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Lower lift curve slope than in real life, more induced drag


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Is the flight model done? Does the aircraft really lose this much energy so easily? It seems like it gets stuck too easily at low speed/energy state. It seems to bleed energy too quickly. At least compared to other 4th Gen modules I'm flying. The Su-27 completely kicks the F-16's but in turns...


Edited by mytai01

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Short Answer : No, it’s still WIP

 

Not as short Answer: The F-16 is designed to be flown at the higher 350-450 knot bracket, and use the higher available G as an advantage. We are quite limited by our pilots current inability to sustain 9G for any meaningful period of time, which takes away one of the Vipers main advantages. The Viper is also very AoA limited compared to the Hornet or Su-27 so if you let it get slow you’ll quickly hit the AoA limit and be stuck there barely pulling 3G while the F-18 or Su-27 can still pull that nose around on you. So the key takeaway from that that is keep it above 350kn. Speed is life for the Viper, use the vertical and don’t play the slow speed game with the Hornet or Su-27.

 

we should get pilot and FM improvements once resources transfer over from the Hornet to the Viper as the Hornet gets closer to completion.


Edited by Deano87
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One thing I've noticed is that you have to actively unload the nose when you get in the less than about 250 knots to accelerate with any reasonable amount, I haven't ever looked down to see if I'm at the AOA limiter max. But it will be wallowing around and releasing pressure  won't reduce the small amount of Gs, normally 1.4 with neutral stick, you actually have to push over to get it to 1G and start accelerating better and of course a full 0G unload is best when you get the Viper down to where it doesn't like to be.

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Sad thing is the F-16, the so called one of the best dogfighter with amazing turning capability (2 circle) cannot outturn anything in DCS in the current state. Reason? FM+G-model, and maybe other jets being overpowered...

 

I seriously hope F-16 FM gets a rework, because I love the jet, but I hate taking it to a dogfight sever....

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It’s going to get work, they’ve said it’ll get work. Just going to have to be patient.

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15 hours ago, Deano87 said:

It’s going to get work, they’ve said it’ll get work. Just going to have to be patient.

Yeah, hopefully. Just wish ED could put FM rework on their priorities 🙂

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It's really not in a bad state, but I agree it feels like it loses a little too much speed in turns. Still not like this prevents anybody from winning in BFM if they're good. It's easily a match for any other plane.

 

The Viper really needs to be kept fast. Good rule of thumb is to NEVER get below 250 if you can help it, except certain circumstances like pulling over the top of a loop. Best to keep it at at least 400 whenever you can. If you're neutral or advantaged, it's ALWAYS worth it to unload and regain energy for a couple seconds to pick up your sustained turn rate. 450 - 475 should be the sweet spot for high G turns. Shoot for about 8, since our DCS pilot cannot sustain 9. Slice the nose below the horizon during the turn to maintain speed (and G) a little longer too. Definitely take it into the vertical whenever the opponent gets slow, and be sure not to pull too hard when doing so to preserve energy. Light G until vertical then max G over the top, then light G again downhill to regain energy. Goal in the Viper should be to preserve energy and sustained turn rate while letting the bandit lose energy steadily until they can't hang with you anymore. More energy is more options.

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I know everything you said, but almost everything in DCS out rates the Viper... Impossible to beat the Hornet if pilots are on the same skill level...

So I cannot agree that the Viper is easily a match for any other plane. It's not. 

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On 1/12/2021 at 1:26 PM, kengou said:

It's really not in a bad state, but I agree it feels like it loses a little too much speed in turns. Still not like this prevents anybody from winning in BFM if they're good. It's easily a match for any other plane.

 

The Viper really needs to be kept fast. Good rule of thumb is to NEVER get below 250 if you can help it, except certain circumstances like pulling over the top of a loop. Best to keep it at at least 400 whenever you can. If you're neutral or advantaged, it's ALWAYS worth it to unload and regain energy for a couple seconds to pick up your sustained turn rate. 450 - 475 should be the sweet spot for high G turns. Shoot for about 8, since our DCS pilot cannot sustain 9. Slice the nose below the horizon during the turn to maintain speed (and G) a little longer too. Definitely take it into the vertical whenever the opponent gets slow, and be sure not to pull too hard when doing so to preserve energy. Light G until vertical then max G over the top, then light G again downhill to regain energy. Goal in the Viper should be to preserve energy and sustained turn rate while letting the bandit lose energy steadily until they can't hang with you anymore. More energy is more options.

I've studied the EM charts for the Block 50 in high detail. The magical speed in the F-16 for maximum sustained turn rate is: As fast as possible under 500 knots while not blacking out. That simple. Have a safe flight!

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Nobody mentioned it but the FLCS rules are still based on the NASA test paper which IS NOT how the FLCS works in the operational F-16. The g-onset rate is too low and can't even reach 9g at the correct speed. The negative g is also limited, the real a/c has a limit of -3.5g. 

But they said this is all WIP.

 

The engine is also pretty weird, RPM values are specially off. Not sure if this translates into reduced thrust in game.

 

 

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Be aware, F-16's turn rate below Mach 0.4 is 1 deg/sec lower than the flight manual.

DCSF16vsRealLife.png

A real life F-16 at 26000 lbs should be able to pull 9G with 15 deg AOA at Mach 0.67, and pull 9G with much less AOA at Mach 0.83. However in DCS this is not the case. It requires significantly higher AOA to pull the Gs, resulting in more induced drag.

Check the replay file:

26000lbs (1).trk

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A real life F-16 at 26000 lbs should be able to pull 9G with 15 deg AOA at Mach 0.67, and pull 9G with much less AOA at Mach 0.83. However in DCS this is not the case. It requires significantly higher AOA to pull the Gs, resulting in more induced drag.

 

 

26000lbs (1).trk

DCS F-16 lift curve slope.jpg


Edited by oldtimesake
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  • oldtimesake changed the title to [replay file included] Lower lift curve slope than in real life
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Hi,

 

We do have some AOA / G tweaks planned for a future update. 

 

thank you

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15 hours ago, oldtimesake said:

....

 

 

Thanks oldtimesake.

 

Did you make sure to adjust the temperature in-game? For some odd reason the "standard weather" in the mission editor assumes a temperature of 20C i.s.o. 15C.

 

When all is said and done... I think the performance of the F-16 in-game is pretty close to your performance charts...

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2 hours ago, chaos said:

 

Thanks oldtimesake.

 

Did you make sure to adjust the temperature in-game? For some odd reason the "standard weather" in the mission editor assumes a temperature of 20C i.s.o. 15C.

 

When all is said and done... I think the performance of the F-16 in-game is pretty close to your performance charts...

Of course that is done.

The performance of the F-16 in-game is not close to the real F-16 in many aspects, for instance:

Try acceleration at sea level 300knots-650knots with 21000 lbs total weight. Real vs DCS is 13 vs 15.1 seconds.

The DCS F-16 has significantly lower lift curve slope, which requires F-16 to pull more AOA to achieve the same G load, resulting more induced drag, and this has been confirmed by ED:

 

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On 1/12/2021 at 2:26 PM, kengou said:

It's really not in a bad state.... Best to keep it at at least 400 whenever you can...

I think it's easier said than done. I find myself struggling to maintain a 3g turn against a Mig-29, while watching the speed rapidly drop from 275 to 200 (completely sleek, with about 5000 pounds of fuel).

 

I also find that maintaining a turn at 400+ knots will have a huge radius, rendering it very ineffective in a two circle fight. That's not how the viper got it's nickname. IMHO, something is way off in the Viper's FM. Sorry to say, but It feels like a flying wheelbarrow.

 

 

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52 minutes ago, Zohardv said:

I think it's easier said than done. I find myself struggling to maintain a 3g turn against a Mig-29, while watching the speed rapidly drop from 275 to 200 (completely sleek, with about 5000 pounds of fuel).

 

I also find that maintaining a turn at 400+ knots will have a huge radius, rendering it very ineffective in a two circle fight. That's not how the viper got it's nickname. IMHO, something is way off in the Viper's FM. Sorry to say, but It feels like a flying wheelbarrow.

 

 

Available G is far lower at 275 knots, and AoA is much higher, resulting in much more speed loss compared to higher speeds. Which is why you want to avoid speeds so slow.

 

Also radius doesn’t matter in a two circle fight, rate does. Radius is minimized for one circle fights. Rate on the Viper is top knotch at 450+ knots. Radius is high yes, but doesn’t matter as long as the fight is two circle.

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21 hours ago, chaos said:

For some odd reason the "standard weather" in the mission editor assumes a temperature of 20C i.s.o. 15C.

 

Just a quick note on the temperature. From what I've checked, DCS's standard temperature is 16C. This is the value at which altimeter temperature error doesn't occur (at least to a certain altitude). 20C is nothing more than default ME setting.

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2 hours ago, Syd said:

 

Just a quick note on the temperature. From what I've checked, DCS's standard temperature is 16C. This is the value at which altimeter temperature error doesn't occur (at least to a certain altitude). 20C is nothing more than default ME setting.

That's an interesting observation! I don't have the time to check this but if I change the temp. in the ME, will it reflect the adjusted temperature in-game?

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2 hours ago, chaos said:

That's an interesting observation! I don't have the time to check this but if I change the temp. in the ME, will it reflect the adjusted temperature in-game?

I'm not sure what you mean by "adjusted temperature in-game". If you're thinking about temperature error on the altimeter than yes - once you set temp. other than 16C than you will see that your altimeter indication is different than your ASL.

To be precise - in temps lower than 16C your altimeter shows higher than you actually are, and for greater than 16C it's the opposite. That is why IRL in really low temperatures you have to calculate this error for safety reasons (mainly during approach phase).


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2 minutes ago, Syd said:

I'm not sure what you mean by "adjusted temperature in-game". If you're thinking about temperature error on the altimeter than yes - once you set temp. other than 16C than you will see that your altimeter indication is different than your ASL...

 

 Yes, that's what I meant to say. Thanks for letting me know...

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21 hours ago, kengou said:

Available G is far lower at 275 knots, and AoA is much higher, resulting in much more speed loss compared to higher speeds. Which is why you want to avoid speeds so slow.

 

Also radius doesn’t matter in a two circle fight, rate does. Radius is minimized for one circle fights. Rate on the Viper is top knotch at 450+ knots. Radius is high yes, but doesn’t matter as long as the fight is two circle.

I'm trying all sorts of scenarios, speeds, altitudes ang loads. The best TR I could get so far was about 19.7 deg/sec. and it was instantaneous. I could not sustain that turn rate. Is that considered top notch? (no sarcasm here, asking for real 😐)

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19.7 degrees per second is very good, yes. It's harder in DCS to sustain this rate than real life because there's likely a little too much drag in the turn compared to real life (based on testing). For more help sustaining the rate, try keeping the nose 5 - 10 degrees below the horizon.

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Did you see that?

 

A DCS clean F-16C-50 needs 23.3deg AOA to reach 8.5G at mach 0.75, while a loaded real life F-16C-50 needs only 15deg AOA to reach 9G at mach 0.67!

 

WTF is that lift curve slope, ED? 


Edited by oldtimesake
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