- Aug 5, 2020
- Reaction score
- Belgrade, MT
Having good company isn’t having a workable solution.Here's an example of both gravity turn and weather cocking. I launched a two stage M685W to K550W at XPRS (Black Rock) in 2018. I made a mistake and used a long burn (11.5 seconds) for the boost. Surface wind about 10 mph. Launched straight up, until it cleared the pad, then immediately was under the influence of the wind. The profile would have been much better with a higher average impulse motor for the boost.
And, the criteria of velocity and altitude was met for the 2nd stage to ignite - and it did.
The sustainer was traveling about 300 mph at 24 K' when the two 9" drogues from side bays were deployed. They held, but the shear pins for the main failed and the rocket drag separated. Got pretty ugly after that. At that point, the rocket was 4.1 miles downrange from the pad.
The nose with the GPS drifted back 6 miles and I calculated the high alt wind at about 75 mph from the profile and how far it landed from deployment. The descent track is just the nose/GPS with a 18" parachute.
After that, I began thinking about rocket designs that could help correct for these problems. Glad to have some good company.
View attachment 431289
The vertical control fin system can solve this in principle, but its really complex, and isn’t designed for near Mach speeds.