Sucks, squeezes, bangs, blows, and goes
Engine runs.........Fuggin A! Throwing throttles in an 80,000 lb hunk o metal....the plane lurches and rocks with every throttle movement responding to your commands ...producing so much thrust she blasts everything in her path. Enough thrust to send a small plane taxiing behind her hurling like a tumble weed. What's not to like about engine runs? It is different everytime, never know what could go wrong. And because we are doing maintenance ops checks things do go wrong. From jumping chalks...to emergency shutdowns for any number of reasons, smoke, fire equipment malfunctions. The plane shaking and straining against the chocks when we are pulling power while I run thru the maintenance checks with the run crew. The original write up was a a hung start with low TIT (turbine Inlet temp). It happened in both auto and null. Which means if this engine were a reciporcating engine in a car...it would be cranking over but not starting. Youd have spark but no ignition. Which means your not getting fuel.But The fuel pumps were working. So very simply put....the component that we call a carburetor on a car is called a fuel control for a jet engine. It meters fuel to the manifold, but it has more bells and whistles than a carb. You know when you drive from low elevation into the mountains how you have to adjust the mixture on your carb or the car runs like crap. Well ours has the bells and whistles to do that automatically. Not real practical to have the mechanic get out there while we're flying along to adjust it. To further complicate a simple system we throw the "TD" or temperature datum system into the mix. Well it basically limits the temp of the engine by further adjusting fuel flow. More or less for optimal engine performance. We can actually select "null" and bypass or "null" the whole TD system. Sounds sexy huh? However normal operation is auto or the TD system operating. Dont want to get to technical on the operation of a jet engine.......it is actually pretty simple... if anyone does have any questions about the technical aspects ask away......or about planes in general.......
So today was a great day, cuz it was me against the clock and i won..You can schedule a plane all you want but if she doesnt want to fly she wont. And only a good mechanic can change her mind, No general can order her to fly ....just the crewchief. Can you hear me smiling?
.....i will never forget though in tech school which is AIT for those fluent in army......., when someone raised their hand and asked how a jet engine worked on the first day of class, and the teacher responded "well.....It sucks, squeezes, bangs, blows, and goes."
By the text book there are indeed 4 sections to a jet engine. Intake Section=takes in air=sucks The Compressor Section=compresses air for more efficient burning=squeezes The Combustion Section= burns the fuel air mixture=bangs and the exhaust section=expels heat and unburned gasses=blows + ...goes=the thrust produced by the first four.....moving the aeroplane outta dodge!
You know one day i wanted to get to my site so i typed in the title live from the rear..... and boy was i surprised to find the sights that got brought up....of course mine had not came up until i put in the actual addy. I considered changing the name at that point, pretty embarrassed by my ignorance. I can just imagine where this post will end up!