Thread: Boeing Climb Thrust!!!!!!!
01-06-2008, 02:55 PM #1
Boeing Climb Thrust!!!!!!!
Have to add a few lines here coz i still have the same problem with the clim thrust and maybe someone here can help me now.
I work with FS9 and all the lates PM software as well latesr FSUIPC.
But my problem is the climb thrust. Whatever i do and what kind of settings i use, my 737 always runs into overspeed!!!
I can remember times where the clim automatically limited to 272 kts but even when i reduce the speed in the CLB page the plane follows full thrust set and dont reduce even when it comes to overspeed. when i enter 272 kts in the CLB page ...no effect.
I have also tried the different speed protecion settings and a roll back to a former MCP or CDU build but no effect.....
I think i have some mistage in my planning or i have forgotten to switch on something...
Does anybody have or had the same problem and how can i solv it???
Many thanks to you guys.....appreciate it much..!!
All the best to you all fellow simmers and thank you for your help
01-06-2008, 03:17 PM #2
as far as i know the 737 will run into overspeed unless you reduce the throttle after takeoff a little. you should only have full power or relative full thrust when on the ground when airborne reduce thrust a little so it doesn't go into overspeed. were you refering to under 10,000 ft overspeed (ie. over 250knots) or overspeed in the aircraft 320 ish.
either way as far as i know this cannot be solved apart from the obvious solution of just setting the autopilot speed to less than the maximum speed so it can be maintained by the aircraft automatically.
hope that helps a little in your question.
01-06-2008, 03:47 PM #3
- Join Date
- Jan 2006
- UK / Germany
Boeing Climb Thrust
If your flight model is reasonably good and you follow the correct procedures, and also have set your weight and balance correctly you should not get an over speed condition.
Make a TOGA take-off (this is never going to be full power - if you have full power set I would immediately be suspicious of what is going on)
At V2, rotate initial to 10degrees and then once you have a positive rate (after approx 1 to 2seconds [you have to be quick]) maintain climb to 15+ degrees pitch up or what the FD commands to maintain the V2+20 speed (this is dependent on GW etc). Gear Up select FLCH. Set in an acceleration speed (maybe initial 185kts [or whatever you want / cleared] to) up to 250kts retract flaps pre schedule to clean. If you are 'overspeeding' in this condition or before it, yet following the FD command pitch, then something is wrong - some performance factor or perhaps weights are not properly set in the config files.
Note that with incorrect W&B or power setting and also even with slow response to FD cues the 737 in manual flight can easily get into an overspeed condition in TOGA, the AT may be too slow to correct, the pitch is key to maintaining speed. Much of this is due to Flight Models, but you must follow the correct procedures to find out where the problems lies, i.e. with your own flying or with the flight model or perhaps some error in the pre-flight or type.txt CDU files re weights.
Jonathan RichardsonJonathan Richardson
01-06-2008, 04:08 PM #4
duh, totally forgot about TOGA, i just never use it thats all. Yes i was wondering this when you posted you neveractually set "full power" as in the throttles wide open forward (even though it might be good for the buttkicker) this is not nessessary and you only need around 90% N1 to takoff successfully without stalling. Maybe this is where you are going wrong.
To cut a long story short, set the autopilot to your cruising altitude and set the vertical speed of around say 500 ft p.m. Then your speed of around 245 knots (not over 250) (then if you have a flight plan loaded press/ click nav and do this after takeoff later). tTe autopilot is now tuned. Takeoff, put the gear up maintain steady takeoff of around 15 degrees then retract flaps incrementally. Finally engage the autopilot this is all done pretty fast and by the time the autopilot is engaged it will control the speed for you and keep you out of the "overspeed" area. the aircraft itself wont have enough time after you engage takeoff power ontil it manages to go overspeed because then the autopilot is controlling speed.
finally when you do engage the autopilot dont forget to get the autothrottle so the autopilot has permission (from you) that it can can control power. just in case you didn' know the autothrottle is the white switch at the near left of the autopilot module.
Hopefully no more overspeeds will be coming your way
(If the going gets tough...... eject - oh, no you can't do that on a 737 can you)
01-06-2008, 10:41 PM #5
737Gez - this thread is about PM software, is that what you are describing? Doesn't sound like it. If you are engaging TOGA (which is standard 737 takeoff procedure) then you would already have A/T armed. As soon as you hit TOGA the A/T is engaged on the ground and fully managed by the AFDS from then on, but restricted by MCP speed settings until VNAV (for example) is selected
And Like Jonathon explained you should engage a pitch mode immediately after rotation (LVL CHG), and a roll mode is usually preselected before takeoff on the 737 (such as LNAV). Then going through acceleration height (usually around 1000ft), select 'bug-up' speed on the MCP (usually around 210 kts), reduce flaps on schedule, then when flaps are fully up either bug-up to 250kts (below 10000) or select VNAV as your pitch mode. Autopilot is usually engaged somewhere between that action and reaching 10000 feet.
01-06-2008, 10:47 PM #6
I'm glad I just have to just push the throttles forward after FL100.Boeing Skunk Works
Remember...140, 250, and REALLY FAST!
We don't need no stinkin' ETOPS!
Powered by FS9 & BOEING
01-07-2008, 01:07 AM #7
Thanks folks...i think i will make some test flights and maybe check my W&B and flightmodel.
And good recommendations for a good flightmodel and where to download the files?
Wanted to use the PMDG but the Mod. never worked......
Anyways....thanks you really so much for your help....appreciate it very very much......
Many greetings from cold LOWW
01-07-2008, 01:00 PM #8
Just a question of proper procedure here, but should LVL CHG be used or is it "permissibile" to go straight to VNAV after rotation and initial climb out? I've been going straight to VNAV with no apparent issues but I was curious as to if I am doing it right. VNAV will command the Vref+20 but will then select 250kts and the aircraft will flatten out on climb out to let the airspeed increase, leading to a few GPWS warnings right after takeoff.
01-07-2008, 04:38 PM #9
I think the LVL CHG thing is just a PM work-around for now. We have to do that to get a pitch mode that works reliably just ater takeoff. Shouldn't be a requirement once PM gets the VNAV issues fixed.
01-07-2008, 11:08 PM #10
Got it. Right now I just use SPD INTV as a work around for the descent issues we all know about. Thanks for the info!
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