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CRJ Engine Questions

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FrontierFan

Well-known member
Joined
May 3, 2004
Posts
106
I am writing a paper and I was curious if anyone with CRJ time could answer a couple of quick questions. I could probably find most answers on the net but I thought it would be better to ask the pros who fly the line.



1) Does your model of the CF-34 have a FADEC?



2) Does the engine have any type of variable controlled stator vanes?



3) How does the pilot flying regulate power requests (power up to a detent, up to a desired N1 or EPR, or combination) on takeoff, climb, cruise, and continuous?



4) Are there any main differences between CF-34 models for all the different aircraft they power (A-10, CRJ-100, 700, ERJ-170 etc. ) besides size and thrust output



Thanks in advance.



F9 Fan
 
1) CF-34's in the 700/900 have FADEC



2) Does the engine have any type of variable controlled stator vanes? yes




3) 700/900 has toga and climb detents, 200 is set by N1% with OAT input in the FMS



4) Are there any main differences between CF-34 models for all the different aircraft they power (A-10, CRJ-100, 700, ERJ-170 etc. ) besides size and thrust output many you have to look at all the individual manuals
 
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FrontierFan[font=Times New Roman said:
4) Are there any main differences between CF-34 models for all the different aircraft they power (A-10, CRJ-100, 700, ERJ-170 etc. ) besides size and thrust output[/font]


F9 Fan
The main difference is that the motors on the Hog produce nearly no thrust.
 
Thanks Guys,


Not to bring up old topics, but..

I am trying to determine if the Pinnicle Flt 3701' engines were equiped with a FADEC and if they were not, than could the compressor stall prevention provided by FADEC have helped in preventing the accident.

Any of your thoughts would be helpful.

Thanks

F9Fan
 
Your question was - "I am trying to determine if the Pinnicle Flt 3701' engines were equiped with a FADEC and if they were not, than could the compressor stall prevention provided by FADEC have helped in preventing the accident."


I'll be the first to admit that I am not a CRJ driver, so please, anyone feel free to correct me. To answer your question, it would have depended upon all of the functions of the FADEC controller. Meaning, a compressor stall is a "build-up of air" in the compressor with no where to go until it is forced out of the engine (either the forward portion or aft or both). If the FADEC has an "air reducing" Or "air venting" control function on it, then the answer is potentially yes. However, the CRJ's engines have variable stator vanes that are supposed to solve the problems of a missing FADEC with regards to airflow into and out of the engines, thus eliminating the need for FADEC.

What happened with the CRJ engines in the accident, (granted still not completely determined), appears to be a core lock. What happens with that is airflow decreases into the engine, the internal temperature increase in the core, (in this case, only one engine actually overtemped) causing some of the components of the engine to expand and "lock up". The engines N1's were moving, but the crew had no N2. The only way to be able to relight is to have plenty of airspeed and the core to have cooled off. It does not appear that having FADEC on the engines would have prevented the accident.

Again, just my interpretation. Feel free to tap off of this or correct me if I'm wrong.
 
FrontierFan said:
Thanks Guys,


Not to bring up old topics, but..

I am trying to determine if the Pinnicle Flt 3701' engines were equiped with a FADEC and if they were not, than could the compressor stall prevention provided by FADEC have helped in preventing the accident.

Any of your thoughts would be helpful.

Thanks

F9Fan


The accident aircraft was a -200

They don't have FADEC
 
Regional4life said:
I'll be the first to admit that I am not a CRJ driver, so please, anyone feel free to correct me.

What happened with the CRJ engines in the accident, (granted still not completely determined), appears to be a core lock.

"CORE LOCK" is the very, very thin straw that ALPA lawyers are grasping at to divert attention from the pilots (who hosed themselves, truely(!) sorry to say). I AM a CRJ driver, and the MINIMUM airspeed for a windmilling start is 300kts (and more like 335). . . and they NEVER got above 248 kts (if I'm reading the NTSB hearing transcripts right). 0% N2 fan rotation . . . and they dumped fuel on it and tried to light it! Then did it AGAIN! Can you say MELTDOWN? Pilot error followed by pilot panic and more pilot error.

Bombardier tests EVERY INDIVIDUAL CRJ coming off the line for core lock through flight tests - - and in the RARE cases they encounter it, they have break-in procedures to ensure it doesn't re-occur. Three days of NTSB hearings, and it's darned obvious this was 2 chuckleheads doing everything wrong, over and over and over.

Course you don't see that on the ALPA website. Oh no, it's NEVER the pilot's fault, ESPECIALLY WHEN ITS THE PILOTS FAULT. It's "core lock" . . . a sexy sounding, highly unlikely (but admittedly possible) phenomenon that diverts attention from what really needs to be addressed . . . pilot professionalism.


But I'm no engineer :) We'll see what the NTSB rules soon enough. Definitely no FADEC on the CRJ 200. FADEC is the greatest thing since sliced bread, IMHO.
 
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