Headwinds become Tailwinds

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Re: Headwinds become Tailwinds

Postby beefhole » Thu Feb 10, 2005 4:42 pm

I also believe winds are in MPH not KTS and that is where the problem lies.

Hmm... no, not in my experience. I don't think FS is capable of giving wind speeds in terms of MPH, it's definitely in knots.
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Re: Headwinds become Tailwinds

Postby Saratoga » Thu Feb 10, 2005 10:58 pm

Well I saw this last night, flying today figured I would take a semi scientific study to attempt to help but it probably wont. Tommorow I may rent some sort of turbo-charged piston, head up to around 10,000 and fly around just to see. Climbing out of St. Louis, Missouri today I thought of this topic so I looked at some numbers. If I remember correctly, our indicated airspeed was around 275 knots or so at 12,000 feet and true was somewhere along 320. I didn't think to check the winds so it's probably off, but I will attempt to be more helpful next time, but it gives something to go off.
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Re: Headwinds become Tailwinds

Postby Nav » Fri Feb 11, 2005 6:32 am

Papa, years ago I learned to fly in a T21, which is an open-cockpit glider.  Less hair would have been a positive advantage!

About speeds etc., here's my system.  Plenty on here will disagree, or suggest changes, but it's simple, and it works well enough for me!

1.  Before takeoff, set the autopilot to speed 250 knots, rate of climb 2,000 ft./min.  But DON'T turn it on before you're off the ground with gear up and flaps retracting, of course!

2.  Hold that to 10,000 feet (the speed is an international rule).  But watch N1 - if it goes over 80%, cut the rate of climb a bit (in the interests of fuel economy).

3.  Above 10,000, jack the speed up to 275.  Go on watching N1 and keeping it at 80% or below by fine-tuning the rate of climb.

4.  Approaching 20,000, you should see the Mach speed getting up to about 0.65.  Switch the autopilot to Mach. speed about then.

5.  From there up to operating height, balance speed and rate of climb to keep N1 at about 80%.

6.  On a long trip, some would advise levelling out at 25,000 and staying there until you have burned off some fuel (and therefore weight).  If fuel isn't a problem, go all the way up.

7.  At height, set the cruising speed at whatever the Learning Centre or Pilot's Notes recommend.   For fuel economy, though, if you need it, cutting the speed to say Mach 0.72 has a more than proportionate effect on fuel consumption.

8.  Coming down, my system is to set the 'Speed Hold' to 250 knots straight away.  Of course, you'll be going a lot faster than that at height, particularly in a descent - but when you get down below 10,000 you'll be at a nice reasonable manoeuvring speed.  Some aeroplanes - especially the default 747 - take a helluva lot of slowing down if you start the approach going too fast.
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Re: Headwinds become Tailwinds

Postby Saratoga » Fri Feb 11, 2005 8:34 am

Nav, it actually burns less fuel to park a jet on 100% N1 and hand climb at max climb rate to your altitude, provided you can get ATC clearances fast enough. ;)
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Re: Headwinds become Tailwinds

Postby Nexus » Fri Feb 11, 2005 8:53 am

Exactly, you'd want to get up there as fast as possible to get the advantage of less drag and higher ground speed.

And the N1 should be peaked, since the fan generates most of the thrust. A turbofan engine is as most efficient at high altitudes AND when their compressors are operating in high RPM's, approx 90-95%. You wont reach the engines optimal gas flow condition(=Best specific fuel consumption) with an N1 speed of 80%...

Sounds familiar, yeah well I took the liberty of copy/paste from an older post of mine  :P  ;D
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Re: Headwinds become Tailwinds

Postby Saratoga » Fri Feb 11, 2005 5:59 pm

Yup you aim for high cruise altitudes and engine speeds of above 90% or less than 70% to save on gas. Between those is inefficient and a waste of fuel.
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Re: Headwinds become Tailwinds

Postby Papa9571 » Fri Feb 11, 2005 8:43 pm

Ok....so I just loaded it on my computer and took off. Would have helped if I read the instructions or took lessons I guess.

Typical  ;)

Oh well.

Its amazing what you can do when you do it right. Thanks all for your advice. It has helped me become a better pilot and now I can go further than 3 blocks without running out of fuel. ;D ;D

Seriously though I took the Concorde from KTOL to Heathrow and suprise suprise..I landed with 18,000 kg of fuel. Thats what doing it right will get ya.
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Re: Headwinds become Tailwinds

Postby Nav » Fri Feb 11, 2005 10:40 pm

Great, Papa, you're on your way!
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Re: Headwinds become Tailwinds

Postby Papa9571 » Sat Feb 12, 2005 8:50 am

Actually the only place I am starting out is here. I have FS98, FS2000, Data Beckers Jumbo Jet addon (what a waste), and remember 2 versions of M$ FS where you flew WW1 combat missions on top of regular Cessna 172 flying. I must have worn the skies out flying betweem Meigs and Willard in Champaign. But I actually lost track due to job constraints (less than 6 weeks a year home). I have since told them to take that job and shove it and am getting back into things i used to enjoy. My next step this summer is to resume flight school although I dont think the hours I had previously will count for anything. Who knows... I might find that dinosaur herd I saw last time I flew the teradactyl mod 1

Actually my first flight was in a Cessna 150 N1758M and I was hooked.

Thanks all for reawakening my passions for flying. OOPS....gotta go cause I'm late for school and I dont want  Rod Mochado screaming at me before I climb into the seat..
;D ;D
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Re: Headwinds become Tailwinds

Postby Saratoga » Sat Feb 12, 2005 11:34 am

100.1% is the redline on most airplanes, the "legal" limit. The jet engine is perfectly capable of holding full throttle, which can push 108 or so on most planes at sea level, for a long time, it's just a matter of engine wear. During my Air Force tenure, we revved T-38 engines to full all the time, now nothing said we had to rev them up all the time, but we gotta have some fun, right?
Pilot for a major US airline certified in the: EMB-120, CRJ, 727, 737, 757, 767, and A-320 and military, T-38, C-130, C-141, and C-5 along with misc. other small airplanes. Any questions, I'm here for you.
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Re: Headwinds become Tailwinds

Postby Nexus » Sat Feb 12, 2005 11:49 am

And in modern airliners, pushing the thrustlevers full forward is rarely 100% of engine capacity. The FADEC/EEC will not allow a thrustsetting that will cause any gauge to be in the red zone, let it be N1, EGT, EPR or N2. The thrust ratings are calculated from atmospheric conditions and the current bleed air demand. The EEC limits the thrust to max. certified for the current condition....meaning that it's impossible to blow an engine in a modern  airliner  

The only way you can get away  "red zone readings" is during a Go-around where the turbine RPM can run on a excessive rate for about 1minute or so, if I'm not mistaken.
What's correct here Saratoga? ???
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