Re:385 Feet of Crazy: The Most Audacious Flying Machine
by sandworm101 on Thursday August 23, 2018 @02:38PM
(#17829612)
>> a lot of fuel just getting through the thick low part of the atmosphere
That statement is misunderstood. Google "rocket ISP". Rocket engines work less efficiently at lower altitudes, and cannot be properly optimized due to the rapidly changing pressures between sea level and the near-vacuum at altitude. They burn extra fuel due to this inefficiency. And since rockets are at their heaviest in the lower atmosphere, even little inefficiencies really add up. Atmospheric drag is next to nothing in the equation. Even speed isn't the issue. It is about how they cannot design an efficient engine bell to cover the initial climb.
That statement is misunderstood. Google "rocket ISP". Rocket engines work less efficiently at lower altitudes, and cannot be properly optimized due to the rapidly changing pressures between sea level and the near-vacuum at altitude. They burn extra fuel due to this inefficiency. And since rockets are at their heaviest in the lower atmosphere, even little inefficiencies really add up. Atmospheric drag is next to nothing in the equation. Even speed isn't the issue. It is about how they cannot design an efficient engine bell to cover the initial climb.