This normal for an 18t space plane?

[cwm33]

Greetings fellow Kerbalnauts!

I don't know what it is about SSTO space planes that makes me so obsessed with trying to build a better version, but after downloading B9 Aerospace and using that wonderful Sabre engine I was able to put 2 designs into orbit. My first was a fairly simple little thing which made a 100km orbit with about 5% fuel left. My second successful spacebird (which looks FAR more snazzy than its predecessor) managed to get that 100km with around 18% fuel left over!

One thing that strikes me as a bit weird, is that my second bird seems to fly at a really strange profile for a plane. It was sitting at around a 20 degree incline and just barely gaining altitude at around 18,500m, is that normal when space planes start getting heavier? or is something in my design a tad goofy? Just seems to be a tad bit...off to me, but maybe that's Kerbal physics at work, so I'd just like a bit more insight on the subject from those that might be a bit more in the know.

Anyway here's an image of my spaceplane with an example of what I'm talking about in regards to its goofy angle.

[Tw1]

Idk, I remember seeing the video of someone who flew an SSTO to Laythe, and their plane was flown at 45 degrees for much of the accelerating towards orbit.

Maybe you haven't got enough lift because the air is too thin, and need help from engines?

Perhaps someone with more expertise than myself can advise.

Also, welcome to the forums!

[Vanamonde]

Because the game's current aerodymanic system is a placeholder, KSP wings are not airfoils, and the angle of attack is a primary factor in determining how much lift they will generate. So yes, at high altitudes where the air gets thin, you will need to fly at a significantly nose-up posture for the wings to function effectively.

[TheHengeProphet]

I do not find this kind of behaviour unusual. Many of my later SSTO planes accellerated their way out of the atmosphere on a rather shallow angle, just using speed to fling out.

I would suggest you check out Ferram Aerospace Research, as it completely revamps the aerodynamics system.

[MR4Y]

Ferram aerospace makes things better. Rockets require less fuel and things like that.

[cwm33]

Ferram aerospace makes things better. Rockets require less fuel and things like that.

Just tried out Ferram, and wow that's much better for space plane flight dynamics! Game crashed when I was trying to de-orbit burn to bring her in for a landing, but wow what a difference! Thanks for the suggestion.