in roadmap DCS F16 turn performance

[Theodore42]

Hey that's the "Hi-G Turn" maneuver.

 

Maneuver Description: Beyond the 500’ show line and just prior to show center select full AB and accelerate to 400 knots. At show center, turn away from the crowd using 75 to 85 degrees of bank (<75 degrees inside the 1,500’ show line). Begin the turn with a smooth G onset-rate to approximately 7.5 Gs. G-loading and airspeed bleed-off rate vary with density altitude. Maintain a minimum of 250 knots. The first 180 degrees of turn should be accomplished with a 1¾-degree nose-up attitude and the last 180 degrees should be accomplished with a 1¾-degree nose-down attitude to make the turn appear level to the crowd. Vary the bank angle and pitch to arrive at level flight at the completion of 360 degrees of turn and to ensure the maneuver is finished above the entry altitude. Ensure surface winds are taken into consideration in order to center this maneuver on show center and to avoid overshooting the show line. As you approach show center, smoothly but briskly roll out. Perform a repositioning maneuver to prepare for the next maneuver.

 

As you can see there is a lot of variation in the speed and Gs and turn rate during that maneuver.

I've done the whole F-16 airshow routine. I didn't think to compare the new FM so I'll do that today and let you know if I find anything interesting.

[Hummingbird]

@NineLineWill there be further adjustments to the STR for next update? As we're still lacking some performance on either side of 400 KTAS. 

Edited September 25, 2021 by Hummingbird

[Hummingbird]

Alright, finished the testing of the F-16C:

 

DCS F-16C, 22,000 lbs clean, ICAO Std. day 15 C, Sea Level (40-75 ft):

215 KTAS (M 0.325) = 3.4 G vs 3.4 G chart (0.0 G) V

250 KTAS (M 0.378) = 4.1 G vs 4.3 G chart (-0.2 G) X

300 KTAS (M 0.453) = 5.3 G vs 5.4 G chart (-0.1 G) X

350 KTAS (M 0.529) = 6.5 G vs 6.6 G chart (-0.1 G) X

400 KTAS (M 0.604) = 7.7 G vs 7.7 G chart (0.0 G) V

450 KTAS (M 0.680) = 8.8 G vs 9 G chart (-0.2 G) X

 

ED's own internal testing should confirm this, but here it is for everyone else. 

 

A little more tweaking, and we're there.

 

Footage of one test run at 400 KTAS (Ran 10 seperate test runs at each speed, so 60 test runs in total over 2 days), this one wasn't the prettiest of the 400 KTAS ones, it taking some time for me to get settled near my target speed and alt, and thus the best readings were somewhere near the end, but at least this gives some insight into my approach:

 

Note: In this run I try to settle around 398 KIAS as best I could, as that is 400 KTAS according to the infobar.

 

 

[CypherBlue]

 

[totmacher]

17 часов назад, Hummingbird сказал:

Alright, finished the testing of the F-16C:

 

DCS F-16C, 22,000 lbs clean, ICAO Std. day 15 C, Sea Level (40-75 ft):

 

Here my tests for 10m (33ft) altitude:

215 KTAS (M 0.325) = 3.4 G vs 3.4 G chart (0.0 G) V

250 KTAS (M 0.378) = 4.1 G vs 4.3 G chart (-0.2 G) X

300 KTAS (M 0.453) = 5.4 G vs 5.4 G chart (0.0 G V

350 KTAS (M 0.529) = 6.6 G vs 6.6 G chart (0.0 G) V

400 KTAS (M 0.604) = 7.7 G vs 7.7 G chart (0.0 G) V

450 KTAS (M 0.680) = 9 G vs 9 G chart (0.0 G) V

 

Seems all ok, except 250kts. But here more quetion to  "4.3 G chart" data.

F-16c 10m 22000lbs.xlsx raw data.ZIP

[Theodore42]

I am now more convinced that the sustained turn rate is where ED wants it and it won't be getting any major updates. It feels like they changed everything EXCEPT the STR.

I've been through all the airshow maneuvers and the airframe is modeled completely differently now.

 

Previously there were numerous maneuvers where I couldn't sustain the Gs the manual said I should expect to sustain. I thought I just needed to improve my timing or technique or something. Now they are right on the money. In fact, I need to pull too many Gs if I'm not fast enough on the stick.

 

Speeds over the top were also improved during the maneuvers. It did feel a little different, the knots weren't bleeding off quite as fast as I thought they did before, but I'm still somewhat assuming that since the airframe is so much more efficient during the high G parts of the maneuver that there is just more energy during the slow parts. But every time I'm going through an apex around 200-250kts I feel like the speed used to be ticking down a little bit faster.

 

When the manual says I should have Gs to play with in the vertical I do, whereas before the stick was pretty dead during those parts.

 

I also feel like they did something to pitch inputs during side-load.

For example, the knife edge pass felt much more squirrely. It feels more like you're doing something weird to the airframe whereas before it just felt like flying sideways with full rudder deflection.

I didn't notice the 3/4 inverted pass felt any different, but that maneuver is basically 100% feel anyway so I'm not sure I would notice a difference unless I tried the new FM right next to the old. (You kinda gotta just memorize how to thwack the stick and kick the rudder to get it there, probably why the maneuver was removed from the demo.)

 

Since this has been so interesting to me I may make a compare and contrast video between this updated FM and a demo I did from the old one.

[Hummingbird]

8 hours ago, totmacher said:

 

Here my tests for 10m (33ft) altitude:

215 KTAS (M 0.325) = 3.4 G vs 3.4 G chart (0.0 G) V

250 KTAS (M 0.378) = 4.1 G vs 4.3 G chart (-0.2 G) X

300 KTAS (M 0.453) = 5.4 G vs 5.4 G chart (0.0 G V

350 KTAS (M 0.529) = 6.6 G vs 6.6 G chart (0.0 G) V

400 KTAS (M 0.604) = 7.7 G vs 7.7 G chart (0.0 G) V

450 KTAS (M 0.680) = 9 G vs 9 G chart (0.0 G) V

 

Seems all ok, except 250kts. But here more quetion to  "4.3 G chart" data.

F-16c 10m 22000lbs.xlsx 12.77 kB · 8 downloads raw data.ZIP 1.65 MB · 4 downloads

 

It's impossible to hold 9 G's level at 450 KTAS atm, so Im wondering how you achieved that. 

 

Infact this is the easiest speed to test, because as soon as you hit 450 KTAS full back stick is needed to achieve 9 G, and it cannot be sustained. So something must have gone wrong in your testing.  Did you forget to put on infinite fuel?

 

I'll post a 450 ktas test vid soon to illustrate it. 

Edited September 27, 2021 by Hummingbird

[Hummingbird]

Quick test at 450 KTAS to show it cannot be sustained.

 

 

Note: 450 KTAS is 448-449 KIAS.

 

[Spartan111sqn]

awesome compasion vs the charts.

 

And about other flight level?, 10.000ft, 15.000ft, 25.000ft?, still so precise as RL design charts?

Edited September 27, 2021 by Spartan111sqn

[totmacher]

10 часов назад, Hummingbird сказал:

It's impossible to hold 9 G's level at 450 KTAS atm, so Im wondering how you achieved that. 

I'am attach .XLSX file with my data. there the exact values of sustained turn:
Speed: 830kmh = 448kts
turn rate: 22.12 deg/sec

G: 8.92

 

In "raw data.zip" file you can find track file and trackview file for compare (just need to rewind to the end)

Also you can see that acceleration speed is very low between measures (step of measures 10kmh).

 

[Hummingbird]

1 hour ago, totmacher said:

I'am attach .XLSX file with my data. there the exact values of sustained turn:
Speed: 830kmh = 448kts
turn rate: 22.12 deg/sec

G: 8.92

 

In "raw data.zip" file you can find track file and trackview file for compare (just need to rewind to the end)

Also you can see that acceleration speed is very low between measures (step of measures 10kmh).

 

 

I'm not a fan of tacview, as I find it often contains error readings. Hence why I only do measurements using the infobar. 

 

As you can see in the video attached, 9 G is not sustainable at 450 KTAS (448-449 KIAS) in the actual simulation. Best I can for sure get here is 8.8 G. 

 

So my assessment is the F-16 still needs some minor tweaking of its STR before its right where it should be, being in general 0.1 G off.  As pr. NineLine's previous post ED is perfectly aware of this, so I definitely expect further tweaking. 

Edited September 27, 2021 by Hummingbird

[NineLine]

As posted previously by me, we are quite happy with results we have seen here, we will update if and when any other changes are made to this aspect of the FM. Thanks.