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Guest jcomm

TBL 1506 and Thrust Factor

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Hello all!I am new the to the FDE design and I am trying to figure out how to adjust TBL 1506.I guess that the very first line should be either CN1 or CN2, and the first column shows the Mach number.My question is: What represent the numbers that can be modidied and how can I start adjusting those numbers?Thanks a lot for your answers!Cheers,LFMNboy:)

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Table 1506 tabulates the "gross" thrust factor (Tg) according to CN1 (not CN2) and mach numberThis is a scalar that is used to calculate the "gross" engine thrust (Fg) per engine, the equation beeing:Fg = (Tg * static_thrust * delta2) * thrust_scalarThe static_thrust and thrust_scalar are defined in the aircraft.cfg file.Delta2 is the total pressure ratio (Delta2 = SPR * (1+0.2*Mach*Mach)^3.5), SPR beeing the standard pressure ratioEffective engine thrust (Fn) is "gross" engine thrust minus ram drag (Fr)Fn = Fg - FrSo you will also have to take into account ram drag that can been calculated as:Fr = (Tr * Inlet_Area * delta2 / Sqr(theta2)) * TAS / 32.1740485564(Inlet_area is defined in the aircraft.cfg file, TAS is in ft/s, theta2 is total temperature ratio, the 32.17 constant is for units conversion)The Tr factor is derived from Table 1507, CN1 and mach numberAs you can see, the process is rather complicated but it is how it works at least in jet aircrafts ; turpoprops equations are a bit different. Hope this will helpHerv

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Hi Nick!Thanx for the help (and the link!). I will certainly take a look a this tool which sounds very interesting!Btw, I guess you work at CLS:) so let me say you guys are doing a fantastic job! It is a real excitement to fly one of your plane.(I can't wait for the A330:-hah...)Best regards,LFMNboy

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Although adjustments to table 1506 can be made for may other pourposes the most typical case occurs when someone tries to adapt jet engine net thrust in order to overcome the exhagerated rw/tw friction in MSFS.What can easily be done is to lower the scalars for MACH=0.0 and even add one or two columns to the table, for, say, MACH=0.1 and 0.2, to adjust net thrust at low (taxi) speeds.It is ususaly not difficult to be done, and although the AAM tool is an extraordinay program (BTW: I still look forward for an update os all of their products for FSX...) Jerry's AIrUpdate: http://www.mudpond.org/AirDat.ZIPwill do a better job when it comes to add/subtract columns from an airfile table and then assemble it back!And of course, for this and many other precious data, never forget to poll my preferred MSFS Internals site: Herv

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