Beta Notes- London, Stansted- Single Engine Performance

[KriVa]

First, my mistake, my earlier numbers were wrong, must've misinterpreted them. N1 at 180-ish and 3000 ft ISA should be between 5-8. (on the CFM). Now, as I said before, I have no experience with the GE90, I do have some (very little) experience with the CFM.

 

Robin:

 

Of course, but you have to consider that the fan itself is also 4 times larger(almost exactly) than on the CFM. It's not like you're pushing 4 times the air through the same fan opening. In that case, it would be rather normal to see the fan spin about 4 times as fast.

Consider a car and a 1/50th scale model of that same car. If you make them roll at the same speed, the wheels of the scale model will turn 50 times as fast as the wheels on the original.(If you were to make the full size car's wheels turn that fast, it would be traveling 50 times as fast).

Of course, this comparison is overly simplified, but the general idea is the same.

 

Also, consider that N1 isn't exactly a defined RPM as you read it on the gauge. It's a percentage of a set RPM. On the GE90, 100% RPM translates to about 2500RPM. On the CFM56 it translates to about 5700RPM, if I remember the numbers correctly.

[jcomm]

 

 

N1 at 180-ish and 3000 ft ISA should be between 5-8.

 

Ok! Thx for the info... then the figures we're seeing at 2500' must be right. Great!

[cavaricooper]

A couple on answers.... Keep in mind I'm NOT a typed ATP.... So please go easy on the nit-picking......

 

The 777 actually works towards a wings level approach when making a single-engine AP & A/T approach (starting at 1300' I believe) so the slight right wing down was to compensate for the right cross-wind.

 

I did not de-select the right A/T and continued to move both thrust levers in an attempt to reduce single-pilot work-load. Flying a large transport category aircraft single-pilot is challenging enough, prior to shutting down one of the engines....it's a bit busier after.....

 

As far as my fascination w/ EGSS.... I fly wih a great bunch of blokes that despite being scattered at the ar ends of the globe, are like Richard and I, partial to "This precious stone set in the silver sea, This blessed spot, this earth, this realm, this England." Perhaps the fact that I am at heart an Old Colonial will help you understand...

 

The windmilling N1 dissection I shall leave alone- I fly her because she speaks to my soul, the engineering I am happy to leave to the fine folks at Boeing & PMDG.

 

Hope most if you enjoyed it....

[A320FAN]

And I'll add PFPX to that

Yes

[Richard McDonald Woods]

Carl,

 

Many thanks for another very instructional story. Can't wait to get my hands on her!

 

Regards, R

[CaptCraig]

Nicely done!  

[knutt]

AGAIN- Bravo Zulu PMDG!

Bravo=2 - Zulu= 0 = 20 ??

[davidz]

Not sure how you get Zulu = 0 (I would have thought that it would be 26 given that it's the 26th letter in the alphabet).

 

For those unfamiliar... http://en.wikipedia.org/wiki/Bravo_Zulu

[knutt]

Not sure how you get Zulu = 0 (I would have thought that it would be 26 given that it's the 26th letter in the alphabet).

 

For those unfamiliar... http://en.wikipedia.org/wiki/Bravo_Zulu

 

http://navysite.de/what/zulu.htm

 

GMT DST Military Phonetic Civilian Time Zones +0:00 +0:00 z Zulu UT or UTC - Universal (Co-ordinated)

[cavaricooper]

Perhaps we could research the signal flags Bravo Zulu.... and what they mean when flown, after which we could research "pedantic pundits".....

 

 

C