Extra intake air when sped up?

[Callmedave]

I've never noticed this before but last flying across to the badlands, my intake air was around 0.6, when I speed up time the intake air doubled on 2x speed and quadroupled on 4x. Has anyone else had this happen? Looks like a bug to me.

[Wanderfound]

Yup. Ram-air effect.

It's a standard spaceplane tactic; fly until your air-breathers choke, then kick the rockets in to revive them. Do it right and you'll have the apoapsis over 70km before they choke again.

[Wanderfound]

Ooh hang on: I just noticed the time acceleration thing. When you do that, your air readout will double (or triple, or quadruple) but the actual air available doesn't change. It's just an artefact of the physics compression.

[Clockwork_werewolf]

Yea it's due to the way time is accelerated in KSP. KSP can't just double the number of calculation per second as this would fry computers if you ship is bigger than about 250 parts (or what ever number of parts your computer could handle divided by 2). For 4x acceleration it would be about 125 parts. So what the game does is multiply the ingoing and out going numbers. The air coming in gets multiplied by 2-4 times for the air intakes. Now although the engines should be using 4 times the amount (I'm unclear if they use 4 times the air, it could be a bug) The cut off point it still 0.10 air which is really 0.025 in normal time. The random air turbulence in 2-4 times speed makes suing this affect a little difficult in reality.

[Epthelyn]

The cut off point it still 0.10 air which is really 0.025 in normal time.

That's where the bugs start to show up; I'm not entirely sure whether that's actually the case. I've had planes perform far better at higher and higher altitudes using physics warp than without, which either means that physics warp is messing with physics in such a way that is beneficial to aerodynamics or something's wrong with the way air is worked out. It may be the case that the lower limit of intakeAir before flameout doesn't scale properly and so the engines can run for slightly longer than they otherwise would. However, that only applies to certain aircraft, usually bigger ones with more engines and more intakes.

[vexx32]

No, that does genuinely sound like a bug to me, though I don't know whether it's an actual bug in flight physics, or just with how the IntakeAir is displayed.

[magnemoe]

Yea it's due to the way time is accelerated in KSP. KSP can't just double the number of calculation per second as this would fry computers if you ship is bigger than about 250 parts (or what ever number of parts your computer could handle divided by 2). For 4x acceleration it would be about 125 parts. So what the game does is multiply the ingoing and out going numbers. The air coming in gets multiplied by 2-4 times for the air intakes. Now although the engines should be using 4 times the amount (I'm unclear if they use 4 times the air, it could be a bug) The cut off point it still 0.10 air which is really 0.025 in normal time. The random air turbulence in 2-4 times speed makes suing this affect a little difficult in reality.

You also get rounding errors, you can see this if you mine kethane under warp, at 1x the converter uses all kethane who is mined, at 100x the drills extract faster than the converter can convert. guess the same effect is active here, all the intakes calculate more air inn than the few engines use.