If you want 2 circle in a F-16, stay above 10000 feet.

[oldtimesake]

The peak STR in F-16 is achieved at relatively high speed at high G and you go black out easily in current DCS high g mechanics. There is no planned fix for that I am afraid.

 

Above 10000 feet there is less chance of going black out and with 6 amraams on board you can still sustain more than 14.2 deg / sec in an F-16 at mach 0.85. Try other jets in similar loadout it is hard to sustain even 13.7 deg / sec.

 

If the enemy tries to go down and lure you do the same thing, don't take the bait. Stay above 10000 feet and wait for sufficient lateral separation, cash in some energy for angle. 

 

I leaned it the hard way. F-18, JF-17 and F-14 all have trailing edge flaps deployed automatically in high g turns, which helps them to turn tighter at lower speed. F-15/16's FCS don't do that. If you do it manually you need a multi-threading brain and I don't recommend that.

[Mover]

9 hours ago, oldtimesake said:

I leaned it the hard way. F-18, JF-17 and F-14 all have trailing edge flaps deployed automatically in high g turns, which helps them to turn tighter at lower speed. F-15/16's FCS don't do that. If you do it manually you need a multi-threading brain and I don't recommend that.

 

Say what now?

[Torri]

Trailing edge flaps is for high AoA, no? Not necessarily high G.
Regardless, the F-16 does the necessary things for best performance.

The main things holding back the DCS F-16 right now, is a less than perfect FLCS G onset and questionable pilot G tolerance.
I believe that the flight model will get adjusted in the next patch.

Edited April 11, 2021 by Torri98

[Dragon1-1]

TEFs aren't automatic in the F-14, and they are, in fact, manual and quite risky to use because it's very easy to overstress them either by moving them under G or overspeeding them. The Tomcat is a formidable aircraft, but the flaps are best left alone in most situations.

 

That said, it's true that the Viper likes being fast, and being high is good for staying fast. Lower down, it's easier to lose speed, and fighters like the Hornet or the MiG-29 gain an advantage due to their better high alpha capabilities.

[Mover]

5 hours ago, Dragon1-1 said:

That said, it's true that the Viper likes being fast, and being high is good for staying fast. Lower down, it's easier to lose speed, and fighters like the Hornet or the MiG-29 gain an advantage due to their better high alpha capabilities.

Is this a DCS-ism? 

 

Edited April 11, 2021 by Mover

[Dragon1-1]

No, it isn't, it's just physics. Air is denser down low than it is up high. All drag is higher down low, because there's more air to resist your motion through it. However, jet engines use air for thrust, both by burning fuel and using that fuel to move more air, so more air=more thrust. This is also why you can fly further up high - you get less air, so you can burn less fuel, and at the same time, overall drag is lower (even though you need more AoA to support your weight, because lift decreases, too), so you don't have burn as much to maintain the same TAS. 

 

Here's a thing, though: thrust doesn't increase with AoA, drag does. So, in absolute terms, the difference between your thrust and drag will be higher at lower altitudes when pulling lots of AoA. This means you lose more speed, and you end up slow faster. For jets that like being slow, it's OK (though low energy states in general are to be avoided). For the Viper, not so much. Since dogfights tend to end up on slow and on deck, the Viper needs to end things quickly, because the longer the fight drags on, the less comfortable it is, especially against jets that can stand on their tails and wait for it to overshoot.

 

Same with the missiles, it's a simple calculation: for planes, more air means more drag and more thrust. Only, missiles have no thrust, because by the time they get to you, they're out of fuel (and being rockets, the "more thrust" part doesn't apply to them, in fact they get less thrust due to rocket motors being less efficient in thick air). Thus, dense air hinders the missile much more than it hinders you. The standard tactic is to drag the missile down to the deck, let it speed up and lose energy to drag (the faster it goes, the more drag it has), and then pull up, leaving it in the dust. It costs you plenty of fuel, but it trashes the missile. This is also why missiles loft to a higher altitude, to both decrease their drag and increase the efficiency of their motor a bit.

 

Temperature causes the same thing, BTW. Hotter air is less dense, thus it's less efficient in the jet engine, you get less lift. This burns less fuel, but makes takeoffs and landing more harrowing, because your TWR is lower and so is your lift. Hot and high is especially nasty for this reason, especially to helicopters and VTOLs.

[Mover]

1 hour ago, Dragon1-1 said:

No, it isn't, it's just physics. Air is denser down low than it is up high. All drag is higher down low, because there's more air to resist your motion through it. However, jet engines use air for thrust, both by burning fuel and using that fuel to move more air, so more air=more thrust. This is also why you can fly further up high - you get less air, so you can burn less fuel, and at the same time, overall drag is lower (even though you need more AoA to support your weight, because lift decreases, too), so you don't have burn as much to maintain the same TAS. 

 

Here's a thing, though: thrust doesn't increase with AoA, drag does. So, in absolute terms, the difference between your thrust and drag will be higher at lower altitudes when pulling lots of AoA. This means you lose more speed, and you end up slow faster. For jets that like being slow, it's OK (though low energy states in general are to be avoided). For the Viper, not so much. Since dogfights tend to end up on slow and on deck, the Viper needs to end things quickly, because the longer the fight drags on, the less comfortable it is, especially against jets that can stand on their tails and wait for it to overshoot.

 

Same with the missiles, it's a simple calculation: for planes, more air means more drag and more thrust. Only, missiles have no thrust, because by the time they get to you, they're out of fuel (and being rockets, the "more thrust" part doesn't apply to them, in fact they get less thrust due to rocket motors being less efficient in thick air). Thus, dense air hinders the missile much more than it hinders you. The standard tactic is to drag the missile down to the deck, let it speed up and lose energy to drag (the faster it goes, the more drag it has), and then pull up, leaving it in the dust. It costs you plenty of fuel, but it trashes the missile. This is also why missiles loft to a higher altitude, to both decrease their drag and increase the efficiency of their motor a bit.

 

Temperature causes the same thing, BTW. Hotter air is less dense, thus it's less efficient in the jet engine, you get less lift. This burns less fuel, but makes takeoffs and landing more harrowing, because your TWR is lower and so is your lift. Hot and high is especially nasty for this reason, especially to helicopters and VTOLs.

 

Air down low is more dense which gives you more thrust and more lift.  The increase in lift reduces AOA requirements.  The increase in drag from dense air is a small portion of the drag formula, which depends more on velocity. 

 

An F-16 at 5000 feet will accelerate at 9Gs in full blower.  Ask me how I know.

 

 

 

 

 

Edited April 11, 2021 by Mover

[Dragon1-1]

1 hour ago, Mover said:

An F-16 at 5000 feet will accelerate at 9Gs in full blower.  Ask me how I know.

I'll ask you "at what airspeed?" instead. It doesn't take a whole lot of AoA to hit 9G when you're doing 700kts on deck. Thrust is highly dependent on airspeed (as I mentioned, more air to the engine=more thrust), and so is AoA, with higher speeds biasing the balance towards the former. G also increases with speed, a 9G turn at 700kts is much less tight than 9G at 450kts. I tried to avoid talking too much about velocity, because then you end up with a lot of variables and I felt I was being a bit long-winded already. But yes, as drag increases with v squared, that's a major component, especially if you're fast.

 

The Viper is a neat little rocket, especially when clean, but I found it really hard to get fast again if it gets slow, especially close to the deck.

[G.J.S]

*waits for the penny to drop*. . . 

[Mover]

1 minute ago, Dragon1-1 said:

I'll ask you "at what airspeed?" instead. It doesn't take a whole lot of AoA to hit 9G when you're doing 700kts on deck. Thrust is highly dependent on airspeed (as I mentioned, more air to the engine=more thrust), and so is AoA, with higher speeds biasing the balance towards the former. G also increases with speed, a 9G turn at 700kts is much less tight than 9G at 450kts. I tried to avoid talking too much about velocity, because then you end up with a lot of variables and I felt I was being a bit long-winded already. But yes, as drag increases with v squared, that's a major component, especially if you're fast.

 

The Viper is a neat little rocket, especially when clean, but I found it really hard to get fast again if it gets slow, especially close to the deck.

Between 400-450KCAS.  If you're below 10k, you're throttle modulating because the airspeed will climb above 450 and approach 500KCAS while holding 9Gs.

 

Big Mouth Block 30.  I'm told the Block 50s will as well, but unconfirmed. 

 

[Xavven]

Just an observation -- those of us who are not IRL fighter pilots (most of us, in other words) tend to put a little too much faith in DCS' accuracy and realism. We observe how our favorite planes and/or missiles perform in DCS and assume that since Eagle Dynamics spent a lot of time on the flight model, the real thing must behave this exact way too. Then we build tactics and explanations that might work well in DCS and think that must be the optimal tactic in real life, too.

 

I've made that mistake a few times, myself.

 

We're lucky that pilots and SMEs frequent these forums to help correct these misunderstandings. When that happens, I'd recommend typing less and reading more. ;)

[Dragon1-1]

I'm actually speaking from the other sim experience (and my physics education) and some EM charts, I don't have enough DCS stick time to know how it is in here.  They have SMEs there, too. I do know that Block 30 in question was a real hot-rod, being much lighter (thus less AoA for the same lift to weight ratio) and less draggy than the Block 50. I would actually prefer to have that in DCS, as opposed to the Block 50. 

 

Either way, the charts I have are for DI=38 and GW of 28670lbs, and the PS=0 curve doesn't quite reach the 9G line. That's at full burner at 5000ft. Obviously, if you're in full burner the GW won't stay at that level for very long, and if your DI isn't 38 (say, you're not hauling a centerline jamming pod), the situation probably looks different. Unfortunately, I don't have charts for any other configuration. 

 

Of course, the real DCSism is that you can't actually hold 9G for any length of time without blacking out. It completely fails to model the Viper's unique seat position, which helps reduce the impact of Gs acting on the pilot by a fair margin. 

Edited April 11, 2021 by Dragon1-1

[Xavven]

Charts are pretty convincing on the one hand...

 

On the other hand, maybe you should ask Mover how he knows. Not sure if I can hint any harder than this.

[oldtimesake]

50 minutes ago, Dragon1-1 said:

I'm actually speaking from the other sim experience (and my physics education) and some EM charts, I don't have enough DCS stick time to know how it is in here.  They have SMEs there, too. I do know that Block 30 in question was a real hot-rod, being much lighter (thus less AoA for the same lift to weight ratio) and less draggy than the Block 50. I would actually prefer to have that in DCS, as opposed to the Block 50. 

 

Either way, the charts I have are for DI=38 and GW of 28670lbs, and the PS=0 curve doesn't quite reach the 9G line. That's at full burner at 5000ft. Obviously, if you're in full burner the GW won't stay at that level for very long, and if your DI isn't 38 (say, you're not hauling a centerline jamming pod), the situation probably looks different. Unfortunately, I don't have charts for any other configuration. 

 

Of course, the real DCSism is that you can't actually hold 9G for any length of time without blacking out. It completely fails to model the Viper's unique seat position, which helps reduce the impact of Gs acting on the pilot by a fair margin. 

 

You are obviously referring to the HFFM data in BMS. Block50 viper in BMS has much better energy characteristics than that in DCS. 

 

The only thing DCS is right about is its sustained turn above Mach 0.8 / 10000 feet, and that is the only way I found to win a 2C fight.

Edited April 11, 2021 by oldtimesake

[Dragon1-1]

Well, admittedly, I haven't tested the DCS Viper with any sort of rigor. What I said was based on the other sim, though, and the many times I got my tailpipe handed to me by a MiG-29 (and an AI, at that) doing high-alpha stunts.  Yeah, I'm using the HFFM charts, since they're the most complete, if you want an apples to apples comparison of different blocks, pretty much the only option.

2 hours ago, Xavven said:

Charts are pretty convincing on the one hand...

 

On the other hand, maybe you should ask Mover how he knows. Not sure if I can hint any harder than this.

He had already said that:

4 hours ago, Mover said:

Big Mouth Block 30.  I'm told the Block 50s will as well, but unconfirmed. 

Second hand info from an unknown source.  Jokes aside, I'm not saying he's wrong, but the Viper he flew is quite a bit lighter than ours. Perhaps I should've instead asked what DI and weight he had. The charts suggest it'd have to be even lighter and cleaner configuration than what was used to make them. 

[Xavven]

33 minutes ago, Dragon1-1 said:

Second hand info from an unknown source.  Jokes aside, I'm not saying he's wrong, but the Viper he flew is quite a bit lighter than ours. Perhaps I should've instead asked what DI and weight he had. The charts suggest it'd have to be even lighter and cleaner configuration than what was used to make them. 

 

So you've both made your positions clear, then. I think I've decided which source I believe is more credible and convincing.

[Mover]

1 hour ago, Dragon1-1 said:

Well, admittedly, I haven't tested the DCS Viper with any sort of rigor. What I said was based on the other sim, though, and the many times I got my tailpipe handed to me by a MiG-29 (and an AI, at that) doing high-alpha stunts.  Yeah, I'm using the HFFM charts, since they're the most complete, if you want an apples to apples comparison of different blocks, pretty much the only option.

He had already said that:

Second hand info from an unknown source.  Jokes aside, I'm not saying he's wrong, but the Viper he flew is quite a bit lighter than ours. Perhaps I should've instead asked what DI and weight he had. The charts suggest it'd have to be even lighter and cleaner configuration than what was used to make them. 

 

I'm not talking about DCS.  And E-M diagrams for active U.S. fighters are classified, so there won't be much comparison there.

 

The Block 30 is only about 1000 lbs lighter with around the same difference in thrust (maybe a little less than 1K difference, I can't remember).  I'm reasonably confident the Block 50 will do the same thing.  I'm talking BFM config (Clean, tip 120s, CATM-9).

 

The point being that the idea of "less performance at low altitude due to drag" is wrong.  Any increase in drag (negligible) is overcome by increase in thrust and lift.  Even the Hornet is a VERY different fighter below 10k than it is at 15-20k.    This is just basic physics for any aircraft.  I'd much rather start a fight slow at low altitude than slow at high altitude.  MUCH easier to get your energy back.  

 

Edited April 12, 2021 by Mover

[oldtimesake]

F-16 vs Mig-29 energy maneuverability from test report:

https://www.f-16.net/forum/viewtopic.php?f=30&t=53852&sid=0926774443d861755c0466d79ceeb001

 

This is in line with my experience: fight above 10000 feet and Mach 0.8 and you have a sustained G advantage (12.8%) over your opponent.

[Mirage2425]

Hey Mover, I love your books, I've read most of them.  I have a question about the turn performance of the Viper.  If you can't answer I totally understand.  What is classified should stay that way.  Can the Viper sustain a turn when you pull to the green donut (approx 13 degrees of AOA)?  I've noticed that ED's Viper tends to maintain that AOA in a turn for a few seconds and then AOA starts to increase dramatically and the jet bleeds airspeed.  If you can answer, is this accurate?  This kills the Viper's turn performance, making it underperform vs other aircraft in DCS.

Edited April 12, 2021 by Mirage2425

[Mover]

23 minutes ago, Mirage2425 said:

Hey Mover, I love your books, I've read most of them.  I have a question about the turn performance of the Viper.  If you can't answer I totally understand.  What is classified should stay that way.  Can the Viper sustain a turn when you pull to the green donut (approx 13 degrees of AOA)?  I've noticed that ED's Viper tends to maintain that AOA in a turn for a few seconds and then AOA starts to increase dramatically and the jet bleeds airspeed.  If you can answer, is this accurate?  This kills the Viper's turn performance, making it underperform vs other aircraft in DCS.

 

 

Your question is unclear.  Are you pulling to the limiter? Or trying to hold 13 degrees?

[Mirage2425]

I read somewhere if you pull to the green donut on AOA the Viper will sustain rate.  This may be an incorrect perception.

[Mover]

1 minute ago, Mirage2425 said:

I read somewhere if you pull to the green donut on AOA the Viper will sustain rate.  This may be an incorrect perception.

 

If you're maintaining the green donut, the AOA should stay constant.  If you're on the limiter, of course it won't stay in the green donut.  

[Mirage2425]

What exactly is the limiter?  I've never found a good explanation.

I'm only pulling to the green donut. The stick isn't full back.  Trying to just maintain 13 degrees of AOA.

[Mover]

1 minute ago, Mirage2425 said:

What exactly is the limiter?  I've never found a good explanation.

 

Full aft stick.  G-limiter/command system until it's AOA limited above 15 degrees AOA.  

[Mirage2425]

I'm definitely not doing that.  I'm only pulling to the green donut. The stick isn't full back.  Trying to just maintain 13 degrees of AOA.