Smaller turbine engines

ronnieh said:
Nope, wastegate opens to allow exhaust gas to bypass the turbine. No exhaust gas in the compressor. But I did type open when I meant close. The principle is the same. More exhaust gas into the turbine spins the compressor faster compensating for the thin air in a turbocharger. Compressor speed does not change in a turboprop once maximum thermodynamic horsepower is reached which will be at STP. Good night all.
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Turbochargers have limitations too, that's one reason for the wastegate. And even changing your origional wording from open to closed, it's still wrong.
 
mtuomi said:
Another example where airplanes take the worst possible option that's available :)
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Heh. The only other fixed wastegate I've flown behind was on my Cummins, and it wasn't supposed to be fixed. Someone had taken the effort to wire it shut to "give it more boost". And said wastegate and wiring job wasn't readily visible upon cursory inspection. ;)

Blew the head gasket right out of the front right corner of the head, somewhere around 35 pounds of boost. The gauge going that high was probably hint number one.

Looked for all the world like a water pump leak, so I kept pouring 50/50 into the radiator and flogged it another 1200 miles home pulling a 12,500 lb trailer.

Other than being louder than usual and seemingly sluggish to accelerate, it ran fine on five cylinders! I swear! LOL.

The diesel mech said, "I have good news and bad news. The good news is that it's not your water pump leaking..."

;)
 
N1 and N2 are the same as Ng and Np. Just depends on what model engine you're using. The old Allison 250 used N1 / N2. The newer RR 250 uses NG / Np.
 
Understand that, it's manufacturers choice in designation and there is no industry standard. The references to Np I found pertained to constant speed turbines. All of the turbine engines I've worked with have been variable speed and use N1/2/3 rotor spool denotation.
 
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GlennAB1 said:
Understand that, it's manufacturers choice in designation and there is no industry standard. The references to Np I found pertained to constant speed turbines. All of the turbine engines I've worked with have been variable speed and use N1/2/3 rotor spool denotation.
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Ok, I was just trying to clarify that that Ng & N1 are both compressor / gas producer turbines. It's just a difference in nomenclature.

Sounds like N2 designation for FW is a standard for a variable speed turbine. In helos, you could have N2 or Np. They're both the same; power turbine section.
 
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