All my plane designs keeps on Pitching up while on Space

[lyndonguitar]

I have been building some Spaceplanes(Shuttle like with Booster) using the B9 Aerospace Pack and I'm having problems with literally all my designs, whenever they reach vacuum, When throttled up, They seem to pitch up, SAS can't stablize it, Redirecting Fuel using Tac Fuel Balancer doesn't solve it, hell, even putting the infinite fuel cheat doesn't work. I even tried rearranging all my fuel tanks. So I'm sure it isn't a fuel placement problem

It seems fine while flying in the atmosphere, in fact it is a very good aircraft design, it flies very good. Also the launch vehicle booster it is strapped on functions very well, can take it to space using mechjeb. the problem is when in it is already in space.

I have been building spaceplanes before 0.20.0 and using this pack as well and I haven't encountered any problems. only now.

maybe a bug or something? Any help? I've been trying to do this for days. (afaik all my design's CoT are aligned properly with CoMs)

here are some of my designs

Properly alligned CoT-CoM (still pitches up while on space)

Edited June 15, 2013 by lyndonguitar

[ferram4]

All of your CoM positions are based on having a full load of rocket fuel. Once you get into space the fuel tanks in the main fuselage will weigh less, while all of the RCS tanks you have mounted on the top of your fuselage will weigh the same; this will shift the CoM upwards, causing a pitch up tendency under thrust. I would suggest shifting the RCS tanks down to be lower on the fuselage and see if that helps.

[lyndonguitar]

All of your CoM positions are based on having a full load of rocket fuel. Once you get into space the fuel tanks in the main fuselage will weigh less, while all of the RCS tanks you have mounted on the top of your fuselage will weigh the same; this will shift the CoM upwards, causing a pitch up tendency under thrust. I would suggest shifting the RCS tanks down to be lower on the fuselage and see if that helps.

But I even tried the Infinite Fuel Cheat and teleported it to space immediately(to test if it is a fuel problem), and It still pitches up., I tried removing the all the RCS Tanks, Now it pitches down lmao

I think found the culprit. It's the wings(and little bit of RCS Tanks), not sure why though, did they get heavier with the latest b9 update? Once I removed the wings, launched it. (I use hyperedit to test it on space immediately) The problem is gone. But, How do I put wings??

[Nao]

One more thing to consider is removing landing gear before setting up CoM, as they add mas in SPH but are massless in runaway. (When you removed the wings it also removed the wheels too probably)

Also if you want to fine tune CoM you can place two RCS tanks one on top one on bottom and burn some RCS during ascent. Then in space fine tune the balance with RCS fuel.

[lyndonguitar]

I finally did it, It turned out to be both the RCS tanks and the Wings.

RCS Tanks are making it pitch up, and the Wings making it pitch down, I just had to find a good balance between those two parts

Edited June 16, 2013 by lyndonguitar