L-39 in Flight Model Legacy unflyable?

I just tested it and shortly after take off it goes completely crazy. It rotates extremely and the crash is always unavoidable. Is that problem well known or is there a work around? Or can it only be flown in arcade mode?

check where the centre of gravity is set in the weights setting. mine normally completely aft

Its perfectly balanced. Btw all other planes like the Magister for example or F-18 have no problems at all. Only the L-39.

Do Not Use Legacy Flight Model!
Use Modern Only & it’s an not arcade mode.

Legacy is only for a few, very few aircraft that are purchased outside of msfs.

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Any reason why you would want to use the legacy flight model with the L-39? :thinking:

as a moderator said in another topic :

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The L-39 is the first aircraft to have problems with Legacy. Meanwhile i find some more having the same problem. Why did they do not fix this problem?

I just switched to legacy for more realism. The Magister for example fly will with legacy. I never heard before that L-39 is unflyable in realistic flight mode.

Nothing to fix.
Do not use Legacy Flight Model for any default msfs aircraft.

Yes, it does need to be explained better in options, but do not use it.

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Hello @EuleIowa89,

The “Legacy” flight model is to make some older addon planes that were originally imported from FSX compatible with the current version of Microsoft Flight Simulator. Unless you are using one of those aircraft, you should always set your flight model to “Modern”. Using the Legacy flight model with a plane that was designed for the Modern flight model (which is most of them) can cause issues like you described in the OP.


“Legacy” vs. “Modern” flight model is not a realism setting. Using Legacy is only for a relatively small number of older addon planes imported from FSX. It is not “unrealistic” or “arcade” to use the Modern flight model, which is the recommended setting for almost every plane (including the L-39).



Just to reiterate once more, to overcome your reluctance to accept the truth: there is nothing to fix. The L-39 was developed for the Modern Flight Model, like all native and add-on aircraft for MSFS. The Legacy Flight Model is nothing but a fallback for converted FSX/P3D aircraft and will more or less break the flight model on anything else (as you experienced).

There is absolutely nothing “more realistic” about the Legacy Flight Model. Ditch it and never touch it again.

They might appear to work, but they will most definitely not work as intended by the developers of those aircraft.

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This thread is exactly why the flight model shouldn’t even be selectable. It should be set by the third party dev in the config files.


I couldn’t agree more. It’s the dev who knows which model to use. No reason for the user to select it.
I’m also almost sure even this is not needed and there is some way to detect just by the file content and their structure which model to use.

The problem is that this legacy flight mode uses the term “realistic” with its sliders full right. And the fact that there are boneheads out there that still tell everyone who wants to read it that MSFS is a toy sim and P3D and XP were the only true sims. That might have been so in August 2020. It’s April 2023 now and we have a totally different sim today.

Legacy mode uses a couple of table values that move a vector around. The modern flight model uses the complete list of new technologies that MSFS has introduced to create extremely realistic flight characteristics. It’s not perfect yet, it still has its flaws, plenty, but it’s tremendously better than anything we had before in FS9, X and P3D.


Wish List here:

Yeah and i fell for it thinking its a way to improve my flight skills after nearly 300hrs of flight experience. Thats why i thougth at first moment using legacy aka (at that moment) more realistic wiht L-39 that i am not even at beginners level … or L-39 is buggy nor wont work with Legacy Mode. Anyway its quite confusing.