O/T Jet Engines

OK it passed today even though it was like 35 degrees outside. +2 HP over the limit of what it was designed for (weak engine but I'll take it) BUT it now has high lube pressure. Can't win with this engine.

 

I won!!! Engine passed finally!!! Whewhoo!!!!

 

Hope you don't charge shop rate. They could have bought a new engine for the bucks they paid for labor.

 

Yeah only 11 test cell runs and about 2000 manhours. LOL

 

For future reference:

 

So what was the problem(s)?


R

 

I can't believe i missed this thread! I'm curious as to what caused the engine to be down 250hp tho!

 

Turbine nozzle areas were changed drastically. We were T5 limited which is like saying that if you run this engine any hotter I'm going to blow myself up so what I had to do was figure out how to change the nozzle areas in such a way that I cool it down so I can spin it faster so it can run hot again, get it? We want the turbine spinning as fast as you can to compress more air to spin the turbine faster to compress more air to spin the turbine faster to compress more air to spin the turbine faster to compress more air to spin the turbine faster to compress more air ...It's not an exact science especially with temperatures (OAT) in the 30's which requires the engines to produce more horsepower than say on a nice warm summer's day because the air is denser. Get it Nick?

 

so your nozzle area was too small?

 

No. It was the right size....according to the engineers. We have 4 stages of turbine nozzles. Two to direct hot air to the gas generator that powers the compressor rotor and two to direct the remaining hot air to the power turbine (which powers a gearbox which turns a rotorhead on a helo)So typically you would want smaller nozzles with the gas generator to speed the compressor rotor faster and larger nozzles with the power turbine to keep it cool so you don't reach that dreaded temperature limit. Imagine a nozzle to be like your garden hose nozzle, the smaller you make the hole the faster the water streams out.

 

so is it a "freepower" turbine or is the shaft directly connected?

 

free spinning power turbine yes.

 

i worked on army turbine engines for years. said, screw that, working on my dirt bikes got me my $weet tech rep job!!! pioneer uav's rule!!! (and i make sure i'm never around, that's what they teach ya in school!!!!) ha! ha!!!