SD-10 Dual rack drag

[Creampie]

I noticed some really bad drag issues with the JF17 top end speed quite some time back and never really got around to testing it. Never really needed to test it, but I don't think this is as intended. I know that the RD-93 isn't the most powerful engine & these jets don't neccasirly need to be too far above mach anyway.

Below are 4 screenshots showing the fuel, speed & loadout.

My question is, Is this amount of drag intentional? If so, Why? 

It doesn't seem to make much sense that you lose 33% of your top end speed by adding the additional 2 missiles & their pylons.

I've got some testing yet to do with other weapons and will post them as well when I get a little free time.

In this screenshot, With 100% fuel, we are at 35k on Syria with the temp set to 20C, Max speed of Mach 1.55, Single rack SD10 and dual PL5s

 

In this screenshot we are 51lbs of fuel, 35k feet on Syria with the temp set to 20C, Mach 1.57, Single rack SD10 and dual PL5

This difference is a little irrelevent to my concern, As we are approaching top end speed anyway, But just for testing I wanted to see.

 

In this screenshot, FULL FUEL, 35k, Syria, 20C, Dual rack SD10, Dual PL5s, Speed of Mach 1.10

 

And the last screenshot, 51lbs of fuel, Syria, 35k, 20C, Dual Rack SD10s with dual PL5s and a speed of Mach 1.15

[Creampie]

More testing, Both of these test are something the JF17 can not do in full burner. 

Same parameters, Syria, 35k, 20c - Flight time of 222nm Mach 1.33) (0.22 mach faster than a 40nm flight)

null

Same parameters, Syria, 35k, 20C - Flight of 222nm Mach 1.11 (0.01 Mach faster than 40nm)

Edited August 8 by Creampie

[Creampie]

 

You can ALMOST hit mach with 2 SD10s, 2 PL5s & 2 GB-6 SFWs (0.11 slower than the subject in question....., 2x Dual rack SD10)

Same parameters, Syria, 35k, 20c (40nm trip)

Edited August 8 by Creampie

[Creampie]

Here is the biggest concern one,

2 PL5s, 2 BRM pods (the weapon with the most drag on the JF17,) 

Same parameters, Syria, 35k, 20c 40nm Speed of mach 1.01 (0.09) slower than 2 SD10 & 2 PL5s

[AeriaGloria]

The data mine does show drag index of some objects 

DL: 6

BRM-90 pod: 10

C-802: 9.4

Fuel tank 800L: 5.7

Fuel tank 1100L: 6.1

SPJ: 2.6 

WMD-7: 4.3

AKD-10: 2

SD/LD-10: 2.2

GB/6: 10

LS-6 500: 8

LS-6 250: 8

LS-6 100: 1.7 

PL-5: 1.6 

C-701: 4 

Durandal: 0.7 

 

Launcher:

BRM-1/AKd-10:4

SD-10 single pylon: 2.6

SD-10 dual: 6.14

C-701: 2.5 

C-802/fuel tank pylon: 9.4 

LS6-100: 1.7 

LS6-100 dual: 8.5

LS6-250: 4.9

[Creampie]

On 8/19/2025 at 8:47 AM, AeriaGloria said:

The data mine does show drag index of some objects 

 

DL: 6

BRM-90 pod: 10

C-802: 9.4

Fuel tank 800L: 5.7

Fuel tank 1100L: 6.1

SPJ: 2.6 

WMD-7: 4.3

AKD-10: 2

SD/LD-10: 2.2

GB/6: 10

LS-6 500: 8

LS-6 250: 8

LS-6 100: 1.7 

PL-5: 1.6 

C-701: 4 

Durandal: 0.7 

 

Launcher:

BRM-1/AKd-10:4

SD-10 single pylon: 2.6

SD-10 dual: 6.14

C-701: 2.5 

C-802/fuel tank pylon: 9.4 

LS6-100: 1.7 

LS6-100 dual: 8.5

LS6-250: 4.9

 

 

So forgive my ignorance of understanding this but;

Dual SD10 pylon itself is 6.14, Each SD10 adds an additional 2.2,

Meaning both pylons & all 4 sticks are a total value of 21.08,

21.08 @ 35k, burner, will get you to 1.12 over a 40nm span.

 

Single SD10 pylon itself is 2.6 each, Each SD10 adds an additional 2.2,

Both pylons, both sticks & 2 800L fuel tanks have a drag value of 21 even

If I understand this correctly, 2 800L fuel tanks and 2 SD10s have a slightly less drag value than just 4 SD10s & their pylons

or 1.08 more drag than 2 huge BRM pods? lol 

 

 

 

[Napillo]

Odd that the LS-6-250 and the LS-6-500 bombs have the same drag.

[DSplayer]

6 hours ago, Creampie said:

 

 

So forgive my ignorance of understanding this but;

Dual SD10 pylon itself is 6.14, Each SD10 adds an additional 2.2,

Meaning both pylons & all 4 sticks are a total value of 21.08,

21.08 @ 35k, burner, will get you to 1.12 over a 40nm span.

 

Single SD10 pylon itself is 2.6 each, Each SD10 adds an additional 2.2,

Both pylons, both sticks & 2 800L fuel tanks have a drag value of 21 even

If I understand this correctly, 2 800L fuel tanks and 2 SD10s have a slightly less drag value than just 4 SD10s & their pylons

or 1.08 more drag than 2 huge BRM pods? lol 

 

 

 

The dual SD-10 pylon loadout is ~6.16 (0.00150390623 * 4096), which includes both missiles and the pylon. Each missile itself in that loadout is ~2.64 (0.00064453124 * 4096) and that value is subtracted from the dual pylon loadout when the missile is fired. 

Same for the single SD-10 loadout which has a total drag value of ~2.64 (0.00064453124 * 4096) while the missile itself is 2.2.

The drag for dual SD-10 loadouts are high but aren't that high. For reference, the AIM-120 LAU-115 2xLAU-127 dual pylons has a drag roughly of 8.027.

[Creampie]

On 8/20/2025 at 7:50 PM, DSplayer said:

The dual SD-10 pylon loadout is ~6.16 (0.00150390623 * 4096), which includes both missiles and the pylon. Each missile itself in that loadout is ~2.64 (0.00064453124 * 4096) and that value is subtracted from the dual pylon loadout when the missile is fired. 

Same for the single SD-10 loadout which has a total drag value of ~2.64 (0.00064453124 * 4096) while the missile itself is 2.2.

The drag for dual SD-10 loadouts are high but aren't that high. For reference, the AIM-120 LAU-115 2xLAU-127 dual pylons has a drag roughly of 8.027.

Thats 6.16 per rack?

If thats the case, 12.32 reaching its top speed of 1.33 takes 220nm in full burner, Which unless you're using unlimited fuel is not only impossible it's not viable.

While reaching the top speed with 2 BRM pods and 2 PL-5s takes roughly 40nm with a drag of 23.2 nearly double, and is completely possible.

Or reaching the top speed with  2 GB6 SFWs, 2 SD10s & 2 PL-5s with a drag of 27.6 more than double the drag & a higher weight still takes only 40nm.

I am ignorant to understanding drag values and how they are presented in game. But seeminlgy, either something is wrong with the SD-10 double racks, or everything else.

 

(These are all in level flight, no diving for profiles or anything)

 

 

 

Edited 10 hours ago by Creampie

[DSplayer]

4 hours ago, Creampie said:

Thats 6.16 per rack?

If thats the case, 12.32 reaching its top speed of 1.33 takes 220nm in full burner, Which unless you're using unlimited fuel is not only impossible it's not viable.

While reaching the top speed with 2 BRM pods and 2 PL-5s takes roughly 40nm with a drag of 23.2 nearly double, and is completely possible.

Or reaching the top speed with  2 GB6 SFWs, 2 SD10s & 2 PL-5s with a drag of 27.6 more than double the drag & a higher weight still takes only 40nm.

I am ignorant to understanding drag values and how they are presented in game. But seeminlgy, either something is wrong with the SD-10 double racks, or everything else.

 

(These are all in level flight, no diving for profiles or anything)

I don't know your testing parameters but in my tests, the JF-17 with CMBT engine mode, full internal fuel, QNH 29.92, +20°C, 30k ft altitude hold, starting speed of Mach 0.75 are this:

2x PL-5 + 4x SD-10: Max Speed of Mach 1.15 before complete fuel exhaustion
2x PL-5 + 2x HF20 - 16x BRM-1 rockets: Max Speed of Mach 1.04 before complete fuel exhaustion
2x PL-5 + 2x SD-10 + 2x GB-6 SFW: Max Speed of Mach 1.00 before complete fuel exhaustion

With all three payloads generally starting to plateau in speed after 10nm traveled with the 2x PL-5 + 4x SD-10 loadout taking the longest to get to the max speed I recorded.

The values presented for the HF20 with the BRM-1 rockets in the post by AeriaGloria are incorrect, as they have an effective payload drag value of 8.192 (0.002 * 4096) for one pod. I would personally attempt to double-check the payload drag values themselves for inaccuracies since the ones posted don't seem to be 100% accurate.

I personally do not see anything wrong with the drag for these weapons. The only gripe I have would be the payload drag for the LS-6-250 being the same as the LS-6-500.

Edited 6 hours ago by DSplayer

[Creampie]

23 minutes ago, DSplayer said:

I don't know your testing parameters but in my tests, the JF-17 with CMBT engine mode, full internal fuel, QNH 29.92, +20°C, 30k ft altitude hold, starting speed of Mach 0.75 are this:

2x PL-5 + 4x SD-10: Max Speed of Mach 1.15 before complete fuel exhaustion
2x PL-5 + 2x HF20 - 16x BRM-1 rockets: Max Speed of Mach 1.04 before complete fuel exhaustion
2x PL-5 + 2x SD-10 + 2x GB-6 SFW: Max Speed of Mach 1.00 before complete fuel exhaustion

With all three payloads generally starting to plateau in speed after 10nm traveled with the 2x PL-5 + 4x SD-10 loadout taking the longest to get to the max speed I recorded.

The values presented for the HF20 with the BRM-1 rockets in the post by AeriaGloria are incorrect, as they have an effective payload drag value of 8.192 (0.002 * 4096) for one pod. I would personally attempt to double-check the payload drag values themselves for inaccuracies since the ones posted don't seem to be 100% accurate.

I personally do not see anything wrong with the drag for these weapons. The only gripe I have would be the payload drag for the LS-6-250 being the same as the LS-6-500.

Same testing parameters, Only difference is 35k ft altitude. All have been done with full fuel & no fuel only to see if how much of a factor weight was and tested over a 40nm span, Which the differences in fuel of that have been incredibly insignificant.

"2x PL-5 + 4x SD-10: Max Speed of Mach 1.15 before complete fuel exhaustion"

This of them all is the biggest concern with it all, Now let me also say I am not questioning this in a sense of I am right and it is wrong. I just merely don't understand how a loadout similar to;

"2x PL-5 + 2x SD-10 + 2x GB-6 SFW" 

Has a 45% higher drag value, weighs more (I will see exactly how much more later when I am home) and somehow gets closer to its top end much faster than the first loadout. While at the same time only reflecting a 15% difference in its top end.

 

 

 

 

[DSplayer]

3 hours ago, Creampie said:

Same testing parameters, Only difference is 35k ft altitude. All have been done with full fuel & no fuel only to see if how much of a factor weight was and tested over a 40nm span, Which the differences in fuel of that have been incredibly insignificant.

"2x PL-5 + 4x SD-10: Max Speed of Mach 1.15 before complete fuel exhaustion"

This of them all is the biggest concern with it all, Now let me also say I am not questioning this in a sense of I am right and it is wrong. I just merely don't understand how a loadout similar to;

"2x PL-5 + 2x SD-10 + 2x GB-6 SFW" 

Has a 45% higher drag value, weighs more (I will see exactly how much more later when I am home) and somehow gets closer to its top end much faster than the first loadout. While at the same time only reflecting a 15% difference in its top end.

While the drag increase between the 2x PL-5 + 4x SD-10 loadout and the 2x PL-5 + 2x SD-10 + 2x GB-6 SFW loadout is only a 65% increase based on the Cx_pil values, that doesn't mean the aircraft will be 65% slower with drag being nonlinear relative to velocity. The reason why the GB-6 loadout "gets closer to its top end much faster" is because the ceiling speed limit for that loadout is lower than the 2x PL-5 + 4x SD-10 loadout, with the 2x PL-5 + 4x SD-10 loadout still having better acceleration.

This comes down to general aerodynamics with the interaction between drag, thrust, and weight.

Edited 2 hours ago by DSplayer

[Creampie]

56 minutes ago, DSplayer said:

While the drag increase between the 2x PL-5 + 4x SD-10 loadout and the 2x PL-5 + 2x SD-10 + 2x GB-6 SFW loadout is only a 65% increase based on the Cx_pil values, that doesn't mean the aircraft will be 65% slower with drag being nonlinear relative to velocity. The reason why the GB-6 loadout "gets closer to its top end much faster" is because the ceiling speed limit for that loadout is lower than the 2x PL-5 + 4x SD-10 loadout, with the 2x PL-5 + 4x SD-10 loadout still having better acceleration.

This comes down to general aerodynamics with the interaction between drag, thrust, and weight.

Which is why I ran my tests on unlimted fuel, both with full internal and 51lb as the lowest possible rather than running until an empty state. Achieving that maximum ceiling in both enviroments to see what they are.

Even with just 4x SD10s the top speed is 1.30-1.35 with a span of 220nm, depending on how many minutes after 1.30 you want to wait and test. (Again in an unlimited fuel state.)

and roughly the 1.15 as demonstrated by you in a more viable situation. 

I understand why one gets to its ceiling faster than the other generally speaking.

But not when a payload is signigantly lighter and according to LUA represents 45% of another ones drag. I could certainly see if we had been talking ceilings of maybe 5 or 6% but can't expect there to only be a 15% decrease in the ceiling of a payload with over twice the drag in the same distance. We're talking about 4x SD10s here and 2 pylons vs 2 extremely large cluster bombs 2x SD10s & 2x PL-5s.

Does mass somehow have a play in this through the LUA? 

Help me understand what it is I am missing, you know this stuff far better than I do. I merely play the video game.