very fragiile.
1st and 2nd pic, 3 nicks on a blade, 3rd pic is of the rubbing, 4th pic blade at 6 o clock
Is it normal to get some nicks, have some rub marks, some scoring etc.. if flying off grass or using jets that have a low intake on ashpalt?
I flew this one on asphalt but its a newer runway and is very "gritty".
Let me know if I should send this in
Also, is fllying off dirt/grass runways bad? Normally we have nice grass runways but due to the rought lots of stuff getting sucked up, dead grass flakes, dirt. Seems these things are very fragiile.
1st and 2nd pic, 3 nicks on a blade, 3rd pic is of the rubbing, 4th pic blade at 6 o clock
08-26-2012, 03:30 PM
#2
RE: Is this FOD bad?
Well any damage can cause balance issues and for the turbine to become less efficient, do you run a FOD screen? anything running through a turbine over time will can cause damage, dirt, dust or even grass can wear on the blades.
08-26-2012, 04:53 PM
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RE: Is this FOD bad?
Seen much worse and no broblems!
Remember inlet gas flow is better interrupted, it shouldn't be
Shinny!
These engines can take allot more damage than you think!
Vince is correct no vibration, no problem!
In his opinion and my own. : )
Remember inlet gas flow is better interrupted, it shouldn't be
Shinny!
These engines can take allot more damage than you think!
Vince is correct no vibration, no problem!
In his opinion and my own. : )
08-26-2012, 05:44 PM
#10
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RE: Is this FOD bad?
just a little info
i have had all j central engines and have never run them without screen
i had 2 run offs into grassy areas at end of asphalt runway f16 with rhino
1st time nose gear did not collapse and didnt think much of it
2nd time nose did collapse in grass and i did immediate shut down
long story short the finest granules of dirt did end up causing bearings to start grinding on next few flights
immediately had a 3 day turnaround with kerry at jet central usa in PA he is very efficient pay close attention to the engine spool up and spool down and listen carefully if there is a difference
grindage >>
thnks
i have had all j central engines and have never run them without screen
i had 2 run offs into grassy areas at end of asphalt runway f16 with rhino
1st time nose gear did not collapse and didnt think much of it
2nd time nose did collapse in grass and i did immediate shut down
long story short the finest granules of dirt did end up causing bearings to start grinding on next few flights
immediately had a 3 day turnaround with kerry at jet central usa in PA he is very efficient pay close attention to the engine spool up and spool down and listen carefully if there is a difference
grindage >>
thnks
08-26-2012, 07:17 PM
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RE: Is this FOD bad?
i thought mine was fine after blowing out entire aircraft with compressor
it was about 2 flights after grass runnoff and the grinding started
both bearings needed immediate attention
kerry at j central PA said it was the finest dirt he had ever seen affecting the bearings
i am i guess anal and i sent it in after i heard the grinding
yes i could of flown more and caused more damage or even a seisure
but its better to have it checked out for small fee or get in to trouble and get a higher bill to fix
just some advice
it was about 2 flights after grass runnoff and the grinding started
both bearings needed immediate attention
kerry at j central PA said it was the finest dirt he had ever seen affecting the bearings
i am i guess anal and i sent it in after i heard the grinding
yes i could of flown more and caused more damage or even a seisure
but its better to have it checked out for small fee or get in to trouble and get a higher bill to fix
just some advice
08-26-2012, 08:23 PM
#14
RE: Is this FOD bad?
Like most of the guys are saying here, not to worry or loose any sleep on that ( is my opinion ), you also have to listent to the othe litle guy sitting on your left shoulder and I believe you are because you are asking the questions here, if you are still thinking about it, like gtoro26 is saying send it in for a check up and get your sanity back [:@]
I also have a question ( more like two
), since you said you fly out of grass, is this going to happen again soon? and what could you do to prevent it from happening again?
just food for thought.
I also have a question ( more like two
), since you said you fly out of grass, is this going to happen again soon? and what could you do to prevent it from happening again?just food for thought.
08-26-2012, 08:31 PM
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RE: Is this FOD bad?
yes i also agree i have a few friends who's home field is asphalt
and due to going to a couple local shows nearby on grass or manicured grass
same issues did arise.
kerry did specify that there is no way even with a fod screen to avoid this
the grains of sand are so thin that entry thru screen to engine is almost inevitable
good luck be safe
08-27-2012, 04:19 AM
#16
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RE: Is this FOD bad?
I've become very cautious about flying off grass fields, especially ones that aren't manicured.
Last summer I flew my F-16 off a grass field and ingested a dirt clod right at take-off. The jet lumbered into the air at reduced power and I expected it to fall out of the sky at any time. I nursed it through the first turn and the power thankfully came back on the downwind leg. Later, I removed the FOD screen and found the intake caked with dirt (see picture below). I sent the turbine to JetCat. They cleaned it and replaced the bearings. Bob Wilcox said that if I hadn't sent it in, I probably would have suffered a catastrophic bearing failure very soon.
On the same field, a friend of mine flew his Jet Legend Tutor. During the climb-out, the engine power suddenly fell off, and he essentially had no power for a few seconds until the engine spooled back up. After the flight, we noticed that his FOD screen was covered with dandelions. Evidently the jet had rolled through a patch of dandelions on the take-off roll, and for a few seconds, the reduced air flow going to the turbine almost shut it down. Like me, he was lucky to have an airplane left.
I still fly off grass fields occasionally, but before I do, I ask myself these questions:
1) What is the quality of the grass? Is it short and smooth or long and clumpy? Are there dandelions or grass clippings on the surface that could get sucked in to the turbine?
2) Where are the air intakes on my jet? The low air intake on an F-16 means it will suck up just about anything in its path. Jets with side intakes offer a little more protection, but not a lot. My BVM BobCat, on the other hand, is less likely to suck things up because the turbine sits on top of the fuse and is mostly protected from stuff underneath the jet.
3) Is flying here worth the potential damage to my turbine or worse, the loss of a jet?
Not saying don't fly off of grass. Just be aware of the dangers and be smart about where you choose to fly.
Last summer I flew my F-16 off a grass field and ingested a dirt clod right at take-off. The jet lumbered into the air at reduced power and I expected it to fall out of the sky at any time. I nursed it through the first turn and the power thankfully came back on the downwind leg. Later, I removed the FOD screen and found the intake caked with dirt (see picture below). I sent the turbine to JetCat. They cleaned it and replaced the bearings. Bob Wilcox said that if I hadn't sent it in, I probably would have suffered a catastrophic bearing failure very soon.
On the same field, a friend of mine flew his Jet Legend Tutor. During the climb-out, the engine power suddenly fell off, and he essentially had no power for a few seconds until the engine spooled back up. After the flight, we noticed that his FOD screen was covered with dandelions. Evidently the jet had rolled through a patch of dandelions on the take-off roll, and for a few seconds, the reduced air flow going to the turbine almost shut it down. Like me, he was lucky to have an airplane left.
I still fly off grass fields occasionally, but before I do, I ask myself these questions:
1) What is the quality of the grass? Is it short and smooth or long and clumpy? Are there dandelions or grass clippings on the surface that could get sucked in to the turbine?
2) Where are the air intakes on my jet? The low air intake on an F-16 means it will suck up just about anything in its path. Jets with side intakes offer a little more protection, but not a lot. My BVM BobCat, on the other hand, is less likely to suck things up because the turbine sits on top of the fuse and is mostly protected from stuff underneath the jet.
3) Is flying here worth the potential damage to my turbine or worse, the loss of a jet?
Not saying don't fly off of grass. Just be aware of the dangers and be smart about where you choose to fly.
08-27-2012, 06:25 AM
#17
RE: Is this FOD bad?
Thanks guys for the responses, I will listen for changes in sound on the rabbit. I didnt think it looked to bad but needed some input.
As for my other turbine, a few hundred bucks later she's got a new compressor and ready to go!
I know one of the main reason my other turbine got beat up so bad is that there is a hatch on the bottom of the jet where the turbine installs that is very flimsy, the just acts like a vacuum across the runway. ALso, I had the front gear give out a couple of times and the wheel well is open inside the fuse, so a double whammy!
So I know what I need to do but I was shocked that grass and dirt that can get through the FOD screen could beat up the compressor like that.
I really think it is due to this drought, the grass is dead (not dormant) so it flakes up, and the dirt is exposed.
As for my other turbine, a few hundred bucks later she's got a new compressor and ready to go!
I know one of the main reason my other turbine got beat up so bad is that there is a hatch on the bottom of the jet where the turbine installs that is very flimsy, the just acts like a vacuum across the runway. ALso, I had the front gear give out a couple of times and the wheel well is open inside the fuse, so a double whammy!
So I know what I need to do but I was shocked that grass and dirt that can get through the FOD screen could beat up the compressor like that.
I really think it is due to this drought, the grass is dead (not dormant) so it flakes up, and the dirt is exposed.
08-27-2012, 07:04 AM
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RE: Is this FOD bad?
This is just a hint that I found worked quite well!
If you use an air line to blow dirt out of a turbine, you will more than definitely push in deeper!
It may be out sight but hanging around!
A simple cleaning tool that I made out of an old aerosol lid/cap,
These will normally fit over the exhaust outlet, I just cut a hole in the top of it the same size as my vacuum cleaner nozzle.
With this placed over the exit of the turbine, turn the cleaner on and the lose stuff gets drawn out of the engine and not forced in!
I have made one to go over the inlet out of plastic card made into a cone, this version fits over the starter as well!
JT
If you use an air line to blow dirt out of a turbine, you will more than definitely push in deeper!
It may be out sight but hanging around!
A simple cleaning tool that I made out of an old aerosol lid/cap,
These will normally fit over the exhaust outlet, I just cut a hole in the top of it the same size as my vacuum cleaner nozzle.
With this placed over the exit of the turbine, turn the cleaner on and the lose stuff gets drawn out of the engine and not forced in!
I have made one to go over the inlet out of plastic card made into a cone, this version fits over the starter as well!
JT
08-27-2012, 01:51 PM
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RE: Is this FOD bad?
Not back in the UK yet but I should be able to post some pictures of an AMT Mercury I'm rebuilding at the moment, it will give you a better idea as the intakes are anodised! This makes any rubbings or FOD show up more! Noisy bearings will always mean an engine strip, a good Hoover out is something I do just when removing an engine for what ever reason!
JT
JT
08-27-2012, 02:35 PM
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RE: Is this FOD bad?
it is normal to have machined like markings on your blades on shaft directly behind starter motor
these are placed in specific areas to complete balancing process
these are placed in specific areas to complete balancing process
