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DCS F16 turn performance


Yeti42
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Hi all, apologies if this has already been discussed.
I happened across a YouTube video by @Growling Sidewinder yesterday who was demonstrating and discussing the F16's rate turn performance when compared to the F18 and F14.  The general conclusion of the video is that the F16 is underperforming in a 2 circle rate fight when compared to the F14 and F18 (or obviously the later 2 aircraft are overperforming)  I can see how the F18 and F14 could/should outperform the Viper in terms of radius turns but not in a rate turn.   Has anyone carried out a controlled test using something like Tacview?

GS's video is here:

 

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Haven't done any scientific tests but its been known for quite a while and i hope they sort it properly in the coming months as its high on ED's roadmap list.  "

 

"The planned poll features to be delivered by the end of 2021 for DCS: F-16C Viper includes:

 

  • Flight model and FLCS tuning. This focuses on angle of attack and G, and we believe it will result in more accurate sustained turn performance, instantaneous turn
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We all know Viper's FM is wrong and is being worked on by ED. That's great despite ED is a little slow on that, but as long as they get it right in the end that's fine. 

 

But regarding Hornet's FM and sustained turn performance, many people think it's overperforming (I am one of those people), but there are also some who think it's either accurate or Hornet lot 20 should match if not beat Viper block 50 (they claim blk 50 is heavier and not as good as previous blks in terms of turn performance, but I would like to point out it also got a more powerful engine, so it's debatable). 

 

IDK if ED has said anything about the Hornet (or Tomcat), or if they are going to revisit its FM in terms of turn performance. I wonder if anyone know any information about that. Would be nice if someone could share what they have read or heard from ED. 

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3 hours ago, SCPanda said:

there are also some who think it's either accurate or Hornet lot 20 should match if not beat Viper block 50 (they claim blk 50 is heavier and not as good as previous blks in terms of turn performance, but I would like to point out it also got a more powerful engine, so it's debatable). 

I am one of these people.  There is documentation out there that says a Lot 20 with 2 AIM-9s and 50% (60%?  don't have the paper on me) fuel has an STR of 19.3dps.  The Block 50, from the HAF manual, and weight corrected at DI0, is pretty much the same.  The difference being that the Hornet does this at a lower G so the same rate in a smaller radius is ideal for both offensive and defensive 2-C fighting.  This is documented fact.

 

The "Slow" hornets are the As and pre Lot 20s.  Now, a Block 30 would eat this things lunch, but a Block 50 matches it.

 

Same with the F-14B.  With all wings and flaps on auto, an F-14 with four Sparrows, four Sidewinders, and 50% fuel hits 16dps at 5,000ft.  accounting for weight reduction ONLY dropping all but two Sidewinders would increase this to 16.8, account for drag too and this could exceed 17 easily.  drop to sea level and it could be 17.5-18, all at under .5M for a tight radius.

 

Fun thing about that video too, he complains that the F-16 gets easily out-rated by the Tomcat, and then he proceeds to win the 2c fight three times in a row.

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9 hours ago, Yeti42 said:

Hi all, apologies if this has already been discussed.
I happened across a YouTube video by @Growling Sidewinder yesterday who was demonstrating and discussing the F16's rate turn performance when compared to the F18 and F14.  The general conclusion of the video is that the F16 is underperforming in a 2 circle rate fight when compared to the F14 and F18 (or obviously the later 2 aircraft are overperforming)  I can see how the F18 and F14 could/should outperform the Viper in terms of radius turns but not in a rate turn.   Has anyone carried out a controlled test using something like Tacview?
 

 

 

Hi,

 

Yes it is known and part of our roadmap as mentioned above. I would suggest waiting until the tweaks have been made before testing again, we will let everyone know once it is completed. 

Roadmap here 

and Wags commented here about the flight model here

 

thanks

bignewy

 

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11 hours ago, Spurts said:

I am one of these people.  There is documentation out there that says a Lot 20 with 2 AIM-9s and 50% (60%?  don't have the paper on me) fuel has an STR of 19.3dps.  The Block 50, from the HAF manual, and weight corrected at DI0, is pretty much the same.  The difference being that the Hornet does this at a lower G so the same rate in a smaller radius is ideal for both offensive and defensive 2-C fighting.  This is documented fact.

 

The "Slow" hornets are the As and pre Lot 20s.  Now, a Block 30 would eat this things lunch, but a Block 50 matches it.

 

Same with the F-14B.  With all wings and flaps on auto, an F-14 with four Sparrows, four Sidewinders, and 50% fuel hits 16dps at 5,000ft.  accounting for weight reduction ONLY dropping all but two Sidewinders would increase this to 16.8, account for drag too and this could exceed 17 easily.  drop to sea level and it could be 17.5-18, all at under .5M for a tight radius.

 

Fun thing about that video too, he complains that the F-16 gets easily out-rated by the Tomcat, and then he proceeds to win the 2c fight three times in a row.

The Tomcat pilot made some pretty big errors and GS capitalized. With the current DCS FM’s the way they are, the Tomcat should have won all the rounds by outrating on the deck with flaps. Seen it done many times in the multiplayer dogfight servers, same with F18 (Yay 13g over-G gun shots) and JF17, both who also can (and shouldn’t be able to) out-rate the F16 in DCS. Not sure what documentation you have seen, but your assertions fly in the face of the prevailing wisdom on Viper BFM doctrine if FM’s were accurate. 
 

The DCS Viper FM bleeds energy far too quickly and the pitch rate seems bad. I won’t mention other sims (BigNewy gave me a warning for just mentioning) but, it all feels very wrong in DCS and I am glad I am not the only one who sees it (Grim Reapers and GS have both mentioned many times in videos with documentation).

 

/Hatsoff /Salute to ED for fixing a very popular module’s FM!


Edited by Swoleymoley
Wanted to thank ED for being agile and valuing their customer feedback!!
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9 minutes ago, Swoleymoley said:

The Tomcat pilot made some pretty big errors and GS capitalized. With the current DCS FM’s the way they are, the Tomcat should have won all the rounds by outrating on the deck with flaps. Seen it done many times in the multiplayer dogfight servers, same with F18 (Yay 13g over-G gun shots) and JF17, both who also can (and shouldn’t be able to) out-rate the F16 in DCS. Not sure what documentation you have seen, but your assertions fly in the face of the prevailing wisdom on Viper BFM doctrine if FM’s were accurate. 
 

The DCS Viper FM bleeds energy far too quickly and the pitch rate seems bad. I won’t mention other sims (BigNewy gave me a warning for just mentioning) but, it all feels very wrong in DCS and I am glad I am not the only one who sees it (Grim Reapers and GS have both mentioned many times in videos with documentation).

 

/Hatsoff /Salute to ED for fixing a very popular module’s FM!

 

You brought up a lot of great points that I would like to reply to. 

 

GS did a fantastic job with the Viper in that video.  Personally I see the use of flaps, manual wing sweep, or the G paddle as evidence of a piss poor pilot.  I never use such things myself.  

 

Now, before I go further forgive me for presuming you also have the HAF -1.  

 

Well I am home now so I can check my sources.  "Navy Aviation: F/A-18E/F will provide marginal operational improvement at high cost" is the GAO document. 

https://books.google.com/books?id=XCcLAAAAIAAJ&pg=PA30&lpg=PA30&dq=F/A-18E+sustained+turn&source=bl&ots=VDPtcyELXn&sig=UJf5CawaEWf0_qeoPm5grVY5xT4&hl=en&sa=X&ved=0CDkQ6AEwBWoVChMI5OyCgpmLyQIVTzqICh1-KQ9S#v=onepage&q=F%2FA-18E sustained turn&f=false

page 29

engine F/A-18C/D F404-GE-402 EPE

page 30

"At sea level the F/A-18C's sustained turn rate is 19.2 degrees per second... (Super Hornet comparison follows) The instantaneous bleed rate of the F/A-18C is 54 knots per second... (Super Hornet comparison follows)   * Weapons load is 2 AIM-9 and 2 AIM-120 carried externally, no external fuel tanks and 60 percent fuel remaining" Ah, I was wrong on the loadout.

 

So here we have a government document given a sample of what OUR F/A-18 should do.  Again, remember the F/A-18A/B and early C/D did NOT have this motor and THIS is where I suspect all the "hornet can't rate" comes from.  I also do NOT think the CURRENT F-16FM is right.  Others have tested and found the STR is correct until you get to ~.35M and lower, but the bleed rate at ITR pulls feels way too high to me.

 

On to the HAF-1!  It has been a few years since I did this comparison initially so I am excited to go through the numbers again.

 

I often hear that the Block 50 in US service is lighter than the HAF model, so lets say the Basic Weight is 19,200 instead of 20,000 (page B1-6)  Basic DI is 4.  60% internal fuel is 4,297lbs, ammo is 287lb.  This gives us a clean weight of 23,784lb.  Now add AIM-120s to the wingtips and AIM-9Ms to the outboard stations (I doubt the GAO was using AIM-9Xs and I want to be fair).  page B1-7 gives us 196lb and 12DI for the AIM-9 Launder and adapter for stations 2 and 8.  Page B1-8 tells us that AIM-9M for stations 2 and 8 uses a rack of "LAUNCHER+ADAPTER" so we have the right thing.  It also says we add 390lb and 10 DI for the two AIM-9Ms, and 682lb and 0DI for the wingtip AIM-120s.  Altogether we have a weight of 25,052lb and a DI of 26.  

 

Page B8-54, Sea Level AB DI 0.  Max STR is 21.75dps at 9G and 0.69M.  Using the GW adjustment to go from 22k to 25k we see -3.2dps.  This drops us to 18.55dps.  This coincides with just above the +400fps Ps line.  If we follow that to 9G we reach 19.3dps at 0.79M.  We also see at worst a ~-500fps PS on the ITR line at 0.5G.  This is -0.89G deceleration or -17kts/second.  

but we need to average this with DI-50.

Page B8-65, Sea level, AB DI 50.  Max STR is 18.5dps at 0.81M and 9G.  GW adjust from 26k to 25k brings it +.75dps so 19.25.  This is above the 9G line so following the shape of the Ps=0 line back to 9G we reach 19.2dps at 0.78M.  max deceleration is ~-700 and 0.6M for -20knots/sec.

 

Averaging these we see that the Viper SHOULD have a best STR around 19.25dps at 0.785M and 9G and at lose ~18-19knots sec at worst of max pull (it would take a while to reach that speed for max negative Ps.

 

If we compare this to the GAO Block 20, 19.2dps at ~0.65M (7.5G assumed) we see that the STR should be nearly equal and the radius of the Hornet will be tighter.  The viper will lose less in a hard turn and as it is flying at a higher speed can more easily use the vertical.

 

My biggest problem with the Viper is only FM tangent.  G tolerance of the pilot.  The reclined nature of the seat means 9G should only feel like 7.8G in terms of blackout.  This is not modeled at all.  THIS is why Viper pilots could use 9G more liberally than anyone else.  THIS is what lets them fight fast.

 

I am so glad that ED is working the FM and I can't wait to see what they come up with as what we have does not let the Viper fight the way it should.  I'm glad you questioned my source and I am happy to share.  

 

 

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I love data! It will take some time for me to digest the numbers you provided and THANK YOU!

 

In the meantime, I would offer, since DCS is a game where actual numbers sometimes aren’t utilized (actual missile ranges, etc) all of the FM’s have to be considered in relation to each other so DCS can keep the “essence of reality” close. While your number’s are probably correct, some of us come at it from the perspective of a VS. POV since 100% FM accuracy will not be in the cards. 

 

For players like me, if we can’t have 100% real numbers across all of the FM’s, a decent compromise should be each module should perform similarly to RL in relation to each other, or as close as possible. If I am going to be fighting AI, for me, the airframe’s FM is the star of the show as AI doesn’t pose a significant challenge. Relative FM accuracy is even more important in a multiplayer environment. The gaps are too large currently.

 

Is all of this to say, it’s only a F16 FM issue in DCS? Probably not. I’d be happy with a narrowing of the gap to employ actual BFM tactics used by Viper drivers vs certain adversaries. Currently, some of those tactics aren’t effective as the FM doesn’t allow it, degrading the overall F16 experience in DCS, IMHO.

 

 


Edited by Swoleymoley
… totally agree on the gloc in Viper.
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1 hour ago, Spurts said:

Others have tested and found the STR is correct until you get to ~.35M and lower, but the bleed rate at ITR pulls feels way too high to me.

 

Hey Spurts, 

 

Great post! But Viper's STR in DCS is definitely worse than what HAF manual says. 

1 hour ago, Spurts said:

Page B8-54, Sea Level AB DI 0.  Max STR is 21.75dps at 9G and 0.69M.

 

The GW on the HAF chart is 22000 lbs right? Please check this out: https://dcs.silver.ru/70-820 (the website uses kg so I have adjusted the weight to 9979 kg, which equals to 22000 lbs, i.e. 25% fuel). So in the same conditions as the HAF chart, Viper in DCS can only achieve about 20.12 STR at 0.69M. And the overall STR of our DCS Viper is notably worse than the HAF chart. Another thing to point out is that our DCS Viper pilot won't sustain 9G for even a single second due to the lack of modeling the reclined seat of the Viper and the overall G modeling for our DCS virtual pilot. 

1 hour ago, Spurts said:

The reclined nature of the seat means 9G should only feel like 7.8G in terms of blackout.  This is not modeled at all.  THIS is why Viper pilots could use 9G more liberally than anyone else.  THIS is what lets them fight fast.

Definitely! 

 

Edit: @Spurts When you open the link, the graph won't show the correct STR, I guess it shows the STR with the default 50% fuel setting. Try to adjust the fuel a little bit with left and right arrow keys, then the graph will work as intended. 

 

Also Spurts, try adding the Hornet to the graph, see if our DCS Hornet is overperforming. 


Edited by SCPanda
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3 hours ago, Spurts said:

Personally I see the use of flaps, manual wing sweep, or the G paddle as evidence of a piss poor pilot.  I never use such things myself.  

Ohhhhh, you went there! You are in good company though. The Folds of Honor dogfight tourney dq’s for such things and rightly so. Last year, a Hornet won without over-g, so it can be done (grats SungHo). Doesn’t happen in the dogfight servers sadly.

 

edit: Much ❤️ for sane discourse in a video game. The DCS community is pretty fantastic.


Edited by Swoleymoley
DCS community is awesome.
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If you meet a 14 or 18 in the 16 and you have no missiles left, push the throttle forward, pitch up a little and then hope it doesn't catch you.
You won't win anything with the current flight model, and there is also no way to beat a MiG-29 currently on which you should have a slight edge above ~10k altitude- unless the other one does some pretty big mistakes. Either you win in the first turns or you're doomed, best is to throw a 9X across the circle. Fast wide turns won't work because of the lack of the reclined seat modelling and tight turns... Well, I feel more confident doing this in the Viggen which is surprisingly good in those fights and I have been able to hold up against a 16 in it. It's just that it carries poor heaters and no internal gun. And you have to be careful to avoid compressor stalls.
I really hope they patch that part sooner than the "whole fix" which was planned for autumn. Until then: Don't enter a turning fight, use boom-n-zoom tactics or pop a few slammers and go home.
The F-16 is still fun if you stay away from dogfights.

The topic is known, and is being worked on for some months now so I hope we'll no longer talk about it at the end of the year.

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9 hours ago, Spurts said:

You brought up a lot of great points that I would like to reply to. 

 

GS did a fantastic job with the Viper in that video.  Personally I see the use of flaps, manual wing sweep, or the G paddle as evidence of a piss poor pilot.  I never use such things myself.  

 

Now, before I go further forgive me for presuming you also have the HAF -1.  

 

Well I am home now so I can check my sources.  "Navy Aviation: F/A-18E/F will provide marginal operational improvement at high cost" is the GAO document. 

https://books.google.com/books?id=XCcLAAAAIAAJ&pg=PA30&lpg=PA30&dq=F/A-18E+sustained+turn&source=bl&ots=VDPtcyELXn&sig=UJf5CawaEWf0_qeoPm5grVY5xT4&hl=en&sa=X&ved=0CDkQ6AEwBWoVChMI5OyCgpmLyQIVTzqICh1-KQ9S#v=onepage&q=F%2FA-18E sustained turn&f=false

page 29

engine F/A-18C/D F404-GE-402 EPE

page 30

"At sea level the F/A-18C's sustained turn rate is 19.2 degrees per second... (Super Hornet comparison follows) The instantaneous bleed rate of the F/A-18C is 54 knots per second... (Super Hornet comparison follows)   * Weapons load is 2 AIM-9 and 2 AIM-120 carried externally, no external fuel tanks and 60 percent fuel remaining" Ah, I was wrong on the loadout.

 

So here we have a government document given a sample of what OUR F/A-18 should do.  Again, remember the F/A-18A/B and early C/D did NOT have this motor and THIS is where I suspect all the "hornet can't rate" comes from.  I also do NOT think the CURRENT F-16FM is right.  Others have tested and found the STR is correct until you get to ~.35M and lower, but the bleed rate at ITR pulls feels way too high to me.

 

On to the HAF-1!  It has been a few years since I did this comparison initially so I am excited to go through the numbers again.

 

I often hear that the Block 50 in US service is lighter than the HAF model, so lets say the Basic Weight is 19,200 instead of 20,000 (page B1-6)  Basic DI is 4.  60% internal fuel is 4,297lbs, ammo is 287lb.  This gives us a clean weight of 23,784lb.  Now add AIM-120s to the wingtips and AIM-9Ms to the outboard stations (I doubt the GAO was using AIM-9Xs and I want to be fair).  page B1-7 gives us 196lb and 12DI for the AIM-9 Launder and adapter for stations 2 and 8.  Page B1-8 tells us that AIM-9M for stations 2 and 8 uses a rack of "LAUNCHER+ADAPTER" so we have the right thing.  It also says we add 390lb and 10 DI for the two AIM-9Ms, and 682lb and 0DI for the wingtip AIM-120s.  Altogether we have a weight of 25,052lb and a DI of 26.  

 

Page B8-54, Sea Level AB DI 0.  Max STR is 21.75dps at 9G and 0.69M.  Using the GW adjustment to go from 22k to 25k we see -3.2dps.  This drops us to 18.55dps.  This coincides with just above the +400fps Ps line.  If we follow that to 9G we reach 19.3dps at 0.79M.  We also see at worst a ~-500fps PS on the ITR line at 0.5G.  This is -0.89G deceleration or -17kts/second.  

but we need to average this with DI-50.

Page B8-65, Sea level, AB DI 50.  Max STR is 18.5dps at 0.81M and 9G.  GW adjust from 26k to 25k brings it +.75dps so 19.25.  This is above the 9G line so following the shape of the Ps=0 line back to 9G we reach 19.2dps at 0.78M.  max deceleration is ~-700 and 0.6M for -20knots/sec.

 

Averaging these we see that the Viper SHOULD have a best STR around 19.25dps at 0.785M and 9G and at lose ~18-19knots sec at worst of max pull (it would take a while to reach that speed for max negative Ps.

 

If we compare this to the GAO Block 20, 19.2dps at ~0.65M (7.5G assumed) we see that the STR should be nearly equal and the radius of the Hornet will be tighter.  The viper will lose less in a hard turn and as it is flying at a higher speed can more easily use the vertical.

 

My biggest problem with the Viper is only FM tangent.  G tolerance of the pilot.  The reclined nature of the seat means 9G should only feel like 7.8G in terms of blackout.  This is not modeled at all.  THIS is why Viper pilots could use 9G more liberally than anyone else.  THIS is what lets them fight fast.

 

I am so glad that ED is working the FM and I can't wait to see what they come up with as what we have does not let the Viper fight the way it should.  I'm glad you questioned my source and I am happy to share.  

 

 

 

I've seen this document cited as evidence for the DCS F18's sustained turn rate. Just be aware that this is a document that was written for congress to dissuade them from funding the Super Hornet by comparing it to the Legacy Hornet, so it comes with a little bias. It also isn't a NATOPS manual, it was written by the General Accounting Office. Another problem is that there are no EM charts for the hornet in it, just claims that it has 19 d/s turn rate with no G specified or DI or weight. To my knowledge there are no publicly available EM charts for the Block 20 hornet, so ED is doing their best approximating the FM with what documentation they have.

 

 

 

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9 minutes ago, coolneko said:

 

... no G specified or DI or weight...  there are no publicly available EM charts for the Block 20 hornet, so ED is doing their best approximating the FM with what documentation they have.

 

 

 

There is a specified configuration (DI) and Weight.  I included it in my post.  And you are right, there are no EM charts publicly available, so for the public this is the only government document that discusses performance.  This is literally the only official data we have.  The document also talks about accelerations, dynamic thrust, and many other things.  I do have data on the E/F and the -400 powered C/D (we have the -402) and it all lines up.

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9 hours ago, SCPanda said:

 

Also Spurts, try adding the Hornet to the graph, see if our DCS Hornet is overperforming. 

 

Okay so I checked the clean and light "HAF" F-16 (2.7.2.7910, no pylons, 9979kg) and got 20.26 at 840km/h for 8.887G, or ~93% is HAF value.

 

the Lot 20 data from the GAO doc (2.7.2.7910, no pylons, 70% fuel as the stores carried in GAO doc have weight of roughly 10% fuel but next to no drag) and got 18.68 at 790kh/m for 7.724G, or 97% of GAO

 

the equivalent Block 50 to the GAO doc (2.7.2.7910, pylons, 60% fuel, pylons added weight and drag approximating weight and drag of the four missiles) and got 16.935 at 955km/h for 8.45G, or 88% of my estimate.  Admittedly this config deviates the most from my estimate config as well.

 

In the end this chart indicates that the F-16 is underperforming and the F/A-18 is not overperforming.  I can't wait to see the Viper "brought up to speed"

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14 hours ago, Spurts said:

You brought up a lot of great points that I would like to reply to. 

 

GS did a fantastic job with the Viper in that video.  Personally I see the use of flaps, manual wing sweep, or the G paddle as evidence of a piss poor pilot.  I never use such things myself.  

 

Now, before I go further forgive me for presuming you also have the HAF -1.  

 

Well I am home now so I can check my sources.  "Navy Aviation: F/A-18E/F will provide marginal operational improvement at high cost" is the GAO document. 

https://books.google.com/books?id=XCcLAAAAIAAJ&pg=PA30&lpg=PA30&dq=F/A-18E+sustained+turn&source=bl&ots=VDPtcyELXn&sig=UJf5CawaEWf0_qeoPm5grVY5xT4&hl=en&sa=X&ved=0CDkQ6AEwBWoVChMI5OyCgpmLyQIVTzqICh1-KQ9S#v=onepage&q=F%2FA-18E sustained turn&f=false

page 29

engine F/A-18C/D F404-GE-402 EPE

page 30

"At sea level the F/A-18C's sustained turn rate is 19.2 degrees per second... (Super Hornet comparison follows) The instantaneous bleed rate of the F/A-18C is 54 knots per second... (Super Hornet comparison follows)   * Weapons load is 2 AIM-9 and 2 AIM-120 carried externally, no external fuel tanks and 60 percent fuel remaining" Ah, I was wrong on the loadout.

 

So here we have a government document given a sample of what OUR F/A-18 should do.  Again, remember the F/A-18A/B and early C/D did NOT have this motor and THIS is where I suspect all the "hornet can't rate" comes from.  I also do NOT think the CURRENT F-16FM is right.  Others have tested and found the STR is correct until you get to ~.35M and lower, but the bleed rate at ITR pulls feels way too high to me.

 

On to the HAF-1!  It has been a few years since I did this comparison initially so I am excited to go through the numbers again.

 

I often hear that the Block 50 in US service is lighter than the HAF model, so lets say the Basic Weight is 19,200 instead of 20,000 (page B1-6)  Basic DI is 4.  60% internal fuel is 4,297lbs, ammo is 287lb.  This gives us a clean weight of 23,784lb.  Now add AIM-120s to the wingtips and AIM-9Ms to the outboard stations (I doubt the GAO was using AIM-9Xs and I want to be fair).  page B1-7 gives us 196lb and 12DI for the AIM-9 Launder and adapter for stations 2 and 8.  Page B1-8 tells us that AIM-9M for stations 2 and 8 uses a rack of "LAUNCHER+ADAPTER" so we have the right thing.  It also says we add 390lb and 10 DI for the two AIM-9Ms, and 682lb and 0DI for the wingtip AIM-120s.  Altogether we have a weight of 25,052lb and a DI of 26.  

 

Page B8-54, Sea Level AB DI 0.  Max STR is 21.75dps at 9G and 0.69M.  Using the GW adjustment to go from 22k to 25k we see -3.2dps.  This drops us to 18.55dps.  This coincides with just above the +400fps Ps line.  If we follow that to 9G we reach 19.3dps at 0.79M.  We also see at worst a ~-500fps PS on the ITR line at 0.5G.  This is -0.89G deceleration or -17kts/second.  

but we need to average this with DI-50.

Page B8-65, Sea level, AB DI 50.  Max STR is 18.5dps at 0.81M and 9G.  GW adjust from 26k to 25k brings it +.75dps so 19.25.  This is above the 9G line so following the shape of the Ps=0 line back to 9G we reach 19.2dps at 0.78M.  max deceleration is ~-700 and 0.6M for -20knots/sec.

 

Averaging these we see that the Viper SHOULD have a best STR around 19.25dps at 0.785M and 9G and at lose ~18-19knots sec at worst of max pull (it would take a while to reach that speed for max negative Ps.

 

If we compare this to the GAO Block 20, 19.2dps at ~0.65M (7.5G assumed) we see that the STR should be nearly equal and the radius of the Hornet will be tighter.  The viper will lose less in a hard turn and as it is flying at a higher speed can more easily use the vertical.

 

My biggest problem with the Viper is only FM tangent.  G tolerance of the pilot.  The reclined nature of the seat means 9G should only feel like 7.8G in terms of blackout.  This is not modeled at all.  THIS is why Viper pilots could use 9G more liberally than anyone else.  THIS is what lets them fight fast.

 

I am so glad that ED is working the FM and I can't wait to see what they come up with as what we have does not let the Viper fight the way it should.  I'm glad you questioned my source and I am happy to share.  

 

 

Correction:

 

GW adjustment in manual is linear approximation, not accurate. The true adjustment should be using "normal load factor is inverse proportional to weight" and do the math.

Proof:

Using linear approximation, 25000 lbs weighted F-16 with DI = 26 sustains about 18.5deg/sec,

However, on another page, 26000 lbs weighted F-16 with DI =50 also sustains 18.5deg/sec.

That is clearly contradictory if you think the linear approximation has high precision.

 

A better reasoning is: 26000 lbs weighted F-16 with DI =50 sustains 18.5deg/sec. Since "normal load factor is inverse proportional to weight", 25000lbs weighted F-16 with DI=50 should sustain 19.24deg/sec, and 25000lbs weighted F-16 with DI=26 should sustain even higher than 19.24deg/sec

On 8/24/2021 at 4:19 AM, Yeti42 said:

Hi all, apologies if this has already been discussed.
I happened across a YouTube video by @Growling Sidewinder yesterday who was demonstrating and discussing the F16's rate turn performance when compared to the F18 and F14.  The general conclusion of the video is that the F16 is underperforming in a 2 circle rate fight when compared to the F14 and F18 (or obviously the later 2 aircraft are overperforming)  I can see how the F18 and F14 could/should outperform the Viper in terms of radius turns but not in a rate turn.   Has anyone carried out a controlled test using something like Tacview?

GS's video is here:

 

One thing to counter the F-14 in a F-16 is to pull infinite half loops (Immelmann turn) to the vertical. The lower T/W ratio of F-14 makes it to drop altitude earlier than F-16 (from 5:14 in your video)


Edited by karasawa
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17 hours ago, Spurts said:

If we compare this to the GAO Block 20, 19.2dps at ~0.65M (7.5G assumed) we see that the STR should be nearly equal and the radius of the Hornet will be tighter.  The viper will lose less in a hard turn and as it is flying at a higher speed can more easily use the vertical.

 

I understand that you did that for SL.  If you do the math for 15,000ft,   It actually looks like the Block 50 viper out rates the 402 hornet. So I used the 19,261lbs empty weight figure shown on Page B1-3 in that listed load out problem example from HAF-1.  I came out with a weight total of 25,113lbs.  Then I used the GW effect-change Turn Rate chart.  I  averaged the 10 ,000ft and 20,000ft DI 50 charts out for 15,000.  I came out with a maximum sustained turn of basically 12.7dps.  I rounded 12.65 up to  about 12.7 because the DI is now down to 26 from 50 I think. But maybe too conservative estimate on new DI effect.  Isn't the 402 Hornet at 12.3dps in that paper.


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3 hours ago, karasawa said:

Correction:

 

GW adjustment in manual is linear approximation, not accurate. The true adjustment should be using "normal load factor is inverse proportional to weight" and do the math.

Proof:

Using linear approximation, 25000 lbs weighted F-16 with DI = 26 sustains about 18.5deg/sec,

However, on another page, 26000 lbs weighted F-16 with DI =50 also sustains 18.5deg/sec.

That is clearly contradictory if you think the linear approximation has high precision.

 

 

 

Even that is not the MOST accurate.  

 

From a physical standpoint it boils down to this.  At a given dynamic pressure (speed and altitude) and configuration there will be one specific AoA where the drag matches the thrust.  This AoA/Thrust relationship doesn't care about weight.  Just as Drag is constant in this instance, so is total lift.  This is where Nz and W are inversely and linearly proportional. 

 

In the Weights and Speeds we are looking at, maximum available G doesn't change as we are under the maneuvering weight and over the top of the corner plateau by a good margin.  So, if you look at the highest point of the Ps=0 line (for argument we will say it is right on the 9G line) and use a linear weight adjustment it will move above or below 9G.  you then need to follow the trendlines of the other Ps curves until you reach 9G.  So you can't JUST do the linear inverse math, that only tells you what your new G is at that AoA, you then have to look at the plot and see what happens with your G and speed.

 

Glad to see that people are thinking critically.  

 

Everyone, even the devs, are in agreement that the FM needs to be fixed.  They are working on it.  I just want people to be ready that a properly flown Hornet COULD still prevent them from out rating it depending on the config.  In the case of the GAO doc, it was 4 AAMs and 2 are BVR.  all four are carried in "dragless" wingtip or conformal positions.  Meaning this Hornet is DI 10 or less.  It is "clean".  My Viper that I matched loadout and fuel fraction with was not clean, but there was not much difference between the DI 0 and DI 50 values I posted.  Now, throw some pylons on a Hornet and things change.  put a tank on it and it changes some more.  In a stripped gunzo fight, the Hornet should remain a potent and challenging adversary to our F-16.

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On 8/24/2021 at 3:17 PM, Spurts said:

 

Same with the F-14B.  With all wings and flaps on auto, an F-14 with four Sparrows, four Sidewinders, and 50% fuel hits 16dps at 5,000ft.  accounting for weight reduction ONLY dropping all but two Sidewinders would increase this to 16.8, account for drag too and this could exceed 17 easily.  drop to sea level and it could be 17.5-18, all at under .5M for a tight radius

 

Actually if you change nothing but the altitude the rate goes from 16.1 to 18 deg/sec for the F-14B. Accounting for the drag and weight reduction of losing all but 2 sidewinders, and you're looking at over 19 deg/sec at SL.  

 

In other words the F16C and F14B are about equal in STR if the load out is similar. And whilst the F14 has the advantage of achieving its max STR at a lower speed, the F16 has the advantage of extra available energy to be converted into the vertical at its max STR. 

 

As for the F/A-18C, I believe it should be lower than both the 14B & 16C in max STR with similar load outs, but not by much. Thing is without any official EM charts, its impossible to tell for sure. 

 

This all concerns the aircraft IRL ofcourse, not how they currently perform in DCS, where both the F16 and F14 are suffering. But it's being fixed, so that's good. 

 

I do hope they increase the F16 pilots G tolerance in DCS at some point too though, because that's one very real and noticable advantage the real F16 has over the others. 


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5 hours ago, Kefa said:

I understand that you did that for SL.  If you do the math for 15,000ft,   It actually looks like the Block 50 viper out rates the 402 hornet. So I used the 19,261lbs empty weight figure shown on Page B1-3 in that listed load out problem example from HAF-1.  I came out with a weight total of 25,113lbs.  Then I used the GW effect-change Turn Rate chart.  I  averaged the 10 ,000ft and 20,000ft DI 50 charts out for 15,000.  I came out with a maximum sustained turn of basically 12.7dps.  I rounded 12.65 up to  about 12.7 because the DI is now down to 26 from 50 I think. But maybe too conservative estimate on new DI effect.  Isn't the 402 Hornet at 12.3dps in that paper.

 

That's exactly what I have mentioned in other threads: From 10000 ft on the viper actually out-rates everything in game.

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7 hours ago, Spurts said:

Even that is not the MOST accurate.  

 

From a physical standpoint it boils down to this.  At a given dynamic pressure (speed and altitude) and configuration there will be one specific AoA where the drag matches the thrust.  This AoA/Thrust relationship doesn't care about weight.  Just as Drag is constant in this instance, so is total lift.  This is where Nz and W are inversely and linearly proportional. 

 

In the Weights and Speeds we are looking at, maximum available G doesn't change as we are under the maneuvering weight and over the top of the corner plateau by a good margin.  So, if you look at the highest point of the Ps=0 line (for argument we will say it is right on the 9G line) and use a linear weight adjustment it will move above or below 9G.  you then need to follow the trendlines of the other Ps curves until you reach 9G.  So you can't JUST do the linear inverse math, that only tells you what your new G is at that AoA, you then have to look at the plot and see what happens with your G and speed.

 

Glad to see that people are thinking critically.  

 

Everyone, even the devs, are in agreement that the FM needs to be fixed.  They are working on it.  I just want people to be ready that a properly flown Hornet COULD still prevent them from out rating it depending on the config.  In the case of the GAO doc, it was 4 AAMs and 2 are BVR.  all four are carried in "dragless" wingtip or conformal positions.  Meaning this Hornet is DI 10 or less.  It is "clean".  My Viper that I matched loadout and fuel fraction with was not clean, but there was not much difference between the DI 0 and DI 50 values I posted.  Now, throw some pylons on a Hornet and things change.  put a tank on it and it changes some more.  In a stripped gunzo fight, the Hornet should remain a potent and challenging adversary to our F-16.

 

That may not be the most accurate to the quantum level, but that is accurate enough and much more accurate than your linear approximation.

 

I have some critical thinking because I used to be a flight control engineer, and guess what, that "inverse proportional law" is exactly what the industry is using to convert aircraft performance from one weight to another.

 

A 26000 lbs F-16C with DI=50 sustains 18.5deg/sec. At Mach 0.74 it sustains 18.25deg/sec, and that is still away from the 9G limit, which means that after the weight conversion, at Mach 0.74 it gets promoted to 19deg/sec without being truncated by the 9G limit, and that is with DI=50. I really don't find any reason why a F-16C with 2 amraams and 2 sidewinders has lower STR than a similarly loaded 402 powered hornet.


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