DC Designs F-15

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1083

So… My impressions after two long-range flight… It’s still good, BUT there is a major issue I am experiencing (it won’t spoil the fun that much as I rarely use AP in fighters)…

Above a certain altitude, not sure if it’s FL250-300ish??? or so the autopilot (and I mean JUST by enabling it without activating any modes) starts wobbling violently from left to right. The higher the altitude, the most violent and oscillatory the wobble becomes - to the point of it being unusable. I am not even sure if that’s something you guys can fix as I have seen this issue previously, most notably, Boeings etc… I think Longitude suffers from that right now at higher altitudes too…

So I was cruising at FL590 and as long as I am hand-flying it, all is well… but no such luck with AP enabled. It’s so bad that I have to zoom in really close to the AP switch to disable it - can’t catch it with my mouse pointer from normal view cause it’s oscillating so bad. This MAY be an Asobo AP issue… not sure what’s up with it, but… here it is.

Other than that, it’s great.

1084

Anyone able to hear other F-15s flying around, or still no sound?

1085

FWIW, the only issue I have is ALT and V/S is removed so I can’t sense what settings I have for altitude or V/S.

1086

Hey @CodenameJack447 or @DEAN01973 - is there a way I can edit the engine sound level? It’s sooo loud. I love the new sounds, but I can’t hear any ATC or anything else because they are so loud. Thoughts?

Also - my observations:

Autopilot not working as it did. When I set my altitude and then V/S, it will follow it for a little bit, then resets. I can’t keep my V/S constant like I used to.

1087

Is not the same autopilot from 1.14_i @moxiejeff. I have not done an Autopilot mod yet with that behaviour. You can try to replace systems.cfg’s [autopilot] content with the 1.14_i (do a backup first) one, or wait I do it as a mod.

1 Like
1088

For the sound, you can go into your sound settings in options, raise “Voices” if that isnt at 100 (voices is ATC voices), and “Aircraft Engines” down to a comfortable level for you.

There is also a setting in sound called communication selection, I don’t personally use this, but you can select “Headphone Simulation” states it applies a simulation of headphone acoustics that filters out external sound environments. (cockpit view only). Might still have to lower aircraft engine volume for external though. Might be worth a shot.

The headphone simulation option is quite peaceful though lol, I may use it more on the F-15

1 Like
1089

Okay :slight_smile:

dcdesigns-aircraft-f15_v.1.0.1_rev_AP_1.14i.pln (22.3 KB)

@BostonJeremy77, @moxiejeff, @olaf65, and everyone else with AP issues.

I have created a minor mod just suporting the AP behaviour as it was in 1.14i

The oscilations should stop because the ai.cfg files (PID values for Autopilot) i include here are more stiffness to maintain the route direction.

On the other hand, if you were familiarized with the 1.14_i, you know it works the same it was used to work: alt hold, nav hold, Vs hold, increase/ decrease etc.

Just rename the file from .pln to .rar, and unzip to community folder like this:

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5 Likes
1090

There it is!!!

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1091

Thanks a ton, Jack! Will try it out tonight after I put my daughter to sleep.

1092

By the way, why does it do that? That whole oscillatory behaviour?

1093

Thanks, if you find it still oscillates i can tune the PID values even more!

1094

What the autopilot does is correct a heading route or nav route, or certain altitude based on a margin of error. If the percentage of error is high, it begins to oscillate, and if that margin of allowed error is high, it never corrects the oscillation but “dances” on the straight line without stabilizing. If the margin of error is low, it does everything in an abrupt way and is not corrected either. You have to find the perfect balance. Those error values ​​are defined in ai.cfg:

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The problem with stock aircrafts is that asobo has not wanted to complicate its life. they has taken a PID template and put them in all the planes, regardless of weight, moments of inertia, maximum speed. So in some it works, like in a vl-3 whose weight is very light and easy to correct, but if you copy it in a 737, things change, due to the tonnage.

With this plane it is simply to dedicate time to it and I did. However, if I make changes to the flight model, it may affect the autopilot. That is why it is important that you tell me in case I have to recalibrate.

Prepar3D defines them like this in SDK:

PID Controllers

PIDs are only used to aid in the handling of AI (computer) controlled aircraft. PID stands for Proportional-Derivative-Integral controller, and is a feedback controller that takes an error for a controlled state and outputs a correction. For example, on an airspeed controller, the error would be the desired airspeed minus the current airspeed. The output is then determined by the sum of three factors using the error and the P, I, and D constants. The “P” factor is simply a factor proportional to the error. The “I” factor is an accumulated factor scaled by the error. The “D” factor is a factor based on the rate of change of the error.

“P factor” = P * error

“Accumulated I factor” = “Accumulated I factor” + (I * error * deltaTime), in Calculus terms, this is simply an integral. The error must reverse its sign to drive this accumulated factor to 0. This is characterized as oscillations, but drives the error to zero.

“D factor” = D * error/deltaTime. As the error gets smaller, this drives the output to be asymptotic towards the desired value.

4 Likes
1095

Wow I never knew this. THANK YOU!

1096

You. Are. AMAZINNNNNNNNNNNNNNNNNNNNNNNNG

1097

Perfect,
altitude change with keyboard (for me) and also the Vs:)
A great surprise also, at 30000ft, the freeze appeared on my cokpit glass (so switch on defreeze:)
The plane is really wonderful, thank’s a lot

1098

Jack,

Just tested this with your mod. It’s PERFECT. I took it up from Pudong in Shanghai to about FL630 and tested AP stability throughout. Oscillatory behaviour is all gone, thankfully. When I activated ALT hold, it stabilized nicely. It’s perfect! Whatever this is, maybe the next release could get THIS. :wink: @DEAN01973 Right? Right? :wink:

This is a dream to fly now. So happy. Thanks for fixing this issue and for all you do.

3 Likes
1099

Just did a group flight, tested C-model at slow speed all less than .8 . Few touch and go’s , slow and sub sonic mountain passes. Wow. What a nice turnout from where it was… Kudo’s to all … Great Work…

1 Like
1100

Going to tweak with the PID controller. So you are changing the constant to see the effect on rate? :wink:

1101

I am not sure if I have the wrong version but I can’t seem to keep the airplane in the air. If I take off and have flaps extended one it just nose dives and crashes. Hard to slow down for an approach etc with this.

So if I am below 300 knots the plane wont climb or wont maintain level flight or altitude. I can’t slow down to approach to land because the plan will just fall out of the sky. All my settings such as flight model etc are correct yet same result.

1102

@SilentG37 So while we were flying along Wales with Severus the other day you were in the test version of this bad boy eh? Lucky dawg you :wink: I have to say Dean, this update to 1.0 (and 1.01) feels great. It just flies so well and sounds so good!! Can’t wait for more!

2 Likes