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spesimen

advice on cleaning up my md-11 takeoffs please

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hi,when i takeoff in the md-11 it seems like i frequently pass v2+10 very quickly and end up in limbo where i am climbing out at a very high, almost-stalling aoa, but the fms speed doesn't update to something reasonable like 250 until very late, like after several thousand feet of altitude. meanwhile it still thinks i want T/O thrust i think or climb thrust even though i'm going way too fast.. i think i'm maybe hitting the profile nav too late as i like to handfly for a bit to get everything somewhat stable? i guess i don't really understand what the trigger is to make the fms think it's cool for me to go any faster, however. i tried lowering the values for acceleration and climb thrust and that sort of helped but i feel like i probably am not doing something right if those defaults aren't typical.. if pitch protection and other stuff start kicking in i override the fms speed to a value of 250 and that gets me in the right spot of the envelope but i'm pretty sure if i was taking off correctly that shouldn't be necessary.using de-rated thrust seemed to help some but i can't really find a chart for how i should be setting that so i have been using around 50.. is that maybe too low still? well, if anyone has any advice for how to get up more smoothly i'd love to hear it!cheers,-andy crosbyedit: note, this happens for me at light and heavy weights although i don't seem to overshoot the speed by as much with heavy weight it still always happens.

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Guest D17S

Yea, me too. We are still waiting for some real world advise on this. Remember there are 2 altitudes to consider in the takeoff sequence. These are the "triggers." 1) Acceleration Altitude (AA)is where the FMS resets V2+10 to the 1st Vref (flaps, etc). The FMS will command a nose over to acellerate. 2) Thrust Reduction is the other. At this altitude the FMS commands a thrust reduction to Climb Thrust. Keep these 2 altitudes in mind during your T/O.So far, the best recommendation is to just point the nose at the sky and try, try, try to maintain V2+10 until AA. Stay out of the Rake (max AOA), but stall is about airspeed. As long as you are still above V2+10, keep pullin' to slow the beast down. I'd say take a guess on a derate, but based on what? We have nothing to even guess by. Also, I've found that I should never hand Otto the airplane (engage the AP) unless I have stabilized on-speed. During this 1-2nd segment, he really is quite the newbie FO.I think part of the secret will be these derate charts. This is a real deal in the real world. This will be a complicated calc and likely runway specific. A derate will change all the Vs and cannot be lightly considered. This is MD11 is a very real model and goes to show the RW planning that is RW necessary to operate this airplane. Without those derate numbers, any crew would be engaging in a Shuttle Launch on every TO.

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One trick I use is to lower the acceleration altitude to 1000 agl.. just seems more realistic to me but I too am watching for real experience to advise.


Dan Downs KCRP

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I too am anxiously awaiting a TOPCAT performer. There is simply no adequate solution- proper derates are a must- but compromising safety of flight is not acceptable either!The aeroplane is abundantly powered- and higher assumed temp take-offs will be the answer- in the mean time its still a lot of guess work. Not an issue with lower TOWs or longer runways, but when you try to shoehorn her off the shorter (Rwy) freight locales she handles so well at MTOW- that's when all the fun starts!Just sent Christian another prod...........Best-Carl F. Avari-Cooper BAW0225http://online.vatsimindicators.net/980091/523.png| XP Pro SP3 with FS-GS System Unification | 2 x APC UPS | Coolermaster Stacker 830 SE | Asus P5E-Deluxe (X48) | e8500 @ 4gHz | Tuniq Tower 120 | EVGA 8800GT 512MB | Sony 40" Bravia XBR | NaturalPoint TrackIR Pro | 2 x 1 GB Corsair XMS2 | 500GB Seagate Barracuda 32MB SATA2 x2 (Acronis) | Corsair HX620W PS | PFC Jetliner Yoke and Pedals | Aerosoft 747MCP-EFIS-EICAS |


Best-

Carl Avari-Cooper

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thanks for the comments.>So far, the best recommendation is to just point the nose at>the sky and try, try, try to maintain V2+10 until AA. Stay out>of the Rake (max AOA), but stall is about airspeed. As long as>you are still above V2+10, keep pullin' to slow the beast>down.i tried a few more flights, i noticed i wasn't really following the FD vertical crosshair as closely as i should have.. i'm reaching 25degrees aoa a lot more quickly now and that helps a lot, if anything it is getting me to acceleration altitude very fast. i think i wasn't being aggressive enough with pitch and that's where a lot of the extra speed was coming from. cheers,-andy crosby

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Guest PPSFA

Ive never flown the MD11 in real life, but I do have a bit of experiance flying the line years ago. I still use the same procedure with the 11, set TO thrust, accelerate to VR, pull the nose up, gear up at positive rate, fly the 'bars' to 1000', flaps up on schedule and engage AP, sit back and take a nap until TD or ATC call :-)JayXPPro SP2FSX SP2AMD64 FX-60 Dual Core 2.61 GHz8800GTS-640 megs2 Gigs Kingston RAMFEX-GEX-UTUSA-FSGenesis-and a bunch of other stuffComputer optimized by www.fs-gs.com

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