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Guest RyHoffman113

Modifying descent characteristics

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Folks, I'm using a particular aircraft model that tends to descend unrealistically slow below 10000 feet. When I say unrealistic, I mean the rate is 500-900fpm at idle thrust when it should be more like 1500. I know I can use the spoilers to increase the rate of descent but I'd like to be able to descend faster without use of spoilers. Is there any way I could modify the flight dynamics to accomplish what I'm asking? Thanks.RyanVZDC

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Without asking a lot of questions about pitch, AOA, and airspeed, the short answer is yes, you could just add some drag and accomplish what you want.It could most easily be done from the aircraft CFG file [flight_tuning] section:(flight_tuning)cruise_lift_scalar=1.0parasite_drag_scalar=1.0<---- increaseinduced_drag_scalar=1.0<---- increaseelevator_effectiveness=1.0aileron_effectiveness=1.0rudder_effectiveness=1.0pitch_stability=1.0roll_stability=1.0yaw_stability=1.0elevator_trim_effectiveness=1.0aileron_trim_effectiveness=1.0rudder_trim_effectiveness=1.0but be aware that thrust will then have to be increased to restore the flight model to its original performance level, and depending on whether you are talking about a turbine or a reciprocating engine, a jet or propellor driven aircraft, this could require increasing:(piston_engine)power_scalar=1.0 (turboprop_engine)power_scalar=1.0 (propeller)thrust_scalar=1.0 (jet_engine)thrust_scalar=1.0all of the above are also found in the aircraft CFG file.Increasing power and drag will also increase the fuel consumption, and you then have to change the fuel_flow_scalar:(GeneralEngineData)engine_type=1 //0=Piston, 1=Jet, 2=None, 3=Helo-Turbine, 4=Rocket, 5=TurbopropEngine.0=4.75, -16.1, -2.5 //(feet) longitudinal, lateral, vertical distance from reference datumEngine.1=4.75, 16.1, -2.5 //(feet) longitudinal, lateral, vertical distance from reference datumfuel_flow_scalar=1.00 <---- THIS ONE!!! //Scalar for fuel flow efficiencyto compensate.And if you're talking about a propellor driven aircraft, and you altered the propellor thrust scalar instead of the engine power scalar to restore the cruising airspeed to its previous value after increasing the induced or parasite drag, then the aircraft will have a takeoff roll that is too short and the rate of climb will be too high, and you will have to delve into the propellor tables in the airfile to attain the right combination of propellor efficiency and power coefficients at the takeoff and climb propellor pitch angles to prevent say a 65HP Aeronca Champ from lifting off in 100ft and climbing out at over 1800 FPM after takeoff.And of course the induced drag scalar and the oswald efficiency factor found in the (airplane_geometry) section of the aircraft CFG are interrelated, and who knows how Mr. Oswald is going to react or what he is likely to do if you set his "factor" wrongly from the induced drag side of the equation?Sometimes, I find myself thinking that it is a lot easier to simply lower the nose a little, and use a liitle nose down trim until you see what you want on the VSI.But if you're like me, and are serious about FS flight model realism, and if you really want to make your computer airplane's performance come close to the real thing, then all the tools and most of the information you will need can be found at these websites: http://perso.wanadoo.fr/hsors/FS_Soft/fsdocs.htmlhttp://perso.wanadoo.fr/hsors/FS_Soft/fsairfile.htmlhttp://www.avhistory.org/scripts/MegaBBS/f...w.asp?forumid=5

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Thanks a million Douglas, that's exactly what I wanted to know.Ryan

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