Unfortunately for my little theories I have some ships that fly an even flater trajectory and they actually save fuel even if they spend more time in the atmosphere and cross 30 at an angle of say 35 degree. I have to admit things like that confuses me a little but as I said of you could you would like put all effort into orbital velocity and fly 1 m above kerbin and then just raise your AP and PE after orbit have been established.
Just add kickback SRBs till your design can fly the same profile as your speedy light rockets could at the beginning of your career.. High ISP, but only with engines of comparable thrust and weight. Otherwise, it's just one factor of many. Originally posted by mkunz2 :. Originally posted by maj. Magnaheim View Profile View Posts. Per page: 15 30 Date Posted: 13 Jun, pm. Posts: Discussions Rules and Guidelines.
Note: This is ONLY to be used to report spam, advertising, and problematic harassment, fighting, or rude posts. The choice of units is important when you consider where the definition came from in the first place. Why is that conversion coefficient there? When you're not using metric and you're not careful about the difference between force and mass, you use imperial units and you have a definition of specific impulse without conversion coefficients.
Bad convention. If we just used effective exhaust velocity for everything, there would be no confusion and we wouldn't have to have this debate or clarify to countless new folks that the 9. Exhaust velocity is not an intuitive explanation of why the number matters. It matters because it's a measure of given the same amount of thrust, how long can the fuel last while maintaining that thrust.
And the idea that the people in the US space program were ignorant of the difference between mass and force is hogwash. The fact that they're represented with the same word "pound" does NOT mean the people using that word think they mean the same thing.
It was well understood that depending on context "pound" might mean a measure of weight or a measure of mass. If used in the mass context, the word "pound" changes its meaning to mean "the amount of mass that would weigh 1 pound at sea level on Earth". The metric Mks system starts from mass as a first principle and then derives a measure of force from that. The system in the US used weight as a first principle and then derived a measure of mass from that that happened to carry the same name.
The fact that it confusingly uses the same name does not mean people treated them as identical. The problem is that the question "what is ISP" needs to be answered first in terms of what it means and then second in terms of what the units are that different conventions use.
Velocity is a distance traveled divided by time it took to get that far. The fact that it's meters and seconds in one system is secondary to the definition.
Just like saying ISP is the time it takes to consume a given amount of fuel at a given amount of force is a universal definition of what ISP means that works regardless of what units you use, and is much easier for people to understand. If you are trying to get to Mun, Duna or make some space station with this game, you don't have to know what exactly it is, just knowing that the hight Isp the better an engine is is enough.
But if you're planning visiting Jool, start a return mission to Eve, Understanding of Isp is critical in your rocket design. Except that you've thrown in an arbitrary conversion factor of 9.
Not very universal, is it. The exhaust velocity makes much more sense if you're doing the actual thermodynamic nozzle calculations and talking about conservation of momentum. Of course rocket scientists are skilled engineers and perfectly aware of the difference between mass and force. As I said a few pages ago, strictly from the definition, specific impulse is just impulse per unit [something].
The historical convention that we now have is that [something] is in units of propellant mass times g0. This is a pretty nonsensical choice, that came from dividing thrust in pounds by propellant flow rate in pounds per second, and calling the result specific impulse in seconds.
The factor of g0 is hidden when using imperial units, or any other gravitational unit system - we could use kiloponds and fold the conversion factor into the unit choice in the same way. Even rocket scientists screw up units sometimes. Intelligence is not a substitute for making complicated things easier on yourself. You can post now and register later. If you have an account, sign in now to post with your account.
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If you attempt to do so, it will be clamped down into the allowed range. Note that although a kerboscript is allowed to set the value to a very precise number for example So if you do something like set ship:part[20]:thrustlimit to How much thrust would this engine give at its current atmospheric pressure and velocity if the throttle was max at 1.
Also note that this will read zero if the engine is currently disabled. How much thrust would this engine give if both the throttle and thrust limtier was max at the current velocity, and at the given atmospheric pressure. Use a pressure of 0. Note that this will read zero if the engine is currently disabled.
Pressure must be greater than or equal to zero. If you pass in a negative value, it will be treated as if you had given a zero instead. Taking into account the thrust limiter tweakable setting, how much thrust would this engine give if the throttle was max at its current thrust limit setting and atmospheric pressure and velocity conditions.
Taking into account the thrust limiter tweakable setting, how much thrust would this engine give if the throttle was max at its current thrust limit setting and velocity, but at a different atmospheric pressure you pass into it. Releases 7 Kerbal Isp Difficulty Scaler v1. Dec 16, Packages 0 No packages published. Contributors 2.
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