New FSXBA Hornet

[jimi08]

Gents,

A few things:
-The need for manual use of rudder for turn coordination in the real F/A-18 has been eliminated as the FCS controls rudder input to keep turns coordinated for the pilot during flight.  It's considered a feet/boots on deck aircraft.  Manual rudder can be used, but rarely and from the Hornet drivers I've talked to, it's often discouraged, unless being used for close formation station keeping.

-My initial hunch for the rudder problem lies in the .air file and how much authority the rudder has been given at certain airspeeds.  My guess is that authority needs to be lowered a bit as airspeed increases.  Since the PI system considers "what worked in the past" and correlates that into future corrections, I'm thinking its using the same inputs that it used at lower airspeeds (which require larger inputs to affect movement), and applying them to situations at higher airspeeds (which require smaller inputs to affect the same movement).  The result is a constant and increasingly divergent yaw coordination from the FCS trying to constantly correct from its over-compensations.

-If you have access to the .air file, I would start there.  Don't remember the exact tables, but it should be on the lines of CM_R vs. Q or something like that.

My two cents.

[APUtech]

Gents,

A few things:
-The need for manual use of rudder for turn coordination in the real F/A-18 has been eliminated as the FCS controls rudder input to keep turns coordinated for the pilot during flight.  It's considered a feet/boots on deck aircraft.  Manual rudder can be used, but rarely and from the Hornet drivers I've talked to, it's often discouraged, unless being used for close formation station keeping.

-My initial hunch for the rudder problem lies in the .air file and how much authority the rudder has been given at certain airspeeds.  My guess is that authority needs to be lowered a bit as airspeed increases.  Since the PI system considers "what worked in the past" and correlates that into future corrections, I'm thinking its using the same inputs that it used at lower airspeeds (which require larger inputs to affect movement), and applying them to situations at higher airspeeds (which require smaller inputs to affect the same movement).  The result is a constant and increasingly divergent yaw coordination from the FCS trying to constantly correct from its over-compensations.

-If you have access to the .air file, I would start there.  Don't remember the exact tables, but it should be on the lines of CM_R vs. Q or something like that.

My two cents.

Thank you for your insight, jimi08, and by the way, thank you and your team members for producing such an incredible fighter jet! I'm spending *waaay* too much time flying it of late, mostly basic aircraft handling, patterns and touch n gos and day/night Carrier Operations.

Now that you've clarified how the F/A-18C's FCS/Auto-rudder functions, I've gained an even greater appreciation of and for the craftsmanship that went into refining it; I'm nuts about this jet.

I spent a good part of the day flying my usual route: KNJK to KNUQ doing about 10 touch n gos at one, refueling, then flying up to the other for several touch n gos before refueling, heading back and repeating the routine. The anomaly seems to appear at random and speed doesn't seem to be a trigger factor--it happens at high and low speeds, and most often when I am not pitching, rolling, or yawing the aircraft, as witnessed by Constance while I was on final for KNJK, flaps full, 3 deg pos elev trim, 150kias, 80% RPM, gear green and locked.

Today as I was flying back from KNUQ at 340kias, level at 13,040ft (CPL, BALT engaged) the shuddering began but subsided after a few seconds. Approximately 16 klicks out from KNJK I disengaged AP and configured the Hornet for descent to landing, throttle at 75% , VS -1000fpm. I brought the throttle back up to 80-85% 250kias at 5700ft, then without warning the jet was suddenly thrust from side to side. I applied manual rudder, which stopped the shuddering for a split second, then the violent yawing continued, only subsiding after engaging the BALT and CPL function on the AP.

The weird thing is that I had no shuddering on my trips up to KNUQ, but had a total of 3 incidents on the way down to KNJK, not sure why. As the eminent Mr. Spock would say..."Fascinating..."

APUtech 

[PhantomTweak]

If you have access to the .air file, I would start there.  Don't remember the exact tables, but it should be on the lines of CM_R vs. Q or something like that.

That is R519. Cn_dr(q) or Cn_dr vs Q if you prefer.
I DID bring everything in that down 1 click each. AirEd presents that record as a graph, so I just brought each point down by 1 unit of measure, whatever that turns out to be. I can print our the newer settings and post them if you desire. Just 1 click down isn't the entire fix, but couple that with what I posted from the aircraft.cfg, and the problem IS dealt with. If I overdid the PID controllers changes, please, let me know. I can put it all back to original settings and stick exclusively to the .air file settings. I thought I hadn't really made the changes to the aircraft.cfg all that big, buuuuut...
There are a number of rudder settings in the .air file, but that record seems to be the one you meant. I think (although rarely   ). I also believe the curve may beed to be adjusted a tad more, or maybe more finely, in which case I'll print out the file, make the changes in that record and then restore the file again. Or perhaps just certain points in it, the ones as close to that particular Q as possible. Or maybe more points are needed. I'm kind of jumping in at the deep end here, but I am more than willing to try. I do like tweaking things  
As always, suggestions (from anyone!) are more than welcome I do have, and refer to frequently, Yves' PDF file about the .air file settings, and what they do.

By the way: Always good to hear from you Jimi! I hope your move is going/went well  

The weird thing is that I had no shuddering on my trips up to KNUQ, but had a total of 3 incidents on the way down to KNJK, not sure why.

IF Jimi is right about which record in the .air file is the problem, or certain points along it, that it's the rudder deflection factor vs. Q, then bear in mind that Q changes with altitude, as well as airspeed. I believe. I will double check that to be certain.
I'd have to do the math to present the exact differences, and I'm too tired right now...
Apparently, they made it so the FCS stays active with the autopilot engaged now. It used to be, before this version (v15.6) that the autopilot disabled the FCS. I think...
That's what the gauge presented on SHFT+8 indicated, anyway. Now, due to all the changes, no telling from that gauge!

I'll work in he direction Jimi indicated, and see what I can find...If I find a way to make that fix the entire problem, with the original PID controller settings restored in the aircraft.cfg file, I will post the new .air file.
Pat☺

[PhantomTweak]

Ok, I got it...

I was right. Nice change, really!
Q is related to both altitude and speed, so Q changes with both.
Presuming the problem is in the .air file record indicated, or rudder movement vs Q (R519), the Q increases pretty rapidly with a decrease in altitude, speed remaining constant. It's a exponential function, pressure, that is, so it's a rapid increase. I am thinking maybe, perhaps, the PID controller for rudder (Sideslip, it's labeled) can't "keep up", or adjust rapidly enough, to this changing number, so it's moving the rudder a certain amount for a given Q, but the Q on the plane has "suddenly" increased (more rapidly than the controller is designed to handle. Too much history, so to speak), so the controller overcorrects, then try's to correct back, but again, moves the rudder too far, etc etc, until the controller "catches up" to the conditions applicable now on the plane. Thus, moving the rudder speeds this process, as it "reset's" the controller, as does turing the Spin Control ON for a few seconds then Off again. Thus, the controller is now working with a more current Q rather than a few seconds ago, as it were, if I read Jimi's and Orion's posts correctly.
I am going to presume that the rudder movement vs. Q is developed to make the plane fly correctly at a specific condition, PID controller aside, so it should remain as is. Or mostly so, andway. The controller's length of history (the I portion of PID, I think, I'll double check it) maybe should be decreased? Or the numeric weight of the I portion be decreased on the controller's formualtion in the FSC file, and the P maybe changed up or down to compensate? I am kinda shooting in the dark here. It may well be that the given rudder movement vs. Q is, in fact too high, and needs to be decreased? Or maybe just at the specific Q's related to where the problem occurs?

As I mentioned, PID controllers are far from my specialty. I am on a steep learning curve here. Having said that, the changes I've made so far, to the various aircrat.cfg settings anyway (including the PID controller settings), seem to have the situation resolved. Did I make the correct changes to the correct things? I don't know. Maybe I am totally messing up another flight regime. Or the plane's performance overall. I'm still testing, but it SEEMS to have the problem cured on MY system. My joystick, my computer, my settings for the controls in FSX, etc. without altering the flight characteristics. At least that I can see.

I hope this all at least points somone in the right direction, or maybe gives some idea of where-in lie-eth the rub.
Good fortune to all! I know I am sure loving this plane. Even the challenges
Pat☺

[APUtech]

PhantomTweak, thank you for the .cfg file entries. I apologize for not replying with my thanks sooner; I seem to having fewer shuddering episodes now.
Of late I have been doing some serious bingeing on a tricked-out 747-400, flying all over the place on cargo runs, eventually returning to KSAN (my home town) to strap into the F/A-18C parked at NAS North Island for a "dessert" run: I usually head east to NAF El Centro, run the tanks dry once or twice doing slow flight and touch n gos in the pattern, then fuel up and head north to KNUQ "nuke" Moffett, where I drain a tank in the pattern (rwy 32L) before refueling and heading back to KNZY. Love that Hornet! 
So how are you doing, are how's the flying going?

APUtech

[PhantomTweak]

...and head north to KNUQ "nuke" Moffett,...

Hey now! I was born in Redwood City, and raised up in Woodside. Moffet is where I saw my first F-4 Phantom II, The Blue Angels doing an airshow I remember at least one went through the big blimp hangar (Hangar 1) at full bore. Right over the crowd and into the hangar. It was awesome! I vowed to work on those (or maybe even fly em, but I had a stupid attack and went enlisted). I did wind up working on them, at least. I think I was 8 or 9 at the time.

So how are you doing, are how's the flying going?

Me, I like to take off from Miramar, and go raise havoc in Yuma A high-low-low-high profile. I was stationed there for a long time, and hated the place for every minute of it, so dropping "bombs" all over it is a blast, pun intended...Maybe intercept an airliner or two on the way out, or "bounce" a GA aircraft, just for fun. I love flying this bloody plane!

I seem to having fewer shuddering episodes now.

Feel free to make changes to what I sent to fine tune it. The Sideslip line of the PID controllers seems to be the biggie. Be VERY cautious about the second number (the I of the PID controller) as it can have unexpected effect. Make very small changes at a time.
I also made a few small changes to the .air file, if you want me to post that too. I can post the text version AirEd generates too, if you like. Like I said, I like to tweak things 

Have a great time, and enjoy whatever it is you're doing! After all, if you aren't having fun, what's the point? Of anything...
Pat☺

[Cynide]

First off... to everyone who contributes to developing this plane, THANK  YOU! Awesome work!

My first post... Finally got most stuff working OK on this bird... I was waiting for someone to just come up with a collimated HUD for the FA/18 (I use Flyinside for my Oculus DK2) and stumbled upon this gem! This is like a dream come true!  The thing that would make it the ultimate for me is to fire weapons using Tacpack. I used to work on "A" model hornets in VFA-204 in New Orleans as an avionics tech(AT), and have an idea how the weapons were set up on that jet. I am willing to dig into Tacpack and see if I can contribute to giving my Rattler some fangs. Do you have some pointers to a first-timer Tacpack user? And is there anything I can use so far? Anything would be greatly appreciated.

Cy

[Victory103]

Welcome Cynide, always great to have more members with real world experience contributing to a freeware model. Long time Tacpack user, but hardly a coder, so I would first direct you to the VRS forums and the TP SDK wiki for starters.

http://forums.vrsimulations.com/support/index.php/TacPack_SDK

[PhantomTweak]

Welcome Cynide!
Great to see a fellow Avionics tech (Tweak )
I was AQ at Yuma, in VMFAT-101, back when they were F-4 Phantom II's A little older tech, but hey, still an Avionics rate. I'm going to guess maybe you were I-Level too, no?
Anyway, Welcome, and it looks like Mr. Victory got the answer in before I did

Have fun, and good luck on your endeavour!
Pat☺

[edakridge]

Cynide and anyone else, I have made some progress in enabling Tacpack functions  on the Fleet 15.2 model. I have got AIM-9,MK-82,MK-84,Gun,Chaff,Flares,Tacpack Tacan and ILS working. There is still much work to be done though, if anyone is able and willing. Here is a link to what I have got done: https://backup.filesanywhere.com/fs/v.aspx?v=8d6b668f605f75b86d

I repeat, this is for the 15.2 model. The Panel.cfg is different in the 15.6 model.

[Cynide]

Downloading it now, thanks! How difficult do you think it would be to update to the 15.6 panel? I only ask so I can get insight into what is required...

[edakridge]

Not that difficult, I just have to find time.

[Cynide]

Got the Tacpack gun working in 15.6... I will tackle the AIM-9 selection and firing next.   The help is greatly appreciated!

Question: On the "A" model, I think we only had "smart" weapon provisions on the outboard wing stations( 2 and 8 )... does the "C" allow for all four wing stations  to be "smart" capable?

[PhantomTweak]

I found this

• F/A-18C/D can carry up to 13,700 pounds of external ordnance.
• Weapon stations include: two wingtip stations for Sidewinders; two outboard wing stations for air-to-air or air-to-ground weapons; two inboard wing stations for fuel tanks, air-to-air, or air-to-ground weapons; two nacelle fuselage stations for AMRAAMs, Sparrows, or sensor pods; and one centerline station for fuel or air-to-ground weapons.

on this page:
http://www.globalsecurity.org/military/systems/aircraft/f-18-specs.htm
It appears to me that yes, the inner and outer wing stations can, in fact carry guided weapons for A-A or A-G, whichever. I KNOE this includes JDAMS, AMRAAMs, MAVERICKs, HARPOONs, and so on.
Tells me the short answer to your question is yes, it can.

Hope this helps a little
Pat☺

[Dman]

in P3d V 2.5.. im getting this message: Hornet FCS simconnect exception: SIMCONNECT_EXCEPTION_UNRECONGIZED_ID

any ideas?