Falcon 900 Job

[Timebuilder]

First, your temp will be a lot colder at 390 than "zero". Try plugging in the standard temp for that altitude.

The N1 fan is driven by the inner shaft (or spool) by a planetary gearset in the 731, the same engine used in the Lear and Hawker (at least the ones we fly). The gases turn the turbine blades attached to the inner shaft, and that shaft turns the gearset at the front, turning the fan.

N1 settings are good ballpark figures for setting power for takeoff at rated thrust, but in cruise you set the ITT limit specified for your engine variant. The basic Lear 35 uses 795 C for cruise.

Im not sure what you are seeing in the Falcon book, since I don't have one. Maybe the figures you are finding are based on the "higher" temp for FL390.

 

[banned username 2]

Make sure you are comparing the same temps....

I think you meant 0 as in ISA +0, not 0C

My guess is the two examples your are looking at are actually comparing different OAT's

 

[Gumby]

900EX Job

Last I checked, that small corporation based in Morristown, SHOULD be a PUBLIC and not a PRIVATE company like the ad says? No?

 

[ultrarunner]

N1 settings are good ballpark figures for setting power for takeoff at rated thrust, but in cruise you set the ITT limit specified for your engine variant. The basic Lear 35 uses 795 C for cruise. [/B]

Hmmm, wouldn't you set an N1 MCT or LRC setting for cruise? And let ITT fall where it does? Unless you reach the ITT limit first, I would think you would set a book N1 figure.

 

[bigD]

Well yeah - I meant a temperature deviation of 0 degrees. Sorry for the confusion. I am looking at the ISA temp in both cases, however the TAT listed for the long range cruise setting is a degree lower than that of 0.77 (-32 vs. -31). But in this case, the TAT is different only because of the difference in Mach, right? The actual OAT would be the same, wouldn't it?

 

[banned username 2]

But in this case, the TAT is different only because of the difference in Mach, right? The actual OAT would be the same, wouldn't it?

Yes... I'll have to look at this in the charts and see what I can find...

 

[bigD]

Girlfriend outta town bigD?

LOL...actually no. She was over last night doing some studying for finals. When she saw me looking at the performance tables, she said:

"You know, you have 3 finals this coming Saturday, and you're sitting there studying up on an airplane that you don't even fly. You need to submit yourself to that dorky pilot's thread you're always laughing about!"

 

[banned username 2]

I'm glad to see you guys are making good use of the reading material I gave you!

LOL!!!!!!!!

 

[JetPilot500]

My understanding is that the power levers acually govern N2, but N2 and N1 are aerodynamically coupled such that N2 is simply produces the desired N1 setting....

Well, actually, the power levers control fuel metering to the engines (via engine computers). More fuel means more fire. More fire means the turbines spin faster. The faster the turbines spin the faster the Compressors (N2) and Fan (N1) spin (since they are directly connected to those turbines).

Here's how it really works:

You set the Speed Selector to Mach .82 (or whatever you like). The resulting fuel flow is fed into the FMS. The FMS will now tell you if you have enough fuel to get where you are going!

PERFORMANCE CHARTS? What are those?

JetPilot500

 

[banned username 2]

Hey bigD,

I looked at the charts too. On the "All engine operating chart, long range cruise" for a PA of 39,000 feet at 47,000 lbs, I come up with this:

• IND. MACH: 0.765
• NM/lb: 0.1839
• TAT (deg C): -32
• TAS (kt): 436
• N1 (%): 96.9
• FF (lb/hr): 750

On the "All engine operating chart, Ind. Mach 0.77" for a PA for 39,000 feet at 47,000 lbs, I come up with this:

• IND. MACH: 0.770
• NM/lb: 0.1923
• TAT (deg C): -31
• TAS (kt): 439
• N1 (%): 97.2
• FF (lb/hr): 760

I think you just looked at the chart for Ind. Mach 0.77 and PA of 35,000 feet, which gives you the 92.6% N1 setting.

Now this makes more sense.... I think Dyslexia may have come in play... Now enough with this airplane non-sense, how about some BBQ talk?!?!?!!??!

 

[bigD]

Maybe I misread the chart, Fly, but I swear I double checked it about a thousand times! I'm at work now though, so I can't check it again at present...I'll look again when I get home.

I'm looking at the Normal Procedures Checklist from FlightSafety, for what it's worth.

 

[Timebuilder]

MMMM. Dry rubbed, or wet?

 

[bigD]

Ah - that makes more sense, FlyChicaga. I should have double checked the numbers against the operator's manual. Sorry guys!

As for dry rubbed or wet, I've had good and bad BBQ both ways.

 

[bigD]

I love the way Coopers does their BBQ. You pick a slab of meat from their pit, and they dip it in a paint bucket full of their sauce. Then drop the slab of meat onto a tray for you to take inside. By the time they've cut up the meat, weighed it, and given it back to you, the sauce has been soaked up, and it's just perfect.

Mmmmm.....I need to go to Coopers soon!

 

[banned username 2]

I'm looking at the Normal Procedures Checklist from FlightSafety, for what it's worth.

Flight Safety is notoroious for typos in their checklists and performance tab data.....

As far as BBQ, I think I perfer dry-rub....

But all BBQ is good, having some Brazilian BBQ for lunch today! MMmmm MMmmm!