Huge drag of radial parachutes

[jeancallisti]

So I built that perfectly standard medium-small jet plane and wanted to see how fast it could go. It has Panther engines.

I was extremely surprised to discover that if I add a pair of mk12-r parachutes on it (the smaller, orange ones), it caps around at 380m/s, whereas as soon as I remove the parachutes it almost  goes up to 700m/s.

• I did several tests; with and without. With and without.
• I even deleted and re-added the parachutes to be sure that there was no glitch.
• The parachutes are definitely the culprits.

This tiny pair of unopened parachutes almost halves the top speed of the plane.

Anyone has an explanation for that???

 

 

[DeadJohn]

380 m/s is near Mach 1 supersonic speed. KSP drag increases with speed until you break Mach 1, then it tapers off. Maybe your plane was barely able to break the 380 barrier before, and the chutes add enough drag+mass to prevent those faster speeds.

It's not uncommon to build a plane that can't go much past 380, then remove or rearrange parts or reduce mass and then the plane can go far past 380. KSP planes rarely have a top speed in the 400-499 range. This drag quirk causes KSP planes to be either stuck below 400 or they can reach 500+.

Tips for KSP drag and supersonic flight:

• Try a 3 to 5 degree angle of incidence for your wings with the "3" rotate tool in SPH. That will help the wings generate lift and let the higher drag parts remain more level for less total drag as you reach supersonic speed.
• Press F12 during flight to toggle red drag arrows. That will give you a rough idea of the relative drag of parts. It's not perfect, though, because the arrows from a very draggy nose part might be hidden inside the main fuselage.
• The alt-F12 debug window lets you turn on the aero GUI to show more detailed drag numbers.

[jeancallisti]

Thanks!

[Mahnarch]

Have you tried... a whole lotta floorin'?!

 

[Bej Kerman]

Does the same thing happen with FAR?