can not reproduce Is there an issue with the drag model of the F-16 when wings are not balanced?

[einarabelc5]

On the AGM-65 Maverick Mission, I already reported something that's fixed in the latest BETA version as per QA, see here:

 

Attached is the modified version of that mission I've created. A simple re-configuration of the Player's F-16C payload where the fuel tanks are used as counter balance to the heavier wing with the 3 AGM-65D. So I have right wing, AMRAAM Sidewinder,3 AGM-65D. Left wing, AMRAAM, Sidewinder,  AGM-65K and Fuel Tank. Center, Fuel Tank.

Please drive this configuration to Steer Point 4 where the Boresight mode practice moving vehicle column is and let me know if it is not a frustrating experience trying to control the plane in rolls between 384 and 300 Knots without autopilot engaged as the trainer indicates (since you have to aim with the nose of the plane). Whether the plane is roll trimmed or not, it drops like a brick when turning, making balancing pretty difficult and much less practical to aim with the nose.

Am I wrong about the physics of this and if so, please educate me as to why, I'm willing to learn. Or is there a real issue here deserving constructive feedback?

IMO and compared to how the exact same module on the exact same version behaves when strafing with either guns or in BFM it just doesn't match the behavior. Plus is pretty common knowledge that most modules in DCS de-accelerate too quickly. For this task the strafing MUST be done at slow speeds in order to have the time to aim the reticle while being CLOSE enough to see the vehicle column through the missile's Feed. An unstable plane, which is trimmed and under an FCS makes that pretty incredible. Unless we play with angles of attack but then again, the Maverick doesn't maneuver that much to take that kind of approach.

Lesson 20 - AGM-65 Maverick.miz

[einarabelc5]

Update, it looks to me that using the correct trim modes together with the two auto-pilot switches while avoiding to use bore mode left and right but only change the attitude makes this somewhat effective. Now, for more mission feedback, the tank column stopped moving at a bridge instead of going between red and white smoke. Because of that, I destroyed the bridge, the center T-72 stayed "afloat",  see screenshot.

 

Obviously static tanks are a lot less challenging than a moving column, something to keep in mind when programming this mission, if user waits long enough, user can get easy targets. I would say, if possible update the FOV setting on the BORE mode so aim can be improved. It took many turns and missiles to get the first shack. I can only imagine with a single missile left.
 Attached also is the Tacview and mission Track, right before the last strafe run I pull hard back on the stick, you can see the plane "fall" as I was referring to when trying to get the moving targets originally. In that scenario, which is different, you'd expect to be able to turn fast after you miss a run so you want to go slowly, turn almost immediately and aim again. That's what I couldn't do and what prompted this post, I had to fight the plane instead.

Tacview-20230608-195454-DCS-Lesson 20 - AGM-65 Maverick.zip.acmi

Lesson 20 - AGM-65-Maverick-Finally-Success.trk

Edited June 9, 2023 by einarabelc5

[Lord Vader]

Hi @einarabelc5

I ran that Maverick training mission and there is an intentional wing heavy loadout. The narrator is clear on what to do to counteract it using trim. I saw no odd behaviour, to be honest.

Yes, the F-16 can be quite challenging with asymmetrical loads.
It is advised to use the aileron and rudder trimmers to counteract the plane's behaviour.
It is also wise to avoid very pronounced asymmetries, especially on take-off.  

On your second message, I would clearly avoid abrupt inputs in such conditions. This will make the asymmetry more pronounced, leading to undesired rolls.
There's also an identified issue using Mavericks on moving targets that hopefully will be fixed soon. 

[einarabelc5]

On 6/9/2023 at 1:42 AM, Lord Vader said:

Hi @einarabelc5

I ran that Maverick training mission and there is an intentional wing heavy loadout. The narrator is clear on what to do to counteract it using trim. I saw no odd behaviour, to be honest.

Yes, the F-16 can be quite challenging with asymmetrical loads.
It is advised to use the aileron and rudder trimmers to counteract the plane's behaviour.
It is also wise to avoid very pronounced asymmetries, especially on take-off.  

On your second message, I would clearly avoid abrupt inputs in such conditions. This will make the asymmetry more pronounced, leading to undesired rolls.
There's also an identified issue using Mavericks on moving targets that hopefully will be fixed soon. 

Thanks for the feedback.
Trim helps but what I noticed is that if trimmed towards a wing if you bank over 40 degrees in the direction where the trim is set up or so the lack of lift is so pronounced the plane almost starts falling in that direction, ergo the undesired roll. So it is a lift problem. I think the original complaint/experience I had was caused by the fact that the A/P secondary selector was set to HDG and it was banking the plane around. Because I was practicing the mission was set for unlimited weapons and because a LAU has to be emptied before it's filled again by that set it is also possible that it caused an unforeseen unbalance leading to unexpected behavior causing the frustration.

Another thing to mention: could it be possible to add clip/ragdoll or some method so tanks don't stay floating in mid air.

[TobiasA]

You have a strong asymmetrical drag (not only weight) with a triple rack on one side and a single launcher on the other one. I don't recommend that... However, you can counter that to some degree. 

1. Go to your desired attack speed.

2. Cancel out side slip by applying ridder trim (you can do this in autopilot if you want). Watch your slip indicator.

3. Now, cancel autopilot (or pull the paddle switch) and trim your wing.

It is important to first trim rudder and then roll because rudder trim will introduce a roll component but roll trim won't induce a slip component. 

However, the large asymmetrical weight will make it difficult to maintain nice curves because trim doesn't change with G and the heavier wing will always have a tendency to drop down especially on higher AOA's. Best is to trim for about mach 0.8 and then stick to that speed as good as possible.