• Which the release of FS2020 we see an explosition of activity on the forun and of course we are very happy to see this. But having all questions about FS2020 in one forum becomes a bit messy. So therefore we would like to ask you all to use the following guidelines when posting your questions:

    • Tag FS2020 specific questions with the MSFS2020 tag.
    • Questions about making 3D assets can be posted in the 3D asset design forum. Either post them in the subforum of the modelling tool you use or in the general forum if they are general.
    • Questions about aircraft design can be posted in the Aircraft design forum
    • Questions about airport design can be posted in the FS2020 airport design forum. Once airport development tools have been updated for FS2020 you can post tool speciifc questions in the subforums of those tools as well of course.
    • Questions about terrain design can be posted in the FS2020 terrain design forum.
    • Questions about SimConnect can be posted in the SimConnect forum.

    Any other question that is not specific to an aspect of development or tool can be posted in the General chat forum.

    By following these guidelines we make sure that the forums remain easy to read for everybody and also that the right people can find your post to answer it.

Drag 747

L

lh777

Messages
126
Country
italy
I would like to increase the strength of 747 posky because on the way down, with a very low rate (500 to 1000 ft / min), maintaining high speed (330-350 knots).
I tried to lower engine power than at Idle speed table in 1506, but with no great result.
 
Table 404 in the .air file or the drag parameters in the aircraft.cfg.
 
If you want to just experiment with this problem then play with the aircraft.cfg [flight_tuning] parasite_drag_scalar to see what number gets the effect you want.
If you seriously want to do a study of the 747 then go to https://docs.google.com/document/d/1Kj1zXoqZ83LSKV1g6kg7pZX9YtboFu2qrRq1KI6SPrk/edit?pli=1 and download for free:
Airplane fight characteristics and automatic flight controls part 1 by J Roskam.
Appendix C6 starting page 648 lists all of the stability and control derivatives for the B747.
For example the stock MS B747 drag coefficient at zero lift Cd0 is given as 0.0151, which is a very low value and Roskam gives it as 0.025 for 20,000 ft cruise at 0.65 Mach.
However it is quite possible that MS made the drag that low because their thrust (in common with all MS stock planes) was too low at altitude. So if you just change drag your cruise may well be off.
If you are seriously going to improve the characteristics of a FS model, the place to start is with thrust, then do drag.
Roy
 
You must log in or register to reply here.
Back
Top