Caldera Posted January 9, 2022 Posted January 9, 2022 (edited) Hey All, OK... Coming from the A-10C where the AutoPilot (AP) works pretty well, straight forward and kind of like the cruise control on my truck. It has indication on the HUD. You can turn it on, you can turn it off, also turns itself off and even tells you that it did so. The F-16C AP not so much... The first time I noticed weirdness was on a strafing run as I was engaging a convoy in the CCIP training mission. Some kind of porpoising started happening as I was trying to shoot. I could not understand what was going on. It was kind of like fighting with I-PAC. I could not find out if the F-16C had I-PAC or some such, but I noticed that I had left the AP on. The PITCH switch was in ALT HOLD and the ROLL switch was in ATT HOLD. Could this porpoising behavior be caused by the AP? Does the AP automatically disengage? Manual: PITCH – ALT HOLD. This maintains the aircraft at a constant altitude. The autopilot will attempt to maintain the current altitude from when the switch is set but may not be able to capture the desired altitude if the aircraft is in a climb or dive. An altitude within the control authority of the autopilot will be commanded. The altitude may be changed by pressing the paddle switch, flying to a new altitude, and releasing the paddle switch. How do you "press" the paddle switch? It seems to have only three positions up, middle and down. PITCH – ATT HOLD. This maintains the aircraft’s current pitch attitude, nose up or nose down. The autopilot will not engage if the pitch angle exceeds ±60°, however, the switch may remain engaged. The stick may be used to change the attitude in this mode. If the switch remains engaged does the AP also stay engaged? Does using the stick to change attitude supposed to lock in another attitude setting or does it go back to the original setting? ROLL – HDG SEL. This causes the aircraft to fly the heading selected on the HSI. Roll commands are limited to a 30° bank or a 20° per second roll rate to capture the desired heading. The autopilot will not engage if the roll angle exceeds ±60°, however, the switch may remain engaged. ROLL – ATT HOLD. This maintains the aircraft’s current roll attitude. The autopilot will not engage if the roll angle exceeds ±60°, however, the switch may remain engaged. The stick may be used to change the attitude in this mode. There is actually a ROLL switch mode missing from the manual called STRG SEL. It does seem to work though. These ROLL modes seem pretty cool and are way better than the A-10C. Especially the "fall asleep in the saddle and let the horse find its own way home" mode I like. Because, the F-16C INS Alignment Location (A-10C Initial Point) seems to be missing from the steer points and until I figure out how to navigate better with out it. The switches are held in place until they are returned to the OFF position or any of these situations occur: • air refueling door opened • alt flaps extended below 400 knots • A/P FAIL PFL • AoA exceeds 15° • DBU on • landing gear extended • low-speed warning • MPO switch in OVERRIDE • STBY GAIN PFL • TRIM/AP DISC switch set to DISC Holding the paddle switch presses disengages the autopilot until the switch is released. Holding the paddle switch how? This is confusing to me. Here it implies a press disengages, above a press engages. Sometimes I can't get the AP to engage. The PITCH switch moves up or down but spring returns to the center. That is with the ROLL switch in ATT HOLD. If the ROLL switch is in HDG SEL or STRG SEL it will work just fine. The manual does not explain why this would happen. Thanks in advance, Caldera Edited January 9, 2022 by Caldera
Rongor Posted January 9, 2022 Posted January 9, 2022 (edited) 26 minutes ago, Caldera said: Sometimes I can't get the AP to engage. The PITCH switch moves up or down but spring returns to the center. If the aircraft currently isn't within a certain trimmed limit, let's call it 'unstable', the AP will not engage. This is a safety thing. Your AP has only so much authority to trim your aircraft into stability. It's no different in your A-10C. If your AP Pitch switch centered by itself, effectively disengaging, you are in one of the situations you listed above. 26 minutes ago, Caldera said: Could this porpoising behavior be caused by the AP? I would think so, yes. Does the AP automatically disengage? Yes, you have listed the conditions How do you "press" the paddle switch? It seems to have only three positions up, middle and down. Holding the paddle switch is like ... holding it. If you look up the pics in your A-10C or F-16C manuals, you'll see that the paddle switch is not a button but a tilting paddle which then can be hold in place by your pinkie finger. As long as you do that, the AP won't fight your steering inputs. If the switch remains engaged does the AP also stay engaged? I would assume so, yes, as long as you don't pull and hold the paddle switch Does using the stick to change attitude supposed to lock in another attitude setting or does it go back to the original setting? You can achieve this by using the paddle switch. After your maneuver, release it and the AP will continue the new pitch attitude (if pitch hold is selected) or altitude (if alt hold is selected) and roll attitude (if att is selected) but not the roll attitude when Strng or HDG are selected as a roll mode There is actually a MISC mode missing from the manual called STRG SEL. It does seem to work though. There is a ton of stuff missing currently in the manual Holding the paddle switch how? see above The manual does not explain why this would happen. There is a ton of stuff not explained currently in the manual Edited January 9, 2022 by Rongor
Caldera Posted January 9, 2022 Author Posted January 9, 2022 Rongor, Thanks! 7 minutes ago, Rongor said: Holding the paddle switch is like ... holding it. If you look up the pics in your A-10C or F-16C manuals, you'll see that the paddle switch is not a button but a tilting paddle which then can be hold in place by your pinkie finger. As long as you do that, the AP won't fight your steering inputs. Not quite right here. The toggle switch you call a paddle is just a 3-way toggle switch. It does not change position on its own ie no spring return to center losing the magnetic latch. The button next to that switch engages the AP only. It is the same with the pinky switch. If I am getting this right, then holding the paddle switch, for example the PITCH switch held at the ALT HOLD position (with mouse or keybind), is the same a "pressing" as described in the manual? Caldera
Rongor Posted January 9, 2022 Posted January 9, 2022 You were bringing up the paddle switch. 29 minutes ago, Caldera said: Holding the paddle switch presses disengages the autopilot until the switch is released. Holding the paddle switch how? This is confusing to me. Here it implies a press disengages, above a press engages. the paddle switch is on your stick. It's not a toggle switch, nor is it 3way.
Caldera Posted January 9, 2022 Author Posted January 9, 2022 OK We had a post post simultaneous going on. Let me rephrase: Does the AP automatically disengage? to Does the AP automatically disengage with control stick movements? Thanks again, Caldera 2 minutes ago, Rongor said: You were bringing up the paddle switch. the paddle switch is on your stick. It's not a toggle switch, nor is it 3way. OK The missing link. Caldera
Rongor Posted January 9, 2022 Posted January 9, 2022 (edited) 12 minutes ago, Caldera said: Does the AP automatically disengage with control stick movements? no, but it will try to correct them and return to the attitude it was told to maintain. Of course you could force it to disengage by achieving one of the listed conditions, for example by keeping the stick pulled backwards until you reach a stall. OK The missing link. the pics in F-16 the manual actually don't show the paddle on the stick. In your A-10 manual, it is the yellow switch at the stick's base. here is the modified pic from Chuck's guides: Edited January 9, 2022 by Rongor
Frederf Posted January 9, 2022 Posted January 9, 2022 AP will automatically disengage but it's based on G or AOA (2g or 15AOA iirc). You can stick input in AP without disengaging it unless you trip the AOA/G limits. Stick authority is enough to override temporarily the AP in any case. E.g. if you're going to hit the ground you can grab the stick and pull. AP doesn't trim so out of trim condition counts as stick input which can reduce or eliminate the margin of authority the AP has. The normal way to fly with AP is to depress the paddle, maneuver, release the paddle. If you stick input without paddle it should go back to doing whatever it was doing. For roll channel that's either steering or bank hold which should be the new bank. For pitch it should keep the new pitch or altitude. I don't know if it'll try to fly back to the previous alt.
Rongor Posted January 10, 2022 Posted January 10, 2022 12 hours ago, Frederf said: For pitch it should keep the new pitch or altitude. I don't know if it'll try to fly back to the previous alt. In my experience so far it does. Releasing the paddle defines the altitude just like the initial AP switching to ALT mode.
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