Geostationary altitude is around 8,803 kilometers, as calculated by jacksawild. I've tested it out myself and it seems pretty spot-on. For best results, get an orbital inclination as close to 0° as possible.
@Dracozard Generally, you want the blue indicator (center of lift) to be behind the red indicator (center of mass) for the craft to be flyable. If the blue indicator is in front of the red, then the craft will pitch upwards uncontrollably. If the blue indicator is too far behind the red, then the craft won't be able to take off at all. You can change the position, size, and shape of the wings to change the center of lift, and add or subtract mass from the craft to change the center of mass. The yellow indicator (center of thrust) should be centered on the craft's x-axis, or width, so that the craft flies straight.
Definitely an issue for people who want to build to scale. And just in case you didn't already know, 1 unit = 1 meter.
@Dracozard It's fine if the center of thrust is at the back as long as the craft handles how you want it to. A fighter jet has its center of thrust at the back. The center of thrust is naturally at the engine, as the engine is the source of the thrust. You may have to counter the weight of the rocket engine at the back by moving the primary wings further back or by adding mass to the front of the craft, or both.
@DPSAircraftManufacturer It's a good basis for planes that get their lift and pitch/roll/yaw control exclusively from the wing part rather than things like RCS nozzles or custom wings. Those things can make the blue indicator misleading as I don't think the game takes them into account when calculating where it displays the blue indicator, even though they can influence the center of lift greatly. There are exceptions, but most fixed-wing aircraft handle best with the center of lift a bit behind the center of mass, unless the center of thrust is way at the front or extremely powerful or something like that.
@PhilipTarpley Thank you. That is above and beyond fixing the bug.
This has gotta be the best update since launch. Worth the wait.
@swope Weird. I experience the auto-roll in the latest version, 0.6.9.2. I tried verifying my game files, using both mirrored and non-mirrored wings, locking the nav sphere, but there's always the auto-roll.
@pedro16797 I really like that alpha value idea. I made a suggestion similar to that, but I think your idea makes more sense. Certainly worthy of being a standalone suggestion.