help a guy find some stuff for AirWis

[I.P. Freley]

Six stages!?

Errrrrr....

I don't understand how Fox2 said "suck, squeeze, burn, blow" (4 cycles) and then came up with six "stages"!

The generic "suck, squeeze, burn, blow" is correct... 4 cycles, just like an Otto Cycle piston engine. A 4 cycle engine actually has 5 "events", of which the fifth is ignition. The real "stages" however, are:

Intake
Compression
Power
Exhaust

Obviously, the ignition event occurs between steps two and three.

Referring to "burner cans" can be misleading, as not all turbine engines HAVE burner cans (and they are not a "stage" of the engine as such). There are three types of burner sections, if I am not mistaken: Can, Annular, and Can-Annular.

Guess that Riddle education paid off now, eh?

 

[Fox2]

Help a guy...

I.P.Freely:

in response to your posting I offer the follwing:

1. I presented the mnemonic as a means to aid in correctly remembering the four stages of a turbine engine.

2. I expounded upon the mnemonic because those parts are often asked in interviews.

3. Your reference to a piston engine is a non-sequitur. The question was about turbine engines.

4. Ignition in a turbine engine takes place IN the combustion section, not BETWEEN the compressor and the hot section as your assert ("between steps two and three.").

5. You are correct concerning the three types of burner cans. However, the burner cans are in the hot section which IS a major component of a turbine engine. Typically in an interview, if one were to just say "hot section" it encourages a follow-on question as to what's in the "hot section."

6. A trubine engine develops THRUST, not POWER! Thus, your third stage is incorrect.

I'd get a refund on that "education."

 

[I.P. Freley]

I AM trying to help!

Gosh, what a froth I have whipped you into! Too bad I was trying to help a brutha out and correct your mistakes for his/her benefit, but I guess a fight is all that you want.

1- Your mnemonic device correctly identifies the four CYCLES of a turbine engine, not the STAGES of a turbine engine. You did identify them as "the four stages" and then named SIX. Your words, not mine.

2- Your expansion thereon only partially identifies the STAGES of a turbine engine, and incorrectly identifies at least one of them (burner can).

3- My non-sequitur isn't a non-sequitur at all. If you really claim to know anything about engines, then you would admit that all internal combustion engines accomplish the same four cycles, just by different means. If you were trying to simplify the process by way of mnemonic device, why can't I simplify the process by pointing out that recip engines have the same four cycles?

Answer: I can, but you want to start a fight.

4- Of course ignition takes place in the combustion section. I never said it didn't. I pointed out that ignition is an "event" (go back and read it again)... Just like ignition is an "event" in a radial, a v-engine, and inline engine, a rotary engine, and yes, a turbine engine.

5- I would never simplify an engine discussion in an interview into "hot section" and "cold section", which is apparently what you espouse. I would be more specific, which is what I would assume an interviewer would expect as well.

6- A "trubine" engine only develops "THRUST", not power? Well, well, well... I hope your discussion of a turbine engine would include what happens to all the happy gases that escape the combustion section. Some of that "power" (admittedly thrust, but converted into rotational energy) goes to drive the compressor, some goes to drive the power turbines (fan or prop in most modern engines), and what is left is "thrust". I imagine a number of turboprop pilots, especially, would be interested to know that the engine in their airplanes only produces "thrust". The PT-6 in a 1900, for example, produces only about 10% of its' total ESHP in jet thrust, the rest by the propeller. That is why TP engines are rated in SHP and not in "thrust".

Or... Do TP engines not count as "turbines"?

Sounds to me like your explanation of a turbine engine only includes turbofans and turbojets (your explanation of "low speed compressors" obviously referring to shrouded engines). A shame, there are other kinds as well. No need to pigeonhole our explanations of airplane engines to only include "thrust" engines.

I'm quite happy with my education, thanks. No refund necessary.

If you wish to discuss this further, just send me a PM. I'd be happy to discuss the intricacies of turbine engines with you, but this thread need not be hijacked any further.

 

[watr1]

interview

Hey DashDriver..hope all went well. I've got mine coming up soon, any gouge in addition to the aviation interviews.com stuff would be greatly appreciated.

Take care - hope you got it...

watr1

 

[atpcliff]

Hi Citdrver!

I'm way ahead of you! I have three, count 'em 3 rejection letters from AWAC. I even went down in person and talked to the lady in charge of setting up the interviews--no go!

I have a good chance to get in soon, but it's not clearcut that AWAC would definitely be a better job than what I have now.

CLiff
GRB

 

[citdrver]

Cliff,

What are you doing now?

And of course, are you hiring??

Take Care

 

[DASHDRIVER]

Oct 13th!!!

I got the call and will be going to Class on the 13th of this month!
Everyone is really great up in ATW and I am so excited to get out from under the US Airways WO debacle. The gouge from me will be up soon on the interview site. Current gouge is very acurate. The best advice I can offer is be yourself. They are not overly technical, just want to see if you'll fit in to the group. And practice the sim the night before I was the only one out of my group that did and I was the only one hired.

I guess I'll have to change my ID to DASHDRIVER NOMORE!!

Regards

DD

 

[I.P. Freley]

Congrats... I guess the only question now is if you CAN change your ID!

 

[citdrver]

Congrats Dude!!

 

[belchfire]

In europe, where they do many
strange things turbine engines
(thrust and shaft both) are rated
in kilowatts, which is a power
measurement. They do that because
kilograms are a mass unit and it
would be incorrect to say kilograms
of thrust...could say newtons.

Pounds are a force unit, and forces
can do work (work is a force applied
over a distance, power is the rate
work is done at). I think the english
foot/lb system mass unit is a "stone",
but not sure. weight is the measure-
ment mass being acted on by gravity,
that's why in space you are weightless,
but not mass-less.

Anyone want to get more confused?
Just give the word!!!