Pylon drag in DCS

There's been a lot of recent debate on turn rates for the F-16.

Now I've personally been noticing rates being pretty much where I'd expect them considering the documentation. (Pilot G tolerance notwithstanding obviously)

However, this only applies to a Viper without pylons, with them attached the bleed rates seem quite outrageous.

How are aircraft generally tuned FM-wise and how WIP is pylon drag?

Primarily I'd have some doubts about its consistency between modules. Some seem to fly more accurately to expectations with pylons attached, some of them need to be flown clean.

The hornet comes to mind which, when flown clean in the first couple of months post release, bordered on supercruising and earned quite a few raised eyebrows in BFM. These days the difference isn't all that big.

But then the Viper from the initial release point seems to perform pretty accurately without pylons, but seems to incur too much drag with pylons attached, leading to comments about an apparent lack of engine power and turn rate. The difference here is very noticeable.

Of course it could be like this in the real jet, but I'm curious how this is modeled.

Yes, I was having a really hard time dogfight against Ace level AI JF17, until I removed the pylons, suddenly I was able to match it in one circle and beat it in 2 circles...From Tacview testing, I found that removing pylons add about 2 degrees sutained turn rate on F16C, which is a huge boost, it also recover energy much quicker. F18C dosent seem to have this much of drag with pylons...

There is a HAF manual which I am not allowed to post here that lists all of the drag indexes.
However, I have no clue if this thread is still alive or not...

Anyway, I have been asking myself the same question, particularly with the double JDAM rack and the external tanks drag factor. But until now, I have no idea how to test it since I don't have reliable data on the given end speed per altitude, drag index and weight.
We will have to wait for the FM rework which was delayed a few times, but might come in a july update. Currently, weight hits you hard because the lift factor is slightly off which leads to higher AOA's which leads to more induced drag. This is noteable above about 10° AOA.
The general drag seems a bit too low, leading to higher end speeds than it should be.
Since the drag index is not given per pylon and it is not one drag index no matter which plane, but per pylon on the plane it will change for sure when they change something on the drag.
So all we can do is wait for the reworked FM so we can test turn rates and Ps loss on different altitudes, weights and drag indexes.
I am sure that once the FM rework is out, people will take only a few days if it is still off. Which is the reason that I am also sure that the reason for it taking so long is the testing they do... To avoid exactly that.

However it is interesting how much drag pylons actually add to the plane.

8 hours ago, TobiasA said:

There is a HAF manual which I am not allowed to post here that lists all of the drag indexes.
However, I have no clue if this thread is still alive or not...

 

Anyway, I have been asking myself the same question, particularly with the double JDAM rack and the external tanks drag factor. But until now, I have no idea how to test it since I don't have reliable data on the given end speed per altitude, drag index and weight.
We will have to wait for the FM rework which was delayed a few times, but might come in a july update. Currently, weight hits you hard because the lift factor is slightly off which leads to higher AOA's which leads to more induced drag. This is noteable above about 10° AOA.
The general drag seems a bit too low, leading to higher end speeds than it should be.
Since the drag index is not given per pylon and it is not one drag index no matter which plane, but per pylon on the plane it will change for sure when they change something on the drag.
So all we can do is wait for the reworked FM so we can test turn rates and Ps loss on different altitudes, weights and drag indexes.
I am sure that once the FM rework is out, people will take only a few days if it is still off. Which is the reason that I am also sure that the reason for it taking so long is the testing they do... To avoid exactly that.

However it is interesting how much drag pylons actually add to the plane.

Yup the viper isn't draggy enough in general. 

10 minutes ago, Harlikwin said:

 

Yup the viper isn't draggy enough in general. 

What is this based on again?

I remember hearing stuff about M 1.4 at sea level but as or right now you can't even do that without pylons. You top out at 1.37. With 6 AAM and no tanks 1.23 is as good as it gets.

Interestingly with empty pylons you're limited 1.18, but notice when you do this stations 3 and 7 have an AG pylon and not an AA pylon.

vor 28 Minuten schrieb Harlikwin:

 

Yup the viper isn't draggy enough in general. 

For the hornet the drag bug is even worst.

There is even no drag difference for single and double racks Aim120 at all.

https://forums.eagle.ru/topic/263462-no-drag-difference-between-a-single-rack-and-a-double-rack-aim-120/?tab=comments#comment-4581382

46 minutes ago, Exorcet said:

What is this based on again?

 

I remember hearing stuff about M 1.4 at sea level but as or right now you can't even do that without pylons. You top out at 1.37. With 6 AAM and no tanks 1.23 is as good as it gets.

 

Interestingly with empty pylons you're limited 1.18, but notice when you do this stations 3 and 7 have an AG pylon and not an AA pylon.

DI=50 is basically 4-120's 2-aim9 and 2 empty tank pylons and maybe a tgp. it should be like 1.1 IIRC or thereabouts just barely supersonic in full burner.  So it sounds like its about .1 mach too fast based on your result. IIRC when Fox tested it was about 60kts too fast with a DI50 config. 

The other issue is exceeding 1.2 under 30k. I.e. this you can easily do in a dive. Bad things start to happen past 1.2, even though the charts show the viper can go that fast. Thats the other half of whats not modeled. 

Also good chance of engine flameout with less than 800lbs in the tank. 
 

Then there is all the radar problems. 

Add it all up, and it overperforms pretty dramatically for PVP online. Since DCS isn't modeling any of the limitations for it. Thats not good for "simulator"

39 minutes ago, Harlikwin said:

 

DI=50 is basically 4-120's 2-aim9 and 2 empty tank pylons and maybe a tgp. it should be like 1.1 IIRC or thereabouts just barely supersonic in full burner.  So it sounds like its about .1 mach too fast based on your result. IIRC when Fox tested it was about 60kts too fast with a DI50 config.

 

Alright I didn't test with a TGP, and my tank pylons were removed so I'll need to change a couple of things for consistency, but it sounds like it's probably a little bit over.

39 minutes ago, Harlikwin said:

 

The other issue is exceeding 1.2 under 30k. I.e. this you can easily do in a dive. Bad things start to happen past 1.2, even though the charts show the viper can go that fast. Thats the other half of whats not modeled. 

 

Also good chance of engine flameout with less than 800lbs in the tank. 
 

Then there is all the radar problems. 

Add it all up, and it overperforms pretty dramatically for PVP online. Since DCS isn't modeling any of the limitations for it. Thats not good for "simulator"

 

Yeah I agree that these need to be fixed though I'm separating them from the drag issues.

vor einer Stunde schrieb Harlikwin:

 

Add it all up, and it overperforms pretty dramatically for PVP online. Since DCS isn't modeling any of the limitations for it. Thats not good for "simulator"

 

If you take it seriosly the Hornet does overperforming at the moment in DCS. Just take a look at multiple posts here in the forum with a lot of statistics, tests and charts. For the hornet it doesnt make a difference if you take two AIM120 or just one per pylon as posted before. No word from you about this term of overperforming.

I know you only look at the viper in your posts of overperforming. Your right in some terms of overspeed but thats mostly because of the canopy melting not because the Viper cant do the speed. Just look at "Semper Viper" with "Dont stretch the limits". There are adviseries for the pilots not to push to hard in terms of speed at sealevel, because the canopy will gets broken not because the Viper cant do it.

Hope ED can model a more advanced damage model for all the planes out there including the Viper and the Hornet.

F16 always handled like a brick for me, and I feel like the F18 can out rate F16. After watching other peoples video, I decided to remove the pylons from F16, and did a tacview test. I tried to maintain a 380kts turn at sea level with 50% fuel. It seems like I can maintain about 2 degrees more sutained turn rate without pylons, which is pretty significant, it can also regain energy much quicker at low airspeed. I tried a dogfight against ACE ai JF17, which was very hard to beat, since it used to have better radius and rate. Without pylons, I was able to match the 1 circle after merge, and easily out rate it, and killed it with in 90sec. F16 feels like a different plane without pylon, which is is strange, since other plane like F18 dont really benefit nearly as much without pylons.  

I attatched the tacview files of the turn rate test, my testing method might not be very accurate, but the difference is so big, that it cannot be margin of error.

Tacview-20210703-165725-DCS.zip.acmi Tacview-20210703-170045-DCS.zip.acmi

1 hour ago, jojojung said:

 

If you take it seriosly the Hornet does overperforming at the moment in DCS. Just take a look at multiple posts here in the forum with a lot of statistics, tests and charts. For the hornet it doesnt make a difference if you take two AIM120 or just one per pylon as posted before. No word from you about this term of overperforming.

I know you only look at the viper in your posts of overperforming. Your right in some terms of overspeed but thats mostly because of the canopy melting not because the Viper cant do the speed. Just look at "Semper Viper" with "Dont stretch the limits". There are adviseries for the pilots not to push to hard in terms of speed at sealevel, because the canopy will gets broken not because the Viper cant do it.

Hope ED can model a more advanced damage model for all the planes out there including the Viper and the Hornet.

 

Yup. I dont know the hornet as well. 

And yes that's what I said, bad shit happens above m1.2 below 30k. Regardless of what the charts say, that's why it's not done regularly. Currently there is no mechanic in DCS to address this so its abused. 

1 hour ago, Exorcet said:

Alright I didn't test with a TGP, and my tank pylons were removed so I'll need to change a couple of things for consistency, but it sounds like it's probably a little bit over.

Yeah I agree that these need to be fixed though I'm separating them from the drag issues.

 

 

The tank pylons add a decent bit of drag IIRC.

And yeah it's like combination of separate aero and sensor issues right now. 

I believe the cause to be the cleaner base aerodynamics and lighter standard weight of the F-16, so any drag and weight added has a larger effect. Ultimately this is why the Navy preferred the YF-17, which was later developed into the F-18, it relied more on engine power and less on aerodynamics to achieve it's performance and therefor was less efficient lightly loaded, but more efficient fully loaded. 

Out of curiosity do you mind retesting the pylon by loading them with weapons and then expending the weapons? If you load pylons using the ME, stations 3 and 7 get draggy AG pylons while the rest get AA pylons. You can fix this by loading AA missiles on 3 and 7 and then firing them. I wonder how much of a difference this makes.

55 minutes ago, CrashMcGhee said:

I believe the cause to be the cleaner base aerodynamics and lighter standard weight of the F-16, so any drag and weight added has a larger effect. Ultimately this is why the Navy preferred the YF-17, which was later developed into the F-18, it relied more on engine power and less on aerodynamics to achieve it's performance and therefor was less efficient lightly loaded, but more efficient fully loaded. 

That doesn't make any sense. What's your source?

Technically smaller aircraft is more sensitive to pylon weight and drag.

Tests for drag with the following conditions:

• Default editor weather
• 2000m level flight
• 30% throttle
• 100% fuel weight (infinite)
• Mirror config on stations 6-9

Basic (editor default)

2 16S301, 16S210

3 16S1700, MAU-12

4 NJETT

5 16S951, MAU-12

DI 0, 6, 15, 8, 7 65

538 KTAS

Clean 601 KTAS

Clean + 16S1700, MAU-12 583 KTAS

I did more but they were along the straight line

From DI 0-30 you lose 0.6 knots per index. From 30-65 was a loss of 0.78 knots per index. I don't know if these are helpful numbers but I tried to stay away from the Mach wall because that will squish the numbers together and hide effects.