• 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.

FSXA How to decrease max mach number in dive

Fredrik_85

Fredrik_85

Messages
2
Country
sweden
Hi

I'm new here and I'm also new to tweaking aircraft in FSX!

I would like some help with lowering the maximum mach number in a steep dive. I have downloaded the SAAB J29 Tunnan by Tim Conrad. It's a Swedish sub sonic jet fighter from the 50's. It has a max mach of .93 (F version) and I have read extensively about this cool fighter so I know that it was barely possible to get it up to Mach 1 and then only if you put it in a vertical dive from 15000 m with afterburner.

The max level speed is fairly ok (about 550 knots) but when I dive I can easily push it up to mach 1.2 which is way too much.

I have looked in to the AIR file with AAM v2.1 but I have only fiddled around a bit with the induced and parasite drag but to no avail.

Anyone who knows a simple way to fix this? (More advanced tricks are also welcome even though I'm a rookie at this ;))
 
The issue is quite simple. Mach drag should rise at about 0.85 Mach and peak somewhere around 1.05M. In the sim this is dictated by the air file values for either Record 430 or 154a. The SAAB air file has only 430 and it has a totally insufficient supersonic drag rise. With a better shaped drag rise the beast will struggle to get supersonic. The table has 17 entries at 0.2 Mach intervals. Make the value for 1.0 Mach about 0.4.
Roy
 
Thanks for a good and fast answer!

If I increased up to 0.4 it decreased the mach number too much. In the end I found 0.2 to be a good value. The 0.2 mach intervals in record 430 seemed a bit to course though...

After the mach adjustment the level top speed also decreased so I increased it a bit by decreasing the air inlet.
 
You are quite right, the 0.2 Mach intervals are too course. This was why 154a was introduced with FSXA so the FA-18 could modeled. That record has whatever intervals you want and they can be non-uniform.
Decreasing the air inlet size decreases ram drag which increases the net thrust.
Roy
 
You must log in or register to reply here.
Back
Top