PPRuNe Forums - Help needed on Engines IAE V2527-A5

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ggofpac

30th June 2010 15:37

Help needed on Engines IAE V2527-A5

Quote:

.
The IAE 2527 A5 engine is flat rated up to ISA +31 at sealevel,therefore it requires the same EPR setting at all temp below Tref. The engine is limited for mechanical reasons in this reason. When above Tref the engine is limited by the heat generated and the EPR is reduced so as not to overheat the engine. The main reason for engine wear is excessive heat and the best way of saving the engine is to reduce the heat. This is done by reducing EPR using a Flexible take off.

Questions:
1- What does it mean when he say its flat rated to XXX? I have no idea what is Tref....

2-Where can u find the info as to what the engines are flat rated to? Not in the fcom i think.

Thanks.

divinehover

30th June 2010 15:44

Flat rated means you will receive max thrust up to that temp (I think).

Cough

30th June 2010 17:47

And tref is the temperature that equates to ISA+31, ie at Sea level it is 15+31=46

Plays out that if the flex is less than this temperature then you go for a TOGA takeoff.

IFixPlanes

30th June 2010 18:45

Maybe this can make it clear:
http://img717.imageshack.us/img717/8...dengine.th.jpg

Neupielot

1st July 2010 14:13

Sorry i got a question too. Glad someone ask this question.
With regards to

Quote:

And tref is the temperature that equates to ISA+31, ie at Sea level it is 15+31=46

Plays out that if the flex is less than this temperature then you go for a TOGA takeoff

So does it mean that if I go TOGA thrust take off, it's the SAME thrust as if i'm doing a flex 46 take off?

TyroPicard

1st July 2010 21:13

ggofpac
A320 FCOM 2-02-10 p.1 has a graph ..
TOGA gives the manufacturer's rated thrust up to TREF (varies with altitude) e.g. ISA+31. Above TREF TOGA thrust reduces with increasing temperature up to TMAX, above which the a/c is not permitted to take off.
The graph line is "flat" (horizontal) up to TREF hence the expression "flat-rated".

Neupielot

Quote:

So does it mean that if I go TOGA thrust take off, it's the SAME thrust as if i'm doing a flex 46 take off?

No. See above.

Neupielot

2nd July 2010 01:07

still confused....:O

Quote:

A320 FCOM 2-02-10 p.1 has a graph ..
TOGA gives the manufacturer's rated thrust up to TREF (varies with altitude) e.g. ISA+31. Above TREF TOGA thrust reduces with increasing temperature up to TMAX, above which the a/c is not permitted to take off.

So looking at the chart its Thrust Vs Temp. Assuming at sea level the Maximum Thrust i can get from the engines are limited to Tref's thrust i.e +46 ( sea level). Temp above +46 the thrust available reduced up to a max of Tmax.
Errmm so if i the oat is +30 but i "flex" it to +46, according to the thrust vs temp graph, i'd still get the same thrust i.e TOGA. If i flex it to +47 then there is a reduction of thrust.
Did i get that wrong?.......:confused:

TyroPicard

3rd July 2010 11:46

Sorry, np, I read your first statement too quickly - you are right!
TP

Neupielot

3rd July 2010 13:34

Thanks TP.:)

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