I notice that whenever I add any of the new parts like the Kerbodyne engines, mechjeb will fail to calculate any delta-v for the entire rocket. Even if I only use a LFB KR-1x2 in the first stage, all delta-v calculations for the upper stages will disappear and it will look like my rocket has no stages at all. The only way to get the delta-v readings back is to jettison the new parts and reload the rocket from the tracking station. This also happens in the VAB and it makes it very difficult to design efficient rockets. If anybody knows how to fix this or has a patch, please help me Thanks