SSTO Space Planes: Best time to burn to orbit

[AmpsterMan]

This past week I have been taking on the challenge of building a completely SSTO Space Plane (which i succeeded and will be posting it in the Spacecraft Exchange soon) but through out the ordeal that is learning how to pilot said space plane, I came across one issue that I could not solve to my satisfaction. This is issue is when to engage my rocket engines to go into orbit.

At first, I would go to about 11-13km at an angle of attack of 60*; when I noticed the Prograde marker start falling I would engage rockets and burn into orbit. Though this got the job done I couldn't help but feel that I didn't really use the full potential of my Air Breathing engines. Later on I tried for a more horizontal angle of attack, but then realised that, while I had a faster velocity when I engaged my rockets, I would lose quite a bit of Delta V to atmospheric drag and gravity loss (At least, I think that is what it was). Still, I was able to make it into a sub-orbital trajectory.

Long story short, how do YOU do it? Do you go for a sharp angle of attack and maximise your rockets? Do you go more horizontal? Both? Neither?

Do I make any sense? Discuss your experiences.

[trbinsc]

I just fly horizontally high and fast, until I decide to fire up the rockets, and then I just pilot it like a normal rocket, going nearly vertical and slowly pitching towards 90º.

[Shiny]

Personally, I go straight up to around 12k, then start angling down to around 60 until 20k, at which point I would level out and cut thrust until around 20 seconds before AP. Then I burn until I have a circular orbit.

Then again, I don't actually have any air breathing engines on my plane. Just two aerospike engines.

[trbinsc]

Yeah, If you don't have any jets on your plane, the best thing to do is just launch it vertically like a rocket.

[Gobbles Gusto]

Just landed my first space plane on Mun today, could have been a SSTO but then it would surely have been a one way vehicle, anyway after decoupling the two 400-FC side tanks shortly beyond the runway I easy my self into a vertical position only needing four more to get to Mun and hopefully back, I haven't tried yet.

[Omega500]

I somtimes coast up to orbit with my space planes i find this helps with my fuel. also if you do the burn to the mun when it comes up over the horizon i or kerbin you dont need to waste fuel doing orbital burns.

Also whats SSTO mean?

[Cykyrios]

Single Stage To Orbit.

I really need to work on my own design, I have only tried 2-3 times to actually get a space plane into space...

[AmpsterMan]

Well after just about a week of designing, testing, flying, crashing, and landing multiple space planes I have come to the conclusion that it is best to try and get as much a verticle angle of attack as possible. My current space plane flies to about 12km at 70-80 degrees at which point it reaches 220 m/s, I fire my Rockets and then start trying to do a gravity turn.

This weekend I will be designing a second SSTO Space plane to see if I can increase my efficiencies and my skills. Thank you all for your imput