investigating Hornet's Slow-State Energy Bleed?

[Svend_Dellepude]

You don't need to pull the paddle to win in a D/F in the hornet. Don't fly it like the F-16. F-18 likes to be slow. So when the fast guys want's to accelerate just send a missile up their a**.

 

Btw: Jetstream is excellent!

Edited August 8, 2021 by Svend_Dellepude

[IvanK]

The paddle/G lim override is intended to only be used for "Oh S... I need more to stop hitting the ground type events". You then get 33% more available G above the current limit for as long as you hold the paddle down.

Edited August 8, 2021 by IvanK

[Double Dutch]

Hi, newby here.

 

Still learning (and I need to learn a lot!!), for now I turn and indeed slow down a lot when turning. Are there like rules of thumb like:

- speed to take with you into a battle (350+?)

- min speed you wish to maintain during a turn?

- more tips?

[Hulkbust44]

18 minutes ago, Double Dutch said:

Hi, newby here.

 

Still learning (and I need to learn a lot!!), for now I turn and indeed slow down a lot when turning. Are there like rules of thumb like:

- speed to take with you into a battle (350+?)

- min speed you wish to maintain during a turn?

- more tips?

The Hornet's corner velocity is 360 knots (generally). This is the baseline for your two circle rate fight. get below 350-360 kts in a loaded turn and you will start to bled speed quite quickly, and it will be more difficult to regain that energy.

[wilbur81]

9 hours ago, Hulkbust44 said:

The Hornet's corner velocity is 360 knots (generally). This is the baseline for your two circle rate fight. get below 350-360 kts in a loaded turn and you will start to bled speed quite quickly, and it will be more difficult to regain that energy.

This is true. I rarely beat anyone in the Hornet (guns only) unless I go into the merge below 400kts.  In real life, the Hornet 'rules the roost,' 2nd only to 5th gen fighters, in the slow speed/high alpha fight for American jets (Lord, help us all when the Typhoon arrives in DCS ). Though, to your last point above, if you load up the video I've posted on the original post at the top of this thread and view starting at 08:19 through 10:42, the real Hornet does pretty darn well with its energy and nose authority below 300kts (I suspect a bit better than our current DCS flight model, though I think they're pretty darn close, amazingly so for a video game) as long as they keep the G's below 4.5/5g. Keep in mind, too, that the pilots flying in the video are extremely novice at BFM. You are correct, though... load up 5 or more G's below 350kts in the Hornet and you're going to be parked for quite some time.

Edited August 9, 2021 by wilbur81

[Svend_Dellepude]

Wags said in an interview some time ago that there were aspects of the Hornets slow speed handling that ED couldn't model. That might have something to do with what you are seeing.

Don't remember when or where it was.

[maxTRX]

2 hours ago, Svend_Dellepude said:

Wags said in an interview some time ago that there were aspects of the Hornets slow speed handling that ED couldn't model. That might have something to do with what you are seeing.

Don't remember when or where it was.

 

They couldn't model?  You mean FCS? I'm pretty sure they can knock out pretty fancy aerodynamic model, if they wanted to.

That reminds me... in one of the builds, a while back the Hornet would fly like it had thrust vector nozzles, at just below 300. Then ED had to mess it up with realistic alpha and airspeed entry criteria into pirouette logic, damn... 

[rob10]

1 hour ago, Gripes323 said:

 

They couldn't model?  You mean FCS? I'm pretty sure they can knock out pretty fancy aerodynamic model, if they wanted to.

I don't think it was a question of whether they were CAPABLE, more whether they were ALLOWED by licensing restrictions.

[Svend_Dellepude]

26 minutes ago, rob10 said:

I don't think it was a question of whether they were CAPABLE, more whether they were ALLOWED by licensing restrictions.

 

This

[maxTRX]

2 hours ago, rob10 said:

I don't think it was a question of whether they were CAPABLE, more whether they were ALLOWED by licensing restrictions.

 

Just out of curiosity... I wonder how much they have to be off to create a gaming sim and not infringe on licensing issues ...  2kts/5'AOA or... 

Is it only for the bottom part of the flight envelope?

[Belphe]

What do you guys think about the below quoted from the 23 July newsletter:

"We are also improving DCS: F/A-18C Hornet and look forward to sharing more details on the flight model improvements soon."?

[Shack]

Anyone know where I can find an EM performance chart for the hornet ?  At least what's being used for the DCS F18 ? 

[MARLAN_]

Attached are DCS EM diagrams for a lot of DCS modules, including the DCS F-18, I didn't make it, looks like the author is "Contact Light"

Subsonic_Energy_Maneuverability_Diagrams_for_DCS.pdf

[SlipHavoc]

This is interesting...  The graphs on page 5 show the Mirage 2000 as having the highest sustained turn rate, higher than the F-18 or F-16.  That would seem to imply that it should be able to out turn an F-16 in a level rate fight on the deck, and yet I don't think I've ever seen a dogfight video (e.g. Growling Sidewinder or similar) show that tactic being used.  Instead, the Mirage 2000 is inevitably used as a one-circle fighter and when it gets dragged down to the deck by a Viper it's game over for the Mirage.  Are people just missing a trick here and the Mirage 2000 has been a world-beater all along if flown properly?  Or is there something I'm not getting?

Edited January 29, 2023 by SlipHavoc

[TheFreshPrince]

vor 4 Stunden schrieb SlipHavoc:

This is interesting...  The graphs on page 5 show the Mirage 2000 as having the highest sustained turn rate, higher than the F-18 or F-16.  That would seem to imply that it should be able to out turn an F-16 in a level rate fight on the deck, and yet I don't think I've ever seen a dogfight video (e.g. Growling Sidewinder or similar) show that tactic being used.  Instead, the Mirage 2000 is inevitably used as a one-circle fighter and when it gets dragged down to the deck by a Viper it's game over for the Mirage.  Are people just missing a trick here and the Mirage 2000 has been a world-beater all along if flown properly?  Or is there something I'm not getting?

 

From what I understand, higher degree of turn radius means the circle is smaller. But the F16 is faster in it's circle, which might make the difference. It then can exchange the speed to turn into the bandits circle. Also the F16 will accelerate to it's rate speeds faster and the Mirage is usually slow after using its energy for the max. instantaneous turns to sit inside the F16 circle and take snapshots. The curves are very different, which determines the fighting style of the aircrafts. The Mirage has very tight turns at low speeds while the F16 needs to be always fast. But this also means, the Mirage WILL get slow when it pulls the bandit into the HUD with tight turns.

Edited January 29, 2023 by TheFreshPrince

[Shack]

6 hours ago, MARLAN_ said:

Attached are DCS EM diagrams for a lot of DCS modules, including the DCS F-18, I didn't make it, looks like the author is "Contact Light"

Subsonic_Energy_Maneuverability_Diagrams_for_DCS.pdf 8.17 MB · 23 downloads

Thanks ! 

[Sandman1330]

On 1/29/2023 at 3:39 AM, SlipHavoc said:

This is interesting...  The graphs on page 5 show the Mirage 2000 as having the highest sustained turn rate, higher than the F-18 or F-16.  That would seem to imply that it should be able to out turn an F-16 in a level rate fight on the deck, and yet I don't think I've ever seen a dogfight video (e.g. Growling Sidewinder or similar) show that tactic being used.  Instead, the Mirage 2000 is inevitably used as a one-circle fighter and when it gets dragged down to the deck by a Viper it's game over for the Mirage.  Are people just missing a trick here and the Mirage 2000 has been a world-beater all along if flown properly?  Or is there something I'm not getting?

 

Look at the configs used for that data. CL used the configs from the DCS Dogfighters server https://discord.gg/dogfighters. In those given configs, and with G modelling on, the Viper has close to the worst STR of all 4th Gen. The Hornet and M2K rule the roost in those configs.

With full fuel / external tanks etc, things even out a bit.

 

PS - if you join our discord you’ll find updated charts that reflect the M2K’s latest FM update, it is still top tier STR but is now beat by the STR king, F18.

Edited February 19, 2023 by Sandman1330

[wilbur81]

https://forum.dcs.world/topic/312608-f16-flight-envelope/?do=findComment&comment=5153812

 

[DummyCatz]

Here's one from the NASA paper COMBAT AGILITY MANAGEMENT (CAMS) https://ntrs.nasa.gov/api/citations/19950007836/downloads/19950007836.pdf

Although it is unclear what the testing conditions are, by looking at the max level speed at Ps=0 (greater than 1.3 Mach), it seems that it might be a clean aircraft or with 2 x AIM-9. But I'm not sure if it's a 400 or 402 engine.

I'll take a look at this one when finished testing the SEP of F-16.

[Figaro9]

7.33g-Limit is for an f-18 that weighs 33325 lbs.

I only know one load out for that weight :

f18 epe, fighter escort (2xa9, 2xa120), 60% fuel.

Just speculating .

 

[DummyCatz]

15 hours ago, Figaro9 said:

7.33g-Limit is for an f-18 that weighs 33325 lbs.

I only know one load out for that weight :

f18 epe, fighter escort (2xa9, 2xa120), 60% fuel.

Just speculating .

 

Yes, looks like this is the closest. https://dcs.silver.ru/Diagram/Fa18c @totmacher @TOT_53

I'll be basing my test on this config.

So it seems to be a 402 engine considering the max STR is at 13 deg/s and at the same time, the max level speed exceeds Mach 1.3.

Edited August 23, 2024 by DummyCatz

[DummyCatz]

Now using the same testing technique from:

https://forum.dcs.world/topic/356579-calculating-the-sep-specific-excess-power-of-an-instantaneous-turn

 

I've completed testing the max performance instantaneous turn of the F-18 at 15000 ft, GW=33325 lbs, with 2 x AIM-9 and 2 x AIM-120. Fuel is at 62% for this GW. Sea level temperature is set to 15°C.

I'm currently only interested in the SEP at Mach 0.75, to see if it's close to -800 ft/s during a max effort pull. Here's two images taken with 1 sec apart:

SEP Calculation: 479 KTAS -> 469 KTAS in 1 sec:

dh = +3 ft

dV = -10 KTAS = -16.88 ft/s

V = 474 KTAS = 800 ft/s (took the average)

g = 32.174ft/s^2

dt = 1s

The resulting Ps = 3 - 16.88 * 800 / 32.174 = -417 ft/s at the speed of 474 KTAS, or 0.755 Mach. So the energy bleed rate is way too low (Ps=-417 ft/s) compared to the EM diagram above (Ps=-800 ft/s). The aircraft overperforms in SEP.

This result is a surprise, as the fighter escort loaded Hornet at 15000ft, 474KTAS bleeds even less speed than the very lightly loaded Viper at 10000ft, 473KTAS.

 

F18 speed bleed test 15000ft.trk

Edited August 29, 2024 by DummyCatz

[Xhonas]

Hello @Lord Vader, pinging you since you're more active in the Hornet forum, the issue described by @DummyCatz might be worth looking at. We all know about the exhausting F-18 vs F-16 turn performance debate. Perhaps this is the clue to solve it once and for all? Thanks.

[Lord Vader]

Hello, @Xhonas

No problem on the ping.

We thank you for your analysis and your conclusions, we can certainly take it into account.
As you realise, we need to make sure the DCS: F/A-18C performance (as well as the DCS: F-16C) is as accurate as possible and not commit to make changes that are not supported with available public data.

All I can say for now is that this matter isn't forgotten and if there are changes to be done, you will be informed. 

[darkman222]

Thanks Lord Vader for adressing the energy bleed discrepancies. And thanks @DummyCatzfor taking the time for investigating. Until this will be adressed I hope this will stop the endless debate about people flying circles for Tacview and discussing a plus minus 0.2 deg / sec turn rate difference to the EM diagram when the real issue is the energy bleed rate. That was what I was suspecting for quite some time but I was not proficient enough to put it to a test like you did.

Edited August 23, 2024 by darkman222