what's the formula for intake air?

[JtPB]

for every intake theres those thing:

1. area

2. amount

3. (while flight) air speed

how do i connect between them? is the area of the intake a bad thing or good?

[Clockwork_werewolf]

1. Area is the intakes, intake area. The more the better. The only downside is that a larger area produces more drag but this is usually negligible.

2. Amount is the parts temporary storage. It is easier to think of it as a flow rate. If you have only one engine and an "amount" of less than 0.1 then it could still even with plenty of air. The intake can be stopped from having it's air flow and this amount can be saved for space BUT it is such a tiny amount this is almost never useful (except for specific challenges).

3. Air speed refers to the speed the air is entering the intake plus about 100 m/s to stop stationary craft on the runway having no air. The higher the speed the more air will enter the intake. At higher altatudes the air speed might be 1000m/s but the air is thin so only a fraction of the usable air is present and at low speeds an engine could not be powered.

[JtPB]

1. Area is the intakes, intake area. The more the better. The only downside is that a larger area produces more drag but this is usually negligible.

2. Amount is the parts temporary storage. It is easier to think of it as a flow rate. If you have only one engine and an "amount" of less than 0.1 then it could still even with plenty of air. The intake can be stopped from having it's air flow and this amount can be saved for space BUT it is such a tiny amount this is almost never useful (except for specific challenges).

3. Air speed refers to the speed the air is entering the intake plus about 100 m/s to stop stationary craft on the runway having no air. The higher the speed the more air will enter the intake. At higher altatudes the air speed might be 1000m/s but the air is thin so only a fraction of the usable air is present and at low speeds an engine could not be powered.

is it something like: area*amount*airspeed

[mhoram]

is it something like: area*amount*airspeed

The exact formula for the amount of the resource IntakeAir that is generated from air intakes is not yet known exactly.

The best description I could come up with is:

- Intake Area is directly proportional to the amount of generated IntakeAir

- Surface Velocity + a base offset (depends on air speed) is probably directly proportional to the amount of generated IntakeAir

- Atmospheric Pressure is probably directly proportional to the amount of generated IntakeAir

- Angle of Attack is probably in a cosinus relation to the amount of generated IntakeAir

[JtPB]

well so the amount of the air in an intake is considered just when the intake is closed and stores air in it?

that means that only area may be a parameter when choosing an intake?

[Clockwork_werewolf]

Right I've been playing around with this for a while and I can't get it quite right but this is near enough for estimates.

Area: A

Air Speed: S

Height (on Kerbin): H

* multiply

/ divide

^ to the power of

flow = ((A*100) * (squareroot(S+144)) * (1/ (2.65^(H/5000))))*4

intake = flow * 0.02

so with a ram (A=0.01) @ speed 1000m/s @ 20,000 meters up

flow = 100 * 33.8230690505755 * 0.0202775977788933 = 2.74340235942122

intake = 0.054 and it would take two rams to keep a jet working.

I did 21 measurements and this equation worked well enough (within about 5%) for all results. I turned off gravity so that I didn't need a positive angle of attack and so did not need to work out the intakes angle to air flow.

it's also worth noting that an engine doesn't instantly cut out at lower than 0.1 air AND it can be throttled down to save air as well to two rams equation is just for full throttle 0% failure.

[Red Iron Crown]

well so the amount of the air in an intake is considered just when the intake is closed and stores air in it?

that means that only area may be a parameter when choosing an intake?

The intakes need a small amount of air storage to hold the air until an engine has a chance to consume it. The storage is not relevant to the generation of intake air, though as mhoram notes the precise calculation is unknown.

[JtPB]

come on, guys, cant you just check out the code to see the algorithm/formula?

[Red Iron Crown]

come on, guys, cant you just check out the code to see the algorithm/formula?

The source code for KSP is not viewable to non-devs. We can only experiment or beg them to reveal it.