Onboard Xombie rocket video, engage the air brake - 2010.03.20

[blah979]

Wow awesome video. That was really cool the way you put 3 different views together and also liked the way you used high def video. A lot of vids like this are not to clear. Hope you show other stuff your doing in the future.

[sparkybluefox]

This is among the best rocket video's that I've ever seen! In fact.. I've NEVER seen anything like this!

Bravo!

SBF

[mrplease66]

This clearly is a great piece of kit, and it seems to work extremely well, but I would like to know what the eventual aim is? It would never reach orbital velocities, so what do you intend to do with it? Sample returns?

[gaynorglowellxsingh]

how long is it's flight time and how high will it go?

[ambruskis]

Nice job!

[dhrjani]

nice work

[mojaverockets]

It was a beautiful flight, I'm glad I was there to see it.

[solidskateboards]

Just awesome!!

[McdonaldSpecial]

fake

[bbrockert]

roflcopter

[scasey1960]

Great video!

[bbrockert]

Thanks, Sean.

[robotguy]

Were the winds really high that day, or is your control system slightly underdamping?

[bbrockert]

It was fairly calm. It's very tightly wound, it kept the vehicle within an average distance of two inches from flying perfectly vertical.

Because it's twitchy, issues like tolerance stackup and actuator backlash create the limit cycle oscillation you can see in the video.

In a flight where it's not trying very very hard to hold its horizontal position, it won't oscillate like that.

[gk123434534]

@bbrockert Great video and nice precision landing! ... How much more power does it use for the actuators when it's that 'twitchy'? How much power margin is there to keep it that tightly controlled?

[bbrockert]

It used about a quarter of the battery on that flight. There's a lot of margin.

Just moving the actuator around doesn't consume much energy, it's moving it really quickly that uses the most. Here it's not trying to go very fast, so it doesn't have much of an impact.

[ianmga]

@robotguy It's a combination of things. High gain on the velocity controller (what ben describes as twitchy) combined with underdamping. Good catch.

[JustAnAdjunct]

I like how it flies and lands. Congrats :)

[bbrockert]

Thanks, we do too. It was a good day's test.

[predatortheme]

@bbrockert Wow I love that. What Did you guys Study to get the knowledge about rocket engineering? Aerospace engineer?

[bbrockert]

@predatortheme I went to school for computer engineering, but dropped out. The CEO was a dropout as well. The propulsion guy was Manufacturing Engineering, the GNC guy was AeroE from MIT. It's a different company now, though, almost none of the same employees as during this flight.

[predatortheme]

@bbrockert Thank you for the answers. What would you recommend to study/learn To get the knowledge of rocketengineering ?

[oz9aec]

Wow, it's coming down fast! Congrats with the good flight!

[bbrockert]

Thanks! We limited it to 60mph for this flight. We'll do faster soon.