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Stable T/O EPR Before TO/GA Press On B747-400?  
User currently offlineWindshear From Denmark, joined Mar 2000, 2325 posts, RR: 11
Posted (4 years 4 months 3 weeks 4 days 4 hours ago) and read 4480 times:

Dear Aviation experts...

What EPR thrust setting do the pilots spool up to before pressing TO/GA on aircraft with PW/RR engines?

I know that on GE engines aircraft this value is 70% N1.

Boaz.


"If you believe breaking is possible, believe in fixing also"-Rebbe Nachman
12 replies: All unread, jump to last
 
User currently offlineAirbuster From Netherlands, joined Mar 2007, 424 posts, RR: 0
Reply 1, posted (4 years 4 months 3 weeks 4 days 2 hours ago) and read 4468 times:

RR TAY: 1.3 EPR, it's more or less 70% N1

I don't know about the RB211 but guess it'll be somewhat the same.

rgds

AB



FLY FOKKER JET LINE!
User currently online747classic From Netherlands, joined Aug 2009, 2021 posts, RR: 14
Reply 2, posted (4 years 4 months 3 weeks 4 days 1 hour ago) and read 4442 times:

PW 4000 engines on MD11 need 1.1 EPR , before engaging TO/GA.

Ref : FCOM2 MD11.

Regards Peter.

[Edited 2009-11-30 02:37:22]


Operating a twin over the ocean, you're always one engine failure from a total emergency.
User currently offlineBellerophon From United Kingdom, joined May 2002, 583 posts, RR: 59
Reply 3, posted (4 years 4 months 3 weeks 4 days 1 hour ago) and read 4427 times:

Windshear

...What EPR thrust setting do the pilots spool up to before pressing TO/GA on aircraft with PW/RR engines?...

For a B747-400 with RB211 engines, my airline requires the engines to be stable at 1.20 EPR (roughly 60% N1) prior to pressing TOGA.

Best Regards

Bellerophon


User currently offlineWindshear From Denmark, joined Mar 2000, 2325 posts, RR: 11
Reply 4, posted (4 years 4 months 3 weeks 4 days ago) and read 4415 times:



Quoting Bellerophon (Reply 3):
For a B747-400 with RB211 engines, my airline requires the engines to be stable at 1.20 EPR (roughly 60% N1) prior to pressing TOGA.

Very nice thanks... Now all I need is the info on the PW engined 747-400. perhaps it is the same?

Boaz.



"If you believe breaking is possible, believe in fixing also"-Rebbe Nachman
User currently offlineJayeshrulz From India, joined Apr 2007, 1027 posts, RR: 2
Reply 5, posted (4 years 4 months 3 weeks 3 days 21 hours ago) and read 4375 times:

Sorry but what is EPR?


Keep flying, because the sky is no limit!
User currently offlineAirbuske From United States of America, joined Jun 2007, 466 posts, RR: 0
Reply 6, posted (4 years 4 months 3 weeks 3 days 21 hours ago) and read 4372 times:



Quoting Windshear (Reply 4):
Very nice thanks... Now all I need is the info on the PW engined 747-400. perhaps it is the same?

Hello Windshear,

According to NW B747-400 AOM Volume I, TO/GA switch is to be pushed at 1.1EPR by 50 KIAS. Above 50 KIAS, autothrottle engagement is inhibited until the aircraft is above 400 feet AGL.

Hope it helps.

Jinal


User currently online747classic From Netherlands, joined Aug 2009, 2021 posts, RR: 14
Reply 7, posted (4 years 4 months 3 weeks 3 days 21 hours ago) and read 4360 times:



Quoting Jayeshrulz (Reply 5):
Sorry but what is EPR?

At present, the thrust of an engine in flight can not be measured. As a result, one has to resort to other measurable variables that represent the thrust.
In the real world they use two variables for that : EPR or N1, depending on manufacturer.
EPR = Engine Pressure Ratio
This is the ratio of turbine exit to compressor inlet pressure and this is used to measure the thrust of a jet engine.(P&W , RR )
Another way to measure the thrust is via the low pressure rotor speed N1 (GE).

Both methods have their advantages and disadvantages and are applied at the preference of the manufacturer.

Quoting Windshear (Reply 4):
Now all I need is the info on the PW engined 747-400. perhaps it is the same?

IMO all PW 4000 engines (as also installed at the 747-400) have to be at or above 1.1 EPR and stabilized before engaging the TO/GA switch.
I checked this with the MD11/PW 4462 and the B767-300ER/PW 4062 .
I am searching for the 747-400/PW 4056 in my library, but couldn't find it (yet).



Operating a twin over the ocean, you're always one engine failure from a total emergency.
User currently offlinePGNCS From United States of America, joined Apr 2007, 2758 posts, RR: 45
Reply 8, posted (4 years 4 months 3 weeks 3 days 20 hours ago) and read 4346 times:



Quoting 747classic (Reply 7):
Quoting Windshear (Reply 4):
Now all I need is the info on the PW engined 747-400. perhaps it is the same?

IMO all PW 4000 engines (as also installed at the 747-400) have to be at or above 1.1 EPR and stabilized before engaging the TO/GA switch.

Have flown the 744 and 767 with PW 4000 series engines, and in our procedures 1.1 EPR was set by hand, then TOGA (in 744, on throttles) or EPR (in 767) switch pushed.


User currently offlineCCA From Hong Kong, joined Oct 2002, 799 posts, RR: 14
Reply 9, posted (4 years 4 months 3 weeks 3 days 13 hours ago) and read 4254 times:

We use both PW and RR on the 744 and we set 1.1 EPR for both prior to pressing the TOGA switch.


C152 G115 TB10 CAP10 SR-22 Be76 PA-34 NDN-1T C500 A330-300 A340-300 -600 B747-200F -200SF -400 -400F -400BCF -400ERF -8F
User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 10, posted (4 years 4 months 3 weeks 3 days 9 hours ago) and read 4224 times:



Quoting 747classic (Reply 7):
In the real world they use two variables for that : EPR or N1, depending on manufacturer.
EPR = Engine Pressure Ratio

There are two others...THR and TPR.

TPR (Turbofan Pressure Ratio) is what RR uses on the 787...it's like a normalized EPR.

THR is what Airbus has on the A380 and, as I understand it, is basically current thrust as a % of max thrust in the current mode.

Tom.


User currently offlineEx52tech From United States of America, joined Dec 2006, 559 posts, RR: 1
Reply 11, posted (4 years 4 months 3 weeks 3 days 6 hours ago) and read 4209 times:



Quoting 747classic (Reply 7):

This is the ratio of turbine exit to compressor inlet pressure and this is used to measure the thrust of a jet engine.(P&W , RR )
Another way to measure the thrust is via the low pressure rotor speed N1 (GE).

Just an FYI here, but GE did offer "optional" EPR, but it was strictly a reading of exhaust pressure, and it was much higher than what you guys are used to, T.O. would be in the neighborhood of 8.0 to 9.0 EPR. Most carriers used it as an advisory system to troubleshoot problems not as a means to set power for flight.



"Saddest thing I ever witnessed....an airplane being scrapped"
User currently offlineWindshear From Denmark, joined Mar 2000, 2325 posts, RR: 11
Reply 12, posted (4 years 4 months 3 weeks 2 days 18 hours ago) and read 4151 times:

So PW is set to 1.1 and RR are set to 1.2?

I thought I saw RR set to 1.17 or 1.18 in an aviation video, but you all helped me.

Boaz.



"If you believe breaking is possible, believe in fixing also"-Rebbe Nachman
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