DCS F16 performance

[Top Jockey]

4 hours ago, Aquorys said:

Where do you get much more than 9G? Mine doesn't, most of the time it'll rather do some 8.5 to 8.9. Maybe you'll get 9.2 for a second at 650 knots before it drops to 9 or below, just like you'll probably get 7.7 briefly on the Hornet every now and then.

9.2 instead of 9 for one second isn't the same as 9 instead of 7.5 all day though.

 

By mere curiosity, got 9.3 G ( horizontal turn or down portion of the loop ? ) without much effort, if i recal correctly:

- "very low" fuel;

- no external stores / ordnance of any kind;

- clean wingtips;

- no gun rounds;

- very close to sea level;

- sharp pull on the stick with speed slightly above 450 kts.

[wilbur81]

6 hours ago, Aquorys said:

I guess it kind of does, because the Hornet is a 7.5G aircraft, and that's what the real-world assessment of the Viper outperforming the Hornet in real life is generally based on. Yeah, if you decide to destroy your aircraft by overstressing the airframe, then a Hornet will do pretty much the same 9G turns as the Viper (same speed, same Gs means pretty much the same turn rate and the same turn radius). And it can possibly outperform the Viper if you do that, in real life. But if you do, you're just gonna lose two aircraft instead of one.

Correct.

[Theodore42]

Paddle switch is totally valid to use when comparing the Hornet to the Viper in those kinds of tests. Obviously the Viper isn't just a Hornet FM that can pull 9Gs. They're completely different in what they're doing and how you should fly them. When I'm in the Viper and I see a Hornet disappearing under me while going over the top, I want nothing more than for him to pull his paddle switch. That's just winning the energy fight for me lol. 

Give me any specific instance of the paddle switch giving the Hornet an advantage over the Viper and I'll give you a specific instance of the Viper pilot flying wrong. The paddle switch is for gaining angles and the Viper is about gaining energy. If you see a Hornet ripping his nose around with his paddle switch, you know he's blowing through all his energy. It's a low wing-loaded vs high thrust-to-weight ratio fight. The amount of advantage gained isn't much more than the Flanker's Cobra maneuver.

As for the matter of Gs, if you're simulating training then you should limit Hornet testing to 7.5Gs. But dogfighting isn't the Hornet's mission and in a real war it's hard to imagine the 1/1000 sorties where a Hornet actually gets into a dogfight adhering to the 7.5G limit. It's not like a pilot has never overstressed a wing during a war before.

[captain_dalan]

6 hours ago, HWasp said:

 

Spiral climb at 450 kts at 7,5 G sustained, check what is the rate of climb, while holding these values for the F-16, and crosscheck it with the others. This would give a Ps value for the F-16 at that point, because if speed is constant, then Ps = rate of climb, and that could be crosschecked with the charts.

My thoughts on your methodology of testing. There are some pitfalls in the relative comparison tests, especially when based on interpretative indicators. 
For one, we often test a plane for a given configuration. Say clean with 50% internal fuel. Why? Because it's the configuration we fight in on most dogfighting servers. But, when we use this to reference the difference in performance between two planes mentioned in this or that source, is this comparison valid? How often would a Viper or Bug fight without any pylons? Or tanks? How often would both be at 50% fuel states? Isn't most of the training done based on bingo states and time over target? When dealing with such situational contexts, choosing an arbitrary state of evaluation may lead to skewed data samples and conclusions. I.E. it might not be the planes that perform different then they should, but the mission.

To counter the above mentioned issue, IMO a much better choice is to test the actual performance data. Yes, i agree, STR in ITR is not always enough. You need the portions above and bellow the state of equilibrium to make sure the plane performs as it should. That is bleed rates and recovery rates. And you have made some attempts of doing this. But again, the choice for the test initial states is rather arbitrary. For one, just pulling on the stick and bleeding to 250 knots may be beneficial for some planes, but not so for others. And for the other, configurations (externals, dirty wings etc) must be take into account. 

Now as much as i'm aware, there are two ways to test a planes' performance based on performance manuals. If the STR's match, then you need to test climbs, dives, glides and acceleration rates with PRECISE climb and acceleration profiles described in the manuals. IF these numbers match, that the plane is probably very close to what it should be. That's the first way. The second is closer to what are attempting. But it much more tedious and harder to pull (personally i can't do it, i'm not that good of a pilot and i have tried). Namely, you need to take a page of the performance manual with the E-M chart of the state that you are testing. Find the starting condition for that test. Say (purely hypothetical) 450 knots, 10000ft, drag index 0, total weight <some number here>. 

1. Now, step one. You want to see how much you bleed at full AB. Find the -200f/s curve. See how much g you need to pull to bleed this much. What does 200ft/s bleed mean? It means you either need to:
-lose 200ft of altitude every second to maintain your g at this (450 knots) speed;
-alternatively lose this much speed in a level turn (a bit less then 120 knots) every second.
Both can be hard to do. This is transient performance. Bu definition it can't be sustained as the conditions change during the test. If say, you can sustain 6g at 450, but pull 7g to bleed 200ft/s, then after 1s of doing this, you are either at 370 knots of airspeed and at 10000ft or at 450knots but at 9800ft. So you have to either decrease g as you bleed to stay on the -200ft/s "curve" or maintain constant descent as you dive. Whichever you chose, your runs can't be longer then a second or two, as the longer you change your state, more irrelevant you data will be. 
2. Step two, find the -400ft/s and do the same. Then the -600, -800 and so on.
3. After testing the bleed rates, it's time to test the recovery rates. Now find the 200ft/s curve. This means that your plane will need to either climb at a constant rate of 200ft/s or gain speed (roughly 120 knots every second) when under the said g-load. 
4. repeat the same tests for other recovery rates available in the charts. 

And, of course, the final problem is chart availability. For the F-14 and the F-16, such detailed charts can be acquired. For the other planes, not so much. Not even for the F-15 do we have them. The F-18 is even more elusive as we lack even STR's for it. But in the end, it's the only way to have a relevant test result. You can't just pull on the stick and say, this feels wrong. Feels play no part here. This is a computer game from a sim genre. The only measure we have is performance values (that are often approximations themselves) and the input of people that flew them to cover the grey areas.

Hope this helps and sorry for the long post! 

EDIT: nearly forgot, because your runs must be so short, in order to minimize the room for error, you gonna have to reset and do them over and over again, and then average out the results  

Edited November 26, 2021 by captain_dalan

[Cab]

2 hours ago, Theodore42 said:

But dogfighting isn't the Hornet's mission and in a real war it's hard to imagine the 1/1000 sorties where a Hornet actually gets into a dogfight adhering to the 7.5G limit.

I am not sure how to reconcile that with the reality that the Hornet is the only fighter on the decks of US carriers. Granted today it's the E/F rather than the C, but they are still 7.5G aircraft so the principle is the same.

[HWasp]

8 hours ago, captain_dalan said:

My thoughts on your methodology of testing. There are some pitfalls in the relative comparison tests, especially when based on interpretative indicators. 
For one, we often test a plane for a given configuration. Say clean with 50% internal fuel. Why? Because it's the configuration we fight in on most dogfighting servers. But, when we use this to reference the difference in performance between two planes mentioned in this or that source, is this comparison valid? How often would a Viper or Bug fight without any pylons? Or tanks? How often would both be at 50% fuel states? Isn't most of the training done based on bingo states and time over target? When dealing with such situational contexts, choosing an arbitrary state of evaluation may lead to skewed data samples and conclusions. I.E. it might not be the planes that perform different then they should, but the mission.

To counter the above mentioned issue, IMO a much better choice is to test the actual performance data. Yes, i agree, STR in ITR is not always enough. You need the portions above and bellow the state of equilibrium to make sure the plane performs as it should. That is bleed rates and recovery rates. And you have made some attempts of doing this. But again, the choice for the test initial states is rather arbitrary. For one, just pulling on the stick and bleeding to 250 knots may be beneficial for some planes, but not so for others. And for the other, configurations (externals, dirty wings etc) must be take into account. 

Now as much as i'm aware, there are two ways to test a planes' performance based on performance manuals. If the STR's match, then you need to test climbs, dives, glides and acceleration rates with PRECISE climb and acceleration profiles described in the manuals. IF these numbers match, that the plane is probably very close to what it should be. That's the first way. The second is closer to what are attempting. But it much more tedious and harder to pull (personally i can't do it, i'm not that good of a pilot and i have tried). Namely, you need to take a page of the performance manual with the E-M chart of the state that you are testing. Find the starting condition for that test. Say (purely hypothetical) 450 knots, 10000ft, drag index 0, total weight <some number here>. 

1. Now, step one. You want to see how much you bleed at full AB. Find the -200f/s curve. See how much g you need to pull to bleed this much. What does 200ft/s bleed mean? It means you either need to:
-lose 200ft of altitude every second to maintain your g at this (450 knots) speed;
-alternatively lose this much speed in a level turn (a bit less then 120 knots) every second.
Both can be hard to do. This is transient performance. Bu definition it can't be sustained as the conditions change during the test. If say, you can sustain 6g at 450, but pull 7g to bleed 200ft/s, then after 1s of doing this, you are either at 370 knots of airspeed and at 10000ft or at 450knots but at 9800ft. So you have to either decrease g as you bleed to stay on the -200ft/s "curve" or maintain constant descent as you dive. Whichever you chose, your runs can't be longer then a second or two, as the longer you change your state, more irrelevant you data will be. 
2. Step two, find the -400ft/s and do the same. Then the -600, -800 and so on.
3. After testing the bleed rates, it's time to test the recovery rates. Now find the 200ft/s curve. This means that your plane will need to either climb at a constant rate of 200ft/s or gain speed (roughly 120 knots every second) when under the said g-load. 
4. repeat the same tests for other recovery rates available in the charts. 

And, of course, the final problem is chart availability. For the F-14 and the F-16, such detailed charts can be acquired. For the other planes, not so much. Not even for the F-15 do we have them. The F-18 is even more elusive as we lack even STR's for it. But in the end, it's the only way to have a relevant test result. You can't just pull on the stick and say, this feels wrong. Feels play no part here. This is a computer game from a sim genre. The only measure we have is performance values (that are often approximations themselves) and the input of people that flew them to cover the grey areas.

Hope this helps and sorry for the long post! 

EDIT: nearly forgot, because your runs must be so short, in order to minimize the room for error, you gonna have to reset and do them over and over again, and then average out the results  

 

Thank you for the detailed reply! Some further explanation, why I did things the way I did:

-As you have said, sadly there are no detailed performance charts available for many modules (Jf-17, M2000, F-18 afaik), so trying to do a detailed comparison like that, against real data, is already impossible unfortunately. What remains is crosscheck for possible gross errors.

- The main goal of the test was to try to step away from the Ps=0 tests, from which there were plenty already, and I'm convinced, that if there are problems, it is most probably not in that area, because it easily and frequently tested. 
 

-If you look at the second test, it wasn't a random pull on the stick to trade the speed at any rate, but the goal was to achieve the target speed, when possible, exactly upon the completion of the 360 deg turn. (turns were measured between heading north to north).

-The method you propose is certainly good, but as I also mentioned previously, it is very tricky to perform. Advanced tests like that would better be performed by the developers during an fm review, because they probably have better tools (more data from the game) to do things like that. 

-Again, just to confirm, simplified tests, like this are not meant to give accurate results, these are meant only to discover possible large anomalies, and trigger a review by the devs, who actually have the data and the tools for real accuracy. I think one anomaly is already found.

 

 

[totmacher]

10 минут назад, HWasp сказал:

no detailed performance charts available for many modules (Jf-17, M2000, F-18 afaik)

Some data for F/a-18c with compare in game
https://dcs.silver.ru/Diagram/Fa18c

 

[HWasp]

43 minutes ago, totmacher said:

Some data for F/a-18c with compare in game
https://dcs.silver.ru/Diagram/Fa18c

 

Thanks, any data might help.

[Mars Exulte]

13 hours ago, captain_dalan said:

in order to minimize the room for error, you gonna have to reset and do them over and over again, and then average out the results

That's an often neglected aspect of testing, especially in the FM debates around here. Real life test results are not produced off a single experiment. If it's done less than 3 times, it's irrelevant, as you can't even generate the necessary statistics that way. The more times the test is performed, the more accurate the results become as they will tend to cumulatively smooth over individual inconsistencies. And that this process must be repeated every time a variable changes. Most people run out, perform a routine that confirms their opinion, and then call it a day.

[wilbur81]

On 11/25/2021 at 8:03 AM, HWasp said:

 

I pointed out the difference with the Hornet, because it is too large in my opinion, and it suspicious to have one module that stands out so much, simple as that.

Only because you pulled the paddle switch...fly the Hornet as it is designed, it is not outperforming the Viper, except in the well documented areas which it is supposed to. Pull flight control circuit breakers in the Tomcat, Viper, and Eagle and your comparisons  would also be invalid. 

Edited November 26, 2021 by wilbur81

[Aquorys]

FWIW, there is a pitch override switch in the Viper that would possibly give you more AoA when you're slow, but I don't think people use that a lot. It's meant for recovering from deep stalls. If you used it for dogfighting, I guess it would be more likely to make you depart than help you win the fight.

[TobiasA]

vor 3 Stunden schrieb Aquorys:

FWIW, there is a pitch override switch in the Viper that would possibly give you more AoA when you're slow, but I don't think people use that a lot. It's meant for recovering from deep stalls. If you used it for dogfighting, I guess it would be more likely to make you depart than help you win the fight.

The pitch override does give more elevator deflection in the NEGATIVE direction so you can get out of a deep stall. You would gain nothing but a probable departure from controlled flight.

[Theodore42]

On 11/25/2021 at 8:49 PM, Cab said:

Posted Thursday at 08:49 PM

  On 11/25/2021 at 6:07 PM, Theodore42 said:

But dogfighting isn't the Hornet's mission and in a real war it's hard to imagine the 1/1000 sorties where a Hornet actually gets into a dogfight adhering to the 7.5G limit.

I am not sure how to reconcile that with the reality that the Hornet is the only fighter on the decks of US carriers. Granted today it's the E/F rather than the C, but they are still 7.5G aircraft so the principle is the same.

The F-15C missions are 100% in the fighter role so they would have relatively a much higher rate of getting into dogfights. The F/A in F/A-18 is the compounded designation for both fighter and attack. That's why they're the only fighter on the decks of US carriers. Much more efficient that way  Maybe if the enemy saw the Hornets as being tactically vulnerable and specifically ambushed them the Hornets would get into more dogfights than Eagles.

On the matter of pulling Gs and over-stressing the aircraft in a non-training situation: The reason such limits exist is primarily for budget reasons. Materials aren't going to break when they're overstressed once or twice or even ten times. But imagine you're in charge of supplying the AF or Navy of their aircraft. When you buy the aircraft you know they are expected to operate a certain number of hours before being retired. You can even make a budget then and there for the entire life-span of the aircraft. Nice and predictable. The problem is that pilots are a bunch of young Hot Sh** badasses that are going to fly these aircraft to the limits every chance they get. So the limits are there so the $$ guys (you) know they're budgeted all the hours of the expected lifespan of the aircraft.

Now imagine you're a mission commander escorting a JSTARS during a major ground operation and you get jumped. Entire ARMIES are about to lose major support if that JSTARS gets shot down. Obviously you're going to get into a no-holds-barred dogfight in that situation. Fly the wings off your airplane and pull your arms out of your own sockets if that's what it takes to defend the JSTARS during a tactically vulnerable time.

Now imagine you're the general getting his ear chewed off by the $$ guy, "If you utilize these tactics we won't have enough fighters and we will lose the war." and in your other ear the combat commander is saying "if you make us hold back then entire ARMIES are going to die!"

So what ends up happening is a mission commander of a 2-ship doing a BARCAP in a limited skirmish will be trained to engage in some standoffish BVR and go home rather than risking overstressing the airframe. But during a major offensive the mission commander will be trained to get into every knife fight and overstress his aircraft as much as necessary to win in that tactical situation.

Long story short, if a Hornet pilot doesn't want to adhere to realistic G limits I don't consider that unrealistic. And it just doesn't help against the Viper much anyway. Let the Hornet have as many angles as he wants, I'll just undo them in my Viper with a roll while vertical. And the Viper dogfights so fast the ranges are pretty far, making a snapshot utilizing the paddle switch extremely unlikely. A close range high alpha shot is a reasonable tactic but hitting a tiny little Viper from long range is something like a 360 no scope headshot. That's why imo the Hornet's paddle switch is much more useful against a Flanker or Eagle.

Ultimately I hope ED implements realistic G damage and pilot injury. (I have no idea how ED could implement pilot injury though. And realistic G damage has already proven to be really debatable.)

[Cab]

21 minutes ago, Theodore42 said:

The F-15C missions are 100% in the fighter role so they would have relatively a much higher rate of getting into dogfights. The F/A in F/A-18 is the compounded designation for both fighter and attack. That's why they're the only fighter on the decks of US carriers. Much more efficient that way  Maybe if the enemy saw the Hornets as being tactically vulnerable and specifically ambushed them the Hornets would get into more dogfights than Eagles.

On the matter of pulling Gs and over-stressing the aircraft in a non-training situation: The reason such limits exist is primarily for budget reasons. Materials aren't going to break when they're overstressed once or twice or even ten times. But imagine you're in charge of supplying the AF or Navy of their aircraft. When you buy the aircraft you know they are expected to operate a certain number of hours before being retired. You can even make a budget then and there for the entire life-span of the aircraft. Nice and predictable. The problem is that pilots are a bunch of young Hot Sh** badasses that are going to fly these aircraft to the limits every chance they get. So the limits are there so the $$ guys (you) know they're budgeted all the hours of the expected lifespan of the aircraft.

Now imagine you're a mission commander escorting a JSTARS during a major ground operation and you get jumped. Entire ARMIES are about to lose major support if that JSTARS gets shot down. Obviously you're going to get into a no-holds-barred dogfight in that situation. Fly the wings off your airplane and pull your arms out of your own sockets if that's what it takes to defend the JSTARS during a tactically vulnerable time.

Now imagine you're the general getting his ear chewed off by the $$ guy, "If you utilize these tactics we won't have enough fighters and we will lose the war." and in your other ear the combat commander is saying "if you make us hold back then entire ARMIES are going to die!"

So what ends up happening is a mission commander of a 2-ship doing a BARCAP in a limited skirmish will be trained to engage in some standoffish BVR and go home rather than risking overstressing the airframe. But during a major offensive the mission commander will be trained to get into every knife fight and overstress his aircraft as much as necessary to win in that tactical situation.

Long story short, if a Hornet pilot doesn't want to adhere to realistic G limits I don't consider that unrealistic. And it just doesn't help against the Viper much anyway. Let the Hornet have as many angles as he wants, I'll just undo them in my Viper with a roll while vertical. And the Viper dogfights so fast the ranges are pretty far, making a snapshot utilizing the paddle switch extremely unlikely. A close range high alpha shot is a reasonable tactic but hitting a tiny little Viper from long range is something like a 360 no scope headshot. That's why imo the Hornet's paddle switch is much more useful against a Flanker or Eagle.

Ultimately I hope ED implements realistic G damage and pilot injury. (I have no idea how ED could implement pilot injury though. And realistic G damage has already proven to be really debatable.)

You offer a lot of insight and opinions on this topic of combat aircraft employment so I can only assume you are an actual fighter pilot or someone else embedded in the system. If so then I'll defer to you.

[NineLine]

Sorry guys, this thread continues to go off topic, so its time to move on. Closed.