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This will (hopefully) be the first of a series of diaries about how a modern airliner functions. These diaries are meant to be informative and easy to understand for those with little or no technical knowledge.

First off - I'm not an aeronautical engineer. My degree was in electrical and computer engineering. I'm also not an aircraft mechanic. I'm just a guy who drives airplanes for a living and has a workingman's knowledge of them.

Pilots and aviation enthusiasts may find this a bit on the simplistic side. I'm writing these for those with an interest in how things work but little or no aviation background. That way if I get something wrong I can just say "I knew that. I was just trying to simplify it."

So if you've ever been sitting back there in seat 15C and wondered "what was that noise?" or "what's that thing moving out there on the wing?" then you might find these interesting.

I'm starting with the engines - because we're not going anywhere without them.

An airliner won't fly without engines, at least not for very long. In physics, you don't get something for nothing.

In simplest terms, in order to get something to move energy must be expended.

That energy is stored in our fuel tanks, and the engines convert the chemical energy locked up in the fuel into thrust (kinetic energy) to make the plane go forwards. Once we get the thing going forwards fast enough, the wings do their aerodynamic magic and we're flying.

At one time all aircraft were powered by piston engines, similar to the one in your car. Today piston engines or "recips" are found mostly in light aircraft.

A recip engine has pistons which travel up and down and go through 4 cycles. Intake, Compression, Combustion, Exhaust. Or as I like to call it "Suck, Squeeze, Bang and Blow".

We're going to suck in some air, mix something flammable with it, squeeze it tight, explode it, and push out what's left over. The force of the explosion drives the piston, which turns the engine, which turns (in an aircraft) a propeller. Simple enough.

Airliners switched to turbine engines starting in the 1950s. There are three main types of these: turbojets, turbofans and turboprops. I'll explain the differences later.

A turbine engine actually does the same 4 things, it just does them continuously. It's constantly sucking, squeezing, banging and blowing. In a sense, we have a continuous controlled explosion that's driving us forwards.

So what makes it better? A couple things. Speed of course. You can only go so fast with a propeller. There are aerodynamic limits that prevent you from going faster.

Then there's reliability. By the late 1950s we'd pushed piston engine technology about as far as it could go. The last piston engined airliners like the DC-7 had monster 18-cylinder supercharged engines cranking out over 3,000 horsepower. These were wonderfully complex machines that tended to beat themselves to death over time and required a lot of maintenance. A DC-7 or Super Constellation had 72 pistons, 72 connecting rods, plus 144 valves all thrashing back and forth 2000 or so times per minute. The Flight Engineer actually had an oscilloscope to check on each of the 144 spark plugs in flight.

On a side note: piston engines are a lot more complicated for the pilot, as I learned when getting my Airline Transport Rating in a Beech Baron. "Throttles! Props! Mixtures! Carb heat! Cowl flaps! Boost pumps! Help meeeeeeeee!"

In contrast, a turbojet has very few moving parts. We have a compressor, which is basically just a type of fan that sucks air in the front. That air gets squeezed into the combustion chamber, mixed with fuel, and ignited. The hot gases go out the back, past a turbine (basically a reverse fan) which is connected by a shaft back to the compressor. Once you get the the process going it's self sustaining. We don't even need spark plugs except for starting it. Once you light the fire it keeps going as long as you add fuel.

Typical Turbojet Engine
So why didn't we have these sooner? Mainly because we're dealing with some extreme temperatures and pressures in there and it took a while for metallurgy to catch up. Plus we're going to spin it at 20,000 rpm or more. The first jets had a life of about 25 hours before they had to be rebuilt.

"Pure" turbojets didn't stick around for very long. They were noisy, burned a lot of fuel and polluted badly. They only ran efficiently at relatively high speeds and altitudes. We needed something that was a bit better.

We came up with the turbofan, sometimes called a "fan jet". Take a turbojet and stick an extra turbine at the back. Connect that second turbine to a second, larger fan at the front of the engine. Now "bypass" most of the air coming out of that large fan around the engine. It's almost like having a small, covered propeller. What makes this better? Well it turns out that moving a lot of air slower is a better way to make thrust than moving a little air really fast.

Turbofan Engine
In later generations they made the fan much larger, calling it a "high bypass" engine. That's why newer engines are so much fatter than the engines on 1960s airliners. The vast majority of the thrust is generated by the fan with a little bit coming from the jet exhaust.

These are most efficient at medium-high altitudes and air speeds. They're in their happy zone up around 35,000 feet and around .80 mach.

For shorter flights that don't go up as high, a turboprop is actually more efficient. They're similar, except instead of turning a fan that second turbine drives a propeller via a gearbox like the transmission in your car.

Now we just need a way to start the engine and a way to control it.

Only the very smallest of jet engines use an electric starter like your car does. A starter capable of cranking an airliner engine would weigh a lot more than we'd want to carry around. We start them with compressed air, which can come from a ground cart or our auxiliary power unit (APU).

The APU is just a baby jet engine that is small enough to start electrically. It doesn't provide any thrust but it can produce enough air to start the engines plus electricity to power the plane on the ground.

The starter on a jet engine is a small turbine that is geared to the engine. When we send air to it the engine will spin up enough where we can start it. This is usually around 25% rpm. We measure jet engine rpm in % of maximum. Once the engine is running the starter has a clutch that disengages it (or it would come apart in a short time).

At the same time, the igniters will start to fire continuously. These are very similar to the spark plugs in your car, except we only need them when we start the engine. We do sometimes turn them on in flight, usually during takeoff and landing, "just in case".

Once we get the engine spinning to the magic number we move a switch or lever that sends fuel to the engine. It should "light off" in a matter of seconds. Then it's just a matter of watching the gauges to make sure it starts properly. The whole process might take a minute or so.

Once we get one engine running we can even siphon some of the excess air, called "bleed air", from it to start the other engine(s).

To control a jet engine we just have one lever for each engine, called a "thrust lever". Technically only piston engines have throttles, but we still sometimes call them "throttles", old habits die hard.

The thrust lever is connected to the engine's fuel control, which is similar to the fuel injection on your car. In the old days this was a purely mechanical device and you had to manually keep the engines from spinning too fast or producing more than their rated power "over boost".

In the old days you had to be careful not to move the thrust levers too quickly or you might cause the engine to compressor stall (popping and chugging) or to torch (shoot flames out the back). The old J57s on my B-52 would do that occasionally.

Today it's all done electronically. The thrust lever is connected to a computerized engine control - called an EEC (Electronic Engine Control) or a FADEC (Fully Automated Digital Engine Control). In simple terms it keeps the engine happy all the time. No matter what I do with the thrust lever it won't let me hurt the engine.

We also have a few extra gauges that you probably don't have in your car (unless you happen to be Batman).

N1 - This is like the tachometer in your car. It measures how fast the fan is turning in % of maximum. Some number between 0 and 100.

For some engines (General Electric ) we use the N1 gauge to set our power.

N2 - Same thing except this is the speed of the compressor and turbine.

EGT - Exhaust Gas Temperature, how hot the engine is running. Usually in degrees Centigrade. Some really big number around 400 degrees Centigrade.

Oil Pressure - Same as your car.

Fuel Flow - how much fuel the engine in using in pounds per hour.

EPR - Exhaust Pressure Ratio (pronounced "eeper"). This is basically the difference in pressure between the air going in the front and the air going out the back. It's a measure of how much power the engine is producing.  Some number between 1.00 and 2.00 usually.

On Rolls Royce and Pratt & Whitney engines this is how we set the power.

That's about it. They're very simple in concept but difficult to build because of the stresses that they operate under. Until someone perfects the hypersonic scramjet or the warp drive this is what we're stuck with.

Fortunately modern jet engines are very reliable. That's why most airliners have only two engines these days. The odds of one failing are quite low and an airliner will fly just fine with an engine out. In 29 years of flying I have never had to shut down an engine in flight and I hope to keep that streak going.

I hope this has been informative. I'd like to do a whole series of them if people like them.

Originally posted to Major Kong on Mon Apr 01, 2013 at 11:35 PM PDT.

Also republished by Kossack Air Force, SciTech, Aviation & Pilots, and Central Ohio Kossacks.

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Comment Preferences

  •  Tip Jar (173+ / 0-)
    Recommended by:
    basquebob, YellerDog, here4tehbeer, riverlover, JimWilson, lazybum, Chaddiwicker, Margouillat, smiley7, craiger, Clive all hat no horse Rodeo, 84thProblem, koNko, Pluto, Mathazar, bepanda, Tinfoil Hat, Otteray Scribe, BigOkie, eeff, northsylvania, tomephil, DeadHead, radarlady, Habitat Vic, Dood Abides, 207wickedgood, Hatrax, windje, TexasLefty, democracy inaction, Texknight, rimstalker, janislav, Canuck in Ohio, palantir, ExStr8, CwV, subtropolis, Timbuk3, TheC, Mark E Andersen, mofembot, Bob Duck, mconvente, bitpyr8, veinbulge2000, MadGeorgiaDem, MikeBoyScout, twigg, Dahankster, Azazello, midnight lurker, blue armadillo, just another vet, gulfgal98, maryabein, high coup haiku, lotac, Steve15, Pupmonkey, US Blues, judy99, SCFrog, Trendar, lenzy1000, mali muso, Crider, ER Doc, elfling, david78209, boatjones, WiseFerret, shanikka, sawgrass727, johanus, Sparhawk, Ohiodem1, sometv, smokeymonkey, Pilotshark, TheDuckManCometh, wonmug, Involuntary Exile, OIL GUY, implicate order, jjhalpin, Arabiflora, NoMoJoe, prfb, Anthony Page aka SecondComing, fluffy, skod, fixxit, eztempo, doingbusinessas, marathon, ontheleftcoast, BeninSC, Assaf, blackjackal, Byron from Denver, Paulie200, rpjs, JayBat, nom de plume, Loquatrix, Vico, worldly1, Buckeye54, Sean Robertson, clinging to hope, Simplify, statsone, NearlyNormal, Joy of Fishes, killjoy, BRog, Tod, virginislandsguy, GulfExpat, Orinoco, Isara, Battling Maxo, VTCC73, sfbob, Ice Blue, CornSyrupAwareness, badger, jwinIL14, BachFan, leonard145b, Rhysling, alasmoses, Intellectually Curious, Ed in Montana, thestructureguy, Flint, linkage, KenBee, markdd, Mr Robert, JJG Miami Shores, John Barleycorn, rhutcheson, out of left field, flygrrl, randallt, xaxnar, GeorgeXVIII, peterj911, LilithGardener, Bisbonian, Tommy T, GAS, Moody Loner, Larsstephens, Marc in KS, PeterHug, mlharges, Bronx59, terabytes, Jay C, Nebraskablue, native, OceanDiver, Farugia, RiveroftheWest, PrahaPartizan, Brian1066, BlogDog, envwq, Oldestsonofasailor

    If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

    by Major Kong on Mon Apr 01, 2013 at 11:35:42 PM PDT

  •  Thanks again for good reads. n/t (14+ / 0-)

    A bad idea isn't responsible for those who believe it. ---Stephen Cannell

    by YellerDog on Tue Apr 02, 2013 at 12:52:39 AM PDT

  •  I love it when an aviator talks dirty. (30+ / 0-)
    A turbine engine actually does the same 4 things, it just does them continuously. It's constantly sucking, squeezing, banging and blowing. In a sense, we have a continuous controlled explosion that's driving us forwards.

    And they’'ll drink 'til their eyes are red with hate for those of a different kind. -Richard Thompson

    by lazybum on Tue Apr 02, 2013 at 01:56:00 AM PDT

  •  Degrees... (7+ / 0-)

    I would have though that those would be in Celsius (expressed in a centigrade scale)..? :-)

    Nice series idea, I'm impatient to see the rest !!!

    "What can I do, What can I write, Against the fall of Night" A.E. Housman

    by Margouillat on Tue Apr 02, 2013 at 02:16:26 AM PDT

  •  Thank you, MK (7+ / 0-)

    Very informative andmuch apprecieated.  I am looking forward to the rest of the series.

    Dwell on the beauty of life. ~ Marcus Aurelius

    by Joy of Fishes on Tue Apr 02, 2013 at 03:31:33 AM PDT

  •  I had to vote "Not technical enough" (2+ / 0-)
    Recommended by:
    Sean Robertson, Ed in Montana

    Because you failed to mention a very important thing all airplanes need in addition to motive force: lift.

    Without wings that have a larger top surface than bottom surface, propulsion alone will not get the thing very far in the sky unless it starts in a vertical position and has many times the thrust of 2-4 puny turbo jet engines.

    4 basic forces of flight

    Thrust vs Drag
    Lift vs Gravity

    Otherwise, great diary.

    What about my Daughter's future?

    by koNko on Tue Apr 02, 2013 at 03:40:01 AM PDT

  •  Now, if only the people who write assembly (10+ / 0-)

    instructions could master your writing skills, my vocabulary would be reduced considerably.

    Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed. --Herman Melville

    by ZedMont on Tue Apr 02, 2013 at 03:40:28 AM PDT

  •  My youngest son was on his way home from leave. (15+ / 0-)

    He took a DC-9 out of Atlanta.  They had gotten airborne, were out of the pattern and climbing out. He was sitting near the rear when there was a loud THUMP and he felt the plane yaw slightly.  One of the pilots came on the intercom, saying,

    Ladiesandgentlemenwehaveaproblemandwillbereturningtolandimmediately keepyourseatbeltsonandwewillgiveyoumoreinforiinformationinamoment fligthattendantsprepareforememergencylanding.
    The right engine had decided to take a vacation at the worst possible time. In the late 70s, the old DC-9 was having a problem with the fuel tanks getting cold soaked at altitude, and they were having a fast turnaround at the gates.  The very cold tanks in the southern humidity were picking up ice and then shedding it once they took off.  Once in a while ice would hit one of the engines.  Technology advances in both engines and fuel tanks solved the problem.  

    I had gone to the airport to pick him up. The last thing any parent wants to hear is a call for people waiting for Delta Flight XXX to come to the terminal security office immediately.    

    Delta put him on a later flight and refunded his money for the ticket. When he got home, he told me the plane was probably going to be unusable until they replaced all the set cushions.  Said there were probably a lot of new "buttonholes" in all the passenger seat cushions by the time they landed.

    The general who wins the battle makes many calculations in his temple before the battle is fought. The general who loses makes but few calculations beforehand. - Sun Tzu

    by Otteray Scribe on Tue Apr 02, 2013 at 04:28:43 AM PDT

    •  The same problem caused the crash (11+ / 0-)

      of a Scandinavian airliner.  Ice was collecting on the wing near the wing root.  In the case of the Scandinavian MD-81 (later version of the DC-9), the ice got both engines. The plane crashed.  There were a number of injuries, but all souls on board survived. Another case of one hell of a pilot, cut from the same mold as Sully Sullenberger.  Story here:

      http://en.wikipedia.org/...

      It was not until October 2012 an Airworthiness Directive (AD) was finally issued, despite the fact this problem had been known for more than thirty years, and 21 years after the crash of Scandinavian Airlines Flt 751.

      The general who wins the battle makes many calculations in his temple before the battle is fought. The general who loses makes but few calculations beforehand. - Sun Tzu

      by Otteray Scribe on Tue Apr 02, 2013 at 04:43:08 AM PDT

      [ Parent ]

      •  very telling quotes (3+ / 0-)
        Recommended by:
        PeterHug, BlackSheep1, RiveroftheWest
        The flight crew, and especially Captain Rasmussen, were lauded for the skilled emergency landing in a fast-developing, potentially fatal situation. Rasmussen commented that "few civilian air pilots are ever put to a test of the skills they have acquired during training to this degree"[citation needed] and said he was proud of his crew and very relieved everyone had survived. He chose not to return to piloting commercial aircraft.
         my bolds

        I can't begin to imagine the sensory overloads going on...and then the unknown controls defeating the training that then led to the engine losses.
          that detailed two serious failures by the aircraft industry administrators.

        This machine kills Fascists.

        by KenBee on Tue Apr 02, 2013 at 02:52:49 PM PDT

        [ Parent ]

    •  That is one weakness of jet engines (14+ / 0-)

      They don't like to ingest foreign matter - be it ice, large birds or trash left on the ramp by careless workers.

      If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

      by Major Kong on Tue Apr 02, 2013 at 04:49:38 AM PDT

      [ Parent ]

      •  I never understood why they don't put (1+ / 0-)
        Recommended by:
        Simplify

        some sort of mesh on their intakes, coarse enough to not meaningfully interfere with airflow but fine enough to keep out birds and other debris.

        "Liberty without virtue would be no blessing to us" - Benjamin Rush, 1777

        by kovie on Tue Apr 02, 2013 at 06:22:09 AM PDT

        [ Parent ]

        •  If/when the mesh disintegrates, (8+ / 0-)

          it turns into destructive fragments that wreak havoc on the engine. And it would be prone to disintegration -- for example, a bird strike during an approach at 200mph would be enough to shatter the mesh. In other words, a mesh would probably make the debris problem worse, not better.

          And they’'ll drink 'til their eyes are red with hate for those of a different kind. -Richard Thompson

          by lazybum on Tue Apr 02, 2013 at 06:36:09 AM PDT

          [ Parent ]

        •  Some Military Aircraft ... (11+ / 0-)

          with low-to-the-ground intakes have retractable FOD (Foreign Object Damage) screens to prevent things from being sucked up off the pavement. Regardless of their mesh size, they cannot help but impede airflow and are retracted early.

          However, in cruise flight something strong enough to prevent a whole bird from being ingested would be pretty hefty. In addition, it would only strain the pieces down to a smaller size, not prevent ingestion. Large turbofan engines are starting to be designed with blade spacing that will let a certain size object pass through.

          Typically, birds are found at lower altitudes or even on the ground, where airliners spend a smaller fraction of their operating time. There are no birds at 35,000 feet. There is probably no effective screen that could protect against a Canada goose at 250 knots during approach.

          "Facts are meaningless. You could use facts to prove anything even remotely true." -- H. Simpson

          by midnight lurker on Tue Apr 02, 2013 at 06:41:00 AM PDT

          [ Parent ]

          •  I'm aware of some Soviet (2+ / 0-)
            Recommended by:
            PeterHug, RiveroftheWest

            designs that actually close the main inlets and actually intake air over the top of the fuselage for take off (rough fields don't cha no).  And then open the normal intakes for continued flight.  But I don't recall any retractable FOD screens.

            “that our civil rights have no dependence on our religious opinions, any more than our opinions in physics or geometry.” Thomas Jefferson

            by markdd on Tue Apr 02, 2013 at 01:03:13 PM PDT

            [ Parent ]

            •  There Have Been Some (2+ / 0-)
              Recommended by:
              PeterHug, RiveroftheWest
              6.6.3 Engine Intake Protection Screen

              Permanent or in-flight movable intake protection screens can also be used to protect the engine intake. A typical early example of this type of screen is the one used on helicopters. It can be either a true screen, as on the A109, or a screening obstacle, as on the Kamov Ka-52.

              In-flight removable screens are typically present on Russian-designed fighters like Mig-29 or the Su-27.

              A major danger associated with the use of permanent in take screens is the danger of ice formation on the mesh. To prevent ice formation, a de-icing system can be mounted on the screen, as on the F-117 aircraft.

              --RTO-TR-AVT-094 (NATO)

              Retractable screens were also used on the Cessna A-37A and B, which had its intakes only about 18-24 inches above the pavement.

              "Facts are meaningless. You could use facts to prove anything even remotely true." -- H. Simpson

              by midnight lurker on Tue Apr 02, 2013 at 04:05:55 PM PDT

              [ Parent ]

          •  PT-6 (2+ / 0-)
            Recommended by:
            PeterHug, RiveroftheWest

            Pratt & Whitney PT-6 engines used primarily on turboprop airplanes have an "inertial separator," a pilot-activated trap door just inside the air inlet, that theoretically re-routes foreign matter before it can do damage.  

            It's been many decades since I last flew a PT-6 equipped aircraft.  I only remember using them when flying in icing conditions.

            TEA PARTIES: Something little girls do with their imaginary friends.
            (-6.75 -6.51)

            by flygrrl on Tue Apr 02, 2013 at 01:40:22 PM PDT

            [ Parent ]

        •  One plane that did: (3+ / 0-)
          Recommended by:
          Ice Blue, lazybum, PeterHug

          the F-117 Nighthawk. Although the reason that it did was for stealth, to keep radar waves out, not birds.

          Government and laws are the agreement we all make to secure everyone's freedom.

          by Simplify on Tue Apr 02, 2013 at 11:10:16 AM PDT

          [ Parent ]

          •  One little tidbit I read about the Stealth (2+ / 0-)
            Recommended by:
            Simplify, BlackSheep1

            fighter...whenever they left them outside at night sitting on the ramp somebody had to go around them the next morning and sweep up all the dead bats.  Ergo, bats use X-band radar.  I remember reading that in Aviation Week & Space Technology (or A-Waste as we liked to call it) so you can take that with a grain of salt.

            Any jackass can kick down a barn, but it takes a good carpenter to build one.--Sam Rayburn

            by Ice Blue on Tue Apr 02, 2013 at 12:12:20 PM PDT

            [ Parent ]

          •  But they can't fly in any icing condions (3+ / 0-)
            Recommended by:
            Simplify, lazybum, RiveroftheWest

            i.e. clouds at or near freezing, because ice builds yp on the screens, restricting airflow, and then breaks off and gets sucked into the engine, restricting engine longevity.

            "We refuse to fight in a war started by men who refused to fight in a war." -freewayblogger

            by Bisbonian on Tue Apr 02, 2013 at 02:03:01 PM PDT

            [ Parent ]

      •  My dad was an Air Force navigator (3+ / 0-)

        One of his instructors was killed in a jet trainer in the late 1960s. One of the engines ingested a rabbit that got sucked off the runway while accelerating for take off.

      •  Hence the infamous 'chicken cannon' ! :) (4+ / 0-)

        'Per Ardua Ad Astra'

        by shortfinals on Tue Apr 02, 2013 at 07:32:27 AM PDT

        [ Parent ]

        •  "Gentlemen, thaw your chickens!" (6+ / 0-)

          Supposedly during WWII, one of the Allies adopted the chicken cannon to test their airplanes, and were horrified at the results.  The chickens tore through planes like missiles, and nothing they built seemed to have a chance of surviving a bird impact.  They called across the pond - don't remember which way - to the people who first came up with the chicken cannon, and were reminded that real birds don't generally operate at freezing temperatures.

          •  "Urban" Legend, I'm Afraid (1+ / 0-)
            Recommended by:
            RiveroftheWest

            AFAIK bird-proofing did not become a real effort until the sixties or so. And then the concentration was on windshields, not engines.

            BTW I saw the Convair (General Dynamics) chicken cannon in operation during that time. A fresh chicken was trimmed to meet the specified weight and was put into a cardboard deli container that acted as a sabot. It's amazing what the impact will do to an unreinforced windshield. But the most amazing thing is the smell in the test area afterward.

            "Facts are meaningless. You could use facts to prove anything even remotely true." -- H. Simpson

            by midnight lurker on Wed Apr 03, 2013 at 06:48:52 AM PDT

            [ Parent ]

          •  Mythbusters did this (0+ / 0-)

            and it seems that it doesn't make much difference whether they're frozen or not.

      •  Took a duck/s through #2 in the Stratobladder (5+ / 0-)

        at a couple hundred feet above the ground on takeoff from a touch and go way back when. It was dark and flying in the right seat I could see flame shoot forward of the IP in the left seat. Big bang, slight shudder from the compressor stall, and nothing else. All engine instruments remained normal so we landed it on the next one.

        Also took a goose at 350 knots on climb out once. Dead in the middle of the aircraft commander's #1 windscreen. Only a grease streak. Didn't hurt the windscreen either. That was one tough old bird. No, not the goose, he was a mess. Can you imagine what was the last thing that went though that goose's head when he hit us?

        Time makes more converts than reason. Thomas Paine, Common Sense

        by VTCC73 on Tue Apr 02, 2013 at 01:17:07 PM PDT

        [ Parent ]

      •  doesn't have to be that large a piece of debris (0+ / 0-)

        but a bird strike in an A-37 involving a duck is a terrible thing.

        LBJ, Lady Bird, Van Cliburn, Ike, Ann Richards, Barbara Jordan, Molly Ivins, Sully Sullenburger, Drew Brees: Texas is NO Bush League!

        by BlackSheep1 on Tue Apr 02, 2013 at 08:36:28 PM PDT

        [ Parent ]

    •  A cross-country Delta flight I took once (1+ / 0-)
      Recommended by:
      Otteray Scribe

      had to make an emergency landing in Chicago because the windshield had cracked. I can't imagine how they could have survived it actually breaking let alone been able to fly and land the plane at cruising altitude and speed.

      Perhaps all future planes should be made remotely flyable, like drones, to deal with such hopefully rare situations (or if both pilots are incapacitated)?

      "Liberty without virtue would be no blessing to us" - Benjamin Rush, 1777

      by kovie on Tue Apr 02, 2013 at 06:20:54 AM PDT

      [ Parent ]

      •  There are actually two windshields (7+ / 0-)

        There is an inner pane and an outer pane. They would both have to break which is almost unheard of.

        As a precaution you would land if one of the panes cracked.

        If both broke, the cold temperature would be more a problem than the wind blast.

        There's kind of a "bubble" of air over that part of the nose and the airflow there isn't moving nearly as fast as the plane is.

        If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

        by Major Kong on Tue Apr 02, 2013 at 11:04:36 AM PDT

        [ Parent ]

      •  Windscreen failures can be dramatic (3+ / 0-)
        Recommended by:
        PeterHug, BlackSheep1, RiveroftheWest

        but are usually limited to delaminations with one pane failing, most often a crack but occasionally total destruction of a component layer, as MK said. Like all things aviation, windscreens are robustly designed and built with plenty of leeway for damage that does not lead to complete failure.

        I am not aware of an airliner ever experiencing the incapacitation of the entire flight crew. There have been close calls with one incapacitated and the other not doing too well but able to function well enough to recover the aircraft. Complete incapacitation of a crew is certainly possible but, statistically, is unlikely to occur.

        Compare relying on the safeguards to the health of the crew as exists today with the difficulty and expense of designing, building, and installing a remote control capability in thousands of airliners of different types. This is neither an easy nor inexpensive task. I remember reading about how difficult it was to do so with decommissioned USAF fighters that were used as target drones. A system such as that is relatively simple and had to be cheap enough that destruction of the target would not be prohibitively expensive. One for a passenger carrying aircraft would be far more complex and need to be extremely reliable and secure from intrusion. I suspect it would require billions of dollars. Dollars that would have to be returned by paying customers through higher fares to protect against an event that has never occurred before. That's a hard sell.

        Time makes more converts than reason. Thomas Paine, Common Sense

        by VTCC73 on Tue Apr 02, 2013 at 02:43:12 PM PDT

        [ Parent ]

        •  Remote control of all airliners - (1+ / 0-)
          Recommended by:
          RiveroftheWest

          I'm sure that there are people who would propose doing that through the existing network of intelligence gathering fusion centers.

          What Could Possibly Go Wrong?
          :)

        •  ISTR a major incident with a pro golf player's (1+ / 0-)
          Recommended by:
          RiveroftheWest

          jet (commercial but not technically a major airliner) that developed an oxygen leak. Evidently it very quickly killed everybody aboard from oxygen deprivation, and then flew on a sort of autopilot until the fuel ran out. Several hours, no communications from onboard.

          LBJ, Lady Bird, Van Cliburn, Ike, Ann Richards, Barbara Jordan, Molly Ivins, Sully Sullenburger, Drew Brees: Texas is NO Bush League!

          by BlackSheep1 on Tue Apr 02, 2013 at 08:41:45 PM PDT

          [ Parent ]

          •  Payne Stewart (2+ / 0-)
            Recommended by:
            BlackSheep1, RiveroftheWest

            It was a midsize business jet. I don't recall the aircraft type. There was also a similar incident in a 737, Greek IIRC. Both were due to an unrecognized loss of cabin pressurization that caused the incapacitation of everybody on board. The people on the aircraft in these incidents would not have benefited from any sort of remote control as they would be dead long before any problem was recognized and someone on the ground took control. Time of useful consciousness (TUC) is very short during a decompression - measured in a few seconds at high altitude to several minutes for altitudes at 20,000'. A tragic ending is inevitable once hypoxia sets in. The only difference in this kind of event and say losing a wing is a lot of frightened screaming people. Neither is recoverable.

            Some people have a great deal of anxiety over flying. There are lots of things that can go terribly wrong. Some of the things that can go wrong are catastrophic with no remedy that will result in a crash. Those are extremely rare. Neither of the above events fall into the catastrophic category. IIRC both were the result of a system malfunction that should have been recognized and handled by their well trained, professional crew. Both crews were faulted. Which brings me to an important point: the human in the system is the weakest link.

            The aircraft are technical marvels that have been practically fool proofed. Practically. The system of design through construction, preventive and line maintenance, crew qualification and training through operational procedures, and the management oversight by the companies and government agencies have developed a interlocking web of redundancies and feedback loops intended to prevent any mechanical problem or human failure from causing an accident. It works really well and everyone in the industry continues trying to improve reliability. Every hull loss with its attendant loss of life is a system failure with multiple failure points. Like any human endeavor, aviation is not perfectly safe but airline travel is far safer than driving home from work.

            Time makes more converts than reason. Thomas Paine, Common Sense

            by VTCC73 on Tue Apr 02, 2013 at 09:45:13 PM PDT

            [ Parent ]

            •  Yes, that is the name (1+ / 0-)
              Recommended by:
              RiveroftheWest

              I would not have had the details so handy. Thank you.
              What we should consider is not, I fear, how much safer aviation is than driving home from work, but rather that like the sea the sky demands we take nothing for granted at all, any time we venture into its embrace.

              LBJ, Lady Bird, Van Cliburn, Ike, Ann Richards, Barbara Jordan, Molly Ivins, Sully Sullenburger, Drew Brees: Texas is NO Bush League!

              by BlackSheep1 on Wed Apr 03, 2013 at 09:30:57 AM PDT

              [ Parent ]

              •  23,000+ hours of flying for a living (2+ / 0-)
                Recommended by:
                RiveroftheWest, BlackSheep1

                have left me with a deep appreciation of how well the system works. I saw many examples of problems and individual failures in the system but always felt that there was nothing I couldn't successfully handle if I remained vigilant and did my job well while letting everyone else do theirs. The events over which I had no control were never worth contemplating. The system never failed me in my 38 years of military and civilian flying. I trust the system and I'm sure that it will continue to function and improve.

                Time makes more converts than reason. Thomas Paine, Common Sense

                by VTCC73 on Wed Apr 03, 2013 at 09:15:47 PM PDT

                [ Parent ]

            •  the only thing that would prevent a stewart (1+ / 0-)
              Recommended by:
              RiveroftheWest

              incident would be a signal wired into the autopilot that detects a loss in cabin pressure and forces a crash dive to 10,000
              feet and starts a squawk on the transponder of 7700

  •  I'm such an aviation geek... (7+ / 0-)

    All good stuff.

    My brother works up here for GE Lynn Riverworks - he makes those turbine inlet blades for the F-404.

    I'm actually good enough to tell the difference between a GE and a P & W at takeoff thrust by sound alone - there is a different engine note that's quite plain if you know what to listen for.  (roar vs. whine)

    I prefer to remain an enigma.

    by TriSec on Tue Apr 02, 2013 at 04:48:46 AM PDT

  •  I used to fear flying (13+ / 0-)

    and got sick of it, because I knew intellectually there was little danger but couldn't convince my animal brain.  So I learned as much as I could about how airliners worked, and my fear went away.  I have no idea how empirical facts could turn off my animal fear, but there you go.  

    I recently got to pay it forward by helping out a frightened woman on a flight.  She said she was scared of the engines, of their power, of a fire or explosion.  I explained to her that only about 10% of the thrust comes from the "fire" part.  90% of the thrust, I explained, is from the fans in front which are turned by the power provided by the "fire".   I drew a diagram on a napkin to help out visually.  I told her to think of them as great big household fans, blowing us along.  That calmed her down, and I think she enjoyed the rest of the flight (after I explained why "the back of the wing was falling off"... i.e. the flaps were down for takeoff).  Did I do good, Major Kong?

    I love all of your diaries and find them immensely entertaining and informative.  Thank you for sharing them with us!

  •  So is the exhaust end fan pushing air back (2+ / 0-)
    Recommended by:
    Simplify, Orinoco

    toward the engine? 'reverse fan'? to maintain pressure?

    •  It's a windmill (3+ / 0-)
      Recommended by:
      lazybum, Bisbonian, fisheye

      Another way to look at a turbojet engine is to start a the combustion chamber:
      - Fuel mixed with air burns, heats up, expands, and accelerates.
      - Those hot, fast, high-pressure gasses turn the turbine a the back (effectively a windmill) and rush out.
      - It's the gas moving quickly out the back that makes thrust.
      - The turbine has a shaft that turns the compressor up front.
      - The compressor effectively squeezes the air, preparing it for the combustion chamber.

      Pretty much all of the squeezing comes from the compressor. It turns out that, very early in jet engine development, at least one group tried using a piston engine (and not a turbine) to drive the compressor.

      One might ask: why not just have a combustion chamber and not bother with the rest? That would be a rocket engine, for which the vehicle has to carry its own oxygen in addition to the fuel.

      A turbofan or turboprop adds an extra turbine/windmill at the back with a shaft to a fan/propeller up front. As Kong points out, in that case the energy from the hot exhaust drives the fan to move lots of air and cause thrust that way, not just via a small amount of combusted air moving very fast. Depending on the speed, this is more efficient: accelerating lots of air a little bit rather than accelerating a little bit of air a lot.

      Another way to look at a turbofan/turboprop is to compare it to a piston engine: the compressor is like the piston on the upstroke, and the turbine is like the piston on the downstroke. Note that the downstroke, through the driveshaft, both produces thrust (fan/prop) and drives the next upstroke (compressor).

      Government and laws are the agreement we all make to secure everyone's freedom.

      by Simplify on Tue Apr 02, 2013 at 10:44:50 AM PDT

      [ Parent ]

    •  The exhaust end fan, the turbine (1+ / 0-)
      Recommended by:
      fisheye

      is being pushed by the hot air leaving the engine. It provides the power that makes the rest of the fans spin.

      "The problems of incompetent, corrupt, corporatist government are incompetence, corruption and corporatism, not government." Jerome a Paris

      by Orinoco on Tue Apr 02, 2013 at 10:54:05 AM PDT

      [ Parent ]

      •  Funny I always assumed different stages of (1+ / 0-)
        Recommended by:
        RiveroftheWest

        fans and turbines spun at different speeds. But it's all on a solid state shaft? It's actually much simpler than I imagined. I suppose that accounts for it's durability which I could never quite reconcile with a geared system.

        I think there's a multi-stage engine that super-compressed air on that old SR-71. Or like a turbo fan into a hyper turbo fan with maybe even successive ignition stages.  

        And then I read (surfing off this diary) that Pratt & Whitney just developed a gear box for the fan at the front of their turbofan engine and it saves a ton of fuel. Because the fan operates better at lower speed than the turbines and compressor.

        I suppose that's the same effective limitations confronted with a turboprop

        Anyway. Another great diary. I love them all Major.

        •  Different RPMs for Different Stages (1+ / 0-)
          Recommended by:
          fisheye

          The first axial flow turbines had a single compressor attached to a shaft connected to the turbine section.  More modern jet turbines/turbofan have two separate compressor and turbine sections.  The low-pressure compressor section is hard physically attached to the low-pressure turbine section while the high-pressure compressor attaches to the high-pressure turbine via a separate shaft.  The one shaft is hollow to allow the other to run through it.   That enable the high-pressure section to run at a higher RPM than the low-pressure sections.  Some engine designers have even built three-section designs to squeeze out more efficiency from this approach.

          "Love the Truth, defend the Truth, speak the Truth, and hear the Truth" - Jan Hus, d.1415 CE

          by PrahaPartizan on Wed Apr 03, 2013 at 01:58:44 PM PDT

          [ Parent ]

        •  ... (0+ / 0-)

          That fact means that jets/turbines are very inefficient off their design speeds. IIRC, 90% N1 is typically 50% thrust or so.

  •  This is excellent. (4+ / 0-)
    Recommended by:
    Buckeye54, Simplify, Bronx59, BlackSheep1

    I never knew the difference between a turbojet and a turbofan or why there was such a difference. Could you also explain afterburners? Maybe they are not a feature of Commercial jets, but they do exist and their function mystifies me.
    I look forward to the continuation of this series, these birds are some of the finest technology humans have created.
    One other thing I'd love to hear you address: Chemtrails.
    (Yeah, I know, tinfoilhaberdashery...) I have for years argued that the technology to make these chemtrails would be bulky and obvious, involving tanks and valves and sprayers et cetera, that they'd have to be indicated in the maintenance manuals, AP mechanics would have to be trained to maintain them (and sign off on them), that thousands of people would have intimate knowledge of their existence and function, and yet the myth continues.
    Please discuss.

    If I ran this circus, things would be DIFFERENT!

    by CwV on Tue Apr 02, 2013 at 06:02:00 AM PDT

    •  I've been flying for close to 30 years (9+ / 0-)

      I have yet find the "Chemtrail On" switch in any aircraft.

      We'd have to give up most of our fuel or payload to carry the tanks around to dispense chemicals.

      Only dedicated crop dusting and fire fighting airplanes can drop chemicals - and they fly exceedingly low.

      Contrails are caused by hot exhaust condensing water vapor in the air. Even piston engines can cause them. Look at old WWII footage and you'll see the skies over Europe were covered with contrails.

      On combat missions in the B-52 we'd try to avoid the altitudes that might cause contrails because they're so easy to see.

      If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

      by Major Kong on Tue Apr 02, 2013 at 10:48:50 AM PDT

      [ Parent ]

    •  Afterburners are very simple devices (6+ / 0-)

      They're basically an extension of the tailpipe where additional fuel is injected and burned.

      They give you roughly twice the thrust but at the cost of four times the fuel burn.

      They're mostly used on planes that need a quick burst of speed or maneuvering thrust like fighter jets. You can have extra thrust on an as-needed basis without having the weight penalty of carrying a bigger engine around.

      The only commercial use I know of was Concorde and its Russian equivalent the TU-144.

      Concorde only needed them to get up to speed. It could actually cruise at supersonic speed without them. Quite amazing for late 60s early 70s technology.

      If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

      by Major Kong on Tue Apr 02, 2013 at 10:55:29 AM PDT

      [ Parent ]

      •  then there's the contrail/chemtrail video (2+ / 0-)
        Recommended by:
        BlackSheep1, RiveroftheWest

        where a following airliner videoed the plane ahead skipping in and out of the air layer where contrails were produced. It's pretty funny really.

        There was a diary here recently asking about the effect of contrails on atmosphere and weather vs the cost savings of flying higher with contrails. You know, an actual science question.

        Nicely explained Major Kong. Technical writing is hard, evidence all around us.
        thanks.

        This machine kills Fascists.

        by KenBee on Tue Apr 02, 2013 at 03:39:21 PM PDT

        [ Parent ]

      •  IIRC (0+ / 0-)

        There were a number of early civilian jets that used water injection for takeoff. These would inject water into the hot exhaust stream, turning it into steam and creating extra thrust.

        With higher bypass ratio jets (and cooler exhausts), they became pointless.

    •  For all your debunking needs: (1+ / 0-)
      Recommended by:
      CwV

      Government and laws are the agreement we all make to secure everyone's freedom.

      by Simplify on Tue Apr 02, 2013 at 11:13:41 AM PDT

      [ Parent ]

  •  Can an electric motor replace the turbine? (3+ / 0-)
    Recommended by:
    twigg, Simplify, Orinoco

    I've asked around about this before and have gotten a range of answers from "Impossible" to "Unlikely" to "Maybe in the distant future" to "Hmm, interesting idea, never heard of it, sorry, I don't know", so I'll ask again.

    Given that most of the thrust in a modern high-bypass turbofan comes from the fan, not the turbine, which just rotates the fan, in theory there's no reason why an electric motor can't rotate the fan instead of a jet turbine, provided you can make one that's light, powerful and strong enough to replace the turbine, and batteries that are similarly light, powerful and long-lasting enough to take you far enough to make it worthwhile.

    Is there any reason this can't work, other than perhaps the lack of batteries that are light, powerful, safe and long-lasting enough to provide the kind of power needed for such a use right now? But if such batteries existed, and I'm guessing that someday they will, is there any reason this couldn't work?

    Why would one want to do this? Well, aside from how such engines would be quieter than even the quietest turbofan engines, they'd be mechanically simpler and thus cheaper, which combined with the much lower temperatures they'd operate at, would make them more reliable and longer-lasting, further reducing their operating costs. But most of all, you wouldn't have to carry and burn aviation fuel anymore, which is becoming scarcer and more expensive, and is a greenhouse gas pollutant (and dangerous in a crash).

    I believe that this has been done at the model level, successfully. I'm just wondering if anyone's looking at it at the full scale level, if not yet in large commercial airliners, then at least in civilian aircraft, even experimental ones. I'm sure the military is researching this, especially for drones.

    "Liberty without virtue would be no blessing to us" - Benjamin Rush, 1777

    by kovie on Tue Apr 02, 2013 at 06:16:41 AM PDT

    •  Model Electric aircraft (4+ / 0-)
      Recommended by:
      elfling, Orinoco, basquebob, Bisbonian

      fly extremely well, and very fast ... but not for very long.

      As you said ... it's the energy storage that is the issue. Those batteries are very heavy.

      I hope that the quality of debate will improve,
      but I fear we will remain Democrats.

      Who is twigg?

      by twigg on Tue Apr 02, 2013 at 06:21:37 AM PDT

      [ Parent ]

      •  That's likely to change (2+ / 0-)
        Recommended by:
        twigg, Orinoco

        If and when it does, is there any other reason this won't work? It seems like the logical future of aviation for all sorts of reasons, most of them green.

        "Liberty without virtue would be no blessing to us" - Benjamin Rush, 1777

        by kovie on Tue Apr 02, 2013 at 06:25:19 AM PDT

        [ Parent ]

        •  Ah, but with liquid fuel, you only have to carry (8+ / 0-)

          it halfway to where you're going.

          With the battery, you have to haul the weight all the way, so you land just as heavy as when you took off.

          So the energy density of the battery needs to be higher effectively than that of the fuel (accounting for efficiency).

          is there a mechanical engineer in the house?  

          Happy little moron, Lucky little man.
          I wish I was a moron, MY GOD, Perhaps I am!
          —Spike Milligan

          by polecat on Tue Apr 02, 2013 at 06:37:27 AM PDT

          [ Parent ]

          •  It's a differential calculation (3+ / 0-)
            Recommended by:
            polecat, TheDuckManCometh, basquebob

            and High School calculus was a long time ago.

            You have to carry some of the fuel all the way, some of it a fraction, etc ... as opposed to batteries being carried all the way, all the time.

            So the shorter the flight, the smaller the differential and that means that "long-haul" electric flying is much further off than short-haul.

            By the way, I love your sig and I have another favourite from Sopike Milligan:

            I thought I saw Jesus, on a tram.
            I said, "Are you Jesus"?
            He said, "Yes, I am".

            I hope that the quality of debate will improve,
            but I fear we will remain Democrats.

            Who is twigg?

            by twigg on Tue Apr 02, 2013 at 06:47:32 AM PDT

            [ Parent ]

            •  This diary is about simplifying math... :) /nt (1+ / 0-)
              Recommended by:
              twigg

              Happy little moron, Lucky little man.
              I wish I was a moron, MY GOD, Perhaps I am!
              —Spike Milligan

              by polecat on Tue Apr 02, 2013 at 07:28:51 AM PDT

              [ Parent ]

              •  We already hit (1+ / 0-)
                Recommended by:
                polecat

                the outer limits of my knowledge ... so I won't be complicating it further :)

                Even the "simple" math though does explain why it will be a long time before we get long haul electric aircraft :)

                I hope that the quality of debate will improve,
                but I fear we will remain Democrats.

                Who is twigg?

                by twigg on Tue Apr 02, 2013 at 07:31:01 AM PDT

                [ Parent ]

                •  Fuel-cell electric might be interesting, but (1+ / 0-)
                  Recommended by:
                  twigg

                  turbines are really efficient and reliable, not to mention cheaper than fuel-cells.  And I don't see someone putting a Stirling engine in a plane anytime soon.

                  Happy little moron, Lucky little man.
                  I wish I was a moron, MY GOD, Perhaps I am!
                  —Spike Milligan

                  by polecat on Tue Apr 02, 2013 at 07:39:41 AM PDT

                  [ Parent ]

            •  I'm not into perpetual motion, but how about (1+ / 0-)
              Recommended by:
              twigg

              an unpowered fan, a turbocharger if you will, to drive a generator to help with a top off charge to extend range, and potentially reduce battery weight?

              Republicans are like alligators. All mouth and no ears.

              by Ohiodem1 on Tue Apr 02, 2013 at 08:16:15 AM PDT

              [ Parent ]

              •  Well that is pretty much (2+ / 0-)
                Recommended by:
                Ohiodem1, polecat

                the theory behind some cars.

                I can't help but think that aircraft engineers have already thought of it.

                I imagine that a generator large enough to make a significant difference would be large, heavy and require quite a bit of fuel. They can't, for example, recover energy under braking like a car can, and overcoming the rolling resistance from a heavy car is completely different to "lift".

                So I imagine the "perpetual motion" thing applies, as does gravity and stuff :)

                I hope that the quality of debate will improve,
                but I fear we will remain Democrats.

                Who is twigg?

                by twigg on Tue Apr 02, 2013 at 08:21:45 AM PDT

                [ Parent ]

        •  About 20 minutes of flying (2+ / 0-)
          Recommended by:
          lazybum, Orinoco

          is what I could expect from an electric aircraft, compared with maybe two hours from nitro weighing about the same, so there is much progress to be made before they are comparable.

          20 minutes is quite long enough for a hobby, but it wouldn't get me from Tulsa to Dallas at full scale.

          I agree on green reasons. Even electricity generated on a large scale, from fossil fuels, is greener than trying to do it in individual engines. When we can generate power from renewables on a large scale then we will really be in business.

          I don't know quite how green cars like the Volt really are, but they are quite heavy so maybe that's a blind alley for aircraft and we need something better. Of course when we get it, cars will benefit too.

          I hope that the quality of debate will improve,
          but I fear we will remain Democrats.

          Who is twigg?

          by twigg on Tue Apr 02, 2013 at 06:42:31 AM PDT

          [ Parent ]

        •  Engine weight (1+ / 0-)
          Recommended by:
          lazybum

          you are replacing one or two turbine blades with an electric motor, which has heavy coils of wire and permanent magnets, or more heavy coils of wire, plus magnet cores.

          Electric motors might be an ideal solution for powering zeppelins, where the high heat of a turbine engine would be a problem.

          "The problems of incompetent, corrupt, corporatist government are incompetence, corruption and corporatism, not government." Jerome a Paris

          by Orinoco on Tue Apr 02, 2013 at 11:15:52 AM PDT

          [ Parent ]

    •  For Airliner Electric Propulsion ... (4+ / 0-)
      Recommended by:
      elfling, badger, basquebob, lazybum

      right now you would need better batteries or a long extension cord.

      Jet fuel has an energy content of about 43 Megajoules per kilogram or 12 kilowatt-hours per kilogram. That will not change.

      Lithium-ion batteries might contain 0.9 megajoules per kilogram or 0.25 kilowatt-hours per kilogram. That is 100 times less energy by weight. However, that number will continually change as technology advances.

      Hydrogen fuel cells are another high-tech approach, but the weight problem is even more severe. It would be very "green" since the chemical "exhaust" is only water vapor.

      On the other hand, hydrogen itself is a relatively expensive fuel. However, hydrogen can be extracted from methane, which is readily available. The problem then is that you have carbon dioxide as an "exhaust" product in addition to the water vapor.

      TANSTAAFL, I'm afraid.

      "Facts are meaningless. You could use facts to prove anything even remotely true." -- H. Simpson

      by midnight lurker on Tue Apr 02, 2013 at 07:05:01 AM PDT

      [ Parent ]

      •  No one's yet answered my core question (1+ / 0-)
        Recommended by:
        KenBee

        Of whether, obviously important batteries issues aside, there's any reason an electric motor can't replace a jet fuel-burning turbine in a ducted fan engine, in terms of power, weight, reliability, etc.?

        I.e. if the battery issue could be solved--a big if--would this work?

        "Liberty without virtue would be no blessing to us" - Benjamin Rush, 1777

        by kovie on Tue Apr 02, 2013 at 07:09:34 AM PDT

        [ Parent ]

        •  An electric motor certainly can do that -- (2+ / 0-)
          Recommended by:
          kovie, elfling

          but there are efficiency issues.  There is a lot of torque with an electric motor at LOW speeds, not high speeds, so either a torque converter or gearbox would be necessary to get the higher speed airflows you want.

          There are model planes that use EDF's (Electronic Ducted Fans), and for that matter submersibles.

          Energy storage/density is THE big issue.  Sure, electric motors are more efficient than turbines, but the energy density of liquid fuels blows that advantage away.  There will have to be a lot of improvement in supercaps (capacitors) because we're pretty close to the end-of-the-line in battery energy density.  Look at the periodic table of elements to see what the best possible chemistry would be (assuming it didn't go boom): KF (potassium fluoride) would give the biggest electronegativity difference (Francium would do better, but that's radioactive).  But messing around with fluorine carries it's own risks.  Or maybe an air-breathing battery (replacing the Fl with atmospheric O2) would be viable.

          And you have to haul the battery the entire distance.  With fuel, you get to use it up on your route, reducing weight and consumption throughout the flight.

          We've got a looooong way to go to make that viable.

          Burning hydrogen has risks of its own, too.

          Happy little moron, Lucky little man.
          I wish I was a moron, MY GOD, Perhaps I am!
          —Spike Milligan

          by polecat on Tue Apr 02, 2013 at 07:25:53 AM PDT

          [ Parent ]

          •  Ok I'm definitely a layperson here (0+ / 0-)

            But are there "battery" technologies that involve the "burning" of fuel, but at relatively low temperatures and with lower emissions than with turbines? I.e. similar to the way the body burns energy during metabolism. This way you could cleanly "burn off" much of the fuel during flight.

            "Liberty without virtue would be no blessing to us" - Benjamin Rush, 1777

            by kovie on Tue Apr 02, 2013 at 07:32:47 AM PDT

            [ Parent ]

            •  After we figure out how to transmit electrical (0+ / 0-)

              energy wirelessly from space-borne solar power arrays to nice, big, fixed-location earth stations, someone will figure out how to safely aim the power transmitter to a fast moving object.

              See several James Bond villains for examples.

              We must drive the special interests out of politics.… There can be no effective control of corporations while their political activity remains. To put an end to it will neither be a short not an easy task, but it can be done. -- Teddy Roosevelt

              by NoMoJoe on Tue Apr 02, 2013 at 09:03:53 AM PDT

              [ Parent ]

            •  Fuel Cells Do This, in a Sense (3+ / 0-)
              Recommended by:
              polecat, TheDuckManCometh, Simplify

              Hydrogen or reformed methane (or reformed methanol) undergoes a chemical reaction in device in which electrons are trapped and supplied to an external circuit.

              The operating temperatures can be much lower than combustion temperatures, but generally they still require cooling. Then there are still the questions of system weight and fuel storage.

              "Facts are meaningless. You could use facts to prove anything even remotely true." -- H. Simpson

              by midnight lurker on Tue Apr 02, 2013 at 09:35:00 AM PDT

              [ Parent ]

            •  Turbines are remarkably efficient (1+ / 0-)
              Recommended by:
              lazybum

              (even better for power generation because they can run at their most optimal speed) and that has a lot to do with the high operating temperatures.  In fact with actual burning methods, the Carnot cycle's efficiency is defined by the temperature difference between the coldest and hottest point in the system.  At one time it was thought that Ceramic engines would take over because they can get so much hotter than Iron.  Cost and tensile strength are bad, though.

              Turbines have problems -- typically the wear and tear (and cost!!!) of the blades.

              Fuel Cells have problems -- clogging of the ion exchange filter, wear and tear, exhaust gasses, etc.

              Happy little moron, Lucky little man.
              I wish I was a moron, MY GOD, Perhaps I am!
              —Spike Milligan

              by polecat on Tue Apr 02, 2013 at 11:16:31 AM PDT

              [ Parent ]

        •  It's "Not something you would want to do" (0+ / 0-)

          If you were going to go to the trouble of using electric motors to fly, you would drive propellers to do it. For weight, efficiency, and simplicity, props win hands down.

          There are a few 'ducted propeller' aircraft out there, but there are few advantages to the duct - noise reduction being the major one, and not much of a factor at that. And there are substantial downsides -- particularly weight, but also efficiency -- they add a lot of drag.

          For jets, the duct is necessary, because the pressure ratio of the engine -- the ratio of pressure between the engine inlet and the combustion chamber entry -- determines the maximum possible engine efficiency (it limits the maximum possible thermodynamic efficiency, exactly the same way that compression ratio determines both engine efficiency and octane requirements in cars). Large, modern turbines run on the order of 40:1, and require great care in the construction of the engine.

          "Unducted turbofans" have been built, and are in fact extremely efficient. In these engines, the outer/"low pressure" turbine blades have no duct, and are exposed to the outside world. The high-pressure compressor/gas generator contains the turbine that drives all the rest (and has a fairly conventional design).

          The downside of unducted turbofans is that the 'fan blades' run at supersonic velocities, and they are loud. Even with scimitar shaped blades and mismatched numbers of blades between fans (both of which help reduce noise), they are impracticably loud. Further, loss of a single blade will cause the engine to shake itself to pieces, so at least one such engine had explosive charges at the root of each fan blade so that if one blade was lost, its partner would be promptly jettisoned -- away from the aircraft.

      •  Erratum (1+ / 0-)
        Recommended by:
        Simplify
        Lithium-ion batteries might contain 0.9 megajoules per kilogram or 0.25 kilowatt-hours per kilogram. That is 100 times less energy by weight.
        It is reall only 50 times less energy by weight than jet fuel. Makes it much easier, then.

        "Facts are meaningless. You could use facts to prove anything even remotely true." -- H. Simpson

        by midnight lurker on Tue Apr 02, 2013 at 09:38:21 AM PDT

        [ Parent ]

        •  Even 2X is daunting (0+ / 0-)

          Every kilo of energy storage means more airframe weight to carry it, more energy expended to move it, and then a bit more energy storage yet again...

          Look at all the trouble Boeing is going through just to put a slightly lighter battery in the 787, and that's not even for powering the engines.

          A 747 or A380 churns through the power equivalent to something like a quarter of a Boston-sized city. That's chemical energy converted directly to mechanical. Think of the electrical energy storage it would take to do that.

          Of course, we could fly slower...

          Government and laws are the agreement we all make to secure everyone's freedom.

          by Simplify on Tue Apr 02, 2013 at 11:19:55 AM PDT

          [ Parent ]

          •  You just reminded me (1+ / 0-)
            Recommended by:
            Simplify

            of an article I read about the possibility of small dirigibles powered by solar and propelled by electric motors. Perhaps that's a more feasible application where speed isn't as important, like freight, weather monitoring or, er, drones.

            "Liberty without virtue would be no blessing to us" - Benjamin Rush, 1777

            by kovie on Tue Apr 02, 2013 at 03:57:53 PM PDT

            [ Parent ]

    •  There are some light aircraft (4+ / 0-)
      Recommended by:
      Ice Blue, KenBee, kovie, BlackSheep1

      now flying with electric motors.

      I don't know if and when they'll be able to scale up the technology to something the size of an airliner.

      It raise some interesting problems. We currently land at a much lighter weight than at takeoff because of all the fuel we burn off.

      A battery powered plane would have the same landing weight as takeoff weight.

      If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

      by Major Kong on Tue Apr 02, 2013 at 10:43:47 AM PDT

      [ Parent ]

      •  Unless a light, affordable and efficient (0+ / 0-)

        means of generating enough electricity through the consumption of some sort of fuel could be found that changed that, perhaps working in concert with more conventional batteries and solar. I'm talking way out of my league scanning the cover of the latest Popular Mechanics speculation here.

        Incidentally, I was just in a Radio Shack and saw that they had this battery-powered RC plane for around $40 that used these small ducted fans for power. So obviously this works, only on a very, very small scale.

        I just think that with fossil fuels becoming scarcer (and eventually completely depleted) and bad for the environment no matter how clean we make them, and synthetic fuels being expensive and also bad for the environment, even if less so, we're going to need a whole new means of propulsion eventually, and likely sooner than we want to believe.

        "Liberty without virtue would be no blessing to us" - Benjamin Rush, 1777

        by kovie on Tue Apr 02, 2013 at 04:03:35 PM PDT

        [ Parent ]

      •  so in a future diary could you (1+ / 0-)
        Recommended by:
        RiveroftheWest

        compare / contrast JP-4/8 and, say, diesel? (Field expedient BUFF-grade diesel, please -- I'm pretty sure recycled french fry grease would not meet the need).

        LBJ, Lady Bird, Van Cliburn, Ike, Ann Richards, Barbara Jordan, Molly Ivins, Sully Sullenburger, Drew Brees: Texas is NO Bush League!

        by BlackSheep1 on Tue Apr 02, 2013 at 08:49:02 PM PDT

        [ Parent ]

  •  If you can keep the tone (5+ / 0-)

    as conversational as this Diary, and add just a bit more technical stuff it would be pitch perfect. As it is, it's pretty damned close :)

    By the way ... I haven't heard "suck, squeeze, bang, blow" for years!

    I hope that the quality of debate will improve,
    but I fear we will remain Democrats.

    Who is twigg?

    by twigg on Tue Apr 02, 2013 at 06:18:59 AM PDT

  •  LIFT is the reason, they fly. Not propulsion. (0+ / 0-)

    If there wasn't LIFT, propulsion would just give you a giant hotrod on the ground with wings.

    "For we, the people, understand that our country cannot succeed when a shrinking few do very well and a growing many barely make it." - President Barack Obama, Second Inaugural Address, January 21, 2013.

    by surfermom on Tue Apr 02, 2013 at 06:43:29 AM PDT

    •  But he made the point that you have to move first (3+ / 0-)
      Recommended by:
      Crider, TheDuckManCometh, BlackSheep1

      That giant hotrod on the runway isn't going upward at all, if it doesn't get moving forward first. A stationary object on the ground has zero lift no matter how good the wing design.

      It's a series. And off to a good start.

      No, I mean join the club, man. We meet every Thursday. We're trying to raise money for a field trip to Amsterdam. -- Leo (Tommy Chong) on That 70's Show.

      by lotac on Tue Apr 02, 2013 at 06:51:59 AM PDT

      [ Parent ]

    •  You are correct (1+ / 0-)
      Recommended by:
      BlackSheep1

      But we don't get lift without forward motion, which takes some form of propulsion unless we're going to push it off a cliff.

      It's kind a "chicken and egg" problem but I figured I'd start with propulsion first and talk about lift, drag etc. in the next one.

      If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

      by Major Kong on Tue Apr 02, 2013 at 10:38:36 AM PDT

      [ Parent ]

    •  And yet it has been advances in propulsion (1+ / 0-)
      Recommended by:
      badger

      technology that have led to the biggest jumps in airframe development, I'd say more so than the other way around.

      (Until someone builds a blended wing-body airliner, possibly.)

      Perhaps I've just started a pie fight...

      Government and laws are the agreement we all make to secure everyone's freedom.

      by Simplify on Tue Apr 02, 2013 at 10:55:59 AM PDT

      [ Parent ]

  •  Keep 'em coming, please (4+ / 0-)

    We want more!

    No, I mean join the club, man. We meet every Thursday. We're trying to raise money for a field trip to Amsterdam. -- Leo (Tommy Chong) on That 70's Show.

    by lotac on Tue Apr 02, 2013 at 06:53:31 AM PDT

  •  Now I see why it might take (0+ / 0-)

    Occupy a while to engineer the necessary propulsion to fly...

    What's the point of letting neoliberals into the tent when neoliberalism is burning down the campground?

    by Words In Action on Tue Apr 02, 2013 at 07:00:40 AM PDT

  •  lifespan of Gen 1 Turbojets (2+ / 0-)
    Recommended by:
    elfling, BlackSheep1

    was closer to 8 hours

    then tear out, overhaul.

    The new ones get 10,000 hours between overhaul.

    you also may want to mention ETOPS

  •  Just a coupe of things... (6+ / 0-)

    Actually, the last of the 'big bangers' in recip terms, which was used in airliners, was the P & W 4360 of 28 cylinders. This went into the Boeing 377 Stratocruiser (BOAC had 'em) and many other aircraft.

    The coolest recip engine for aircraft applications has to be the Wankel rotary (with absolutely NO cylinders!) and its various clones. This may be the recip of the future for light aircraft.

    The Rolls-Royce Conway was the first successful commercial turbofan (with a VERY modest bypass ratio!) It went into the 707s of various airlines, and the VC-10 amongst others. IIRC the bypass ratio was only 0.25

    Nice post, rec'd and tipped!

  •  propfans, or unducted fans or ultra-high bypass (3+ / 0-)
    Recommended by:
    BRog, Simplify, basquebob

    Trying to bridge the gap between turbofans and turboprops: get the speed and altitude of a fan jet but the fuel efficiency of a turboprop.  Think of them as an unducted fan: remove the duct and have fewer but thicker blades.  Some versions look more like propellers, others look more like old low-bypass turbofans with blades sticking out.  They work, and they're about 30% more efficient than turbofan engines, but the problem they're running into is noise.  When the tips of your blades are traveling faster than the speed of sound, they spin off lots of little sonic booms.

  •  Another great read! (3+ / 0-)
    Recommended by:
    Simplify, badger, BlackSheep1

    Bookmarked to finished later...only got to turbofans. At last, a good explanation of the differences. Thank you.

    Plus,

    At one time all aircraft were powered by piston engines,...
    Ah, gee, my first airplane was powered by a rubber band that I had to wind up by hand.  heh.
    •  I had one of those too! (1+ / 0-)
      Recommended by:
      BlackSheep1

      Never could get the thing to go in a straight line.

      If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

      by Major Kong on Tue Apr 02, 2013 at 10:30:56 AM PDT

      [ Parent ]

  •  GE aircraft engines differ from GE power plants (2+ / 0-)
    Recommended by:
    Simplify, Ice Blue

    The number of control inputs/outputs (I/O's) on a jet engine available to the pilot on an airplane is minimal when compared to a power plant jet engine.

    Pilots do not know much about what is going on inside the jet engine as was mentioned .. % spool speed, oil pressure, EGT, fuel flow, etc.   In total, there are less than 10 I/O's on an aircraft engine.  Pilots do not know oil temp and many other items like burner flame temperatures spreads.

    Operators of a jet engine used on a power plant have over 1500 pieces of information (I/O's) available on the control system.  There are multiple flame temp signals for each combustion can, vibration monitors, etc.

    The difference in control system design is always interesting to look at and study.

    •  I don't have access to it (2+ / 0-)
      Recommended by:
      Ice Blue, BlackSheep1

      but I think a lot of that data is being collected in flight and sent back to the maintenance folks via datalink.

      On the 757 I do have oil temperature and oil quantity plus vibration as digital readouts.

      If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

      by Major Kong on Tue Apr 02, 2013 at 10:27:57 AM PDT

      [ Parent ]

    •  Trust me, (1+ / 0-)
      Recommended by:
      Farugia

      most aeronautical engineers don't know squat about aviation, either.

      Any jackass can kick down a barn, but it takes a good carpenter to build one.--Sam Rayburn

      by Ice Blue on Tue Apr 02, 2013 at 12:28:41 PM PDT

      [ Parent ]

  •  where do the mice go? (2+ / 0-)
    Recommended by:
    ArchTeryx, bobinson

    the ones that power the engines?

    I already knew about the snakes in the plane. It gets everyone up, jumping out of their seats, making the plane that much lighter when they jump, so the plane pops up into the air.

    I understand that taking off is the most difficult part, requiring a whole lot of power and fuel, stuff that is not needed once you finally reach the air. That is why they developed JATOs and other fancy devices for military craft. IN the cause of efficiency and maximum profit, why are JATO devices not used in civilian aircraft?

    What we call god is merely a living creature with superior technology & understanding. If their fragile egos demand prayer, they lose that superiority.

    by agnostic on Tue Apr 02, 2013 at 09:56:41 AM PDT

    •  They're freakishly expensive and quite dangerous. (1+ / 0-)
      Recommended by:
      agnostic

      JATO devices are not routinely used, in fact, they're pretty rarely used even by the military.  They were designed to get heavy or overloaded cargo planes off short or unpaved runways in the field.

      There actually was an accident during testing in 1980 when a C-130 crashed due to a JATO malfunction.  It wasn't on takeoff, though - it was a short field landing test.

      Used to be that the Blue Angels carried Fat Albert (a Marines C-130T) with them to demonstrate a JATO, though I don't think they do that any more due to the expense.

      •  The mice? (1+ / 0-)
        Recommended by:
        ArchTeryx

        We use similar devices when launching the latest craft to space.  They have become cheaper and safer with time. I assure the same could be done with JATOs.

        or even mice.

        What we call god is merely a living creature with superior technology & understanding. If their fragile egos demand prayer, they lose that superiority.

        by agnostic on Tue Apr 02, 2013 at 02:05:14 PM PDT

        [ Parent ]

      •  C-130 JATO Takeoff Is Impressive (2+ / 0-)
        Recommended by:
        BlackSheep1, ArchTeryx

        JATO mounted backwards ahead of the wing for short landings was sort of ill-conceived, to say the least.

        "Facts are meaningless. You could use facts to prove anything even remotely true." -- H. Simpson

        by midnight lurker on Tue Apr 02, 2013 at 08:22:54 PM PDT

        [ Parent ]

    •  JATOs were incredibly dangerous (3+ / 0-)
      Recommended by:
      Simplify, agnostic, BlackSheep1

      Once you fired the JATO units there was no stopping. They also had a tendency to explode on occasion.

      There were mostly used on planes like the B-47 because the early jet engines were so lacking in thrust.

      If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

      by Major Kong on Tue Apr 02, 2013 at 10:16:59 AM PDT

      [ Parent ]

    •  I remember seeing JATOs in Nat'l Geographic photo, (1+ / 0-)
      Recommended by:
      agnostic

      being used on planes in Antarctica; the snow and ice "runway" was short and probably bumpy, and the JATO units were strapped on so that they could take off at all, I guess. It did look dangerous but so far as I know there were no crashes. This was back in the 1960's.

  •  Your engine (turbojet/fan) starting reference is (1+ / 0-)
    Recommended by:
    Simplify

    accurate..

    The APU has a quite a job load to do (when it is on the ground):
      1. provide bleed air to start the first engine
      2. provide electrical power to the aircraft while it is parked at the airport (computers/lights/AC/water/cockpit power)

    Yes, there batteries that are used to start the APU from a cold start (See 787 problem).  

    On the larger twin jets (767/777/787) one of the main engines bleed air is used to start the APU before landing.  The 737 and 747 use electrical power to start the APU.  

    All aircraft can use the external diesel power starter to start one of the engines.  

    "Death is the winner in any war." - Nightwish/Imaginareum/Song of myself.

    by doingbusinessas on Tue Apr 02, 2013 at 09:57:14 AM PDT

  •  This series is an excellent introduction to those (2+ / 0-)
    Recommended by:
    TheDuckManCometh, BlackSheep1

    of us who spend most of our life on the ground.

    I always learn something when I read one of your essays, Major Kong. In fact you're one of the few people on here that I "follow."

    Keep up the excellent work!

  •  Loved it! (1+ / 0-)
    Recommended by:
    BlackSheep1

    I've spent a lot of time in the passenger cabins of aircraft over the years from DC3s still in use in the late 60s to B777s and AB340s more recently (Still haven't had a flight in an AB380, though) not to mention a few odd ones like Ilyushin 18s, Canadair CL44s, and Tupolev 104s.  In all those flights, I've never completely understood how any of the damned engines worked.  Yours is the most succinct explanation of any I've ever read.  Thanks a whole lot!!!  And keep 'em coming.  If I can make a suggestion:  I'd love to read a diary about Russian passenger aircraft.  

    -7.13 / -6.97 "The people never give up their liberties but under some delusion." -- Edmund Burke

    by GulfExpat on Tue Apr 02, 2013 at 10:42:15 AM PDT

    •  That would be an interesting diary (1+ / 0-)
      Recommended by:
      BlackSheep1

      I've never flown one but I've seen a few of them while flying in Europe. I'll see what I can come up with.

      If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

      by Major Kong on Tue Apr 02, 2013 at 12:21:06 PM PDT

      [ Parent ]

      •  BTW, one of the Russian turboprops (0+ / 0-)

        had two counter-rotating propellers on each of its four engines, as I recall.  I can't remember whether it was one of the Ilyushins or Tupolevs, though.  The IL-18 that I mentioned above was a real work horse.  It was really noisy inside, I remember, and rather reminiscent of a DC-6 at least externally, but it could be held together with baling wire, apparently.  (Some nice shots of them on Airliners.net, which I presume you're aware of)

        -7.13 / -6.97 "The people never give up their liberties but under some delusion." -- Edmund Burke

        by GulfExpat on Wed Apr 03, 2013 at 01:02:54 PM PDT

        [ Parent ]

        •  The TU-95 and its variants (0+ / 0-)

          They still use them. It's one of the fastest propeller driven aircraft ever, also insanely loud.

          There was even an airliner version called a TU-114.

          The IL-18 is more conventional and somewhat resembles a Lockheed Electra.

          If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

          by Major Kong on Thu Apr 04, 2013 at 11:29:51 AM PDT

          [ Parent ]

  •  MORE PLEASE! (0+ / 0-)

    This is entirely beyond my comprehension, and I love it!  Hell, suck, squeeze, etc., is beyond me, but it provided a rough basis for comprehension (which has been lost entirely with my somewhat current cars).  I look forward to your continuation.

    Thanks again even if I'm lost; at least I can enjoy rereading it...

  •  nicely put! (0+ / 0-)

    I am/was (now in software) an aerospace engineer, and that's a lot clearer than I could explain it.  I'm eager to see how you explain the actual physics of flying, because I'm never good at doing that even though it makes sense to me...

  •  This is great stuff. Thanks so much Major Kong (0+ / 0-)

    for your writing in layman terms helping me to better understand a subject that's always fascinated me since childhood.  I truly look forward to future installments of this series as your time allows.  Happy skies good sir!

    Father Time remains undefeated.

    by jwinIL14 on Tue Apr 02, 2013 at 11:56:01 AM PDT

  •  Question (0+ / 0-)

    Is the exhaust cone adjustable on an airliner engine? I have seen videos of F-14s take off and it appears that the exhaust cone can get wider or more narrow based on when they need more thrust. Of course, airliners don't have afterburners but it would be cool for a couple of minutes.


    i just baptized andrew breitbart into the church of islam, planned parenthood, the girl scouts and three teachers unions. - @blainecapatch

    by bobinson on Tue Apr 02, 2013 at 12:09:44 PM PDT

    •  Not that I know of (1+ / 0-)
      Recommended by:
      bobinson

      The movable nozzles are normally a function of the afterburners. The nozzles schedule from:

      Idle power - open
      Military power - mostly closed
      Full afterburner - open

      If one sticks open (happened to me on the T-38 once) you get little or no thrust from that engine.

      Supersonic aircraft also normally have movable intakes, ramps or shock cones to keep the air going into the engine subsonic at higher speeds.

      If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

      by Major Kong on Tue Apr 02, 2013 at 12:18:13 PM PDT

      [ Parent ]

  •  tippen recced / nm (0+ / 0-)

    The "extreme wing" of the Democratic Party is the wing that is hell-bent on protecting the banks and credit card companies. ~ Kos

    by ozsea1 on Tue Apr 02, 2013 at 12:30:21 PM PDT

  •  With enough propulsion even a pig will fly. n/t (1+ / 0-)
    Recommended by:
    lazybum

    Never argue with an idiot. They will drag you down to their level and beat you with experience.

    by thestructureguy on Tue Apr 02, 2013 at 12:41:45 PM PDT

  •  "These diaries are meant to be informative and (2+ / 0-)
    Recommended by:
    lazybum, BlackSheep1

    easy to understand for those with little or no technical knowledge."

    You did it...even I understand it.

    Takeoff EPR for a water injected KC-135A: 2.83  
    Loud.

    "We refuse to fight in a war started by men who refused to fight in a war." -freewayblogger

    by Bisbonian on Tue Apr 02, 2013 at 02:16:48 PM PDT

  •  It's funny you should say.... (1+ / 0-)
    Recommended by:
    RiveroftheWest
    Until someone perfects the hypersonic scramjet the or warp drive this is what we're stuck with.
    Because those are my next two projects!

    ;0)

    In the Fox News Christian Nation, public schools won't teach sex education and evolution; instead they'll have an NRA sponsored Shots for Tots: Gunz in Schoolz program.

    by xynz on Tue Apr 02, 2013 at 03:09:31 PM PDT

  •  Is that before or after (2+ / 0-)
    Recommended by:
    BlackSheep1, RiveroftheWest

    you cure cancer and establish a permanent Middle East peace?

    If the pilot's good, see, I mean if he's reeeally sharp, he can barrel that baby in so low... oh you oughta see it sometime. It's a sight. A big plane like a '52... varrrooom! Its jet exhaust... frying chickens in the barnyard!

    by Major Kong on Tue Apr 02, 2013 at 04:07:28 PM PDT

  •  Thanks Kong (3+ / 0-)
    Recommended by:
    BlackSheep1, lazybum, RiveroftheWest

    Really enjoyed the entire post.

    I once was on a L-1011 headed for Seoul from Portland, OR.  Just about the time the pilot rotated, there was a loud bang.  He dropped the nose back on the ground and slammed on the thrust reversers.  We managed no to roll off the end of the runway.  Taxied back to the terminal deplaned and got to wait for 11/2-2 hours, while they replaced a "fuel filter".  Longest 11 hour flight I've ever taken....

    I voted for more technical.  Like do jets suck or do they blow??? 8^)

    “that our civil rights have no dependence on our religious opinions, any more than our opinions in physics or geometry.” Thomas Jefferson

    by markdd on Tue Apr 02, 2013 at 07:36:53 PM PDT

  •  Thanks (1+ / 0-)
    Recommended by:
    RiveroftheWest

    Great read, I love these. I was a Aircraft Structural Maintenance Mechanic in the Air Force, but always wanted to be a pilot and still spend alot of time playing flight sims. Thanks.

    "Always do sober what you said you'd do drunk. That will teach you to keep your mouth shut." -- Ernest Hemingway

    by keithcfh11 on Wed Apr 03, 2013 at 11:37:10 AM PDT

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