Kerbal Space Program

[NeonSamurai]

Originally Posted by Oberon

The KSF-1, the first of my plane creations to make it out of the atmosphere. On returning though the aircraft became uncontrollable and crashed into the sea for reasons unknown. Two top theories are either 1) center of gravity problems with the empty rocket fuel tank, or 2) the stylish 'I wish I was an SR-71' tail fin positioning.

I guarantee it was fuel throwing your balance off. Having the center of gravity matching or slightly ahead of the center of lift is very important to stability. But there are fuel balancing mods out there that are great. Otherwise you have to try to balance by eye which can be real tricky with both jet and rocket fuel (fuel+oxidizer).

Anyhow some fuel balance mods:

This one will automatically balance all fuel tanks based on the center of mass you set in the VAB
http://kerbalspaceport.com/pwb-fuel-balancer-for-rcs/

This one is more of a manual fuel balancer, and is really great for refueling and quickly shifting fuel around. It can also automatically balance, but it does this by having the same % fuel in all tanks. Depending on design though, this may not work unless your craft is highly symmetrical.
http://kerbalspaceport.com/tac-fuel-balancer-v1-0/



Oh and for anyone reading that wants a good tutorial for learning how to fly spaceplanes, this is a pretty good tutorial from Scott Manley