Reading the description of the rocket I was surprised at how low was the
rotation rate for the upper stages, only 2.2 hz, rotations per second. Then
why couldn’t this be induced by the fins on the first stage?
Bob Clark
On Monday, February 19, 2018, Ed LeBouthillier <codemonky@xxxxxxxxxxxxx>
wrote:
Bob Clark said:
Thanks for that. The propellant mass values for the stages are givenhere, but not the Isp values or dry mass values:
The values for the 1st and 3rd stages have references (with fudge factor
for average Isp for the first stage: 266 s vac). The 2nd stage, I assumed
the same Isp as the 3rd stage. I'm still researching for more details for
the each of the stages.
For the SS-520 first stage, I used the values available for the S-520
stages (from which the SS-520 first stage was developed). The Lambda
(body:propellant ratio) is from the S-520 with tail fins. Contact me if you
want the references.
But there's still a lot of variability possible: the delta V for each of
the stages is guessed and the Lambda for upper stages is guessed. But, the
numbers work pretty closely to all currently available published figures.
