Post AVzIfpi06jy9jQzT96 by frank@f.reun.de
 (DIR) More posts by frank@f.reun.de
 (DIR) Post #AVzIfpi06jy9jQzT96 by frank@f.reun.de
       2023-05-24T12:57:05Z
       
       0 likes, 0 repeats
       
       Soyuz launch! 🚀 https://www.youtube.com/watch?v=F_qGxq4AEc4#space #soyuz
       
 (DIR) Post #AVzIfqcMjB3WYFMU08 by avia@mu.zaitcev.nu
       2023-05-24T17:51:05.107253Z
       
       1 likes, 1 repeats
       
       @frank My favorite is this video of M-67, because one can see clearly how the rocket sways side to side. This effect exists because R-7 engines do not start simultaneously.https://www.youtube.com/watch?v=Su9LkLb5_y4
       
 (DIR) Post #AVzKsJZ38AmVi7so0u by ThatWouldBeTelling@shitposter.club
       2023-05-24T18:29:12.348400Z
       
       1 likes, 0 repeats
       
       @avia @frank Very interesting.  While I can understand in principle not simultaneously starting all the engines, one thing I believe I saw was the various engine sets adjusting their output before it was let go (and that’s extra visible given our view for a long ways below the engines).  Per Wikipedia: https://en.wikipedia.org/wiki/RD-107“One important innovation of this engine was the capability to use variable mixture ratio between fuel and oxidizer. The natural variations in manufacturing between each engine meant that without an active propellant consumption control, each boosters would deplete oxygen and fuel at different rates. This might result in as much as tens of tonnes of unburned propellant near the end of the burn. It would generate enormous strains on the structure and control authority due to the mass imbalance. Thus, the mixture ratio control system was developed to ensure the simultaneous consumption of propellant mass among the four R-7 boosters.”