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scott967

Take off trim / climb out

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I've gone through some threads on trim setting and I'm not sure if this has ever been answered, or at least I haven't had success fiddling with things. This is with the Terry Gaff model using -17R engines. I played with my loading to get a GTOW of about 100,000 and a CG of 20. For a flaps 5 take off I find I need a T.O, trim setting of about 4.2 (per AFDS +1.10) in order to rotate @ indicated Vr. But during the initial climb pitch will increase above 20 degrees until stall unless immediate nose down yoke pressure is applied. I find a pitch of about 13 degrees is required to maintain V2+10 or 15, and to achieve that I have to crank in nose-down trim until the pedestal is showing about 2 units, or in AFSD -3.3. Then I can accelerate and change pitch as required to achieve climb speed.Is this the way trim should be working?scott s..

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Scott, I'm no expert and certainly not a pilot but...when you say "trim setting of about 4.2 (per AFDS +1.10) in order to rotate @ indicated Vr"...are you saying you set trim so that you don't have to pull back on the yoke and the AC just rotates without your intervention? Another thing I've discovered lately is that, sometimes, I have the issue you describe in an extreme version and I just re-start the flight and everything is fine. Not sure what is causing that but it seems to have shown up with v1.24? Vic

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Scott,I've noticed the same behaviour. I use the hidden gauge below the VSI to obtain my CoG and then set the trim according to the table from the perf documentation folder. Just wondering, what do you mean by "AFDS +1.10"?Anyway, this works well initially - the aircraft rotates smoothly with a slight pull back @ VR and initially maintains a stable 15 - 20

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Sorry for the typo, I meant Herve Sors' AFSD v3 app which gives a real-time display of trim and elevator inputs via FSUIPC.I find if I move the CG forward to around 20%, then when I trim I can just about get it to rotate at Vr with stick full back. If I add any more trim (to allow for smoother rotation), then after lift off even with full forward stick I get excessive pitch attitude until I dial down the trim. Lately I have been using an assumed temp TO thrust of around 55 degrees using the PDCS.If the CG is much further aft, then it is almost impossible to keep pitch from increasing rapidly with a workable take-off trim (it either won't rotate will full back stick, or shoots up like a missile). Once I get trim sorted in the initial climb out, then everything is nice and smooth (with control acceleration set in FSXUIPC).I currently have a flight saved using TM II going into the 9Dragons VHHX and I'm having a lot of fun trying to nail that approach.scott s..

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There is no correlation with Horizontal Stab deflection (in degrees) with Stab Trim Units.i.e., In the real aircraft, the Horizontal Stab deflects from 0 degrees (and this will be 0 units value) to 12 degrees (17 stab trim units).This range is only achieved through manual trim input.Yes, I know that the TM2 FDE is out-of-date due this, but this info I just have recived after a long chat and a long wait with the maintenance chief of a 737-200 line (in Brazil).Also, the usual range of neutral deflection of the 737-200 H. Stab is around 3.75 - 4.25 units of trim (a tolerance range of 0.5 units). This in H Stab angle, would be ~ -2.6 deflection (or AoI).For a long time I don't put my filth hands in the TM2 fde, so, I can put this blame on me for not update Bob and you guys, and also for letting the FM inaccurate.Maybe when my joy with FS cames back, I try to change this and others things.Best Regards,

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