[CHECKING] Turn Rate

Taking this diagram (not sure how reliable it is) :

Superposed to HAF diagrams :

blue : f18 as above, 2x9, 2x120, 60% fuel (!! For me it seems to mean 60% of the initial fuel taken for the mission, they say "fuel for 550nm escort mission", so how much was it ? Looking how the curve stops at about 6G, i think it must have at least 1 external fuel tank. Edit : 1 centerline fuel tank with this configuration gives a limit of 6.1G), 15000 ft

If we take the viper in a AA configuration with 4xaim-120, 2xaim-9, 2x370 gal tanks, it takes it to a drag index of about 70, and a gross weight fully loaded around 28'000 lbs, and with this you'll be in cat III limiter configuration !

red : f16, drag 0, 22000lb, 15000 ft

green : f16, drag 50, 26000lb, 10000 ft (almost perfectly aligned to red line, except for sustained turn above 0.9 mach)

purple : cat III limiter for red and green

orange : f16, drag 50, 26000lb, 20000 ft

dark blue : cat III limiter for orange

(no curve at 15000 ft for direct comparison, i guess it should be right in the middle between orange and green lines)

The highest curve of the same color is instant turn, lowest is sustained turn.

 

Also don't use tacview in an effort to measure ingame, use the ingame ctrl + y info bar and measure sustainable load factors at TAS, it's the only way to get an accurate measurement.

I would not measure sustain turn rate this way, it might be not precise enough.

Use the .miz by bushmanni instead.

(ED Forums » English » DCS World Topics » Mods and Apps » F-15C turning performance App Post#15). It measures the turn rate only when flying 5 sec. within certain limits. User manual is in the miz and data is safed in the logs.

I adapted it to f18, see attached file.

Thanks for your verification by the way.

I did the same thing and I have posted the results already in post #34, with quite the same results as robin hood (see post #28 ).

I got 0.3deg/sec less than you, maybe because of the 5 second rule for precision sake.

thanks

Sustained turn rate test flight f18.miz

 

blue : f18 as above, 2x9, 2x120, 60% fuel (!! For me it seems to mean 60% of the initial fuel taken for the mission, they say "fuel for 550nm escort mission", so how much was it ? Looking how the curve stops at about 6G, i think it must have at least 1 external fuel tank. Edit : 1 centerline fuel tank with this configuration gives a limit of 6.1G), 15000 ft

 

 

Just look at the picture upper right corner of the em chart. Test is with 3 fuel tanks…, 60% initial fuel.

I got 10.7deg/sec with this config.

DCS F/A-18C STR w/ 2x AIM9 + 2x AIM120 @ 60% fuel (Std. Atm 15 deg C SL temp):

Sea Level

M 0.54 = 6.0 G's (19.0 deg/sec)

M 0.58 = 6.5 G's (19.0 deg/sec)

M 0.60 = 6.7 G's (19.2 deg/sec)

M 0.65 = 7.4 G's (19.3 deg/sec)

15,000 ft

M 0.65 = 4.6 G's (12.5 deg/sec)

M 0.75 = 5.5 G's (13.0 deg/sec)

M 0.80 = 6.0 G's (13.3 deg/sec)

Note I could achieve a higher rate at SL if I wished but that would require exceeding the 7.5 G Navy limit.

So biggest discrepancy I could find was the performance at altitude where 1.1+ deg/sec more than what is specified in the document provided earlier can be held.

Fully agree with you at sea level

Can not reproduce your datas at 15'000ft

Mach 0.777 12.1

Mach 0.780 12.1

Mach 0.802 12.5

Mach 0.822 12.3

Fully agree with you at sea level

 

Can not reproduce your datas at 15'000ft

Mach 0.777 12.1

Mach 0.780 12.1

Mach 0.802 12.5

Mach 0.822 12.3

Remember std. day 15 deg C, no wind.

Also note the load factor.

DCS F/A-18C STR w/ 2x AIM9 + 2x AIM120 @ 60% fuel (Std. Atm 15 deg C SL temp):

 

Sea Level

M 0.54 = 6.0 G's (19.0 deg/sec)

M 0.58 = 6.5 G's (19.0 deg/sec)

M 0.60 = 6.7 G's (19.2 deg/sec)

M 0.65 = 7.4 G's (19.3 deg/sec)

 

15,000 ft

M 0.65 = 4.6 G's (12.5 deg/sec)

M 0.75 = 5.5 G's (13.0 deg/sec)

M 0.80 = 6.0 G's (13.3 deg/sec)

 

Note I could achieve a higher rate at SL if I wished but that would require exceeding the 7.5 G Navy limit.

 

So biggest discrepancy I could find was the performance at altitude where 1.1+ deg/sec more than what is specified in the document provided earlier can be held.

That chart is comparing a super hornet with one tank to a F/a-18c with 3. It’s marketing material to try and sell Congress the Super.

That chart doesn’t account for the 402 enhanced performance engine which increased the thrust output by 1,754 lbs in the F/a-18c. Since sustained turn rate is Ps 0 and Ps = V(T-D/W). Increasing the thrust pulls the sustained turn line (Ps =0) up the chart closer to instantaneous line.

Based on the years modeled, the DCS Hornet should have those engines. Meaning that chart and many of the ones floating around publicly on the internet are not accurate, given the engines installed on the DCS hornet. I would concur with Nineline that it will be hard to find charts to compare the Hornet with. Since most of what’s online is outdated.

The issues has more to do with the viper under preforming. The DCS viper is using an early NASA FLCS. Which is problematic due to the pitch rate integrator not allowing maximum pitch rate through the envelope. Remember that FLCs was designed to prevent the so called deep stall not maximum performance. It was seen as the starting off point for designing the modern FLCS.

Comparing the two with an array of source material is just going to create controversy. As the majority of source material doesn’t pertain to the performance modeled in DCS.

Charts aren't real life my dudes. Nor do they apply to a game like DCS:

Remember std. day 15 deg C, no wind.

 

Also note the load factor.

Sure, that is what I did. Watch post 28 by Robin Hood, he neither gets your rates but rather mine. Please check them once again.

Charts aren't real life my dudes. Nor do they apply to a game like DCS:

The official performance charts are real life, as they're the results of real life performance testing.

What's problematic is that we lack proper charts for the F/A-18 whilst we have very detailed ones for the F-16. Hence we have to rely more on pilot observations here than usual.

Sure, that is what I did. Watch post 28 by Robin Hood, he neither gets your rates but rather mine. Please check them once again.

You didn't note the load factor, which makes me worried you used tacview.

Checked it again myself, I can consistently hold 6.0 G's at M 0.8 @ 15 kft.

You didn't note the load factor, which makes me worried you used tacview.

 

Checked it again myself, I can consistently hold 6.0 G's at M 0.8 @ 15 kft.

I'm interested in why exactly would Tacview be less reliable ? For one thing, it gives more than one decimal for the g-load (note that I do not rely on Tacview for turn rates, but calculate them from G and TAS).

By the way, my tests were done without removing the unused wing pylons.

I'm interested in why exactly would Tacview be less reliable ? For one thing, it gives more than one decimal for the g-load (note that I do not rely on Tacview for turn rates, but calculate them from G and TAS).

By the way, my tests were done without removing the unused wing pylons.

Because of often seen inaccuracies in tacview recordings, hence why ED usually aren't willing to accept tacview either.

Anyway your method of measuring is the proper way and the same as mine, i.e. load factor & TAS. My tests were without any unused pylons, so that would explain the difference.

The reason for not including the pylons is that no empty pylons is what the two EM diagrams show for both Hornets, and that is also the norm if a specific load out is listed.

My tests were without any unused pylons, so that would explain the difference.

 

The reason for not including the pylons is that no empty pylons is what the two EM diagrams show for both Hornets, and that is also the norm if a specific load out is listed.

Empty pylons in DCS have no effect on aircraft mass and from what is known no effect on drag either.

You didn't note the load factor, which makes me worried you used tacview.

 

Checked it again myself, I can consistently hold 6.0 G's at M 0.8 @ 15 kft.

No, I use the .miz I shared, and I hope you use it too, your data could be way off otherwise....

I Removed the pylons for my testing. G-Factors are not saved to log in those testing...

By the way, why do you do the loop, measuring g-force in game, then go to a simplified formula to compute the rate? Just check turn rate in game properly. This is by far more reliable and precise than doing loops.

We simply want to check if in game turn rate fits real world data, (not if g correlates with in game or rw-turn rate)

No, I use the .miz I shared, and I hope you use it too, your data could be way off otherwise....

I Removed the pylons for my testing. G-Factors are not saved to log in those testing...

No my data can't be way off as it's measured live, not looked at afterwards.

By the way, why do you do the loop, measuring g-force in game, then go to a simplified formula to compute the rate? Just check turn rate in game properly. This is by far more reliable and precise than doing loops.

We simply want to check if in game turn rate fits real world data, (not if g correlates with in game or rw-turn rate)

I am not comparing load factor with rate, I am comparing ingame load factors with real life load factors. The reason I am focusing on load factor figures is because these are what are being measured in flight in real life, and the rate is then subsequently calculated from these load factor measurements. It's quite simply the proper way of doing it within the field, and also the reason the load factor figures are more accurate (sometimes the rate figures aren't completely accurate on the doghouse plots at very low speeds).

Empty pylons in DCS have no effect on aircraft mass and from what is known no effect on drag either.

Well that's a big issue then.

 

I am not comparing load factor with rate, I am comparing ingame load factors with real life load factors. The reason I am focusing on load factor figures is because these are what are being measured in flight in real life, and the rate is then subsequently calculated from these load factor measurements. It's quite simply the proper way of doing it within the field, and also the reason the load factor figures are more accurate (sometimes the rate figures aren't completely accurate on the doghouse plots at very low speeds).

Nope, guess you did not. We do not know rw sustained load factors at sea-level nor at 15k ft. If you do, please share numbers and source.

Let us assume you were really able to hold exactly M0.80, 15 kft and 6.0g. fine, very good job.

HUD shows accordingly 6.0g. But, did you pull 5.95g or 6.04g? Makes a difference of approx. 0.2deg/sec! You simply do not know because there is only one digit printed on hud.

HUD shows M0.8. But, did you fly M0.795 or M0.804? You again do not know, Mach is only shown with one digit on hud. Difference is again approx. 0.2deg/sec.

Makes a margin of 0.4 deg/sec, and you simply do not know.

No sustained rate test is perfect for sure, but there are much more precise approaches (like logs) than simplified g calculations based on rounded hud datas.

Never mind, I knock it off, unless further facts arise. Thanks.

It won't read 6.0 G's in the Ctrl + Y infobar if its 5.95 G's, then it will read 5.9 G's until 6.00 is reached. Hence I can at most be measuring wrong by 0.09 G's too little, thats accurate enough for our purposes here.

So ED,

any update on this? Still marked as checking and you said you were looking into this.

Regards,

Snappy

Give them time, I think they intended to work some more on the flight model anyway, but their flight model engineer(s) may be already caught up in something else.

Tweaks to the sustained turn rate?

Is anything being done to tame the overly-optimisitc STR of the Horent down to more believable levels?

At the moment, as some of you may know, it is outperforming every other jet in DCS, including F-15 and F-16.

I've been personally flying in hundreds of MP dogfights and can easily beat anyone flying F-15s or F-16s, even when those virtual pilots are the same or better than me in BFM. Conversely, against a well-flown F-18 I've had very little luck with anything except the F-14.

With the current FM it's possible to easily catch up and out-rate an F-15 flying at 450kts at 20k feet, as well as out-rate the F-16 at any altitude.

I'm not an expert on Hornets but after turning and burning with AI JF's and Fulcrums I really had to make a conscious effort not to pull the stick too much. This thing would bleed energy very quick.

I usually started the fight at 370, 380 kts, mid altitudes. With the HMD on, giving me a constant IAS feedback I was able to outturn the AI UFO's every time. Couple of times, I was too cautious with the stick and let the speed get away past 460 or 480... then it takes a bit too long to get rid of "extra" a/s. I don't know if real Hornets perform this way.

Cannot speak for the F-15/14 but based the charts I’ve seen for the hornet with the 402 and F-16 with the 129 engines respectively. It depends on how they are loaded, but there definitely are situations where the hornet has better STR. Such as when they are both loaded with 4 missiles and half fuel at 10k or above.

Drag plays a HUGE factor, there is not data available for total clean F/A-18, but the totally clean F-16 should be able to out STR the clean hornet at most Alts but that’s a guess on my part, considering the difference at 10k between EPE hornet in FE config and clean F-16 with 129 is about 3-4 degrees/second. Which is significant. But again that’s a clean viper vs a hornet in FE. Clean hornet is actually unknown.

The STR comes really close, if not better, under more realistic situations with actual pylons and weapons on the wings for both jets but ITR is significantly (at least 2 sometimes up to 5 degrees/second) better for the hornet pretty much across the board, in just about every situation and Alt. Even higher if you’ve got MP yahoos yanking with the paddle switch and breaking the jet.

I can’t speak to DCS accuracy though, I know they've repeatedly stated drag specific to stores is very WIP and right now rudimentary at best, so it possible that is coming into play here. Or maybe it is as you say.

All that aside, I’m not sure what your expectations are, but the RL hornet can out rate a lot of jets. Since in practice both pilots are only referencing max STR and ACM is extremely fluid. In DCS For myself personally in the bug, the whole hop I’m basically just maintaining energy, while waiting for the right time to swing my nose around and ITR the bandit to death. That’s what the hornets good at. Conversely against the hornet I’m waiting for the enemy to try that, always making sure I’m ready for it. So I can pounce back when they loose all their energy attempting that. And I would dare to say I’m an ok hornet driver and yet I’ve been spanked by people in all those jets as well MiG-29 in particular. Every situation is different. It’s hard for me to say if I think it’s over performing or if they are under performing or it’s all wrong lol :)