SSTO's Angel of Attack

[phhs]

Hi guys

I've build my first SSTO a few days ago.

Till 12000 Meter, i flew with an angel of attack of ca. 45°, then I changed to 10-20°.

But I dont think, that thats the most effective way to fly into orbit right?

[Sirine]

Please try this out.

45°, climb to 17000 Meter, change to 1~3°. Until Air-Intake 0.05 (Decrease thrust to 70%, then 50% until intake run outs).

http://forum.kerbalspaceprogram.com/threads/50790-BSC-Ravenspear-Mk-1-This-time-for-real!?p=668836&viewfull=1#post668836

To make it SSTO, just add TWO radial rocket (20 thrustx2), when you are at 2200m/s.

[Hodo]

Depends on the SSTO, some of my smaller SSTOs I can climb to 22km at 40-45deg, some of my other heavy lifters I can only climb at 30-35deg to 15km. But I also admit some of my heavy lifters are less efficient than my small crew shuttles.

[bsalis]

It really depends on the craft... so much so that you are best to try different things and see what dV you can get to orbit.

IMO angle of attack is a secondary thing. What matters more is things like altitude, velocity, rate of ascent and available Intake Air.

[RoboRay]

Just to clarify, what you're talking about is simply the pitch angle. "Angle of attack" is the difference in pitch between the nose and oncoming airflow. In KSP, it's seen as the vertical angle between the nose (w marker) and the prograde marker on the NavBall. AoA is not related to the horizon.

[Geschosskopf]

As others have said, it depends on the design of the spaceplane. Specifically, ascent profile depends on 2 things: jet TWR and wing loading. The higher the jet TWR, the steeper you can climb to start with and the faster you pick up speed. The smaller the wing, the faster you have to be going for it to generate enough lift to keep you up as the jet TWR decreases with altitude. Relatively small spaceplanes without much wing for their weight but with big engnes really can only work with a steep initial climb relying mostly on thrust instead of wing. Because this is the most common type of spaceplane, this sort of ascent profile has been enshrined as dogma.

However, big, heavy spaceplanes have to do things differently. Generally, they don't have enough TWR to climb steeply so they have lots of wing instead. Spaceplanes like this make long, gentle climbs relying on lift to gain altitude instead of thrust. One big spaceplane I made climbed the whole way with the nose only 10^ above the horizon because it had so much wing.