Fixes for DCS Huey compatibility mode

I have noticed a few bugs in DCS compat mode and fixed it. Also, I decided to pair it with “BUTTON_PRESS_ON_THROTTLE_CUTOFF” option, which from now on must be enabled for the Huey compat mode to work. Here are a few notes about it:

• IDLE REL joystick button (compact coll. head joystick button 5 by default) MUST be assigned to the corresponding button in the sim!
• connect your Simchair with closed throttle. In this case, no additional actions are necessary =)
• if you are not sure, before starting the helicopter, open the throttle past the detent mark, press and hold the IDLE REL button (red button on the compact collective head by default), and close the throttle. When you will turn the throttle grip to the left, the firmware will then send PgUp button press to open the throttle from “fully closed” position.
• DCS Huey compat mode only works in the middle position of the mode switch, this allows you to avoid sending PgUp / PgDn keys when you close the throttle in other sims, without disabling compat mode in the firmware each time.
• sadly, with the way it’s implemented in DCS, precise control of throttle below the idle stop detent is not possible. Therefore, for maximal realism, perform the startup with GPU connected. With external power supply connected, you can be sure that the battery won’t die during the startup and you will have enough power to open the solenoid driven throttle latch of the Huey. That allows you to perform startup at flight idle position of the throttle. Without GPU, the startup is usually performed with the throttle pushed slightly below the idle stop detent.
• Before closing the throttle, take a look at the state of the virtual IDLE REL button in the cockpit. If you have accidentally pressed it in flight and the virtual one is pushed in, just press it once more before shutting down the engine.

And a simple guide on how to use it:

1. open the throttle past the detent, press and hold IDLE REL, close the throttle.
2. perform the startup as described in the Flight Manual.
3. prior to shutting down the engine, check the virtual IDLE REL button state. If you see it pushed in, press the IDLE REL button once more to depress the virtual one.
4. to close the throttle completely, press and hold IDLE REL button on your collective and close the physical throttle. The virtual grip will follow.

Enjoy!