Autopilot

[tf_neuro]

I'd like the plane to keep its heading and altitude while im working on my weapon systems.

However, the autopilot doesnt seem to work. It is armed and set to alt/hdg, I hit the engage/disengage button, it goes 'ding!'... and the plane keeps drifting all over the place.

 

I tried putting it in straight and level before hitting the button, same result.

 

Also, it only goes 'ding' the first time I hit it. After that, no matter how straight and level I fly, I never hear that 'ding' sound again.

 

What am I doing wrong?

Any A/P tutorials around?

 

BTW, I can't find any autopilot assignment in the controls GUI. It'd be real nice to have the engage/disengage A/P button on a keyboard key but I can't figure out where to assign it.

[ptako]

Ensure you're between 0 and 10 deg. of bank and between -5 and +5 deg. of pitch else AP won't engage in this mode.

Also check if you have EAC on.

Edited August 21, 2013 by ptako

[PFunk1606688187]

The Engage disengage button is in the HOTAS sub-category of controls as well as the LASTE category of the controls. There are two buttons to engage it in the A-10, one is on the throttle (which should be under the HOTAS sub-category) and the other is on the LASTE panel which is just aft of the throttle.

 

There are lots of reasons it won't engage. If EAC isn't turned on I'm not sure you'd hear the ding though. Likeliest culprit is that you're not trimmed properly and the airplane wants to deviate from straight and level more than the autopilots control tabs can correct it.

 

If its not that maybe you're double pressing the autopilot engage button.

[Flamin_Squirrel]

It'll display "ALT/HDG" in the HUD (bottom left I think) if it's engaged properly, so check for that.

[Catweasel]

Also make sure your aircraft is trimmed for level flight.

[tf_neuro]

Thanks for the suggestions.

One thing kind of worries me: Catweasel's tip 'make sure you're trimmed for level flight' seems to imply that if I increase or decrease throttle the A/P will disengage instead of retrimming for the new speed. Is that the case?

 

Also, does the A/P auto-disengage if I move stick/pedals?

 

 

EDIT:

Answers to my questions seem to be no, and yes.

A/P working flawlessly. Thx.

Edited August 22, 2013 by tf_neuro

[Hamblue]

One big thing to check is that you waited for alignment during the start procedures. If you didn't then auto pilot won't work.

 

Look at the trouble panel on the right side by your knee. Are any lights on? especially the EAC? If so then the auto pilot won't work.

[PFunk1606688187]

Thanks for the suggestions.

One thing kind of worries me: Catweasel's tip 'make sure you're trimmed for level flight' seems to imply that if I increase or decrease throttle the A/P will disengage instead of retrimming for the new speed. Is that the case?

 

Also, does the A/P auto-disengage if I move stick/pedals?

 

Radical changes in the throttle could over time cause your current trim to disengage the A/P, but not minor ones. The trim tabs that it uses are rather substantial and they provide a lot of deflection, but if you're changing your throttle setting a lot you should be manually flying anyway.

 

The reason it works this way is because of the whole way you're supposed to trim the aircraft. Its said you trim for airspeed, but this isn't completely true. You're really trimming for Angle of Attack which for straight and level flight occurs at a particular trim setting for a particular power setting. Adding or reducing power will cause the necessary trim for level flight to change, which is what the A/P is able to do within a limited range. As you add or reduce power the angle of attack necessary to maintain level flight is different. If you were to set perfect trim for a single power setting at a particular altitude you'd get a particular speed, hence the phrase "you trim for speed". By trimming for a particular angle of attack/speed you're going to get that one speed at level flight then as you raise and lower power you'll see yourself gain or lose altitude, but your angle of attack and therefore your speed will remain the same. Your trim setting has remained the same so your angle of attack is the same and so your speed is roughly the same. If you were to radically reduce or increase power you'd see gains or losses in speed as well, but in general they'd even out to the same speed, provided you have enough altitude to even out or you retain enough power to actually generate enough lift to avoid entering a sharp dive. Gentle additions or subtractions of power would lead to a loss or gain of alt with no discernible change in Speed outside of A/P. This is how correct landing occurs, at a particular fixed angle of attack which is set by trim and then sink rate is adjusted by moderated changed in power setting.

 

The other thing about angle of attack is that your plane will always stall at the same angle of attack, so you can trim to a particular AOA then its only your power that'll cause you to stall in that configuration. Lowering the nose lowers the AOA so you don't stall, however with no power applied this lower non stalling AOA is incapable of achieving level flight so you lose altitude. This is the conundrum of the unpowered glide mode.

 

So in short, minor changes in power will not cause your A/P to disengage if you were trimmed for level flight, but when you do disengage it you will immediately depart from level flight as the trim setting is incorrect for that configuration. Radical changes in power will cause A/P to disconnect but doing this is just weird, so why are you doing it. :P

 

Yes the A/P will disengage if you move the stick. I don't know about rudder, but I've never tried to apply rudder while in A/P without touching the stick. I believe Alt mode may not disengage the A/P because I can remember a few times thinking my plane was damaged or bugged out because I couldn't control it when it was that I hadn't disengaged the A/P, but for the level modes it should disengage under strong inputs from the stick at least, rudder pedals likely, but again why would you only input rudder?

[WildBillKelsoe]

are you playing in dynamic weather? If so, make sure you're into the wind/away from it... I think ED should redesign missions to make use of the dynamic weather.

[NhiTrac]

That 'ding' engage sound. Is that what it's like in RL? Sounds like they took a sound file straight from windows 95!