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Horizon Fast Erect (no, I'm not selling pills)

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There are several issues with FAST ERECT button in the cockpit and the overall performance of artificial horizon.


Issue 1. Pressing the fast erect button resets HSI to zero. The button has nothing to do with HSI in real life. The HSI is controlled by a separate panel on the right console.

Issue 2. Pressing the fast erect button resets pitch and bank on the ADI to zero. This is not correct. Pressing and holding the button increases the rate at which the gyroscopes erect to vertical position, as explained in the manual:


Screenshot 2021-04-02 233614.png


Screenshot 2021-04-02 233631.png


A little explanation: a spinning gyroscopes maintain their position in space. Literally in space, and not relative to Earth, which is in constant move. Also some random error is being introduced as a result of friction in the mechanism. To counter that, an artificial horizon has a built in erection mechanism, that constantly "erects" the gyros to vertical position (as indicated by gravity vector). The erection rate is slow, because otherwise it would introduce even more errors during manoeuvring, when the g forces pull the aircraft in different directions. The "fast erect" button simply increases the rate of alignment, to at least 15 degrees /minute as stated in the manual. So the pilot can quickly realign the artificial horizon, as long as he is flying steady during the process. 


Issue 3. There's still something wrong with the attitude indicator. There seems to be some sort of erection system already implemented, because the horizon will adjust by itself after few minutes of level flight or by just sitting on the runway after landing with horizon gauge out of alignment.

But at the same time, if you try to fly level according to the artificial horizon, then the aircraft will get in a progressing bank angle after just a few minutes. This is shown in the attached track, where I get into such situation after just a few minutes of such stable flight. If I then switch to flying according to the outside horizon, the artificial one will correctly readjust itself after a while. 


Not to mention the artificial horizon also accumulates the same error as the standby attitude indicator, despite them being completely independent. 




Edited by some1
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Hardware: Virpil T-50CM, Hotas Warthog, Hotas Cougar, Slaw Rudder, Wheel Stand Pro, GVL224 Trio Throttle, Thrustmaster MFDs, Saitek Trim wheel, Trackir 5, Reverb

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Thanks for writing this up. I previously complained about the drift rate and accumulation of error in another post. 

"Subsonic is below Mach 1, supersonic is up to Mach 5. Above Mach 5 is hypersonic. And reentry from space, well, that's like Mach a lot."

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