Some info about air intakes and mach

[Foxster]

I was a bit stumped as to why this little SSTO flew up to 30km with two Adjustable Ramp Intake (Radial)s  but with one XM-G50 Radial Air Intake it ran out of air at 15km...

There's nothing to help in the displayed info for these intakes. One XM-G50 has more Intake Area and Intake Air Amount than the two ARI(R)s. It was this that had me confused. 

So I dug around in the part config files and came up with this information about a Mach Curve for each intake...

What this tells us is:

The Shock Cone does not change with Mach, it's intake amount remains unreduced by increasing speed. So if you have an aircraft that travels at ridiculous speeds (2000+ m/s) and you want to minimise the number of intakes then this is the one to go for.    

The Circular Intake, Small Circular Intake and XM-G50 are dead after Mach 3.5 but don't suffer a drop-off at <Mach 1. 

The Adjustable Ramp Intake (Radial) and Adjustable Ramp Intake keep going until Mach 8. They make good spaceplane intakes and weigh less than the Shock Cone. 

My little SSTO only gets up to Mach 4 at 30km, so the 50% mach-caused intake drop-off at that speed doesn't matter as there is no useful air by then anyway. 

 

Edited January 26, 2016 by Foxster

[fourfa]

Great info, thanks!

[Val]

@Foxster I saw your thread in Gamplay Questions and remembered that someone did research it. Was gonna link it there, but now I see you already did the research yourself. Great work.

Anyways here's the link in case you're interested.