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Guest melf12

PSS B772LR - Pitch settings

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Does anyone have information re Standard Pitch Settings for the T7? I've checked the Manuals but 'nothing found'.Ken

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Use the fuel planner and load editor; that will give you the %COG. Enter the %COG into the FMC and you will get the correct trim settings for takeoff. Other than that, I'm not sure what you mean by 'Standard Pitch Settings'...DJ

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This one I still struggle a bit with - planner COG/fmc computed trim usually gives me a figure that causes delayed rotation. Now I just leave it at default (7 or so if memory serves - been a while) and off Igo.regards,Mark

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That works - the computation seems to be a bit low, so I just add a bit for dear old mum and away we fly. I suspect it works this way in an attempt to eliminate being way over trim as the aircraft begins to fly and gain speed.DJ

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['Standard Pitch Settings'...]That was something that our VA T7 Training Captain suggested. He is holiday at the moment, be back this week-end.However, I've been doing some tests, it seems to me that 'my' T7 flies fine, most of the time - no problem with Take off or Landing; just an uncomfortable nose up attitude when flying acute turns in the STAR or similar. Enroute course turns are as expected, nice and easy :)Now, I could be very wrong here....but having spent more than 20 years building and flying R/C model aircraft (sadly no longer), yes, I know they are not full size a/c! In acute turns, sometimes approaching knife edge, you need input from the elevator, rudder and ailerons - using a decent transmitter you can factor some of this in :)So, to cut a long story short; could the nose up problem be a lack of co-ordination between some of the T7 control surfaces? It could be rubbish in the rw, but it worked for me, model aircraft!Ken

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I doubt that lack of coordination is the problem - FS works very differently from real world a/c (whether r/c or full scale) since it uses a mathematical approximation of the fluid dynamics of real flight. It's been my experience that most FS models tend towards a fairly alarming nose up configuration at low speeds in turns; I haven't had one fall out of air or stall because of that though. It's just disconcerting. If you know something of aerodynamics get yourself a copy of AirEd and read the ini file that goes with it to get an idea of what factors might be at play. There are some fairly simple things that you can do to modify behaviour, and a lot of much more complex ones as well. Ron Friemuth was the expert whose explanations I followed, but he is no longer with us...DJ

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Hi D], well, that's found something for me to chew on :) The extreme nose up of the T7 is disconcerting, I'm sure I never had this problem with PMDG B738 I used to fly.There was one other weird thing going on with the T7, on a flight from Heathrow to Dubai yesterday, I noticed that the Gross Weight steadily increased as I flew...when I first noticed this the GW was 214.2, just before descent it was 217.1? Whether Vref took this into account I don't know.Anyway, thanks again for your advice, I'll keep you posted.Ken

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Hmmm -- I've never seen GW on the T7 increase in flight. Do make sure that the FS option 'aircraft never runs out of fuel' in the FS realism settings is not turned on. If it is, you are trying to land at heavy weights that will certainly cause the nose up attitude you describe.DJ

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Yes, Unlimited Fuel is unchecked - good thinking on your part though, I've never given it a thought, in recent years anyway :)Under RealismFlight ControlsAuto Rudder is checked?Talking about 'concentrating the mind' - I've just remembered that a couple of months ago I changed the air.file to one by Johan Dees, - yesterday I noticed that Johan had 'pulled' all his info re the PSS B777 off his website - he said someone had found out that it was not correct!!Best thing I can do is replace it with the original PSS air.file?Ken

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Here's a screenshot of my T7, worst case nose up.Do you think the nose up is excessive?Ken

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In response to both of your posts... I really didn't think you'd have the fuel thing checked but it was worth asking. I use the JD modified FDE dated from last August and I haven't noticed a particularly high angle of attack from that -- it seems to work pretty well. I can't tell from the screen shot if the aoa is excessive since it depends on weight and speed. What do you see on the artificial horizon in terms of degrees? Bear in mind that the T7 is darn near the size of a 747 and they have a pronounced nose up on approach; seems to me I recall 5 to 8 degrees is pretty normal at anything above very light weights. I tend to keep my speed up in 180 to 210 knot range until established on the localizer (with flaps in the 10 to 20 range), when I begin to slow her down to Vref plus whatever. I have no idea what the real deal does, but this works well in FS for this plane and most other heavies.I've looked all over the web for more real world data on this bird and there is a remarkable absence of material. Most of my flights have had a TOGW in the 430K to 490K range, so my approach weight is around 370K to 390K which I translate to around 150 knots with full flaps and gear diminishing to 130 to 140 after the marker and just before touchdown.Auto rudder shouldn't make a difference, although it might be interesting to uncheck it and test the difference. In most cases modern swept wing heavy a/c don't use it a heck of a lot anyway.DJ

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You've given me something to chew on there :)I'll check on the items you have mentioned; also I'll have a look at my LoadConfig, just to make sure there's not too much weight at the back. I have the max. number of persons on board i.e. 306 plus baggagecargo. Also turned Auto Rudder off.Probably be tomorrow before I can reply, got my PC Guru coming today, I've a couple of Software issues.Ken

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I got to looking at the aircraft.cfg and noted that, in addition to using the JD .air file, I've made some of his recommended changes to the config file...[airplane_geometry]wing_area = 4604.801wing_span = 212.58wing_root_chord = 21.65wing_dihedral = 3.9wing_incidence = 1.0wing_twist = -2oswald_efficiency_factor = 0.81wing_winglets_flag = 0wing_sweep = 0wing_pos_apex_lon = 5.4wing_pos_apex_vert = -4.46htail_area = 1089.954htail_span = 70.04htail_pos_lon = -100.23htail_pos_vert = 5.78htail_incidence = 0.0htail_sweep = 40vtail_area = 572.963vtail_span = 33.23vtail_sweep = 35vtail_pos_lon = -94.60vtail_pos_vert = 10.63elevator_area = 137.0aileron_area = 76.5rudder_area = 232.0elevator_up_limit = 30.0elevator_down_limit = 20.0aileron_up_limit = 26.0aileron_down_limit = 25.0rudder_limit = 25.0elevator_trim_limit = 20.0spoiler_limit = 60.0aileron_to_spoileron_gain = 3spoiler_handle_available = 1min_ailerons_for_spoilerons = 9min_flaps_for_spoilerons = 0spoilerons_available = 1[flight_tuning]cruise_lift_scalar=1.0 parasite_drag_scalar=1.0 induced_drag_scalar=1.0elevator_effectiveness=1.0 aileron_effectiveness=1.0rudder_effectiveness=1.0 pitch_stability=1.0 roll_stability=1.0 yaw_stability=1.0 elevator_trim_effectiveness=1.0 aileron_trim_effectiveness=1.0 rudder_trim_effectiveness=1.0 [jet_engine]thrust_scalar=.993 //1.03[stall_warning]type=2[Flaps.1] //Slattype= 2span-outboard= 0.800extending-time= 15.000system_type= 1damaging-speed= 260.000blowout-speed= 270.000lift_scalar= 0.02100drag_scalar= 0.300pitch_scalar= 0.00flaps-position.0= 0.000, 0.000flaps-position.1= 15.500, 255.000flaps-position.2= 15.500, 235.000flaps-position.3= 15.500, 215.000flaps-position.4= 15.500, 195.000flaps-position.5= 30.000, 185.000flaps-position.6= 30.000, 170.000 The geometry changes to wing incidence, twist, and oswald factor have particular bearing on pitch. Note that several other changes have been made in that section, as well.I take no position with regard to the realism (or lack thereof) of the these changes, but they do result in an excellent flight model.DJ

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Some significant changes there from the JD aircraft.cfg I have.In the words of Fagin from the film Oliver..."I think I'd better think it through again" :)In other words I had better try these changes, before I mess about with anything else!Terrific job you're doing, thank you.Ken

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Hi D],I made those changes to my aircraft.cfg file, and did my usual EGLL to OMDB flight; enroute I noticed that GW slowly reducing (that was new!) - but at 820 nm from Dubai the GW started increasing again?Pitch up in the turns did not seem as dramatic as previously. As I intercepted the G/S I set flaps 30 spd 145 kts, as the T7 slowed to that speed it began to 'waggle' it's wings aka a WW2 Spitfire after a successful mission :) That experience was uncomfortable, to say the least, but I landed OK, and now the inquest! Maybe too slow for the GW, at the time 279.1 tonnes (metric)?Ken

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