F-14B acceleration correct?

[fat creason]

2 hours ago, The_Doktor said:

This Forum is getting more and more ridicules. People asking for "in there opinion" most realistic FM to fight unrealistic multiplayer dogfights. Turning 2 minutes at 7 g constant until fuel is empty. outrateing the f-18 in a f-14. what are we talking about?? And always telling the developers what to do and what is the only truth.

 

I think ED should rename DCS in Digital Circle Simulator.

 

I fully understand where you're coming from with this comment and partially agree. Certain metrics of FM performance can be measured so I feel I have an obligation to match them (at least to what the manuals say, which is all extrapolated/estimated data anyway), a process which is ongoing. That being said, I have yet to see anyone on these forums provide definitive and quantitative proof of turn performance issues, besides just saying they think it's currently "wrong", without providing numbers along with proof of how those numbers were obtained.

 

I'm not saying it's perfectly correct at the moment, but it's funny to see some people get so up in arms about something they can't even quantify or define. Regardless, in terms of the "gamified" BFM scenarios that play out on MP servers, the validity of a "dogfight" outcome is only as good as the worst FM in DCS. At the end of the day it doesn't really matter if the F-14 has the mostest bestest FM ever and perfectly matches accelerations, turn rates, EM charts, etc because it's likely that very few other aircraft match their respective performance metrics throughout the envelope. Did you lose your fight with a F-18 or Su-27 because the F-14's underperforming or because your opponent's plane is overperforming in a certain area? Are you a bad pilot? Was the other guy a better pilot? Maybe you just got unlucky? There are many knowledge gaps in DCS that have to be filled by educated guessing, perhaps you got taken out by a weapon that's somewhat fictitious? Maybe a combo of all the above? Does anyone go and blame a FM when they win? I doubt it. That mentality is similar to questioning the legitimacy of an election only if you lose. 

 

Obsessing over in-game performance numbers for a particular airframe down to the last ft/sec of excess power is silly to me. Losing a fight and immediately blaming it on the FM is silly to me. People just need to get out there and enjoy the experience of these planes and be thankful they didn't have to join the military to do so. End of rant.

Edited May 14, 2021 by fat creason

[Katj]

On a semi-related note, I have reviewed all the stores drag data (primarily for AIM-9/AIM-7/AIM-54 and their launchers/adapters) and correlated it to drag index data in the performance manual. You can expect significantly reduced drag for all tunnel mounted missiles and slight drag reductions for shoulder mounted AIM-7s and AIM-9s when the FM update comes out. @Victory205and I are making good progress on tuning airframe drag primarily in the transonic and supersonic regions (the magnitude of deceleration is too small on power chops). Thrust re-tune comes next once we've decided on the drag changes. A fixed bug that was preventing partial deployments in the automatic maneuvering slat/flap schedule will help turns and maneuvering above ~10 units AOA in the 0.5-0.85 mach range depending on altitude. Obviously, more tuning will be done to dial in excess power throughout the EM charts once thrust has been tuned to match level flight accelerations and max mach, but the above items needed to be correct before this can be done.

Good stuff! Especially the semi-recessed Sparrows have seemed way too draggy.

I'm really looking forward to these changes, and I'm glad to hear you're making good progress!

In contrast to what many believe this isn't all about dogfighting, for me it's mostly about being able to punch through the sound barrier and send off some missiles with good energy.

[captain_dalan]

2 hours ago, fat creason said:

On a semi-related note, I have reviewed all the stores drag data (primarily for AIM-9/AIM-7/AIM-54 and their launchers/adapters) and correlated it to drag index data in the performance manual. You can expect significantly reduced drag for all tunnel mounted missiles and slight drag reductions for shoulder mounted AIM-7s and AIM-9s when the FM update comes out. @Victory205and I are making good progress on tuning airframe drag primarily in the transonic and supersonic regions (the magnitude of deceleration is too small on power chops). Thrust re-tune comes next once we've decided on the drag changes. A fixed bug that was preventing partial deployments in the automatic maneuvering slat/flap schedule will help turns and maneuvering above ~10 units AOA in the 0.5-0.85 mach range depending on altitude. Obviously, more tuning will be done to dial in excess power throughout the EM charts once thrust has been tuned to match level flight accelerations and max mach, but the above items needed to be correct before this can be done.

 

Great news! Looking forward to the new changes

[fat creason]

On 5/14/2021 at 1:34 PM, Katj said:

Good stuff! Especially the semi-recessed Sparrows have seemed way too draggy.

 

Yeah, the tunnel AIM-7s used to have about half the drag of an AIM-7 fully out in the slipstream/outside of any boundary layer effects, but according to the drag index data we have, it should be closer to about 1/8. Tunnel AIM-54s went from about 0.7 to 0.57 of the drag of a Phoenix in the slipstream. When you sum that across 4 missiles, it adds up.

Edited May 16, 2021 by fat creason

[Skysurfer]

Good stuff! Hopefully we can soon arrive on a mostly final rendition of the FM as constantly adjusting to the small changes since release over time can kinda get tiring. Also, I think the thrust update should be included with the drag update as thrust is fundamental for anything sustained, as well as transsonic and top speed.

[fat creason]

11 minutes ago, Skysurfer said:

Good stuff! Hopefully we can soon arrive on a mostly final rendition of the FM as constantly adjusting to the small changes since release over time can kinda get tiring. Also, I think the thrust update should be included with the drag update as thrust is fundamental for anything sustained, as well as transsonic and top speed.

 

That's why this FM update may feel like it's taking a long time to some people; it can only really be released all at once, not piecemeal. It's a multi-step process where each step blocks the next, and each step is massively time consuming. Add on the fact that it's being done for both airframes at the same time. Turn rate (aka excess power/EM chart tuning) is the very last step in this process because changes in previous steps will affect it. That's why I can't just immediately fix turn rate that has "tanked".

 

After the performance update comes out, we'll go back to handling adjustments that are more "subjective" (be thankful that @Victory205is willing and able to help us in this, it wouldn't be possible without him!)

Edited May 14, 2021 by fat creason

[Skysurfer]

1 minute ago, fat creason said:

 

That's why this FM update may feel like it's taking a long time to some people; it can only really be released all at once, not piecemeal. It's a multi-step process where each step blocks the next, and each step is massively time consuming. Add on the fact that it's being done for both airframes at the same time. Turn rate (aka excess power/EM chart tuning) is the very last step in this process.

 

Gotcha! And agreed - hence the question. I'm sure the result will be outstanding once it's all done and dusted. 

[Cpt. Weber]

On 5/14/2021 at 9:55 PM, fat creason said:

 

That's why this FM update may feel like it's taking a long time to some people; it can only really be released all at once, not piecemeal. It's a multi-step process where each step blocks the next, and each step is massively time consuming. Add on the fact that it's being done for both airframes at the same time. Turn rate (aka excess power/EM chart tuning) is the very last step in this process because changes in previous steps will affect it. That's why I can't just immediately fix turn rate that has "tanked".

 

After the performance update comes out, we'll go back to handling adjustments that are more "subjective" (be thankful that @Victory205is willing and able to help us in this, it wouldn't be possible without him!)

 

Amazing stuff, thank you for the hard work and taking the time to explain the workflow here!

[Hummingbird]

On 5/14/2021 at 9:27 PM, fat creason said:

At the end of the day it doesn't really matter if the F-14 has the mostest bestest FM ever and perfectly matches accelerations, turn rates, EM charts, etc because it's likely that very few other aircraft match their respective performance metrics throughout the envelope. Did you lose your fight with a F-18 or Su-27 because the F-14's underperforming or because your opponent's plane is overperforming in a certain area? Are you a bad pilot? Was the other guy a better pilot? Maybe you just got unlucky? There are many knowledge gaps in DCS that have to be filled by educated guessing, perhaps you got taken out by a weapon that's somewhat fictitious? Maybe a combo of all the above? Does anyone go and blame a FM when they win? I doubt it. That mentality is similar to questioning the legitimacy of an election only if you lose. 

 

Obsessing over in-game performance numbers for a particular airframe down to the last ft/sec of excess power is silly to me. Losing a fight and immediately blaming it on the FM is silly to me. People just need to get out there and enjoy the experience of these planes and be thankful they didn't have to join the military to do so. End of rant.

 

 

 

Just to be clear, this is not what I am doing. I only test fly to see where/how closely the aircraft matches the official charts (which are based on exhaustive flight testing, so not all extrapolated, I think that's important to make clear) or not, which as you know is hard work and takes a very long time. In other words wether or not I lose a dogfight in the F-14 I won't go straight to blaming the FM, that would be silly as too many other factors are at play to ever be sure.

 

That said comparing against another airframe/FM that hasn't changed, and finding you're now sunddenly and consistently (i.e. over many fights) losing in particular areas where before you clearly had the upper hand, is often what triggers further investigation and the discovery of flaws. Infact this is how I even got a clue to begin with that something big had changed, as in my first evening BFM'ing after the patch I found myself unable at any point to outrate opponents that beforehand I had no issues against, and clearly felt a loss in performance. Hence I went to investigate wether my feeling that performance had "tanked" was just that, a feeling, or factual.

[Victory205]

I asked for the methodology of your exhaustive flight testing, including a video or three of the actual turn performance and your chart references. Just posting numbers on a spreadsheet isn’t enough. That’s basic analysis.

 

You’ve shown up in multiple forum slots contending that other aircraft performance is inaccurate, it’s your thing. It would help if you’d show us how your are deriving your information, including standards for stabilization and data sources.

 

What referenced post was stating, is that to ascertain individual skill, the engagement should be flown 1v1 similar, with a neutral set up, fight’s on at the pass. Applying dissimilar aircraft in a simulator will end up in a never ending debate without any means to determine what is valid.

 

You want to know how good you are? Fight 1v1 against the same aircraft, guns only, or rear quarter IR missiles. The ability to maneuver to in phase in the rear quarter defines skill. The rest is rubbish.

[captain_dalan]

On 5/14/2021 at 9:55 PM, fat creason said:

 

That's why this FM update may feel like it's taking a long time to some people; it can only really be released all at once, not piecemeal. It's a multi-step process where each step blocks the next, and each step is massively time consuming. Add on the fact that it's being done for both airframes at the same time. Turn rate (aka excess power/EM chart tuning) is the very last step in this process because changes in previous steps will affect it. That's why I can't just immediately fix turn rate that has "tanked".

 

After the performance update comes out, we'll go back to handling adjustments that are more "subjective" (be thankful that @Victory205is willing and able to help us in this, it wouldn't be possible without him!)

 

Will drag changes involve alterations of the external tanks too? Right now the F-14A has a hard time going trough the mach with them on. Or will that be addressed with the thrust changes?

[fat creason]

25 minutes ago, captain_dalan said:

Will drag changes involve alterations of the external tanks too? Right now the F-14A has a hard time going trough the mach with them on. Or will that be addressed with the thrust changes?

 

Tank drag was already pretty close, it's similar to the drag generated by an AIM-54 outside the boundary layer. The thrust change should fix acceleration.

[fat creason]

Here's a high level drag "cheat sheet" for A2A loadouts based on data in the F-14 performance manual. All adjustments were done relative to the default DCS drag values for each missile, correlated to drag index integer values for stores + their adapters at each station:

• Shoulder AIM-54 adapter: adds 25% additional drag compared to AIM-54 fully outside the boundary layer (missile + adapter = 2.2x drag of a tunnel AIM-54 and 2.1x shoulder AIM-7 drag)
• Tunnel AIM-54: 57% of the drag compared to AIM-54 fully outside the boundary layer (~10x tunnel AIM-7 drag!)
• AIM-54 has more than twice the drag of an AIM-7 outside the boundary layer
• Shoulder AIM-7 adapter: add 33% additional drag compared to AIM-7 fully outside the boundary layer (missile + adapter = ~10x drag of a tunnel AIM-7!)
• Tunnel AIM-7: 12.5% of the drag compared to AIM-7 fully outside the boundary layer
• Fuel tanks have slightly less drag than an AIM-54 + adapter on the shoulder
• AIM-9: highest drag shoulder option when summing all 4 missiles + adapters/launchers, but this changes quickly as number of missiles is reduced. Each AIM-9 is roughly equivalent to a shoulder mounted AIM-7 + adapter.

In short, bring tunnel mounted Sparrows if you like going fast. The F-14's tunnel provides a place to mount stores well inside the boundary layer, allowing significant drag reductions particularly for the AIM-7 which is recessed even further into the fuselage of the Tomcat.

[TLTeo]

edit: nevermind, need to double check my math. Woops!

 

second edit: ok so, if I did the math right, the drag index for each a2a loadout assuming no tanks is:

2x0x6: ~14.9 times that of a single AIM7 outside of the boundary layer

2x2x4: ~11 times that of a single AIM7 outside of the boundary layer

2x3x2: ~8.3 times that of a single AIM7 outside of the boundary layer

2x6x0 OR 4x4x0: 5.8 times that of a single AIM7 outside of the boundary layer

Edited May 17, 2021 by TLTeo

[Hummingbird]

14 hours ago, Victory205 said:

I asked for the methodology of your exhaustive flight testing, including a video or three of the actual turn performance and your chart references. Just posting numbers on a spreadsheet isn’t enough. That’s basic analysis.

 

You’ve shown up in multiple forum slots contending that other aircraft performance is inaccurate, it’s your thing. It would help if you’d show us how your are deriving your information, including standards for stabilization and data sources.

 

Keep in mind that at the time where I did my testing and posted my results I was absolutely sure HB had a scripted program to specifically check performance in terms of ITR, STR, acceleration and level speed, and thus could much more easily and quickly run the same tests and verify my results if needed. Hence I didn't really feel the need to video record many hours combined worth of flying and writing down notes. 

 

As for methodology, I did explain it as pr. request last time, but to quickly rehash I picked certain speeds to focus on, picked SL, 5 kft and 10 kft as the altitudes for testing, and then I located specific locations on the maps available where there was level terrain at those altitudes to make it easier to visually coordinate the turns altitude wise. I then made sure the atmospheric conditions were standard, i.e. no wind, 15 deg Celcius @ SL (as on the charts), and that the weight and load out was identical to the charts. Next I made sure that fuel burn was turned OFF, so as to allow all the time needed to stabilize any Ps=0 turn without losing weight in the process, as otherwise the whole exercise would be essentially pointless.

 

Finally all recordings/checks were done with the Ctrl + Y infobar set for KTAS and TMN.

Edited May 18, 2021 by Hummingbird

[Victory205]

You have a meticulous approach to be sure, but to make it valid, the turns must be flown smoothly and consistently, and the G, altitude and airspeed must be validated by video, all things considered. Not all of them, but there should be a demonstrated ability to fly the profiles at different altitudes within strict, tight parameters, and show how the data was then distilled from those flown maneuvers. Including whether the Ctrl Y correlates to cockpit IAS, Mach and G. Which data display  is correct?

 

 

 

 

[stuart666]

Speaking for multiplayer, the F14 never seems to behave in a way that seems unlikely or ridiculous. I think FC is quite right, its overmodelling in other aircraft. I name no names, but its usually the same aircraft. I think there is likely going to be some attitude readjustment when the F15E drops.

 

Keep up the good work fella's, its the most enjoyable dlc on DCS. I only fly this and the Mig21 now.

 

[Hummingbird]

@Victory205 , understood and I'll  get some footage next time I take her out for some testing for sure. I've done this for the issues plaguing the F-16 atm as well, specifically a lack of ITR where I documented my testing with footage - although ITR is also a lot easier and less time consuming to test, esp. with a FBW aircraft. 

Edited May 18, 2021 by Hummingbird

[captain_dalan]

On 5/17/2021 at 9:15 PM, fat creason said:

 

Tank drag was already pretty close, it's similar to the drag generated by an AIM-54 outside the boundary layer. The thrust change should fix acceleration.

Ah, good to know! Thanks!

[captain_dalan]

9 hours ago, Victory205 said:

 Including whether the Ctrl Y correlates to cockpit IAS, Mach and G. Which data display  is correct?

 

 

 

 

I would recommend comparing those two values with the numbers shown it the tackview as well, just to make sure all numbers play along. I would do the flights myself, but these take several hours to do, just for a single altitude set, and i'm not likely to get any fly time before the weekend.

[Victory205]

Don’t anyone do anything yet. Everything is about to change, and other than it’s always good to practice turns, you’d be wasting your time. 

 

The point of all of this is to get it right, using valid, objective analysis. Tacview isn’t a workable tool for this in my opinion. 

 

[Hummingbird]

Yeah I wasn't planning on taking her for a spin until the next patch, as clearly things are about to change.

 

Btw I use KTAS & TMN because the graphs on the performance charts are for TMN. That way I know wether the aircraft matches the charts or not, as the Ctrl + Y infobar shows what the aircraft is actually doing in the DCS simulation. I don't see any reason to believe the infobar is wrong as it merely records the movement of the 3D object within the parameters of the simulation. So that in my mind is not a possibility, esp. since other DCS aircraft's infobar KTAS & TMN figures match official performance charts almost perfectly (F-15C for example).

 

 

[Victory205]

Some performance charts use TMN, some use IMN, and whenever the former is in play, indicator error is an issue. If you look at your manual, you will see significant instrument error in the transonic range. Alpha is another value that has an impact on velocity indications.

 

In other words, determining performance more complex than it may seem at first blush. We don’t have a test aircraft instrumented with a pitot/alpha boom, we have a simulator with algorithms that may or may not model  instrument error. I am not sure that the other modules model the sonic shock wave phenomenon on the pitot static system. I will investigate a few of the other modules at some point, time permitting.

[Hector45]

You guys are awesome, thanks for all the hard work!

[Katj]

Here's a high level drag "cheat sheet" for A2A loadouts based on data in the F-14 performance manual. All adjustments were done relative to the default DCS drag values for each missile, correlated to drag index integer values for stores + their adapters at each station:

• Shoulder AIM-54 adapter: adds 25% additional drag compared to AIM-54 fully outside the boundary layer (missile + adapter = 2.2x drag of a tunnel AIM-54 and 2.1x shoulder AIM-7 drag)
• Tunnel AIM-54: 57% of the drag compared to AIM-54 fully outside the boundary layer (~10x tunnel AIM-7 drag!)
• AIM-54 has more than twice the drag of an AIM-7 outside the boundary layer
• Shoulder AIM-7 adapter: add 33% additional drag compared to AIM-7 fully outside the boundary layer (missile + adapter = ~10x drag of a tunnel AIM-7!)
• Tunnel AIM-7: 12.5% of the drag compared to AIM-7 fully outside the boundary layer
• Fuel tanks have slightly less drag than an AIM-54 + adapter on the shoulder
• AIM-9: highest drag shoulder option when summing all 4 missiles + adapters/launchers, but this changes quickly as number of missiles is reduced. Each AIM-9 is roughly equivalent to a shoulder mounted AIM-7 + adapter.

In short, bring tunnel mounted Sparrows if you like going fast. The F-14's tunnel provides a place to mount stores well inside the boundary layer, allowing significant drag reductions particularly for the AIM-7 which is recessed even further into the fuselage of the Tomcat.

Very nice!

When the dust has settled I would very much appreciate if store drag index and weight could be added to the manual. I.e. including launchers, adapters, rails, etc.

Perhaps it's even possible to add a dynamic kneeboard page or two, that show drag index and weight of current loadout? But I digress...