pedro16797: For some reason, landing gears drift to one side (usually the left). I've seen this previously happening on other crafts and it may be related to the springs they have, but reproducing this is a bit inconsistent. This craft's log shows the drift on the first seconds after launch. Another guess is that landing gears may be partially under the runway upon launch.
Andrew: I wonder if this is related to the bug where the Wasp bounces when Quick Saved / Quick Loaded on the runway.
Original title: Aircraft launched not pointing straight down the runway
launch this aircraft. it does not point straight, and will roll off to the left side of the runway when the engines are used. remove the ejection seat and astronaut and the aircraft launches pointing almost perfectly straight. I dont think there is anything wrong with the placement of the seat - it is placed symmetrically at x=0. In the designer, this aircraft point perfectly at the blue arrow, and is perfectly centered.
After working exclusively with my aircraft build for several months now i have learned the following things. 1) aircraft bouncing on load can be caused by either the nose wheels having a different y-level than the rear gear or because mass isnt exactly balanced amongst all wheels causing the shocks to oscillate at first. 2) aircraft pull to one side or the other for many reasons. Here are just a few: a) the slight effect of orbital angular momentum. b) craft mass not being exactly centered on x=0. c) slight difference in aerodynamic characteristic of each side of aircraft. this can be caused by unmatched drag settings changes, and even an inlet connection not being correctly duplicated in a mirror operation. Mass not being exactly centered is the major culprit and almost impossible to avoid, here are some techniques, you have to know how to check the parts x,y,z pos with the move tool, but also when you are moving a part in the x y z axes you have to "clip" the number of each coord by putting your mouse cursor after the last digits and hitting return because the XML stores many digits of precision and you want to cut off the random invisible extra numbers that can only be seen on the XML. Make sure your centerline part is clipped to exactly 0,0,0, after grouping the whole craft, before you do any mirror, so the mirror isnt offcenter. check the coords are matched after each mirror. Be very careful when using the resizing tool on the ends of any centerline part because even the slightest touch on one of the "side" arrows can cause the part to be slightly offcenter and you might not even notice you touched it, but you will see the offcenter mass and the unequal corner radiuses in the XML afterwards. My craft pulls consistently to the right at the moment and i can see fromthe that the craft's COM is slightly off, so eventually im going to have to do another recentering pass to fix it but this time ill wait to the end. thats going to be very tedious, but if you want a perfect craft you either have to get really picky with balance and check and edit your XML, or just make very simple airplanes. I hope some of this helps someone.