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Airplane marketing quiz.


Wilbur

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Was almost a total failure due to errors in the initial wing design.  Became the range and performance leader however by becoming the first "fan jet" airliner as opposed to the straight turbojets used by Boeing and others.

Thus says the "fan jet" maker.  At one point, P&W was shipping almost 800 JT3D engines per month.

 

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36 minutes ago, maddmaxx said:

Was almost a total failure due to errors in the initial wing design.  Became the range and performance leader however by becoming the first "fan jet" airliner as opposed to the straight turbojets used by Boeing and others.

Thus says the "fan jet" maker.  At one point, P&W was shipping almost 800 JT3D engines per month.

 

Can you save me a little wear and tear on my google and ‘splain the difference, Reader’s Digest version?

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In a turbojet, everything happens inside the tube......intake, fuel, ignition and exhaust in a linear flow through manner.

In a fan jet, there is a turbo jet inside and an outer tube that passes some (30%) compressed air front to rear without fuel or ignition.  The "fan" is large enough to cover both inside and outside tube.  The extra external air also provides thrust as the outer part of the "fan" acts like a ducted propellor system.

370px-Turbofan3_Unlabelled.gif

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24 minutes ago, RalphWaldoMooseworth said:

Thanks, maxx. Cool!  

That's the readers digest version.  Did you want to know that there are actually 2 shafts inside the engine, an inner and an outer with the fan being driven slower than the compressors.  The most frontward turbines drive the rearmost compressors and the last stages of turbine drive the fan.

No.  I thought not.

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11 minutes ago, maddmaxx said:

That's the readers digest version.  Did you want to know that there are actually 2 shafts inside the engine, an inner and an outer with the fan being driven slower than the compressors.  The most frontward turbines drive the rearmost compressors and the last stages of turbine drive the fan.

No.  I thought not.

Yet, suck, squeeze, bang, blow still applies.  :) 

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1 hour ago, team scooter said:

Kinda off topic maybe, but I was napping on the couch yesterday when I heard a jet flying overhead. It sounded different, kinda loud and spooky. Checked Flightradar and it was an Antonov 124, one of 55 of them built, flying over my house. Never saw one in the wild before.

AN124-El-Centro.jpg

Thing looks like a caterpillar. Looks like all those wheels are to facilitate landing on rough airstrips. 

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2 hours ago, team scooter said:

Kinda off topic maybe, but I was napping on the couch yesterday when I heard a jet flying overhead. It sounded different, kinda loud and spooky. Checked Flightradar and it was an Antonov 124, one of 55 of them built, flying over my house. Never saw one in the wild before.

AN124-El-Centro.jpg

that's got a lot of taars. 

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2 hours ago, team scooter said:

Kinda off topic maybe, but I was napping on the couch yesterday when I heard a jet flying overhead. It sounded different, kinda loud and spooky. Checked Flightradar and it was an Antonov 124, one of 55 of them built, flying over my house. Never saw one in the wild before.

AN124-El-Centro.jpg

Pfft. Still only a 24 wheeler.

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1 hour ago, wilbur said:

Yet, suck, squeeze, bang, blow still applies.  :) 

That is funny but at one time I had to go through the engine school where gas flow, pressure and temperature are measured in each stage of the engine and how much performance is lost when extracting air from high pressure areas to travel through cooling passages in lower pressure but hotter sections.  It's sort of amazing to think to 1000degf air being extracted from one part of the engine to be routed through the cooling passages in turbine blades that may be seeing 1800 degf.  You can't just use cold outside air because it's at a much lower pressure than the area it's being routed to so you go to high pressure areas in the engine to find colder air than what you need.  Each of these extractions of air contributes to some measurable loss of engine performance......and also a gain as you are returning it to somewhere in the engine.  

The math sucks.  Your head will spin.  Jet engines are really neat machines.

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27 minutes ago, maddmaxx said:

That is funny but at one time I had to go through the engine school where gas flow, pressure and temperature are measured in each stage of the engine and how much performance is lost when extracting air from high pressure areas to travel through cooling passages in lower pressure but hotter sections.  It's sort of amazing to think to 1000degf air being extracted from one part of the engine to be routed through the cooling passages in turbine blades that may be seeing 1800 degf.  You can't just use cold outside air because it's at a much lower pressure than the area it's being routed to so you go to high pressure areas in the engine to find colder air than what you need.  Each of these extractions of air contributes to some measurable loss of engine performance......and also a gain as you are returning it to somewhere in the engine.  

The math sucks.  Your head will spin.  Jet engines are really neat machines.

Tell me about it!  My job is juggling system demands and available bleed with operational needs. 

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7 minutes ago, maddmaxx said:

Ah, that's right.  I had never considered crew options for pulling air out of the engine.  Do you have some lists of performance decreases per system drawing air?

Multiple charts, especially where takeoff and first two climb segments are concerned. 

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