ferram4 changed the topic of #RO to: Welcome to the discussion channel for the Realism Overhaul (meta)mod for KSP! Realism Overhaul Main Thread https://goo.gl/wH7Dzb ! RO Spreadsheet http://goo.gl/Oem3g0 ! Code of Conduct http://goo.gl/wOSv2M ! | Maximal & soundnfury's RP-1 Race Into Space Signup: http://bit.ly/2DEVm2i [15:01] <soundnfury> Straight Eight Stronk (and) RP-0/1 is basically "Space Agency Spreadsheet Simulator"
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<wb99999999>
hello
<ProjectThoth>
wb99999999: hello!
<wb99999999>
it's amazing, I built an Ariane 5 core based on loaded mass number I find online
<ProjectThoth>
Nice!
<ProjectThoth>
I love doing stuff like that.
<wb99999999>
and I emptied the tank to compare the dry mass
<wb99999999>
it's only off by a couple of hundreds of kg
<wb99999999>
what is amazing is the maker of the configs XD
<wb99999999>
I didn't even fiddle with tank util. yet...
<ProjectThoth>
wb99999999: I designed a rocket from "scratch" using an Excel spreadsheet.
<wb99999999>
I found that for boosters it is a lot helpful to think in terms of sec. burn time and total thrust than in dV
<ProjectThoth>
I'm particularly proud of the calculating pmf method I came up with.
<wb99999999>
it is very cool
<wb99999999>
now here's a problem...
<wb99999999>
what made Zenit first stage's dry mass so large???
<ProjectThoth>
Ukrainian space magic.
<wb99999999>
27.5 t dry mass compares to 354.3 t loaded
<wb99999999>
what the hell
<wb99999999>
like, F9FT has a pretty similar dry mass for its first stage
<wb99999999>
but it is about 438 t loaded
<wb99999999>
a good 84 t more propellant???
<ProjectThoth>
wb99999999: Russian rockets are pretty chonky in general, plus also consider that Zenit was supposed to be used as strap-on boosters for Energia (not mass optimized as it could be).
<wb99999999>
I guess so... the lifting power of Soviet boosters are always a bit misleading
<wb99999999>
they have so much thrust and such good Isp for engines, but heavy structure and high latitude launch
<ProjectThoth>
wb99999999: Well, it stems from Soviet military philosophy and technological development at the start of the Space Race. They just didn't have the tech to build extremely lightweight airframes like the US did, and instead focused on improving engine performance.
<wb99999999>
maybe this is why Atlas V works so freaking well
<ProjectThoth>
The US had the tech to build lightweight airframes, so they did. Engine performance took a backseat from there, and the decision to develop submarine-launched ICBMs et al shifted development to solids rather than liquid motors.
<ProjectThoth>
End result: Soviet/Russian rockets have shit propellant mass fractions, but have black magic engines. American rockets are gossamer thin, but the engines are shit (except the SSME and RL-10, but the Soviets' LOX/LH2 engine development only really began in earnest in the 1970s/1980s, because their kerelox engine tech was so good).
<wb99999999>
more like their kerolox engines are good *enough*
<ProjectThoth>
wb99999999: I mean, yeah. You marry Soviet engines with American tankage, and you can cobble together an SSTO pretty easily.
<wb99999999>
for deep space high energy stages are almost always desirable
<ProjectThoth>
Or glue an SSME to, well, pretty much anything.
<wb99999999>
I mean the development plans for Buran-Energia still sounds snake oily today
<wb99999999>
fly back boosters? orbiter with jet engines for landing?
<ProjectThoth>
Energia II was even crazier.
<ProjectThoth>
All that, except the core had wings duct taped to it for recovery.
<ProjectThoth>
wb99999999: Reusable rockets have been possible for years, but there isn't an economical excuse to develop them.
<wb99999999>
well the Shuttle IS a reusable rocket
<ProjectThoth>
Yeah. It just cost an assload to operate and didn't have much to do.
<wb99999999>
and Starship is just shuttle but without the stupidity added to satisfy the DoD and Airforce
<wb99999999>
here, I said it: Star ship is just shuttle
<ProjectThoth>
wb99999999: Starship is just Shuttle but with an even smaller market. :P
<wb99999999>
man Zenit booster is such a shame
<wb99999999>
I have tried it, if I use the light-weight Western tankage
<wb99999999>
guess what, I can lift the entire Ariane core and then some payload
<wb99999999>
this whole stack makes a huge rocket and it can just fling at least 20 tons to GTO