Sport_Pilot

Yeah, and he was right. We now suck.

HoundDog

My Feedback: (49)

Originally Posted by HoundDog
Do U suppose that has some to do with that "Giant Sucking Sound" - Ross Perot 1992

Not to be Political or "Nutt'n" but it was Billy Mr. Perot was debating with about trade treaty's.
How'd that turn out?

Sport_Pilot

Billy of Billy's Beer? Or his brother? Billy was in the late 70's and Perot in the 90's. I think you mean Bill, not Billy? One a drunk and the other a philanderer.

HoundDog

My Feedback: (49)

I mean Billy soon to be the first (LADY) man These debates is where it came from:
https://www.youtube.com/watch?v=Rkgx1C_S6ls

Hydro Junkie

NO, YOU'RE THE ONE THAT ISN'T GETTING IT!!!!!!!!!!!!!!!!! For a turbine engine to run, it has to be pulling air through the fan. The result of pulling air through the fan is negative pressure. For the plane to stay in the air, it has to have sufficient thrust to maintain airspeed, EVEN IN A LANDING CONFIGURATION OR DIVE!!!!!!!!!!!!! Now, going back to the GE90 used in the 777, it has a maximum operating speed or 2550RPM with a MINIMUM N-1 OF 50% or 1275RPM while in flight. This prevents positive pressure from building up in front of the fan as well as providing enough speed to keep the accessory pack running within prescribed limits. You also have to remember that, while on a landing approach, the aircraft is in a "dirty" configuration, requiring more thrust to overcome the additional drag of the flaps, slats and landing gear now extended in preparation for landing. To drop below 50% N-1 reduces electrical generation, hydraulic pressure and thrust below operational requirements needed to operate the aircraft properly

Sport_Pilot

You are still not getting it. Even at full thrust there is little suction in flight. At minimum thrust (idle) there is none or almost none. The airflow that is pushed into the engine from airspeed is enough to provide the minimum thrust, just as with the ram jet getting all its air from the incoming air. You have the same but less so with a jet engine at minimum thrust. None of the numbers you have presented disputes that.

Hydro Junkie

So where did you get your PHD on turbine engine theory? Your A&P License? Your jetliner maintenance and repair experience? Anything that would tell the rest of us you actually know what you're talking about because those of us that do have experience don't see you saying anything credible when it comes to jet engines. Init4fun verified my statement is in line with what is put out in A&P training programs so it sounds to me like you're the one that has faulty information

HoundDog

My Feedback: (49)

miss post sorry

Sport_Pilot

I don't know how it happened but edited my post and ended up with two, one edited and the original.

Sport_Pilot

QUOTE=Hydro Junkie;12239993]So where did you get your PHD on turbine engine theory? Your A&P License? Your jetliner maintenance and repair experience? Anything that would tell the rest of us you actually know what you're talking about because those of us that do have experience don't see you saying anything credible when it comes to jet engines. Init4fun verified my statement is in line with what is put out in A&P training programs so it sounds to me like you're the one that has faulty information[/QUOTE]

It is basic hydraulics. You have a pump or engine squirting fluid to the rear and the fluid is entering from the front. If the fluid is not moving then the pump creates a large negative pressure area in front and at angles from the inlet. You then put the pump in a moving stream and the negative pressure is less. If the stream flow equals the pump velocity you no longer have a negative pressure area in front. A jet engine is just a huge air pump.

No PhD but I do have a PE license.

Hydro Junkie

No, it's not basic hydraulics. The density of air going through the engine, regardless of altitude, is at least 500 times thinner than water. Therefore, fluid to air comparisons don't work. First off, if there is positive pressure in front of the fan, there will be the corresponding coefficient of drag that will be slowing down the plane. To use the 100 inch fan on the GE90, that would equate to 15,708 square inches of flat frontal area from both engines. Truth be told, the push out of the rear of the engine only gives 40% of the effective thrust moving the plane. 60% is actually from air being drawn in to the fan. I'll continue this later since I just got told to go home

Sport_Pilot

There is little drag because the engine is running and preventing the air from piling up in front of the engine. There is positive pressure, but not as much as it would if the engine was off.
BTW air is a fluid. Hydraulics is not limited to liquid's.

Hydro Junkie

Are you really that stupid or just, as we all think, playing games?
Giving you the benefit of the doubt, let's talk terminology for a minute:
1) The term HYDRAULIC is based on the word hydro, meaning water. This can be expanded to oils and fluids made specifically for the purpose of operating equipment or, if you really want to push the envelope, anything that is in a liquid state, such as wet concrete. A good example of this would be hydroelectric power, being electricity generated by the flow of water spinning a generator, normally at a major dam such as The Grand Coolee in Washington or the Hoover in Nevada
2) The term PNEUMATIC is defined as anything being powered by air or gas under pressure.
3) WHAT'S THE DIFFERENCE BETWEEN THE TWO? IN A NUTSHELL, GASSES CAN BE COMPRESSED WHERE FLUIDS CANNOT!!!!!!!!!!!!!!!!!!!!! This simply means that since air is a gas, it cannot be a fluid and therefore IT CANNOT be used in a hydraulic type system. By the same token, a turbine cannot operate using a liquid medium because it can't be compressed 7 to 10 times like is done in a turbine engine
4) THESE ARE KNOWN SCIENTIFIC FACTS, TAUGHT TO SCHOOL KIDS STARTING IN 1ST GRADE

Hydro Junkie

Now, to finish what I started yesterday.
If there is positive pressure in front of the front fan, that means the engine is not producing thrust and therefore has to be freewheeling, effectively acting as a parachute on a funny car. Since the engines CANNOT pull enough air through the compressors on their own without the help of the front fan forcing air into the 2nd stage compressor, the front fan has to be pulling air through itself, putting higher pressure behind it than in front, THERE CANNOT BE POSITIVE PRESSURE IN FRONT OF THE FAN!!!!!!!!!!!!!
What also must be taken into account is the fact that the ACTUAL AIRSPEED of the aircraft WILL NEVER EXCEED THE SPEED OF THE AIR GOING THROUGH THE FRONT FAN DUE TO THE DESIGNED IN AERODYNAMIC DRAG OF THE AIRCRAFT'S STRUCTURE. This is why, on ALL SUPERSONIC FIGHTERS, they have doors in the engine air intakes that limits the amount of air into the engine, to prevent the possibility of positive pressure. To have positive pressure at the front of the engine, AT SUPERSONIC SPEEDS, would literally shear the engine mounts off and push the engine out of the aircraft

Sport_Pilot

Sorry but hydraulic is all fluids.

[h=2]hy·drau·lics[/h] (hī-drô′lĭks)n. (used with a sing. verb) The physical science and technology of the static and dynamic behavior of fluids.

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Not taught well in high school, but college teaches that the science is for all fluids, both liquid and air.

Sport_Pilot

I guess then per you second stage turbine compressors should not work because of the positive pressure in front of them. Really I think we have been talking positive pressure as pressure over atmospheric pressure. If you understand that actually all pressure is positive from 0 then it is easy to see that your statement is absurd.

init4fun

...

Hydro Junkie

And I'll bet you're talking a home air compressor, which is a totally different animal since the second stage does nothing more than increase the pressure capability of the pump when the tank gets full. Never seen a turbine compressor, always recip types with either one or two cylinders, the second being smaller in diameter than the first for the increased pressure output. BTW, I used to work at a shop that sold, maintained and repaired compressors so you're not going to fool me with that one. On an added note, there are also tankless constant run compressors that use a pressure switch to operate the inlet and outlet valves. These are almost always used in industrial settings with a dryer unit between the compressor and the load

Hydro Junkie

Which is why, in the first line of the post you quoted, I asked "Are you really that stupid or just, as we all think, playing games?". I think the answer is obvious, he's playing games. He obviously doesn't know anything about how a turbine engine works or even the theory behind how they move an aircraft. His trying to use the comparison between a turbine engine and a ramjet is so apples to coconuts that it's beyond laughable. I know I said in one post that a ramjet has no moving parts, other than a fuel regulator and takes forward movement to force air into the intake, something a turbine doesn't need. I guess stupid kids will be stupid kids, considering grade school kids know the difference between gasses and fluids and he doesn't. Just had a thought. If school kids know the difference between gasses and fluids and he doesn't, wouldn't that make him an infant in preschool?

Sport_Pilot

You guy's don't have a clue. I suggest you read the following especially chapter 1. "1. The nature and properties of fluids, forces, and flow."

http://johndfenton.com/Lectures/Hydr...Hydraulics.pdf

Sport_Pilot

I am talking about any two stage compressor but especially the jet engines that have a two stage compressor. The fact that it is are is not a positive displacement compressor does not matter in this instance.

BTW large refrigeration engines often have two stage turbine and centrifugal compressors that work much the same as a jet turbine compressor.

Sport_Pilot

Hydraulics has several sub sciences which are speculations of hydraulics. Pneumatics is one of them. As is hydrology and aeronautics.. Actually aeronautics has some elements not covered in hydraulics, but incudes many.

BTW I am only referring to the science of hydraulics, I did not call an oil operated actuator "pneumatic" or and oil operated actuator "hydraulic".

Hydro Junkie

Fine, Sport, believe what you want. I've stated my case based on KNOWN SCIENTIFIC FACT. It's too bad you and your buddy just can't help but twist things to suit your immature game playing. I'm done wasting time in this thread and any other you two are in as you are nothing more than trolls that should have been banned long ago

porcia83

My Feedback: (8)

Always interesting to see people calling others trolls, when I think that's the very definition of trolling. Why not just agree to disagree, or better yet not respond. And whats with the current trend of lumping people who agree with each other as "buddies", "pals" etc. If there's one or two people who also agree with you, wouldn't that also be the same case? So confusing!

Sport_Pilot

BS you posted some definitions that were incorrect. I showed you an online course on hydraulics that discussed fluids and that gas's are fluids and it included discussion of both. Look I have a college degree in mechanical engineering and a professional license in same. I have run the calculations to include compressible factors. You have not shown any proof you know anything about the subject. And no being able to do a hot inspection and repairs to a jet turbine engine counts.