Options for diagnosing plane drag problems

[DeadJohn]

Is there any stock or mod feature to list the draggiest parts of a plane in flight?

I want the current snapshot of drag in order to find things like unshielded cargo, bugged mod parts that are creating extreme drag, etc. The static value from drag cubes is inadequate to find if a game bug is causing the actual drag to be higher than the cube suggests.

Options I've considered so far:

• F12 to turn on red arrows: Works well with small craft. Poor with large craft and many parts: can't tell if arrow is from cargo bay or the cargo, can't tell which component in a long stack is causing the longest red arrow, drag arrow from nose and cockpit is often hidden inside body, etc.
• Alt-F12 aero GUI: This can help detect an overall problem but provides the total only, not each part.
• Alt-F12 show aero in part window: Gives per-part drag values. When there are many parts, though, as I cycle through the stack reading each value, the flight has changed and altitude/speed/AoA may have changed. This is unusable with 100+ parts.
• Kerbal Wind Tunnel mod: It highlights in the SPH which parts are likely to create the most drag. If there's an aero bug during flight, though, where a part creates more drag than it should be creating, Wind Tunnel doesn't help.
• FAR: I am using stock aerodynamics, so FAR's features don't seem relevant.

 

[Lt_Duckweed]

The mod CorrectCoL is useful for many other things, but it has one esoteric use that is likely unintentional.

When you update the CorrectCoL window with a new altitude and speed setting, all the parts on the craft update their debug data as if they were actually traveling at that speed and altitude, even though you are in the SPH.  Though for whatever reason it always simulates as if the airflow is coming from the left of the root part, so to get accurate values you have to rotate the rest of the craft 90 degrees to the left relative to the root part.  It's the only way I've seen to do anything like what you are looking for.

Edited May 3, 2022 by Lt_Duckweed

[DeadJohn]

@Lt_Duckweed Can you clarify that? I use CorrectCoL but it's only available in SPH and VAB. It's good but doesn't help when there are aero glitches during flight that cause a part to have drastically more drag than expected. I need to find those parts during flight and take extra steps to get their shielding to work right, or replace the part with an alternative part.

Things can seem shielded in SPH/VAB but not during flight. Some of those cases can't be detected by CorrectCoL and Wind Tunnel.

Even the f12 red arrows can be wrong in flight, with a correctly shielded part showing a long red arrow yet actual drag in the part window is 0. (I haven't looked for that since KSP v1.10 but I don't think 1.12.3 fixed it)