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Any idea why they shutdown some engines during ascent? Seems efficient as you are fighting gravity with less acceleration and more dead weight.
by raphaelj 5y ago
Any idea why they shutdown some engines during ascent?
Seems efficient as you are fighting gravity with less acceleration and more dead weight.
- hiharryhere 5y agoThey’re not trying to go fast. They’re trying to get to the target altitude to test the flip. No need to rush or overshoot. In “production” it will be atop the booster, so taking off like this from sea level isn’t part of the plan.
- nickik 5y agoThey don't want to go to high or to fast. So they start out pretty heavy and as the fuel is consumed they turn of engines in order keep the TWR the same. They don't want to test supersonic flight profiles with this vehicle. This flight profile is not at all optimized for fuel use.
- oconnor663 5y ago> This flight profile is not at all optimized for fuel use. I suppose you could say it's optimized to use almost all the fuel :)
- NobodyNada 5y agoEach Raptor engine cannot throttle down below about 40% of its maximum thrust [0], so they must completely shut down some of the engines in order to achieve the lower required thrust for hovering or landing. [0]: https://twitter.com/elonmusk/status/1295553672454311941 https://twitter.com/elonmusk/status/1295553672454311941
- adgjlsfhk1 5y agoIt is less efficient. That said, they aren't carrying a payload and they don't have to run it full on fuel, so it doesn't matter. More importantly, they care about testing the landing which requires them to be a certain horizontal distance from the landing site, so it's easier to do that by hovering sideways so they don't get way too much height.