[NO BUG]Lift curve slope significantly lower than published data

[oldtimesake]

When checking this video, I found something interesting:

 

At 3 min 01:

 

At almost sea level, mach 0.83, even at 15deg AOA, the F-16 could not reach 9G.

 

From published data, at CAT I (15 deg limit at 9G), a loaded F-16C-50 (26000 lbs flying weight) could reach 9G at Mach 0.67, with 15 deg AOA.

 

Given the dynamic pressure increases at a power of 2, at M0.83 and 15 deg AOA, F-16 should exceed 9G easily (13.8G theoretically). In DCS it's almost halved.

 

Conclusion: in DCS the F-16 requires much higher AOA to pull a given maneuver than in real life.

 

To DEV team: This paper is very useful for you to generate flight model (TRIMMED lift curve and drag polar are included)

 

Correlation of F-16 Aerodynamics and Performance Predictions with Early Flight Test Results," AGARD CP-242, by TS Webb, DR Kent, JB Webb

 

https://i.postimg.cc/Fs1b1hfh/F16-test-242.jpg

 

https://i.postimg.cc/fTXPk7Sz/F16-test-242-2.jpg

 

(The curves above are trimmed)

 

(to moderator: this is an old article and does not violate rule 1.16)

Edited May 20, 2020 by oldtimesake

[BIGNEWY]

Hi

 

the video is unavailable at the moment

 

if you have a track replay showing your test please attach it

 

thanks

[oldtimesake]

Hi

 

the video is unavailable at the moment

 

if you have a track replay showing your test please attach it

 

thanks

 

Hi, the video is available again by this link:

 

Please investigate

[Sharpe_95]

Oldtime - I am not sure that vid will be helpful to them as it has no continual telemetry nor is it from the perspective of the F16. Even still, they prefer actual tracks from DCS.

 

To help them out are you able to provide the tacview and (ideally for them) a track file of the incident or make one for them?

 

Hope you issue gets resolved.

 

-S

Edited May 21, 2020 by Sharpe_95

[oldtimesake]

Oldtime - I am not sure that vid will be helpful to them as it has no continual telemetry nor is it from the perspective of the F16. Even still, they prefer actual tracks from DCS.

 

To help them out are you able to provide the tacview and (ideally for them) a track file of the incident or make one for them?

 

Hope you issue gets resolved.

 

-S

 

The problem is that I don't have a joystick and mainly use keyboard. I can't control the AOA precisely. It would be greatly appreciated if anyone could help me making such a track file, with the following condition:

 

26000 lbs weight, sea level, M0.83, maintain 15 deg AOA for a couple of seconds.

[Sharpe_95]

The problem is that I don't have a joystick and mainly use keyboard. I can't control the AOA precisely. It would be greatly appreciated if anyone could help me making such a track file, with the following condition:

 

26000 lbs weight, sea level, M0.83, maintain 15 deg AOA for a couple of seconds.

 

I am not 100% sure this is what you wanted but I have given it a go:

 

Parameters:

- 25999 lbs weight (sorry couldn't get it bang on 26000 for some reason it was always 1 above or 1 below).

- Fuel set to unlimited (to maintain aircraft weight).

- Clean aircraft.

- Sea level.

- No wind.

- G effects turned off.

 

Results:

a. I tried a turn at M0.83 but the pilot blacks out after a second or two so I had to turn the G effects off.

 

1. I perform a series of circles, full aft stick maintaining about M0.83: Max AoA achieved is about 7-8 degrees, G is 9.0

2. I bleed speed to find out where the 15-degree AoA point is and it looks like its around M0.64, G is 8.8g.

 

I hope this track is what you wanted and helpful to you and/or the Devs?

 

-S

Lift Curve Slope track.trk

Edited May 22, 2020 by Sharpe_95

[Hummingbird]

I am not 100% sure this is what you wanted but I have given it a go:

 

Parameters:

- 25999 lbs weight (sorry couldn't get it bang on 26000 for some reason it was always 1 above or 1 below).

- Fuel set to unlimited (to maintain aircraft weight).

- Clean aircraft.

- Sea level.

- No wind.

- G effects turned off.

 

Results:

a. I tried a turn at M0.83 but the pilot blacks out after a second or two so I had to turn the G effects off.

 

1. I perform a series of circles, full aft stick maintaining about M0.83: Max AoA achieved is about 7-8 degrees, G is 9.0

2. I bleed speed to find out where the 15-degree AoA point is and it looks like its around M0.64, G is 8.8g.

 

I hope this track is what you wanted and helpful to you and/or the Devs?

 

-S

 

At M 0.67 9.0 G's should be reachable according to the real life performance charts, but 8.7-8.8 is the best that can be achieved.

 

This is with 2x AIM9 + 4x AIM120 + 2xfuel tank wing pylons + centerline pylon (i.e. DI = 50), and 26,000 lbs, 15 C std. atm, exactly replicating the conditions in the performance charts.

Edited May 22, 2020 by Hummingbird

[oldtimesake]

Ok, seems the video was done under non-standard atmosphere. The DCS F-16 model looks legit. This thread can be closed.