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A comment on 385 Feet of Crazy: The Most Audacious Flying Machine.

Re:385 Feet of Crazy: The Most Audacious Flying Machine by walrus01 on Thursday August 23, 2018 @11:46AM (#17828215)
What exactly is the back of the napkin calculation for Delta v saved by dropping a rocket from 40,000 ft and 400 knot airspeed vs launching from ground level?

If we assume that 7800-8000 m/s is required for low earth orbit, how much does stratolaunch plan to shave off? How much Delta v is saved in the current small rocket setup with the pegasus dropped from an ex commercial airliner at approximately the same altitude?

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Re:385 Feet of Crazy: The Most Audacious Flying Machine by walrus01 on Thursday August 23, 2018 @12:08PM (#17828417)
Replying to myself, these seem to be the rough numbers:

https://news.ycombinator.com/item?id=14456602

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Re:385 Feet of Crazy: The Most Audacious Flying Machine by CarVac on Thursday August 23, 2018 @01:35PM (#17829105)
Max Q occurs at roughly 40,000 feet for ground launched rockets.

If you start at 40,000 feet, you can accelerate largely sideways and reduce gravity losses without running into the atmosphere too hard and needing a stronger structure.

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Re:385 Feet of Crazy: The Most Audacious Flying Machine by ChuckMcM on Thursday August 23, 2018 @11:51AM (#17828265)
1400 knot orbital velocity if you're flying east.
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