fowlplaychiken Posted July 10, 2012 Share Posted July 10, 2012 Bawk!Hello gents. So, heres the issue:My spaceplane is perfectly balanced and flys great atmospherically and in space. However, on return, it seems to be extremely rear-heavy due to being bingo on fuel. I am unable to make a powered landing; the moment I take off the ASAS, my nose lurches skyward due to the unbalanced weight.How does one design a spaceplane that is stable when both full and empty? any suggestions?Image of my spaceplane attached, although I am unsure it will be any help. Link to comment Share on other sites More sharing options...
The Cobbler Posted July 10, 2012 Share Posted July 10, 2012 If youre too lazy, like me, you can tryvusing smart sas on mechjeb. If possible, Itll use flaps and such for stabilisation Link to comment Share on other sites More sharing options...
UmbralRaptor Posted July 10, 2012 Share Posted July 10, 2012 Fuel tanks near the center of mass, and roughly evenly placed around it, so to minimize the shifting as fuel burns? Link to comment Share on other sites More sharing options...
cardgame Posted July 10, 2012 Share Posted July 10, 2012 Yep, you\'ll need to have your fuel balanced around the CoG - and have the CoG close to the center of the plane, as well. This is possible to do by placing underslung engines near the middle of the craft, among other options. Since this may or may not upset the balance in space or prove to be a large hassle, it may be worth investing in VTOL. Link to comment Share on other sites More sharing options...
fowlplaychiken Posted July 10, 2012 Author Share Posted July 10, 2012 I am unsure; the COG seems fine. I suspect it has something to do with my fuel cross-feed; I can not seem to get the lines to work properly for the life of me. The tanks are emptying in an odd order, and the center one is empting before the two outer nacelles (despite trying between 1 and a dozen fuel lines all leading from the outer nacelles to the center column)I think the strange fuel distribution is causing the imbalance. I went full-bingo fuel and without a drop in the bucket it glided fine (until I hit about 32G\'s(!) on a steep decent and had to eject, at least!)Epic aerobraking fail. hahaBawk! -FPC Link to comment Share on other sites More sharing options...
Australian Sloth Posted July 10, 2012 Share Posted July 10, 2012 Tried moving the wings further forward? Or maybe putting more wing like objects on the back Link to comment Share on other sites More sharing options...
the_bT Posted July 10, 2012 Share Posted July 10, 2012 I noticed, any craft created in the plane hangar will drain fuel tanks in a way so that the center of mass doesn\'t shift if possible. My planes started to fly a lot better when I removed some fuel lines that messed with that. Link to comment Share on other sites More sharing options...
fowlplaychiken Posted July 10, 2012 Author Share Posted July 10, 2012 I hesitate to create anything in the hanger due to the symmetry bug, but fuel lines should be safe. Will give it a go. Link to comment Share on other sites More sharing options...
the_bT Posted July 10, 2012 Share Posted July 10, 2012 They are safe, they do as you expect them to, but in some cases the default behavior works better.Like in a traditional rocket, fuel will be used from the top downwards. I initially asumed, this would be the case for planes as well (from the front backwards) and connected the aft fuel tanks via fuel lines to the tanks in front of them. The Engines where under the wing and connected to one of the middle tanks.That setup did work but due to the fuel lines the plane used the aft tanks first. When I removed the fuel lines the tanks where drained 2 at a time, one in front and one behind center of mass, more or less. Link to comment Share on other sites More sharing options...
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