Sidewinder launch rails have negative drag

[m4ti140]

The launch rails for RB-24/J and RB-74 are reducing drag when carried empty. This reduction in drag is most observable at high speeds. Around SSL conditions the maximum speed with 6 empty launch rails is 1788 (Ma=1.46 on indicator) kph at 5% fuel and 1777 (Ma~=1.455) at full tank. With 2 empty rails and otherwise clean config (happens when rails are jettisoned in flight as well, with aircraft rapidly slowing down after jettisoning 4 rails, see track files) the maximum speeds are respectively 1651 (1.35) and 1638 (1.34) still significantly above maximum sea level speed in clean configuration. The reduction in drag is also observable at low speeds, with RPM held by autothrottle with full tank stabilizing at 82% for 6 rails and 83 for 2, indicating higher thrust required.

 

Steps to reproduce:
1. Start a flight with 6x of any sidewinder missile
2. Launch the missiles without jettisoning launch rails
3. Observe the performance changes with empty launch rails

 

Track and acmi files demonstrating the behaviour are attached to the post.

 

Screenshots:

https://imgur.com/a/SzwxZ6r

 

5% track

viggentest260521.trk

100% track

viggentest260521fulltank.trk

acmi tracks

Tacview-20210526-202016-DCS-viggentest.zip.acmi

Tacview-20210526-204827-DCS-viggentestfulltank.zip.acmi

 

[rossmum]

Issue still persists although the patchnotes mentioned a fix. Upon firing all missiles and then jettisoning the rails, there is a substantial deceleration from 1700km/h IAS (SSL).

 

One thing I will say is that at least this time, acceleration ceased at 1700km/h, not 1789km/h like when I used this mission file to test it a few months ago.

 

 

negative drag fire.trk negative drag jettison.trk

[IronMike]

Heh, this was supposed to be fixed. Thank you for reporting. tracked.