Does anyone have any tips about flying SSTO's ?

[SKYCORN]

I always have trouble using nuclear engines to circularize my orbit. I make the maneuver, but there isn't enough time.

Any tips?

Edited July 2, 2020 by SKYCORN
misspelling

[RoninFrog]

 

Are you only using nuclear engines to circularize, or are you using them to get suborbital also?

Just circularization:  Try aiming slightly above the horizon, maybe 45° up.  The upward thrust will give you a little more time to circularize.

Ascent: If you are having problems getting near orbital velocity without sinking back below 30km, try aiming 15° above prograde and make sure you have a TWR of at least 0.4.

[Spricigo]

Different people have different ideas about how to use SSTOs, so the tips will vary accordingly.

Also, I guess you mean SSTO Spaceplanes.

I can point  you to the good advice I received when asked a similar question.

 Some points I come to after considering all that and experimenting(some personal preference there, take with a grain of salt):

1. DON'T PANIC!
2. Learn how to design/fly regular planes before trying spaceplanes. 
3. Don't overlook panthers+chemical rockets spaceplanes. they are quite capable and useful in a career game.
4. Design your Spaceplane to delivery whatever you'll use in space to orbit and go back to KSC. Jet engines and Wings are useless in space.
5. Design with a health Thrust. "Efficiency" means nothing if you don't have the Thrust to use it.
6. Don't expect to fix with piloting what is a design problem.
7. You don't choose an optimal flight profile, you find the one designed in your craft.
8. Above a certain height your plane will be just like another rocket, that is how you should fly it.
9. Below that heigh your top priority is to avoid drag, there is draggy craft there is draggy piloting.
10. Wings can be a bit draggy but you need some.
11. Changing attitute tend to be draggy. Do only as needed and be gentle.

 

Anyways, as I said back in 2016: is very craft-dependent. For the problem you have with your actual spaceplane we can offer better advice if we can take a look at the craft.