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10-26-2016, 12:51 AM | #1 |
Join Date: Mar 2013
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[Spaceships] Stats for RB545 Rocket Engines or Other Air Augmented Rockets
OK the RB545 was the proposed rocket engine for the British HOTOL SSTO Spaceplane, but as it is apparently still classified I'm not expecting any specific, but rather more general rules.
The secret to how the RB545 was supposed to work is that it was an air augmented rocket, or an hybrid of (ram)jet and conventional rocket, meaning that it doesn't need to carry as much oxidizer. Using a top speed to Mach 17 (Apparently to fastest a ramjet can go) it can reach a speed of 3.6 mps, out of the 5.6 needed for orbital velocity. Using a 2:1 oxidizer to fuel ratio I think that means I can get something into orbit with only 3.2 mps of delta-V, does this sound right? |
10-26-2016, 12:57 AM | #2 | |
Join Date: Feb 2005
Location: Berkeley, CA
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Re: [Spaceships] Stats for RB545 Rocket Engines or Other Air Augmented Rockets
Quote:
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10-26-2016, 03:53 AM | #3 | |
Join Date: Sep 2008
Location: near London, UK
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Re: [Spaceships] Stats for RB545 Rocket Engines or Other Air Augmented Rockets
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For dV calculations, work out the vehicle's top speed on jets (p. 35), convert to mile/second, and subtract that from your rocket's dV requirement.
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10-26-2016, 04:50 AM | #4 |
Join Date: Aug 2008
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Re: [Spaceships] Stats for RB545 Rocket Engines or Other Air Augmented Rockets
You may also want to include fly in the direction of the spin of the earth by flying eastward*, and take into account how high you can fly, since it will reduce dv requirements for overcoming gravity drag, as well.
* This necessarily needs to be a great circle, so if you aren't launching from the equator, you'll need to fly there first. Also, if your destination is inclined, you're better off launching directly into that inclination, since orbital plane changes eat SO much delta-v.
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10-26-2016, 06:46 AM | #5 |
Night Watchman
Join Date: Oct 2010
Location: Cambridge, UK
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Re: [Spaceships] Stats for RB545 Rocket Engines or Other Air Augmented Rockets
The RB545 is still classified, but the SABRE from the same designer is a civilian project and superior, at least in terms of concept. It's about the same thing in Spaceships terms.
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10-26-2016, 03:29 PM | #6 |
Join Date: May 2009
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Re: [Spaceships] Stats for RB545 Rocket Engines or Other Air Augmented Rockets
What is invlunation?
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10-26-2016, 03:39 PM | #7 |
Night Watchman
Join Date: Oct 2010
Location: Cambridge, UK
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Re: [Spaceships] Stats for RB545 Rocket Engines or Other Air Augmented Rockets
A typo for inclination of the orbit.
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10-26-2016, 06:19 PM | #8 | |
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Join Date: Sep 2004
Location: Southeast NC
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Re: [Spaceships] Stats for RB545 Rocket Engines or Other Air Augmented Rockets
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10-26-2016, 06:49 PM | #9 |
Join Date: Aug 2008
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Re: [Spaceships] Stats for RB545 Rocket Engines or Other Air Augmented Rockets
It's Posting-From-My-Phone for "inclination".
Yup, the US got shafted on that one or we'd have put it at about 28.5 degrees inclination.
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