Air intake makes no sense to me

[Foxster]

I have a little SSTO.

If I put an XM-G50 Air Intake on it it runs out of air at 15km. If instead I put on two Adjustable Ramp Intake (Radial)s on then it runs out of air at 30km. 

The spec for the XM-G50 is Intake Air Amount: 2.0 and Intake Area: 0.31sqm. The specs for two ARIs are:  Intake Air Amount: 1.0 and Intake Area: 0.2sqm.

Surely the XM-G50 should be "better" than the two ARIs?

 

Edited January 26, 2016 by Foxster

[Rhomphaia]

2x0.2 > 0.31

Intake air amount is a useless figure, only area matters.

 

NVM.  however now intakes have a mach curve.  Seems the XM-G50 gives up at mach 3.5 the ARI keeps going to mach 8

Edited January 26, 2016 by Rhomphaia

[Foxster]

Just now, Rhomphaia said:

2x0.2 > 0.31

Intake air amount is a useless figure, only area matters.

Please re-read what I wrote. The numbers I gave are for two ARIs. 

0.2<0.31. 

[Rhomphaia]

16 minutes ago, Foxster said:

Please re-read what I wrote. The numbers I gave are for two ARIs. 

0.2<0.31. 

Yeah missed that, made an edit though.  It isn't mentioned in the intake stats, but when the ARI says it is optimised for supersonic flight it isnt kidding, intakes efficiency is now dependant on speed.

 

Except for the shock cone.  that one works the same at any speed.

Edited January 26, 2016 by Rhomphaia

[Foxster]

6 minutes ago, Rhomphaia said:

Yeah missed that, made an edit though.  It isn't mentioned in the intake stats, but when the ARI says it is optimised for supersonic flight it isnt kidding, intakes efficiency is now dependant on speed.

Thanks for that.

I never bother reading the blurb for parts because historically it has been more jokes than information.

I'll take a look at the part file and see if I can figure out some way of telling which parts are best for supersonic from the data there.