Quote from: john smith 19 on 08/08/2017 03:25 pmThat's an interesting one. Impact tests on composite tanks have show a 30% reduction in maximum load before failure but without visual signs of impact damage. I wonder on birdstrikes.
That's an interesting one. Impact tests on composite tanks have show a 30% reduction in maximum load before failure but without visual signs of impact damage.
Quote from: speedevil on 08/08/2017 11:42 pmQuote from: john smith 19 on 08/08/2017 03:25 pmThat's an interesting one. Impact tests on composite tanks have show a 30% reduction in maximum load before failure but without visual signs of impact damage. I wonder on birdstrikes.Birdstrike would be a minor splat.
Quote from: wannamoonbase on 08/09/2017 04:17 amQuote from: speedevil on 08/08/2017 11:42 pmQuote from: john smith 19 on 08/08/2017 03:25 pmThat's an interesting one. Impact tests on composite tanks have show a 30% reduction in maximum load before failure but without visual signs of impact damage. I wonder on birdstrikes.Birdstrike would be a minor splat.Not so minor.The NAO report on crewed Dragon stated this is an issue with why certification is taking so long. That would be a serious delay as NASA looked at the LV for Dragon 2 all over again, unless SX ran 2 separate mfg lines for "A" F9 and "C" F9. We know SX don't like to retain inventory or capability unnecessarily IE F1.
Quote from: john smith 19 on 08/09/2017 06:57 amQuote from: wannamoonbase on 08/09/2017 04:17 amQuote from: speedevil on 08/08/2017 11:42 pmQuote from: john smith 19 on 08/08/2017 03:25 pmThat's an interesting one. Impact tests on composite tanks have show a 30% reduction in maximum load before failure but without visual signs of impact damage. I wonder on birdstrikes.Birdstrike would be a minor splat.Not so minor.The NAO report on crewed Dragon stated this is an issue with why certification is taking so long. That would be a serious delay as NASA looked at the LV for Dragon 2 all over again, unless SX ran 2 separate mfg lines for "A" F9 and "C" F9. We know SX don't like to retain inventory or capability unnecessarily IE F1. What is NAO?
The thread title says "impacts on payload capacity." We can consider the question as a theoretical exercise and ignore the practical certification issues.Assuming 25000 kg 1st stage, 5000 kg 2nd stage, half of the mass of each stage is tank, 30% tank weight savings, and 1/7 ratio of first stage mass reduction to payload gain (a number I have seen thrown around often): 25000*.5*.3/7 + 5000*.5*.3 = 1285.71 kg. I suspect some of my assumptions lead to an optimistic number.Anyone have a rough idea of how much of the mass in each stage is actually tankage?
Isn't it intuitively obvious that a bird strike on the second stage is far less serious than a bird strike on Dragon due to the possible angles involved?
Not a concern. If they lose one out of every 100,000 to a bird strike (unlikely), then who cares?
Quote from: Robotbeat on 08/11/2017 06:01 pmNot a concern. If they lose one out of every 100,000 to a bird strike (unlikely), then who cares?If only that were true. It was cited as one of the reasons neither contractor can make the NASA goal (LOC in 1 in 270 flights IIRC). TBH I'd never thought bird strike was even applicable to VTO rocket systems at all. I can only presume it would have to be something like the bird hitting one of the windows and crashing through it.