[NO FM CHANGES IN UPDATE] Flight Model/Engine Thrust Tweak?

[falcon_120]

To be clearer for you, there have been no changes in FM and drag value for months.

Cant talk about FM, but regarding drag, i'm quite possitive that there is a change in drag somewhere in the last open beta patches either in the bru 55 pylon or in the amraams.

 

1 or 2 patches ago, 6 amraams (double in pilons 2&8), 2 sidewinders and 2 bags could not go past M 1.02-1.1 ish. Lately you can get M1.2 in that configuration.

 

I have no tracks to support this though.

 

Enviado desde mi ELE-L29 mediante Tapatalk

[Swift.]

Cant talk about FM, but regarding drag, i'm quite possitive that there is a change in drag somewhere in the last open beta patches either in the bru 55 pylon or in the amraams.

 

1 or 2 patches ago, 6 amraams (double in pilons 2&8), 2 sidewinders and 2 bags could not go past M 1.02-1.1 ish. Lately you can get M1.2 in that configuration.

 

I have no tracks to support this though.

 

Enviado desde mi ELE-L29 mediante Tapatalk

 

What conditions were these tests in? Temperature? Pressure?

 

Without knowing those then we can't make an accurate assessment of whether any FM changes have been made. All we have to go on is BN saying they haven't.

[Quid]

I've kind of been assuming pylon drag as I know this is something they've been talking about for quite a while, but was pylon drag mentioned in any changelogs? Also, what is "the GAO report?"

 

 

The GAO report is GAO Report B-260367 (GAO/NSIAD-96-98 ) "F/A-18E/F will Provide Marginal Operational Improvement at High Cost" from June 1996. It includes a few references on the performance of both the -402 powered F/A-18C and the F/A-18E/F.

 

 

Charts include samples of installed engine thrust for the F404-GE-400, -402, and F414-GE-400 engines, the 1g flight envelope of the F/A-18C and the F/A-18E/F in a 2-2-gun, 60% fuel configuration, as well as a couple doghouses in different combat configurations. It is Unclassified, publicly released 18 June 1996, and is available through the US GAO's website.

 

 

For your pylon drag, yes, carrying 5 pylons does incur a drag penalty; it's actually worse than clean wings and belly with two fuselage Sparrow/AMRAAM and two wingtip sidewinders, so you're actually in a higher drag configuration than the chart provided in that report.

Edited July 29, 2020 by Quid
Got rid of the "sunglasses" emote from the GAO/NSIAD line

[wilbur81]

 

For your pylon drag, yes, carrying 5 pylons does incur a drag penalty; it's actually worse than clean wings and belly with two fuselage Sparrow/AMRAAM and two wingtip sidewinders, so you're actually in a higher drag configuration than the chart provided in that report.

 

Thanks, Quid!

 

Just tested and pylon drag is indeed simulated in DCS currently. I did one flight with no pylons and saw Mach 1.22 at 10K MSL whereas, with 5 pylons, I was only seeing Mach 1.19 at 10K.

 

Thanks for the info on the GAO. :thumbup:

Edited July 29, 2020 by wilbur81

[TGW]

Interesting, upon looking at the GAO document ID (pg.86) posted above which directly refers to a NAVAIR document (making a comparison of the C/D vs. E/F models) shows the following data for the F/A-18C.

 

 

Configuration:

 

(2) AIM-9

(2) AIM-120

Total Drag Index: 8.0

[sidenote, (2) AIM-9 underwing on LAU-7

launcher has an index of 6.0]

 

(100%) Cannon ammo

(60%) Internal fuel

 

GW=33,325 lbs.

 

Gives the following speeds at Ps=0 (sustained):

~M1.28 @ 10Kft

~M1.45 @ 20Kft

~M1.65 @ 30Kft

Edited July 29, 2020 by TGW

[wilbur81]

Interesting, upon looking at the GAO document ID (pg.86) posted above which directly refers to a NAVAIR document (making a comparison of the C/D vs. E/F models) shows the following data for the F/A-18C.

 

 

Configuration:

 

(2) AIM-9

(2) AIM-120

Total Drag Index: 8.0

[sidenote, (2) AIM-9 underwing on LAU-7

launcher has an index of 6.0]

 

(100%) Cannon ammo

(60%) Internal fuel

 

GW=33,325 lbs.

 

Gives the following speeds at Ps=0 (sustained):

~M1.28 @ 10Kft

~M1.45 @ 20Kft

~M1.65 @ 30Kft

 

Wow. Nice find. Now we need some tester/document-ers. :thumbup:

[drhay53]

Actually, this would have no bearing on the performance of the jet (assuming you have allowed full output to the control surfaces) as the curves function only provide a logarithmic (a finer response on smaller inputs) output to the control surfaces. So, unless you have damped the output to something less than 100%, then this would make no difference in flight performance measurement.

 

The curvature would have an effect depending on how the user was performing certain tests, because the user is likely pulling the stick initially with the same force in both versions, however if the curvature values are different, that could lead to different output values for the control surfaces. So there could be different energy loss scenarios even if ultimately the user is shooting for a specific G for a testing maneuver.

 

Basically just thinking of all of the variables that need to be investigated to make sure that the tests are valid test of the FM only, with no external factors.

Edited July 30, 2020 by drhay53

[Figaro9]

Wow. Nice find. Now we need some tester/document-ers. :thumbup:

 

I did max speed-tests a while ago:

I started at 50kft M1.6 and dove to the test altitude. Here is what I got:

 

https://forums.eagle.ru/showpost.php?p=4391704&postcount=28

 

Checked sep too in 1g acceleration tests (standard atm.), see attachments.

 

Sep @ 10kft M0.9 Gao 699ft/s, dcs 613ft/s

Sep @ 20kft M0.9 Gao 512 ft/s, dcs 420ft/s

Sep @ 35kft M0.9 Gao 247 ft/s, dcs 213ft/s

 

Ps. Based on those sep charts I managed to reach 49kft & M1.33 from brake release in 4min 15sec.

[TGW]

The curvature would have an effect depending on how the user was performing certain tests, because the user is likely pulling the stick initially with the same force in both versions, however if the curvature values are different, that could lead to different output values for the control surfaces. So there could be different energy loss scenarios even if ultimately the user is shooting for a specific G for a testing maneuver.

 

Basically just thinking of all of the variables that need to be investigated to make sure that the tests are valid test of the FM only, with no external factors.

 

 

DrHay you are correct, but for the most consistent testing you would need to run the aircraft through a preplanned script to obtain the most accurate flight performance results and, then the input curves profile would be nulled . . .

Edited August 4, 2020 by TGW

[TGW]

I did max speed-tests a while ago:

I started at 50kft M1.6 and dove to the test altitude. Here is what I got:

 

https://forums.eagle.ru/showpost.php?p=4391704&postcount=28

 

Checked sep too in 1g acceleration tests (standard atm.), see attachments.

 

Sep @ 10kft M0.9 Gao 699ft/s, dcs 613ft/s

Sep @ 20kft M0.9 Gao 512 ft/s, dcs 420ft/s

Sep @ 35kft M0.9 Gao 247 ft/s, dcs 213ft/s

 

Ps. Based on those sep charts I managed to reach 49kft & M1.33 from brake release in 4min 15sec.

 

 

@Figaro9 +1!

[Top Jockey]

@Figaro9 +1!

 

Help me here if you will: so based on these numbers, we can conclude that the Flight Model isn't up to par with real life ?

[TGW]

Help me here if you will: so based on these numbers, we can conclude that the Flight Model isn't up to par with real life ?

 

Agreed . . .

[wilbur81]

Hey, Bignewy and/or Nineline.

 

Quick (annoying, I know) question: Were any changes made in today's (Jan. 27th) patch to the Hornet's flight model, engine performance, parasitic drag, energy bleed, etc... or new atmospheric effects that would degrade acceleration, turning or slow speed performance? I'm probably imagining things, but just wanted to check for an official word. Sorry to be a nag, especially if I'm just 'placebo-ing.' 

Edited January 28, 2021 by wilbur81

[wilbur81]

Hey, Devs.

 

Were there any undocumented flight model, engine thrust, FCS, or drag factor changes made to the Hornet in 2.7 and supplemental updates?

I've done some testing where I have the same mission/scenarios open on both latest Stable and latest O.B. and it appears that the Hornet cannot achieve as high an AOA now in OB and that g-onset has changed.  But I guess we'll never know... 

Edited May 24, 2021 by wilbur81