F/A-18 vs F-16 Turn rate?

[Hammer1-1]

Its not cancelled, just put on indefinite hold. Last I heard it was going to be a Sierra model or a Whiskey, but they definitely had to start from scratch with it.

[wilbur81]

5 hours ago, TobiasA said:

I'm pretty sure it is not abandoned

You're "pretty sure it is not abandoned?" Good Lord... folks around here seriously underestimate ED. When they are complete, the DCS Viper and Hornet will be THE definitive civilian simulation treatments of these two airframes... period. They will both be as close to reality as unclassified pixels can get. They are already magnificent (with the Hornet naturally having more time in the oven as it came first), but this kind of niche' perfectionism that they're pursuing takes A LOT of time and care... 

Edited May 13, 2021 by wilbur81

[TobiasA]

vor 12 Stunden schrieb deadpool:

 

Can you copy that post over? I don't use Facebook and it would be nice to hear these important news in .. well .. the forum of that plane that it's about ^^

  

The text was "Viper work is currently focused on IAM (JDAM, JSOW, and WCMD) weapons. In parallel, the FM is being tuned so there is a lot going on behind the scenes, we will share more news as we get closer to releasing more features. "

Was a post in reply to someone who bought the viper.

 

So this means at least the most notable problem with the F-16 which is the poor lift is being worked on. Actively. Probably right now.

[totmacher]

12.05.2021 в 18:22, karasawa сказал:

I wonder if anyone has made the same test at 10000 feet.

same test at 10000 feet

 

 

 

f-16c 3048m.xlsx

Edited May 14, 2021 by totmacher

[karasawa]

3 hours ago, totmacher said:

same test at 10000 feet

 

 

 

f-16c 3048m.xlsx 17.75 kB · 1 download

 

Hi, I just converted your figure to 26000 lbs and compared it with HAF manual.

DCS F16, clean, 26000lbs, 10000 feet, sustains 10.19 deg/sec at TAS = 500km/h (278 knots)

Real F16C-50, 6 amraams + pylons, 26000lbs, 10000 feet, sustains 11.5 deg/sec at TAS = 500km/h (278 knots)

DCS_f-16c_26000lbs_10000ft.xlsx

Edited May 14, 2021 by karasawa

[karasawa]

DCS_f-16c_26000lbs_10000ft.xlsx

Oh boy, the real F-16C-50 with much higher loadout drag index (=50, equivalent to 6 amraams + pylons) sustains 12.9% higher turn rate than a clean DCS F-16 at 500km/h. (11.5dps vs 10.19dps)

 

Mind explaining this, ED?

 

(You can guess where I found the real F-16 manual.)

 

Edited May 15, 2021 by karasawa

[SCPanda]

On 5/15/2021 at 2:39 AM, karasawa said:

Mind explaining this, ED?

 

 

 

 

ED: WIP, be patient...

 

xD

[Spurts]

So, everyone likes to reference that one F-16 manual to compare their own test data.  Has no one noticed that in that manuals turn rate diagrams that even 1G is listed with a turn rate?  as the turn rate equation is (G^2-1)^.5/V, and I am ignoring the g acceleration and radians to degrees on purpose, than 1G should have 0 turn rate.  That is because that equation assumed you are not losing altitude.  So why does the manual show a turn rate for 1G?  I am left to think it assumed you are at 90 degree bank and ALL G is radial and you lose altitude no matter what.  

 

"But Spurt, you idiot, Sustained Turn /Ps=0 means you aren't losing speed or altitude!"  Well, it doesn't say Sustained Turn, it says Ps=0.  If Ps due to altitude loss is -100ft/s and Ps due to speed gain is 100ft/s then total Ps is indeed 0.  

 

I didn't write the charts, so I don't know, but that is the easiest answer I can see for having a 1G turn rate listed.  Which means everyone complaining about the Ps under 0.5M... you know, there 1G starts to have a real impact, might want to see what happened if they subtract the 1G turn rate from the Ps=0 turn rate to see what actual Sustained Turn Rate should look like and see if that suddenly lines up.

Edited May 18, 2021 by Spurts

[GGTharos]

The other option is that it wouldn't be the first chart with a mistake in it, or unwritten 'you should interpret it like this' instructions or 'someone took a ruler and drew on there, it's an estimate you should obviously ignore'.

[karasawa]

1 hour ago, Spurts said:

So, everyone likes to reference that one F-16 manual to compare their own test data.  Has no one noticed that in that manuals turn rate diagrams that even 1G is listed with a turn rate?  as the turn rate equation is (G^2-1)^.5/V, and I am ignoring the g acceleration and radians to degrees on purpose, than 1G should have 0 turn rate.  That is because that equation assumed you are not losing altitude.  So why does the manual show a turn rate for 1G?  I am left to think it assumed you are at 90 degree bank and ALL G is radial and you lose altitude no matter what.  

 

"But Spurt, you idiot, Sustained Turn /Ps=0 means you aren't losing speed or altitude!"  Well, it doesn't say Sustained Turn, it says Ps=0.  If Ps due to altitude loss is -100ft/s and Ps due to speed gain is 100ft/s then total Ps is indeed 0.  

 

I didn't write the charts, so I don't know, but that is the easiest answer I can see for having a 1G turn rate listed.  Which means everyone complaining about the Ps under 0.5M... you know, there 1G starts to have a real impact, might want to see what happened if they subtract the 1G turn rate from the Ps=0 turn rate to see what actual Sustained Turn Rate should look like and see if that suddenly lines up.

 

 

Only the 1G line is problematic. From 2G to 9G line they are all accurate (one can verify any point on the 2G-9G line satisfies the equation turn rate = sqrt(G^2-1) * 9.8 / airspeed * 57.3 )

 

You can not simply subtract a delta turn rate because the equation is not linear, and the 2g - 9g lines are accurate that need no correction. 

 

2g - 9g lines are not based on the 1g line. They are calculated separately. The deviation on the 1g line is not accumulated onto other lines.

Edited May 18, 2021 by karasawa

[Mover]

2 hours ago, Spurts said:

So, everyone likes to reference that one F-16 manual to compare their own test data.  Has no one noticed that in that manuals turn rate diagrams that even 1G is listed with a turn rate?  as the turn rate equation is (G^2-1)^.5/V, and I am ignoring the g acceleration and radians to degrees on purpose, than 1G should have 0 turn rate.  That is because that equation assumed you are not losing altitude.  So why does the manual show a turn rate for 1G?  I am left to think it assumed you are at 90 degree bank and ALL G is radial and you lose altitude no matter what.  

 

"But Spurt, you idiot, Sustained Turn /Ps=0 means you aren't losing speed or altitude!"  Well, it doesn't say Sustained Turn, it says Ps=0.  If Ps due to altitude loss is -100ft/s and Ps due to speed gain is 100ft/s then total Ps is indeed 0.  

 

I didn't write the charts, so I don't know, but that is the easiest answer I can see for having a 1G turn rate listed.  Which means everyone complaining about the Ps under 0.5M... you know, there 1G starts to have a real impact, might want to see what happened if they subtract the 1G turn rate from the Ps=0 turn rate to see what actual Sustained Turn Rate should look like and see if that suddenly lines up.

 

The turn rate equation is: (degrees per second) = (Gradial x 1092)/KTAS

 

[karasawa]

3 hours ago, GGTharos said:

The other option is that it wouldn't be the first chart with a mistake in it, or unwritten 'you should interpret it like this' instructions or 'someone took a ruler and drew on there, it's an estimate you should obviously ignore'.

We are complaining around 4g - 7g lines, which has nothing to do with the 1g line.

[Spurts]

1 hour ago, karasawa said:

 

Only the 1G line is problematic. From 2G to 9G line they are all accurate (one can verify any point on the 2G-9G line satisfies the equation turn rate = sqrt(G^2-1) * 9.8 / airspeed * 57.3 )

 

 

Fair enough, it was just something I noticed.

 

1 hour ago, Mover said:

The turn rate equation is: (degrees per second) = (Gradial x 1092)/KTAS

 

That's a good final version as it incorporates the 32.2ft/s^2 for the gravity, 180/Pi for radians per second to degrees per second, and the conversion from nm/h to ft/s.  

 

I was referencing the engineering version.  the Sqrt(G^2-1) is how you get Gradial for a level turn.

[Mover]

2 minutes ago, Spurts said:

 

Fair enough, it was just something I noticed.

 

That's a good final version as it incorporates the 32.2ft/s^2 for the gravity, 180/Pi for radians per second to degrees per second, and the conversion from nm/h to ft/s.  

 

I was referencing the engineering version.  the Sqrt(G^2-1) is how you get Gradial for a level turn.

 

Okay, but with the one we actually use, you can see how even at 1 G you still get a turn rate.  

[Spurts]

5 minutes ago, Mover said:

 

Okay, but with the one we actually use, you can see how even at 1 G you still get a turn rate.  

certainly, 1 radial G will give a turn rate whether it comes from a 1G (plane body reference) condition at 90 degrees of bank or from a level 1.41G turn.

[karasawa]

So the question is whether the 1G is the normal load or centripetal component only. 

[Xavven]

Just now, karasawa said:

So the question is whether the 1G is the normal load or centripetal component only. 

 

^^ Yes, that's my question too, and the source of much of our past discussions in some other threads. Can anyone authoritatively confirm?

[karasawa]

I am about to get my new joystick, then I'll do a complete test myself

[Hammer1-1]

Honestly I wouldnt bother; I flew the Viper for the first time in a month yesterday and it absolutely does feel underpowered and neutered. Yes, I am contradicting what Ive been saying these past few days, but Im man enough to admit my mistake. Feels very underpowered at the moment.

[Xavven]

'sall good, man.

[karasawa]

Here is my estimation:

DCS adopts a wrong drag polar. To reduce the error of peak sustained turn rate, DCS increases the thrust as compensation, however the equation does not hold at lower speed or at higher turn rate, which means the sustained turn rate error at lower speed is still significant, and the energy bleed rate in an instantaneous turn is higher than the manual. 

 

In some "competing product flight sim" (can't mention the name here) the F-16 feels have much more energy, even though the peak sustained turn rate is similar. 

Edited May 21, 2021 by karasawa

[totmacher]

5 часов назад, karasawa сказал:

So the question is whether the 1G is the normal load or centripetal component only. 

 

5 часов назад, Xavven сказал:

 

^^ Yes, that's my question too, and the source of much of our past discussions in some other threads. Can anyone authoritatively confirm?

"TRY"G = G/cos(AngleOfAttack)
so...

 turn rate = sqrt(   ( G/cos(AngleOfAttack) ) ^2-1) * 9.81 / airspeed * 57.3

also 

"TRY"Speed = Speed/cos(AngleOfAttack)

 

It's easy to verify (see track and tacview file):

sustained turn at 20m, TAS 216kts, AoA 22.85deg, turn rate 14.115 deg/sec, 2.735g

 

HUD speed is 199kts .         199tks /cos(22.85 *pi/180 ) = 216kts

 

with  "turn rate" same story - "TRY"G = 2.9679

calculated turn rate with "try"G = 14.11 deg/sec

 

1G with AoA=30deg  = 1/cos(30 *pi/180) = 1.15G

 

Maybe Mover confirm or decline how showing G and speed in DCS world...

 

f-18-400.trk Tacview-20210519-015206-DCS.zip.acmi

Edited May 18, 2021 by totmacher

[karasawa]

It's worth noting that even at sea level, when the AOA is high, the indicated air speed is significantly lower than true air speed. This is due to the deflection of the incoming airflow inside the pitot tube.

 

Surprised that this effect is simulated for the F-18, because the look up table is related to the type of the aircraft, and normally not published. The calibration curve in flight manual is for low AOA only.

[Mover]

9 hours ago, karasawa said:

It's worth noting that even at sea level, when the AOA is high, the indicated air speed is significantly lower than true air speed. This is due to the deflection of the incoming airflow inside the pitot tube.

 

Surprised that this effect is simulated for the F-18, because the look up table is related to the type of the aircraft, and normally not published. The calibration curve in flight manual is for low AOA only.

 

We use calibrated airspeed, not indicated.  This corrects for instrument/position errors.

[karasawa]

3 hours ago, Mover said:

 

We use calibrated airspeed, not indicated.  This corrects for instrument/position errors.

Thanks for the update