orbitingpluto
Orbiteer
- Joined
- May 1, 2010
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Pure dV derived from rocket equation is not enough. You have to acount for gravity losses, which are determined mostly by thrust/weight ratio in initial phases of flight.
Silverbird rocket calculator says that Titan 1st stage with single LR-87-5 can't achieve orbit on it's own. Adding second engine to the stage gives me astonishing payload of 28kg! And that's for straight eastward launch on equator.
My thrust values are about one-half of the actual, thanks to some Wikipedian who thoughtfully decided to list the specs of the LR-87-5 as if there was only one combustion chamber. I did go ahead and post it without sanity checking it first, so I'm glad you caught my error.
Anyway, I do know the Titan 2 first stage is marginal on usefulness as a SSTO(in my opinion at the very least), and the idea of making it a space plane doesn't make sense to me- but it did seem a passable reason to hand out resources so someone so they can use the rocket equation to explore how rocketry works. My estimate of ~9000 m/s does include margin for gravity losses and drag, but I do realize I was making things a bit too simple. :shrug: