VTOL shenanigans

[OlWilly 100]

So I looked into the VTOL behavior to see what is wrong with it.

From my experience (on Hard of course), all stock and modded VTOL aircraft in the game are impossible to hover and thus, you can't take-off or land in trve VTOL mode. When your airspeed is low enough aircraft starts to show stall behavior (default in-game) and is subjected to sudden sideways jerking movements, quickly taking it out of control.

This restricts you to using only the STOL take-offs and landings - on take-offs you had to input horizontal acceleration as soon as possible, and on landings you have to maintain minimal airspeed. This is fine, I learned to land Yak-38 on the deck going at 70-100km/h, but having proper VTOL would be good too.

Debug mode shows the reason for this - AoA values go all over the place.

When you climb vertically, it goes around -90, when you sink - 90. If you sink backwards it shows close to -180, and on backwards climb - close to 180.

Technically, this kinda makes sense as it shows the direction of "relative wind". But because the airspeed is well below the stall speed, this shouldn't really matter. Aircraft is not yet producing any lift and it doesn't really have AoA yet to speak of.

The game thinks otherwise. It sees AoA value going overboard and freaks out because of it, applying stall and then trying to spin your aircraft. This is the reason for wackiness during hover.

To test this, I picked Harrier and plainly deleted all stall and spin related values in its DATA file. No surprise, it started behaving fine in VTOL, I could hover, take-off and land alright. But this is not the solution because:

1 - by deleting all stall and spin entries I just turned Harrier into a complete UFO in the normal mode. Unacceptable

2 - the game still freaks out when I "flip 180". With backwards movement, if I cross the line between positive and negative AoA at 180/-180 - read sink backwards and then apply power and start climbing or vice versa - the game simply flips the aircraft over

I've thought about using the usual fake highlift surfaces or editing the tables, but neither solution worked or didn't affect the normal flight.

And thus the bad news, I don't think this could be solved using the DATA files alone. The proper solution should be implemented on the game engine level, simply disabling all stall and spin behavior (for example, simply locking AoA to zero) when nozzles are deflected downwards. Since we don't have access to engine's code - alas.

And likewise, this problem is legit for modded helicopters too. You can disable all stall and spin values from their FMs, but "flipping the 180" issue will remain.

This is really unfortunate because on game engine level this could be solved with just few lines of code. With the simplest approach, the engine has to track only one variable (thrust vectoring input) and after a certain threshold simply lock AoA to zero

[+EricJ 3,972]

Years ago I thought I knew what was doing (and I was wrong) with the F-35B. I wanted that VTOL takeoff and landing, but some wise hands told me it was impossible. I wish we could open the code and adjust the values so it could work.

[+Cliff7600 1,146]

It's not a fix, it's not working either, but this might be slightly better :

F-35B_Data test.7z

[+EricJ 3,972]

21 minutes ago, Cliff7600 said:

It's not a fix, it's not working either, but this might be slightly better :

F-35B_Data test.7z

Thanks, I'll check it out sometime

[+EricJ 3,972]

Tried it out at least once and I think I need to master it as well... I took off, but wasn't a graceful takeoff...