sprout5199
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Engine Tests

Thu Jul 17, 2008 1:52 am

Saw this on youtube, and wondered if any of you had any good stories when doing tests:

http://www.youtube.com/watch?v=T4bn1WG5LS0

Dan in Jupiter

Edit: How do you make the video play here in the thread?

[Edited 2008-07-16 18:53:29]
 
tdscanuck
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RE: Engine Tests

Thu Jul 17, 2008 2:37 am



Quoting Sprout5199 (Thread starter):
Saw this on youtube

Well that's just cool! Hope nobody was hurt.

Quoting Sprout5199 (Thread starter):
Edit: How do you make the video play here in the thread?

On the top right of each YouTube page (where the author and description are) is a field called "Embed". Copy and paste this HTML into your post.

Tom.
 
gocaps16
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RE: Engine Tests

Thu Jul 17, 2008 9:36 am

Wow, that thing shot like a slingshot. Good thing nobody was hurt, or at least I hope not.

I've actually troubleshoot engines in the cell when I was deployed. Luckily, our only incident was just a fire on the augmentor section on a tomcat engine and had a hot and wet start and flames shot out of the burner section causing flames to erupt on the fuel nozzles. The person controlling the engine let the engine windmill and the flames were out. I had the fire bottle ready to go outside out of the ship in case if the flames didn't go out. Other then that, we always made sure everything was secured before we light off.
 
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jetmech
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RE: Engine Tests

Thu Jul 17, 2008 9:41 am



Quoting Sprout5199 (Thread starter):

Here's a good video of a 763 / CF6-80C2B6 doing a take off power run. Nothing too spectacular, but interesting nonetheless. The second video is of a 737 / CFM-56 engine run after an engine change. I believe the fire is from the fuel system preservative fluid burning off.

Quoting Sprout5199 (Thread starter):
wondered if any of you had any good stories when doing tests:

Nothing too exciting, but I do remember spending smoko one night shift listening to our colleagues repeatedly take a RB-211 to high power. The interesting aspect was how many times they almost surged the engine, and the awesome chuffing noise it made! We waited with bated breath to hear the tinkle of titanium upon the tarmac.

A colleague of mine once stood in the test cell as a JT3D was taken up to full power. Apparently, he could fell his entire chest cavity reverberating. Incidentally, you can see the exhaust stack mufflers of the JT3 test cell in the background of the first video.





Regards, JetMech
JetMech split the back of his pants. He can feel the wind in his hair :shock: .
 
Nicoeddf
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RE: Engine Tests

Thu Jul 17, 2008 10:32 am



Quoting JetMech (Reply 3):
The second video is of a 737 / CFM-56 engine run after an engine change. I believe the fire is from the fuel system preservative fluid burning off.

Is the burning not a problem for the wing and the surrounding structure?
 
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jetmech
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RE: Engine Tests

Fri Jul 18, 2008 8:31 am



Quoting NicoEDDF (Reply 4):

Possibly. I'm not too sure how much hotter a naked flame is compared with the heat contained in the exhaust under normal operations. I suspect that the duration of naked flame is short enough to not be of real concern.

Regards, JetMech
JetMech split the back of his pants. He can feel the wind in his hair :shock: .
 
Nicoeddf
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RE: Engine Tests

Fri Jul 18, 2008 11:25 am

With the EGT at roughly 700-800°C (correct?) I think the naked flame must be hotter, no? Not sure though.

But did I understand it correctly that the burning out as seen in the video is some kind of normal procedure or am I way off?
 
boeing767mech
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RE: Engine Tests

Fri Jul 18, 2008 12:29 pm

I was on the porch of a DC-10 doing leak checks on a #2 engine and got a sunburn because the Moron in cockpit was to good to follow the checklist. Nothing like pushing in the ignition circuit breakers after wet motoring the engine for 2 minutes. Was kind of like the 737 video posted in this thread.

David
Never under-estimate the predictably of stupidty
 
ex52tech
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RE: Engine Tests

Sat Jul 19, 2008 6:43 pm



Quoting JetMech (Reply 3):
A colleague of mine once stood in the test cell as a JT3D was taken up to full power. Apparently, he could fell his entire chest cavity reverberating. Incidentally, you can see the exhaust stack mufflers of the JT3 test cell in the background of the first video.

Our new, test cell at the base I was stationed at was an open concrete block building, with the test stand attached to the floor by the back door. We ran J-57s (JT3Cs) and TF-33s (JT3Ds) in there. The noise would cause the building to set up a harmonic vibration that could be heard above the noise of the engine running at full power. You could hear the test cell building noise at the main gate of the base over three miles away, and the engine noise was just a rumble. The bad thing was that the base horse stable and pasture was right behind the blast fence for the test cell. Those horses had to be deaf as a post.

That noise would go right through you, you could feel it, it was unnerving. We would switch off being the ground man in the bay (when needed) just so no one guy would have to deal with that vibration every engine run.

The J-57s actually ruined the original test cell building with the water cooled and water injected exhaust noise suppressor. The building started cracking and parts started falling out of the ceiling. When it was operating the noise suppressor would blow an ash like substance into the air with the exhaust.

The J-57s were more impressive at full power than the TF-33s, because they were SOOOO LOUD.
"Saddest thing I ever witnessed....an airplane being scrapped"
 
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jetmech
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RE: Engine Tests

Mon Jul 21, 2008 7:02 am



Quoting Ex52tech (Reply 8):
The noise would cause the building to set up a harmonic vibration that could be heard above the noise of the engine running at full power. You could hear the test cell building noise at the main gate of the base over three miles away, and the engine noise was just a rumble.



Quoting Ex52tech (Reply 8):
The J-57s were more impressive at full power than the TF-33s, because they were SOOOO LOUD.

I imagine it would be very loud! Once I was working in the hangar during an engine run of this particular DC-8.


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Photo © Craig Murray



I'm not sure of the exact engine type, but I would hazard a guess that they may have been some version of the JT3 (database says JT3D-3B). As you recall, the noise and more so the vibration was extreme! And this was from a location about 400 metres away.

Aside from the loud rumbling noise, what was most impressive was that the entire hangar floor was vibrating more than enough to feel through my feet. And this was a very solid floor, much more so than the concrete floor of an office building. This was in addition to the general "throbbing" I could feel in the surrounding air.

Quoting Ex52tech (Reply 8):
That noise would go right through you, you could feel it, it was unnerving

Keep in mind, that this particular engine run was occurring on an open air run bay, so I can only imagine how much worse it would have been to be subject to the noise and vibration inside an enclosed engine test cell.

Quoting Ex52tech (Reply 8):
The building started cracking and parts started falling out of the ceiling.

It's awesome to think that a jet engine is powerful enough to damage a building due to noise alone Big grin . I shudder to imagine the damage that could be caused if a building was also subject to impingement from the exhaust and fan gases.

Regards, JetMech
JetMech split the back of his pants. He can feel the wind in his hair :shock: .
 
keesje
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RE: Engine Tests

Mon Jul 21, 2008 11:53 am

I'v been very close to a CF6 and T56 at full power & your belly is starting to feel strange.. many engine test on youtube : Trent 900 blade failure, TP400 and many others. I think this is a nice one..

These guys beat my CF6 experience anyway Big grin

"Never mistake motion for action." Ernest Hemingway
 
DaBuzzard
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RE: Engine Tests

Mon Jul 21, 2008 5:24 pm



Quoting Keesje (Reply 10):
These guys beat my CF6 experience anyway

I guess that's one way to dry the ramp  Smile
No way the sound on my pc does this one justice!

Heck, my home theatre wouldn't do this one justice  hypnotized 
 
Tristarsteve
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RE: Engine Tests

Mon Jul 21, 2008 8:03 pm



Quoting NicoEDDF (Reply 6):
But did I understand it correctly that the burning out as seen in the video is some kind of normal procedure or am I way off?

No its not normal. When newly overhauled engines are fitted to an aircraft, the fuel system is full of a preserving oil. What you should do is drain it off. After fitting the engine you open the LP Fuel filter drain, and turn on the wing boost pumps until pure fuel comes out. Then when you start the engine it starts relatively normally.

I have had a jet pipe fire on start up once. We had done a compressor wash on a JT8D on a B732. As we started the engine the wash fluid that was sitting in the jet pipe ignited. When the engine got to idle it was all blown out. Unfortunately we were pointing down a quite steep hill and the burning fluid ran back down under the engine. We got the engine shut down, and the fire out without any damage.
What had happened was that the maintenance worker had filled the wash rig with pure kerosene, instead of a mix of distilled water and 5% kerosene. After that we used pure water in the rig.
 
ex52tech
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RE: Engine Tests

Tue Jul 22, 2008 3:03 am



Quoting JetMech (Reply 9):
This was in addition to the general "throbbing" I could feel in the surrounding air.

I got a real good dose of that vibration and noise that would travel right through your body when adjusting the water injection screw on the fuel control on a B-52-G with J-57-43W. You had to have both engines on the pod in water injection if you had to adjust the fuel control on the odd numbered engine, due to the water pump being installed on the pad for the CSD and GEN. on the even engines. That wing moves around a lot on a windy without the engines running, imagine how much it flexed with engines running in water injection, not to mention the noise and vibration. I got a real kick out of the experience.

It would scare even the bravest of the brave. When you came out from under those two engines running in water, you knew you were a mere mortal.
"Saddest thing I ever witnessed....an airplane being scrapped"
 
Legs
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RE: Engine Tests

Tue Jul 22, 2008 7:38 am



Quoting Keesje (Reply 10):
These guys beat my CF6 experience anyway

Hehe, afterburners are cool arent they?

Even in a soundproofed control booth, with triple layer windows, twin doors and an 'airlock' etc, we still get vibrations that play hell with the computer equipment inside when we do full power installation runs on F-111s.
Leak checking underneath an engine roaring in zone 5 is incredible, the sound just pummels you, especially through your chest cavity.
 
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jetmech
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RE: Engine Tests

Wed Jul 23, 2008 1:15 am



Quoting Ex52tech (Reply 13):

I'm not sure if I can beat that one. Sounds intimidating just reading about it Big grin ! I think the most "humbling" experience I've had was spending much time under a running 767 APU attempting to diagnose a fault. IIRC, the APU had a cooling fan that has been known to fail, and this was located quite close to your head.

After performing FMU changes on RR D4's, adjustments were often made as the engine was running. Mind you, the engine was brought back to idle whilst the adjustment were made, so it was actually a relatively safe activity.

Regards, JetMech
JetMech split the back of his pants. He can feel the wind in his hair :shock: .
 
9VSIO
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RE: Engine Tests

Wed Jul 23, 2008 1:37 am

Any one remember that poor A346 that jumped it's chocks and went straight into a blast wall?
Me: (Lining up on final) I shall now select an aiming point. || Instructor: Well, I hope it's the runway...

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