Jet airliner question

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Draenog

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Hi Guys, this is not about any one particular flightsim model, but jet airliners in general.

Eg.. My 737 is setup for a domestic flight. I start the takeoff run at 90% N1, rotate at lets say 138kts. Standard rate climbout. By the time the gear is up the aircraft has almost touched 300kts. I have to pull the throttles back to flight idle to allow speed to drop off!!!!!!!!!

When i watch real aircraft takeoffs in the cockpit, everything is in control and speed gain is gentle.

WHAT THE HELL IS WRONG WITH THESE FS JETS??? Maybe some of you guys know....PLEASE??

Gary
 
Gary, after take-off most jets reduce power to a 'climb' setting, things like the A320 can do it automatically, typically about 80% after you've got the airframe cleaned up but i'm not sure on power setting.... in the cabin it's an audible difference but to those on the ground it's not so audible....

http://www.youtube.com/watch?v=Reok7isbseQ&

^http://www.youtube.com/watch?v=Reok7isbseQ&My favourite Engine fitted to airliners, can hear the thrust reduction after rotation.... 4:40 onwards..... cutting the power to 'climb'
 
Not only what Smoothie said is true but some airlines are doing reduced power take-offs like Southwest. Thanks Smoothie for the RB-211 vid, we do not get enough of these here at Minneapolis MN where I fuel for the airlines.
 
Thanks guys, i understand the derate and climb power, but the bit i'm getting at is flightsim jets always accelerate to extremes before the gear is tucked away, not even giving a chance to clean up the plane, let alone set climb power. By the time you're ready to engage the AP the plane is almost breaking up. You lift off and whoooosh!!! it all too fast and wrong. They always feel like they are too light and have no drag.
I find payware airliners the same.
I think i'll just stick to prop planes, i'm probably just too old for this...LOL!!

Oh, yeah thanks Matt for the vid...what a great engine sound!

Gary
 
Are you talking about the default MS jets, if so their dynamics are terrible to start with, I would advise getting some payware a/c PMDG or Level D are good starting places, or real enthusiasts freeware, like the 1-11's, Trident by Maltby. There are several more but I cannot think at the moment. These a/c are examples of near-as-dammit correct flight dynamics.
 
Yes ,most FS Jets are only a reasonable facsimile's....by the numbers?? Its a variable from one model to the next...In many areas of the USA,Noise Abatement is the critical factor....noise,direction,rate of climb!.....Like at ,KEWR,ya got KJFK,KLAG,KHPN,and KPHL....all in close proximity of each other...in IFR,and weather...its heads up!...the single sim Pilot ,in a heavy iron cockpit has to be most challenging....But to "WALTER MITTY" LINE CAPTAINS??....a piece of cake....Have fun!!
icon25.gif
 
Yeah, most operations use a reduced thrust take-off (although some conditions may negate it's use), but when you say that you "climb at a standard rate" may be the problem. After take off in jet airliners, you try to climb at V2+20 knots until 1000 to 1500 feet (depending on terrain), then lower the pitch and start the flap retraction schedule, and accellerate to 250 until 10,000 ft. When you pitch for V2+20 you're going to get a different climb rate just about every time, because each take-off is different...ie weight, density altitude, ect.

There are certain airports that call for noise abatement, as Beana51 said, and each of those airports have their own procedure. However, out of the hundreds of airports I fly into every year, relatively few have them. My fave is John Wayne Orange County in the Los Angeles area.
 
Don't get hung up on the too much speed thing, as if the model was meticulously made to perfect realistic flight characteristics. Most likely what you are seeing is something less than that kind of effort, and it is a lot of effort and time to get something believable. And even then, toss in different joysticks, FS realism preferences, etc and one mans perfection is another's disappointment. Which model is it BTW? Chances are someone's done some tweaking for it.
 
The FDE inaccuracy of default jets aside, if you are accelerating too much there is always the option to increase your climb rate. After initial rotation simply pitch up some more as soon as you have adequate ground clearance to avoid striking your tail feathers on the ground.
In real life some of the biz jets have trouble much like you describe to comply with both the speed and initial altitude restrictions. My former CFI now flies a Hawker for a local charter outfit and I got to ride along on one reposition flight. 200kts and 4000ft came up wayyyy fast. A little too fast to be honest.
On the noise abatement front there probably is no equal to Orange County/Santa Ana. It's often quite a bit unsettling to infrequent flyers when the engines go back almost to flight idle soon after takeoff. I am told that on occasion the airplanes are only slightly above stall margins by the time they coasted out of the "sensitive" areas.
And all that because dimwits buy a house next to a commercial airport and then file complaints about airplane noise.

Cheers
Stefan
 
if you are accelerating too much there is always the option to increase your climb rate.
Click to expand...

I very much agree with the original point by Gary that tubeliners in FS too easily accelerate under full/takeoff power after takeoff - for me to the point I not only hit the 250knt speed limit but then enter "overspeed" and overstress etc all too easily. I fly IRL - as a passenger - regularly and pay close attention to the fact that many jetliners don't seem to ease off on the power at all through the flap raising schedule and for a long time thereafter. I therefore too find it difficult to reconcile the FS takeoff flight profile with jetliners IRL in this regard. It does seem like there isn't enough drag - or maybe its weight. Watching the viideo flightplan/readouts on real jetliners they seem to climb at 1-2,000 fpm forever under full power and only slowly accelerate to 250 knts by 10,000ft. The suggestion of increasing climb rate to keep the speed down is probably the least worst, realistic compromise.
 
OK:

At some time or another I flew all the pre NG 737's. 90% N1 would be a bit low for takeoff, depending on the engines installed. 138 knots might be a decent VR for a plane perhaps in the 115,000 lb weight, depending on the flaps. These things have a lot of power for takeoff and climb. A light 300-400 might start out at 6,000 fpm. Rotate to an initial attitude of 13-15 degrees and keep pitched up enough to keep the speed down to 250 kts IAS till 10,000 ft then accelerate to perhaps a 320 knot/M.74 climb.

Try to level one of these off at pattern altitude and the thrust levers come almost to idle. The -200 can do 350 knots IAS at low altitude on about 1/3 or less power.

T
 
Remember also that these birds have to be able to continue a takeoff on one engine if they lose one after V1. So there is no shortage of power when both plants are making thrust.
I think Les Abend in Flying Mag detailed a JFK departure in his 757 where he also mentioned the 4-5k positive climb rates.

Stefan
 
Draenog said:
Thanks guys, i understand the derate and climb power, but the bit i'm getting at is flightsim jets always accelerate to extremes before the gear is tucked away, not even giving a chance to clean up the plane, let alone set climb power. By the time you're ready to engage the AP the plane is almost breaking up. You lift off and whoooosh!!! it all too fast and wrong. They always feel like they are too light and have no drag.
I find payware airliners the same.
Click to expand...

Two things:
1- have you set the plane's payload correctly ? Usually, by default, the planes are empty. You have to compute a total weight from a certain number of passengers + corresponding luggages. The plane will not accelerate so fast anymore.

2- liners ARE overpowered in real life. Don't forget they are built in order to be able to fly even with half of the engines out (just like Sunny9850 said just above). So if you apply 90% of thrust on all the engines, you will reach overspeed very soon, and the same will happen in real life. What you have to do is to reduce the power, and/or increase your climb rate.
 
On a somewhat related note, I have a question for Fliger and the rest of the resident bus drivers...

I know that less fuel is burned at higher altitudes due to the thinner air. So do you save more fuel by leaving the throttles up and getting to altitude faster, or is it better to level off to a more reasonable climb rate and reduce thrust earlier? Or does it depend on the individual plane and its load?
 
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