04-14-2014, 06:36 PM | #31 |
Join Date: Mar 2013
|
Re: [Spaceships] Winged Spaceships
OK then, if I use the Merlin-1D thrust to weight ratio of 150, yielding 7.5 Gs my atmospheric speed is 1.9 mps, with a 5.74 needed for orbit I only need 3.84 mps.
Using the KVD-1's Isp of 462 I get .154 mps per tank of fuel, 15 fuel tanks will get me into orbit with room to spare (0.318 mps) carrying 190 tons of cargo (I think that can work) Altogether this means it takes $600,000 of rocket fuel to lift 190 tons of cargo to orbit, that's $3157.89 per ton or or $1.41 per pound |
04-14-2014, 08:07 PM | #32 |
Join Date: Feb 2005
Location: Berkeley, CA
|
Re: [Spaceships] Winged Spaceships
Remember, accelerating to atmospheric speed costs fuel. There's no point unless you have an air-breathing thruster that has better performance than your rocket.
|
04-14-2014, 08:32 PM | #33 |
Join Date: Mar 2013
|
Re: [Spaceships] Winged Spaceships
Yes, but it uses a lot less fuel. The F1 has a 2.27:1 ratio of oxidizer to fuel
|
04-14-2014, 08:55 PM | #34 |
Join Date: Feb 2005
Location: Berkeley, CA
|
Re: [Spaceships] Winged Spaceships
The systems you mentioned are rocket engines. They don't change fuel consumption for atmospheric use -- if you want to use less fuel, you'll need an air-breathing engine.
|
04-14-2014, 09:02 PM | #35 |
Join Date: Mar 2013
|
Re: [Spaceships] Winged Spaceships
The thread of discussion had moved onto rocket engines with air intakes
|
04-14-2014, 09:25 PM | #36 |
Join Date: Feb 2005
Location: Berkeley, CA
|
Re: [Spaceships] Winged Spaceships
The performance of such engines is at best incidentally related to the performance of rocket engines from fuel tanks, as liquid oxygen has somewhere on the order of 5,000 times the oxidizer density of air. Realistically, you probably need a completely different engine, and in any case you should model it as a ramjet or scramjet, not a rocket.
|
Tags |
spaceships |
Thread Tools | |
Display Modes | |
|
|