Search found 238 matches

by MarkC
Thu Jan 10, 2013 11:37 pm
Forum: Technical/Operations
Topic: Can Airlines Change Their Engine Types?
Replies: 11
Views: 7157

RE: Can Airlines Change Their Engine Types?

Its about certification. DC8's could do it because of the vast amount of engines involved. There was also some 747-200's re-engined from JT9-7's to JT9D-7R4G2's on cargo planes. It actually caused an increase in demand for -7R4G2 parts. Belive me, a much different engine. Its because this engine was...

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by MarkC
Wed Nov 07, 2012 10:26 am
Forum: Technical/Operations
Topic: Jet Engine's And Breakthrough Development
Replies: 28
Views: 15210

RE: Jet Engine's And Breakthrough Development

Well, looking at history, I would say: 1. The bypass duct. This made engines move air outside the combustion air for much better efficiency. 2. Varible vanes. This is used in the first stage of the HPC stators, and is similar to the wastegate of a turbo to limit the air into the engine at throttle i...

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by MarkC
Wed Sep 19, 2012 4:59 am
Forum: Technical/Operations
Topic: GEnx Engine Shaft Anti Corrosion Coatings
Replies: 1
Views: 4525

RE: GEnx Engine Shaft Anti Corrosion Coatings

I am not familiar with the GENX, but I have overhauled this part on the PW4000 and GP7000. I have been out of the business for 4 months and did not hear about this. Wow, thats bad. In reading the related articles it appears that <acronym title="Trans Asia Airways (Taiwan)">GE</acronym> is making a c...

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by MarkC
Mon Sep 10, 2012 11:29 pm
Forum: Technical/Operations
Topic: An Explanation For These Engine Differences?
Replies: 11
Views: 6199

RE: An Explanation For These Engine Differences?

FYI, there is no such thing as an unpainted spinner. They all have several coats of Laminar X-500 or equivalent paint. Some maybe pure white, and may seem unpainted. The actual color of the unpainted kevlar layers in the PW4000's is yellow. Not sure of other engines as I have not personally worked o...

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by MarkC
Mon Sep 10, 2012 3:12 am
Forum: Technical/Operations
Topic: An Explanation For These Engine Differences?
Replies: 11
Views: 6199

RE: An Explanation For These Engine Differences?

Even if the engines were sourced from different overhaulers, its the operator who provides the paint pattern, and it would be the same. I have overhauled spinner cones. My two guesses: One is a leased engine. One is a new part that was replaced after a bird strike or something, and they did not have...

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by MarkC
Tue May 15, 2012 11:02 pm
Forum: Technical/Operations
Topic: Any Airworthy R-4360 Wasp Major Engines?
Replies: 20
Views: 29236

RE: Any Airworthy R-4360 Wasp Major Engines?

My company has one of these engines in the museum area. Every time I go over there, I look at this thing. Very impressive.

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by MarkC
Sat May 12, 2012 4:02 pm
Forum: Technical/Operations
Topic: P&W 747SP GTF Testbed - AW&ST Blog
Replies: 13
Views: 4546

RE: P&W 747SP GTF Testbed - AW&ST Blog

This flew right past our office window on a flyby of <acronym title="Precision Air Services (United Rep. of Tanzania)">PW</acronym> <acronym title="Air Sofia (Bulgaria)">CT</acronym> facilities. Low and slow, with flaps partially down. Very interesting looking airplane. As we all gathered at the win...

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by MarkC
Fri Mar 23, 2012 12:23 am
Forum: Technical/Operations
Topic: Scrapped High Pressure Turbine Blades
Replies: 2
Views: 3836

RE: Scrapped High Pressure Turbine Blades

They get sent to the scrap contractor. Usually in a big bin with everything. We don't separate nickels, titaniums, and aluminums like you do at home. You would either have to go to engine overhaul shops, and get them to separate specific blades. They would charge you a premium for that, and it might...

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by MarkC
Mon Mar 19, 2012 10:10 pm
Forum: Technical/Operations
Topic: 747 And PW JT9D Questions
Replies: 13
Views: 10363

RE: 747 And PW JT9D Questions

The -7 conversion also brought a noise reduction benefit. Because the aircraft could gain altitude faster, it was less noisy from the ground as it was further (higher) away.

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by MarkC
Wed Mar 07, 2012 10:06 pm
Forum: Technical/Operations
Topic: What Is An Engine Exit Guide Vane?
Replies: 8
Views: 19330

RE: What Is An Engine Exit Guide Vane?

No pictures, but I'll bet the picture database here has some shots. Look for a head on shot of a spinning engine. You can usually see the Exit vanes, as well as the first stage stator (core entrance). They are the vanes that straighten out the airflow from the fan. <acronym title="Trans Asia Airways...

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by MarkC
Fri Jan 27, 2012 12:20 am
Forum: Technical/Operations
Topic: JT9D Vs PW4000
Replies: 19
Views: 11975

RE: JT9D Vs PW4000

<table border="0" align="CENTER" width="95%" class="quote"><tr><td><font size="2" face="ARIAL, Helvetica, Geneva" color="#9A9DA0">Quoting <a href="/profile/western727" class="quote" target="_blank">western727</a> (<a href="#12" class="quote">Reply 12</a>):<br/><i>Further, are/were the JT9D powerplan...

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by MarkC
Wed Jan 25, 2012 11:23 pm
Forum: Civil Aviation
Topic: When The 727 Was The Backbone Of The Fleets
Replies: 71
Views: 11464

RE: When The 727 Was The Backbone Of The Fleets

When I was a child, the company my father worked for had an ex <acronym title="Lufthansa (Germany)">LH</acronym> 100 that was configured as a business jet with 44 seats. The cabin was arranged in groups of 4 seat (two facing front, two facing back) with a table in between. At night two seats convert...

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by MarkC
Wed Jan 25, 2012 10:56 pm
Forum: Civil Aviation
Topic: CO EWR-HKG?
Replies: 38
Views: 9619

RE: CO EWR-HKG?

UA have 90k engines, and thats the limit for that type. CO used to have 90k and had to block 50 seats east. Now CO upgraded to 94k and fly full pax loads both ways.

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by MarkC
Wed Jan 25, 2012 10:27 pm
Forum: Technical/Operations
Topic: JT9D Vs PW4000
Replies: 19
Views: 11975

RE: JT9D Vs PW4000

JT9's and 4000's are very similar in design. That is, if I showed you a part from one, you would recognise it the other. 4000 used more composites, but I doubt this had a difference on thrust. Weight, yes. Big differences was materials in the combustor and high turbine allowing higher pressure ratio...

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by MarkC
Fri Jan 20, 2012 1:31 am
Forum: Technical/Operations
Topic: JT9D Vs PW4000
Replies: 19
Views: 11975

RE: JT9D Vs PW4000

You can't swap a JT9 from a 767 to a 747, but you can do it with a 4000. But, the maintenance tools and such are almost the same on a JT9 from 767's to (later) 747's. I would have to look it up, but the first 4000 could have been on a 767, 747, A300, A310. Actually, now you have me curious. I will l...

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by MarkC
Fri Jan 06, 2012 11:52 pm
Forum: Technical/Operations
Topic: Could The A390 Be A Twin Engine A380 Replacement?
Replies: 22
Views: 17196

RE: Could The A390 Be A Twin Engine A380 Replacement?

<table border="0" align="CENTER" width="95%" class="quote"><tr><td><font size="2" face="ARIAL, Helvetica, Geneva" color="#9A9DA0">Quoting <a href="/profile/tdscanuck" class="quote" target="_blank">tdscanuck</a> (<a href="#10" class="quote">Reply 10</a>):<br/><i>It's not an engine technology problem....

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by MarkC
Fri Dec 16, 2011 11:09 pm
Forum: Technical/Operations
Topic: Why US A332/3 Has Different Engines?
Replies: 10
Views: 4975

RE: Why US A332/3 Has Different Engines?

This was <acronym title="Precision Air Services (United Rep. of Tanzania)">PW</acronym>'s first engine with an aluminium / kevlar fan containment case. USair recieved some of the very early engines, and they had titanium fan cases as there were problems with the other ones. These weighed several hun...

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by MarkC
Wed Nov 23, 2011 10:58 pm
Forum: Technical/Operations
Topic: 777 With De-rated Engines
Replies: 23
Views: 10860

RE: 777 With De-rated Engines

People confuse "derate" with pilot controlled "reduced thrust". As Lightsaber says, derate engines are fitted with a different plug, and can only get the power corresponding to the plug no matter what the pilots do. Reduced thrust is what the pilots control based on local conditions. I'll give you a...

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by MarkC
Wed Nov 23, 2011 10:51 pm
Forum: Technical/Operations
Topic: Engine Fuel Consumption
Replies: 16
Views: 21042

RE: Engine Fuel Consumption

An225, those percentages from the emissions data can be misleading. Like someone else said, they appear to only apply in the vicinity of the airport. I assure you that climb thrust at altitude is nowhere near 85%. More like 20%. But the TSFC changes as well. Anyway, you have a Private Message with w...

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by MarkC
Fri Nov 11, 2011 1:07 am
Forum: Technical/Operations
Topic: Comparison: P&W GTF Engine Vs. CFM Leap Engine
Replies: 2
Views: 11840

RE: Comparison: P&W GTF Engine Vs. CFM Leap Engine

I will preface this by saying that I do not work on the <acronym title="Great Falls - International (GTF / KGTF), USA - Montana">GTF</acronym> (given my employer), and will defer to Lightsaber in all areas except my personal areas of expertise (overhaul). I did not know that CFM was going for a 2 st...

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by MarkC
Wed Nov 02, 2011 11:13 pm
Forum: Technical/Operations
Topic: Deterioration Of Modern Turbofans
Replies: 7
Views: 3237

RE: Deterioration Of Modern Turbofans

<table border="0" align="CENTER" width="95%" class="quote"><tr><td><font size="2" face="ARIAL, Helvetica, Geneva" color="#9A9DA0">Quoting <a href="/profile/ferpe" class="quote" target="_blank">ferpe</a> (<a href="#4" class="quote">Reply 4</a>):<br/><i>airline to judge an engine in the 100' class </i...

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by MarkC
Wed Nov 02, 2011 10:44 pm
Forum: Technical/Operations
Topic: Deterioration Of Modern Turbofans
Replies: 7
Views: 3237

RE: Deterioration Of Modern Turbofans

<table border="0" align="CENTER" width="95%" class="quote"><tr><td><font size="2" face="ARIAL, Helvetica, Geneva" color="#9A9DA0">Quoting <a href="/profile/ferpe" class="quote" target="_blank">ferpe</a> (<a href="#2" class="quote">Reply 2</a>):<br/><i>My wild guess would be in the ballpark of 25% o ...

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by MarkC
Fri Oct 28, 2011 10:19 pm
Forum: Technical/Operations
Topic: Engine Performance-degarding Over Time
Replies: 7
Views: 7333

RE: Engine Performance-degarding Over Time

It depends on what you mean by "performance". You probably mean thrust decrease. No chance. The FADEC or fuel control ensures this. To a powerplant engineer, "performance" means EGT rise. Those levers in the cockpit that control thrust are not throttles. They are power setting levers. Meaning that a...

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by MarkC
Fri Oct 14, 2011 12:27 am
Forum: Technical/Operations
Topic: Engine Re-Fanning
Replies: 11
Views: 4688

RE: Engine Re-Fanning

<table border="0" align="CENTER" width="95%" class="quote"><tr><td><font size="2" face="ARIAL, Helvetica, Geneva" color="#9A9DA0">Quoting <a href="/profile/tdscanuck" class="quote" target="_blank">tdscanuck</a> (<a href="#3" class="quote">Reply 3</a>):<br/><i>CFM has done it a couple of times. It's ...

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by MarkC
Sat Oct 08, 2011 12:25 am
Forum: Technical/Operations
Topic: Delta MD-88 Compressor Stall In Flight
Replies: 13
Views: 10752

RE: Delta MD-88 Compressor Stall In Flight

<table border="0" align="CENTER" width="95%" class="quote"><tr><td><font size="2" face="ARIAL, Helvetica, Geneva" color="#9A9DA0">Quoting <a href="/profile/lowrider" class="quote" target="_blank">lowrider</a> (<a href="#4" class="quote">Reply 4</a>):<br/><i>Unless you have some contacts inside the D...

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by MarkC
Wed Sep 28, 2011 11:18 pm
Forum: Technical/Operations
Topic: Issues With The CFM-56 On Inter-Island Flights?
Replies: 19
Views: 7306

RE: Issues With The CFM-56 On Inter-Island Flights?

I've seen a CFM56-5B getting torn down from a Carribean operator, and, it was unbelievably corroded without a huge amount of cycles and time. Not sure if it was the environment, short trips, or maintenance practices. Sample size of one I know, but typically fleet engines are similar to each other.

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by MarkC
Fri Sep 16, 2011 2:08 am
Forum: Technical/Operations
Topic: Airlines Paying For Engines Against Hour Flown?
Replies: 30
Views: 8689

RE: Airlines Paying For Engines Against Hour Flown?

<table border="0" align="CENTER" width="95%" class="quote"><tr><td><font size="2" face="ARIAL, Helvetica, Geneva" color="#9A9DA0">Quoting <a href="/profile/474218" class="quote" target="_blank">474218</a> (<a href="#18" class="quote">Reply 18</a>):<br/><i>Suggest you read the follow for more informa...

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by MarkC
Thu Sep 15, 2011 11:46 pm
Forum: Technical/Operations
Topic: Airlines Paying For Engines Against Hour Flown?
Replies: 30
Views: 8689

RE: Airlines Paying For Engines Against Hour Flown?

You guys sure that the OEM's can swap engines between operators. I work for an OEM, but no on the engine lease side of the business....the overhaul side. And I have never heard of one operator accepting another operators parts, let alone the whole engine. Not to say it does not happen. I just do not...

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by MarkC
Mon Jul 18, 2011 11:54 pm
Forum: Technical/Operations
Topic: Jets Nay Be Able To Taxi Using Just APU By 2016
Replies: 30
Views: 8501

RE: Jets Nay Be Able To Taxi Using Just APU By 2016

FYI, a big PW4000 does 2,200 pounds per hour. I would assume the GE and Rolls 777 engines are also similar. If this happens, it will be on large aircraft.

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by MarkC
Sun Jun 05, 2011 7:53 pm
Forum: Technical/Operations
Topic: Go-Arounds At Derated Or Max Rated Thrust?
Replies: 35
Views: 8468

RE: Go-Arounds At Derated Or Max Rated Thrust?

On a PW4000, you only get max of whatever plug you installed. The engines are not necessarily the same, even for the same diameter version, so you just can't change plugs freely (more thrust) without doing a lot of configuration research. If you were a large 777 operator, and had both 777-200's (wit...

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by MarkC
Thu May 05, 2011 8:33 am
Forum: Military Aviation & Space Flight
Topic: Saw The J20 Today (5/5)
Replies: 1
Views: 5806

Saw The J20 Today (5/5)

Circling overhead for over almost 2 hours today. It made 7 or 8 passes right over the office a a decent bank angle. The last two were low. So low I could see the white paint in the gear wells. Quite a little airshow. Interesting no chase plane. A little louder than the J10s normally are, but maybe t...

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by MarkC
Mon Apr 25, 2011 8:25 am
Forum: Technical/Operations
Topic: DC-10-30 Vs. DC-10 Super 30?
Replies: 4
Views: 5145

RE: DC-10-30 Vs. DC-10 Super 30?

NW also got rid of the -40's because of the engine support issue. They had JT9D-20/20J's. This was internally very similar to the -7's, but most of the parts that interfaced with the airframe were different. This was such a small number of these made that it became a real pain to maintain the engine...

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by MarkC
Sun Apr 17, 2011 1:23 pm
Forum: Technical/Operations
Topic: Why Is Max Starting EGT Lower Than The Continuous?
Replies: 14
Views: 6006

RE: Why Is Max Starting EGT Lower Than The Continuous?

The reason that the start EGT is lower is because, at that relatively low RPM, if the temp goes about 725, then, its obvious some thing is wrong. Like a hot start. There are no thermocouples in the combustion chamber. You can only surmise whats going on by the downstream readings. Its got nothing to...

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by MarkC
Fri Apr 08, 2011 8:16 am
Forum: Technical/Operations
Topic: Jet Engine Temperature Shock?
Replies: 16
Views: 11059

RE: Jet Engine Temperature Shock?

To go back to the original question, this is not a problem at all. No damage. A few 10's of degrees rapid change is nothing compared to when you shut the engine off. The cases will cool faster then the rotors. On a new engine with new seals, you can lock the rotor. This easily happens in a test cell...

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by MarkC
Mon Jan 31, 2011 3:18 am
Forum: Technical/Operations
Topic: What Happens To Old Engines?
Replies: 15
Views: 8171

RE: What Happens To Old Engines?

I can understand why a scrap dealer would not be too interested in a complete engine. These are very difficult to take apart without special tools and fixtures, and the only people who have those are in the business of overhauling the engines. Even if a scrap dealer could take it apart, all the part...

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by MarkC
Fri Dec 31, 2010 3:55 am
Forum: Technical/Operations
Topic: PW407x/409x Sound Differences
Replies: 4
Views: 2622

RE: PW407x/409x Sound Differences

The majority of the parts in a 77k engine are comparable and interchangeable with the 90k engine. However, there is a big difference in the fan case design. The older engines had composite fan exit guide vanes, and the 90k's had aluminium ones. The sound liners were also different. I can see how thi...

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by MarkC
Fri Nov 05, 2010 10:33 am
Forum: Technical/Operations
Topic: Can Pilots Smoke?
Replies: 34
Views: 28103

RE: Can Pilots Smoke?

If you want to smoke in the cockpit, just join China Eastern.

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by MarkC
Tue Nov 02, 2010 10:17 am
Forum: Technical/Operations
Topic: Life Cycle Of An Airplane
Replies: 21
Views: 11140

RE: Life Cycle Of An Airplane

What would it matter if the metal was recycled? I really do not understand this. If its got the same chemistry and property, what is the difference if it came from metal rather than ore? I would think recycled metal would be better. I don't know airlpanes, but I know engines, and I have never come a...

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by MarkC
Sat Oct 16, 2010 7:43 am
Forum: Technical/Operations
Topic: Vertical And Horizontal Separation In China
Replies: 2
Views: 3477

Vertical And Horizontal Separation In China

Anyone know the minimum separation between aircraft in the <acronym title="Prescott - Ernest A. Love Field (PRC / KPRC), USA - Arizona">PRC</acronym>? On October 2, I was on an Air China flight from Chengdu to Shanghai Pudong. From my window seat, I saw a Sichuan Airlines A320 zip by in the opposite...

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by MarkC
Thu Jul 01, 2010 10:40 am
Forum: Technical/Operations
Topic: Engine Overhaul Intervals
Replies: 3
Views: 9405

RE: Engine Overhaul Intervals

You're talking about an engine shop visit, right? This is where the engine is removed from the wing and sent to an overhaul shop. Its based on cycles, not necessarily hours. And, you are correct, I would say the CFMs on Southwest are going to be about every 3 - 4 years. The only CFMs I have worked o...

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by MarkC
Fri Jun 25, 2010 6:59 am
Forum: Technical/Operations
Topic: CFM56 On A320 Vs 737 - Difference?
Replies: 10
Views: 15194

RE: CFM56 On A320 Vs 737 - Difference?

Besides the obvious fan differences between the 3 models (3,5,7), the internal parts are much different. The -3 is really similar to a -2, and is much older technology than the -5,-7's. The 5's also have an extra booster stage, and an extra LPT stage. That is needed for the extra thrust. Still amazi...

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by MarkC
Sat May 08, 2010 8:02 pm
Forum: Technical/Operations
Topic: Transferring 767 Engines To The 747
Replies: 15
Views: 12093

RE: Transferring 767 Engines To The 747

Its the ETOPs, but its also the EGT margin. If you had, say CFM56-5B's on a mixed A321 / A320 / A319 fleet, you would start out with the high margin engine on the 321, then, when it might not make power on that, you would bump it down to the lesser thrust rating. On that particular engine, the diffe...

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by MarkC
Fri Apr 23, 2010 11:10 am
Forum: Technical/Operations
Topic: Transferring 767 Engines To The 747
Replies: 15
Views: 12093

RE: Transferring 767 Engines To The 747

There is a large PW4000 747 and 767 operator who also freely changes these engines between the types, along with the thrust rating plugs. On a 4000, the Boeing installations are identical and interchangable. The <acronym title="Air Madagascar">MD</acronym> and Airbus have different interfaces. But, ...

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by MarkC
Wed Apr 21, 2010 1:46 pm
Forum: Technical/Operations
Topic: Engine Hot Section/cold Section Modules
Replies: 3
Views: 9890

RE: Engine Hot Section/cold Section Modules

Depends upon the engine. On a very big engine the LPT gets very expensive with the huge airfoil count. So more than 70%. On a small engine, this is not so bad, so less than 70%. Of the cold section cost, the major portion of it is the high compressor. If it was not for that the cold cost would be mo...

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by MarkC
Wed Apr 21, 2010 1:38 pm
Forum: Technical/Operations
Topic: Volcanic Ash And Newer GE, Trent's And Pratts
Replies: 29
Views: 7622

RE: Volcanic Ash And Newer GE, Trent's And Pratts

Sand does the same thing. High altitude fine sand. I have seen the internals of a middle east PW4000 operator. They show the long term effects of fine sand damage. The ash clouds that can shut down an engine have to be much more concentrated. I just saw the CFM explaination of how ash can shut down ...

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by MarkC
Sat Apr 17, 2010 2:06 pm
Forum: Technical/Operations
Topic: Volcanic Ash And Newer GE, Trent's And Pratts
Replies: 29
Views: 7622

RE: Volcanic Ash And Newer GE, Trent's And Pratts

Clogging the feul nozzles puzzles me also. I am well aware of their design, and how they fit into the engine. Obviously, these are at a very low temp, and molten ash would solidify on them, but, I would think it would be on the exterior, not on the outflow of the nozzle itself. I also would not thin...

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by MarkC
Fri Apr 16, 2010 10:41 am
Forum: Technical/Operations
Topic: Engine Smoke On Startup
Replies: 5
Views: 20694

RE: Engine Smoke On Startup

I would say that lots of times it is the starter that is starting to need an overhaul. These will smoke like you would not believe. I witnessed a CFM56 start of a freshly overhauled engine on a test stand, and there was a thick haze of blue smoke, and it had absolutely nothing to do with fuel. Not c...

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by MarkC
Mon Mar 15, 2010 10:56 am
Forum: Technical/Operations
Topic: PW 4000 On The T-7s?
Replies: 3
Views: 3881

RE: PW 4000 On The T-7s?

OK, I have worked on more than my share of these things. The 747 / MD11 / A300 / A310 / 767 PW4000's are the 94" fan version. The 777 is the 112" version. There are three versions of the 112. The first is the original 74 / 77k thrust version. The second is the 90k version, which is similar, but slig...

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by MarkC
Mon Mar 01, 2010 10:13 am
Forum: Technical/Operations
Topic: 747 100 On Long Haul Flight?
Replies: 32
Views: 11998

RE: 747 100 On Long Haul Flight?

<table border="0" align="CENTER" width="95%" class="quote"><tr><td><font size="2" face="ARIAL, Helvetica, Geneva" color="#9A9DA0">Quoting <a href="/profile/LTU932" class="quote" target="_blank">LTU932</a> (<a href="#11" class="quote">Reply 11</a>):<br/><i>Question: Did the 747-100s eventually get re...

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by MarkC
Wed Jan 27, 2010 12:01 pm
Forum: Technical/Operations
Topic: Uncontained Engine Failures: A Thing Of The Past?
Replies: 43
Views: 11517

RE: Uncontained Engine Failures: A Thing Of The Past?

<TABLE BORDER=0 ALIGN=CENTER WIDTH=95% style="border-top: 1pt #28455E solid;border-right: 1pt #1B2E3F solid;border-bottom: 1pt #1B2E3F solid;border-left: 1pt #28455E solid;table-layout:fixed;border-spacing:0;padding:0;border-collapse: collapse;" bgcolor=#1E3951><tr><td><font size=2 face="ARIAL, Hel...

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