dblitz » May 9th, 2017, 4:16 pm wrote:When something explodes, anything nearby is pushed away by the force of a blast wave. This is what I thought propelled rockets, the restriction of the blast wave into a narrow channel, pushing not against air, but against the rocket. I never thought a terrestrial rocket was pushing against air, it seemed like the blast of the continuously exploding fuel pushed the rocket upward because anything near an explosion is going to move away from it at speed. I'm not sure why there is a need for something to push against like air, The explosion pushes the rocket along.
I don't believe anything either way, but I lean towards no rocketry because of NASA fakery of Earth images. If they could do it, why wouldn't they? I'm just not sure the free expansion idea really debunks it.
I agree. I think this is all being over-complicated and all this “pushing against air”, “no air to push against in space” is missing the point. To re-phrase what you said a little: The combustion expands rapidly pushing against the top of the combustion chamber pushing the rocket along. There is no cancelling force from the expansion in the opposite direction because that end of the combustion chamber is open, ie the flames you see coming out the back of the rocket are all sound and fury signifying nothing. The combustion also expands to all sides of the combustion chamber - these forces cancel each other out, but if the chamber is cone shaped, as most are, then the molecules hitting the sides also create a component of forward thrust.
So in theory a rocket can work in space. Presumably the the fuel and oxidant would need to enter the combustion chamber with force and be ignited instantly before the “vacuum” disperses them.
A bigger problem before the rocket gets anywhere near space is the amount of rocket fuel needed. NASA’s large fireworks (Saturn V, Space Shuttle) can only carry enough fuel to go a couple of miles before they fall back into the Atlantic. You can see rockets level off and then head down in extended launch films. Officially they are entering orbit and following the curvature of the earth but in reality are only a couple of miles away. (The flat earthers have posted this kind of analysis, they are actually educating me lol, but not about the shape of the earth).
The 3 stage rocket idea (illogically complex and heavy at launch with redundant rocket motors) was invented so if a plane or ship got into the cordoned area a few miles out of Cape Canaveral and saw something fall into the ocean they would merely think that was the first stage rather than the whole thing. Or in the case of the Shuttle – one of the detachable solid rocket boosters.