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CobaltWolf / Bluedog-Design-Bureau

Stockalike parts pack for Kerbal Space Program
https://forum.kerbalspaceprogram.com/index.php?/topic/122020-131mostly-functional-141-bluedog-design-bureau-stockalike-saturn-apollo-and-more-v142-%D0%B0%D1%82%D0%BB%D0%B0%D1%81-1feb2018/
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SOLTAN and short UA boosters #1558

Open JacobB094 opened 2 months ago

JacobB094 commented 2 months ago

According to what are the smaller Titan UA boosters balanced? I have built three vehicles with a nearly identical core: SOLTAN, Titan 3X-2 and Titan 3X-3. The difference is in the boosters: SOLTAN has the 1.5m boosters, 3X-2 has two UA1202s, while 3X-3 has two UA1203s. The results surprised me: SOLTAN lifts 6.7T to 200x200 LEO at 1.47 launch TWR, slightly exceeding the 3X-3, which lifts 6.5T at 1.45, and greatly outperforming the 3X-2, which only manages 4.3T, and has quite a TWR deficit at 1.09.

IRL, SOLTAN was the first proposal, which evolved into Titan 3X (what I call 3X-2), and then a third segment was added to make my 3X-3 configuration, which then got two additional segments to become Titan 3D (which lifts 8T at 1.79 TWR, as you could expect from the progression). My hunch is that the 1.5m boosters are too capable (especially since the cores are nearly identical because SOLTAN has a weaker AJ-5 engine, and it still blows others out of the water), and that UA1202 might have a touch too little thrust. Now, I know that BDB has an algorithm for balancing solids that usually gives good results, but considering none of the aforementioned SRMs have actually flown, I wonder what is the source for the values used.

CobaltWolf commented 2 months ago

Source would have been my copy of Dyna Soar: Hypersonic Strategic Weapon System. It has a couple pages of primary documents regarding them. I will have to take another look and share what it says here.

JacobB094 commented 2 months ago

That would be great, although Titan 3X was not a Dynasoar LV (Titan 3C was what succeeded SOLTAN there), but rather a sort of parallel offshoot meant for a much smaller and lighter predecessor of KH-9. Are these in that book, too? Ed Kyle guesstimated his values for boosters on both variants of Titan 3X, while he doesn't say anything about where he got SOLTAN data from, I wouldn't be surprised if it was from the same book.

BTW, if that book has any good numbers on any of the "Plan C" Titan derivatives or the Astro IV, I'd appreciate that, too. There were several obscure launchers proposed for Dynasoar, mostly based on the Titan, and I'm trying to get as many as can be done with what is currently in BDB.