Suspicious drag coef for the MER7-Rack

[NAUNUAUB]

Evening all,

After doing a mission carrying 8x OFAB 100 High Drag bombs, I had a serious doubt on the drag model of the rack they are mounted on..

This rack is a MER-7 according to my research.

To investigate, I experimented flying 3000ft in ISA conditions with 103% RPM and different config to measure speed at which stabalize. Here are the results :

4x MER-7 Rack + 8x OFAB100 = 230 kts

4x UB16 Rockets                           = 240 kts

4x MER-7 Rack                              = 250 kts

2x MER-7 + 4x OFAB100          = 280 kts

2x UB16 Rockets                          = 290 kts

2x MER-7 Rack                              = 295 kts

4x OFAB100                               = 330 kts

Clean                                          = 350 kts

According to DCS, MER-7 rack weights 103kg while OFAB100 is 120kg and Rocket pod 129kg. So we can approximate they are all the same and conclude the measured speed difference reflects exactly the drag coef difference.

Conclusion of the above is that an MER-7 rack has almost the same drag coefficient than a rocket pod which does not make sense to me when you look their shapes (attached picture below).

I know it's a lot of effort for few, but when you're painfuly doing 230 kts for your run where you should make around 280 ish, that starts to be a problem !

Happy landings !

 

Edited Wednesday at 07:52 PM by NAUNUAUB