Seggy
Well-Known Member
Must be the position of the moon
Turbine DONT's
- Thread starter chrisreedrules
- Start date
Must be the position of the moon
SpiraMirabilis
Possible Subversive
Wasn't there a American Eagle Saab or ATR or something that crashed and killed everyone because they went into Beta during flight? I recall, because they had to put a WoW logic so that they can't do that anymore in the Dash-8 after it happened and I learned about it in systems class.
Cptnchia
Dissatisfied Customer
Hopefully it's not with the Obamalove they wrap themselves in.
dasleben
That's just, like, your opinion, man
Noooooo.
NickH
Uber Driver
Yeah stay away from that, it's sticky.
X-Forces
Big Black Guy
It is what it is, and it is 8 seconds
Think what you like. Just came from recurrent last month. we talked about it for some time, think is why I was able to recall the FAR 25.119. We talked a lot about that too. Look it up, it is in the specs.
dasleben
That's just, like, your opinion, man
I'm not arguing with you; like I said, I've never flown one. Just find it strange for a smaller high-bypass turbofan. I just looked at my wall clock and counted out 8 seconds, and that is a heck of a long time.
SlumTodd_Millionaire
Most Hated Member
Yeah, can't say I ever personally experienced an eight second spool time on the CF34s. Maybe if they had been at idle at slow airspeed, but even then, I never removed it being that bad.
X-Forces
Big Black Guy
Totally agree.
And I wasn't trying to argue it back, just saying that it was a major topic of discussion during our last ground. I am no CRJ expert.
MNFlyboy
Well-Known Member
ok so here's a question I have for you turbo-prop fans, on right engine start on a KA, right engine lights, idles at 52% in low idle. Gen on, charge up, gen off. Left engine, ignition and starter on. (Notice I never moved the condition lever to high idle to increase N1 to 70%). Right Gen on, Left condition lever to low idle. As the left engine spools up, the right one, due to gen load, spools down to as low as 46%. Once the left is started and the starter is disengaged, low idle comes back up. What's the theory on how low a PT-6 would have to go before it quits? I've also watched the ITT during this, and although it increases significantly, it never gets close to red line.
Thoughts?
Thoughts?
The TF-34 varied......6 to 8 seconds for full spool-up depending on how the motor was trimmed. Little power changes from idle or low power were quicker to react. Certainly wasn't a fast engine in acceleration, which is really the point you're making and which I agree with.
undflyboy06
Well-Known Member
That's a very good question. I'll take a shot in the dark and say upper 30's for the N1. My theory is because since the gas turbine is still spinning, everything on the accessory case is still working; high pressure pump, oil scavenge pumps...ect.). As you are getting into the upper 30's, there is a insignificant amount of airflow for proper cooling, and you still have all primary and secondary fuel nozzles pumping out fuel. Therefore, I think the engine would temp out around that range instead of quitting.
MNFlyboy
Well-Known Member
That's true, plus you're close to losing the secondaries due to low fuel pressure.
I should clarify......small power changes across the band, working the throttle a bit, the lag wasn't very noticable. On very short final with the proverbial school bus full of kids that magically appears on the runway and you have to go from idle to full spool up, was very noticable....in comparison to other airplanes. But, like anything else, when the Hog is all you fly, you stop noticing any lag because it's "just normal"
Our biggest problem was in ACM, as the jet had a large engine disturbance zone in varying combinations of AOA and G loading, to where the wrong combo would cause anything from a minor hiccup on the good side, to a full compressor stall and overtemp on the bad side. Really had to be aware of any kind of asymetric maneuvering while making power changes (and even if not) due to this problem being such an issue.
I'm not afraid if jet fuel will hurt you (it probably causes cancer) but the smell doesn't leave you, especially if you get in on your clothes. Might not matter in the airline world but in corporate jets whether or not prist is required or recommended is a fair amount of money for your particular operation. Start a jet engine with a 20 not tailwind and see how hot your start is. Spool time has already been discussed.
auw2fly
Goldmember
For PT6's, know your starter limitations, and know how long a normal start takes. The difference between those two is the amount of time you can spool the engine to bring the ITT down.
And if on the start sequence you forget to turn on the igniters, DO NOT turn them on after fuel has been introduced. I know a guy...
(No seriously, I know a guy that did that, it wasn't me)
And if on the start sequence you forget to turn on the igniters, DO NOT turn them on after fuel has been introduced. I know a guy...
(No seriously, I know a guy that did that, it wasn't me)
TFaudree_ERAU
Mashin' dem buttons
I know a guy that made big flames come out of the back of a CF-34...
z987k
Well-Known Member
I've only flown 1 model pt6, but the igniters come on with the start switch. Up and you get the starter and igniters, down is starter only.... but you have to hold it down... seems like it'd be incredibly hard to make that mistake.
X-Forces
Big Black Guy
I have. Trust me, it seems like a REALLY long time.
