Sorry, I forgot to add the word "nozzle" in there, so the nozzle is in the lower stage prop tank.Its quite common.
Quote from: sitharus on 05/13/2011 05:02 amQuote from: Danderman on 05/13/2011 04:55 amQuote from: LegendCJS on 05/12/2011 07:59 pmQuote from: Danderman on 05/12/2011 07:37 pmFor rockets where the 2nd stage engine is housed inside the 1st stage prop tanks, how exactly does the engine leave the tank during staging? Is the prop tank blown up?Do you know of a rocket where the second stage engine is immersed in the fuel of the first stage tanks before staging? Don't you mean inter-stage volume?Sorry, I forgot to add the word "nozzle" in there, so the nozzle is in the lower stage prop tank.Its quite common.So the nozzle of the second stage forms part of the pressure structure of the first stage? I don't think I've ever seen such a design...No, the nozzle extends into the first stage prop tank, saving loads of interstage area.
Quote from: Danderman on 05/13/2011 04:55 amQuote from: LegendCJS on 05/12/2011 07:59 pmQuote from: Danderman on 05/12/2011 07:37 pmFor rockets where the 2nd stage engine is housed inside the 1st stage prop tanks, how exactly does the engine leave the tank during staging? Is the prop tank blown up?Do you know of a rocket where the second stage engine is immersed in the fuel of the first stage tanks before staging? Don't you mean inter-stage volume?Sorry, I forgot to add the word "nozzle" in there, so the nozzle is in the lower stage prop tank.Its quite common.So the nozzle of the second stage forms part of the pressure structure of the first stage? I don't think I've ever seen such a design...
Quote from: LegendCJS on 05/12/2011 07:59 pmQuote from: Danderman on 05/12/2011 07:37 pmFor rockets where the 2nd stage engine is housed inside the 1st stage prop tanks, how exactly does the engine leave the tank during staging? Is the prop tank blown up?Do you know of a rocket where the second stage engine is immersed in the fuel of the first stage tanks before staging? Don't you mean inter-stage volume?Sorry, I forgot to add the word "nozzle" in there, so the nozzle is in the lower stage prop tank.Its quite common.
Quote from: Danderman on 05/12/2011 07:37 pmFor rockets where the 2nd stage engine is housed inside the 1st stage prop tanks, how exactly does the engine leave the tank during staging? Is the prop tank blown up?Do you know of a rocket where the second stage engine is immersed in the fuel of the first stage tanks before staging? Don't you mean inter-stage volume?
For rockets where the 2nd stage engine is housed inside the 1st stage prop tanks, how exactly does the engine leave the tank during staging? Is the prop tank blown up?
The second stage nozzle is immersed in the fluid propellent of the upper first stage tank? Let me see a diagram of that! Some part of the nozzle throat or combustion chamber or engine would have to be part of the pressure containing boundary of the first stage tank in that case.Or do you mean that the first stage tank's top is not a dome, but contains a concave region sized for the nozzle of the second stage engine, and there is no fluid communication between the second stage nozzle and the first stage propellant?A simple diagram (even in paint) would save a lot of confusion for me and other people here it seems.
Why did they do that? The nuclear arms treaties limited the length of the silos. So having the upper tank extend up around the second stage nozzle got them a teeny bit more kilotons or a few more miles of range.
For the rest of us, the build and operational complexity of that doesn't make sense for a commercially viable rocket. Just sacrifice some performance for simplicity.
Doesn't H2 beyond stoichiometry contribute to thrust thru greater mass flow through the engine, the extra hydrogen being heated and expanded by combustion?
D. L. Jensen states in this paper that most current US H2 engines are develop with the "wrong", mixture ratios. Given that H2 needs such a huge volumes, it would only seem natural to try to use as little as possible, specially if you get better isp.But since I know that there's a lot of intelligent people behind current engines, and I've learned better than to blindly trust random papers from the internet, specially when written as angry as this one, I would like to know what he's not saying. In particular, it doesn't makes any sense to me dual clone turbopumps against low pressure and high pressure.From what I could grasp, the higher the mixture ration, the higher the pressure and temperature that the engine has to handle. And so it becomes more expensive and heavy. A reduction in the proportion of H2 would lower the tank's sizes, so it should offset a bit of the extra weight. And the reduced use of H2 should reduce the turbopump sizes. But there's so much that I guess I'm missing that I would love someone knowledgeable to tell me.
1) Does chemical propulsion have an inherent speed limited that prevents it from doing a much faster transit to Mars? Is it that you need a large amount of propellant to slow down and circularize the orbit? Could a huge craft with multiple stages assembled in space speed up the mission?
I've heard of NTRs being able to allow faster transits, but I was never sure why they allowed this. I also heard that New Horizons reached the orbit of Mars in two months with chemical. Would this speed be just too fast to be captured by mars without melting the craft or a crash landing?
2) Does the gravity when closely approaching Mars or the Moon help slow down craft significantly and capture them or does this require lots of propellant and using the atmosphere to slow the craft?
1) Does chemical propulsion have an inherent speed limited that prevents it from doing a much faster transit to Mars?
I also heard that New Horizons reached the orbit of Mars in two months with chemical. Would this speed be just too fast to be captured by mars without melting the craft or a crash landing?