BPS Space and moveable fins for roll control

The Rocketry Forum

Help Support The Rocketry Forum:

cerving

Owner, Eggtimer Rocketry
TRF Sponsor
Joined
Feb 3, 2012
Messages
4,792
Reaction score
2,424
Looks like it was fine as long as there was thrust... went unstable at burnout. That's the problem with hobby rocketry TVC... the motors generally don't burn long enough for stability through the entire ascent. Maybe some small fins would help.
 

Charles_McG

Ciderwright
Joined
Sep 12, 2013
Messages
3,025
Reaction score
1,142
Location
SE Wisconsin
Looks like it was fine as long as there was thrust... went unstable at burnout. That's the problem with hobby rocketry TVC... the motors generally don't burn long enough for stability through the entire ascent. Maybe some small fins would help.
But this wasn’t TVC - the fins were servo driven. Aft fins, rather than canards. It looked like the gain was too high to me. And I didnt listen all the way through (the pie finished warming up) - but did he loose one of the servos in flight?
 

Bowman

Well-Known Member
Joined
Mar 8, 2014
Messages
335
Reaction score
232
But this wasn’t TVC - the fins were servo driven. Aft fins, rather than canards. It looked like the gain was too high to me. And I didnt listen all the way through (the pie finished warming up) - but did he loose one of the servos in flight?
He lost linkage between the fins.
You can see them shortly after launch going opposite directions.
 
Joined
Sep 22, 2020
Messages
633
Reaction score
502
Location
Weimar, TX
the motors generally don't burn long enough for stability through the entire ascent. Maybe some small fins would help.
I recently misread the specs on a 29mm motor. I thought it said 17s burn time not 1.7s. For just a few seconds I was dreaming of a 17s burn motor. :D :saintnick: and then... reality struck...

I watched it to the end, he said that he used epoxy to connect the linkage (no comment) and that as the rocket sat on the launch pad for an hour it heated up and softened the epoxy. I know it (30m Bob Smith specifically) will do that because I recently heated an epoxied in fin to move it just a tad and that worked. He said that when the rocket was indoors and cooled down the epoxy hardened and the fin rigidity returned but if heating softens epoxy what does that say about a rocket built with epoxy? Idk... I think that, even though I've seen that heating it will allow movement, unless he's launching in hell it's not all that likely for epoxy to soften that much. His servos, gears, and 3D printed parts were all plastic. I guess he'll lets us know when he finds out.
 

sh4un

New Member
Joined
Dec 13, 2021
Messages
3
Reaction score
1
There is a guy in China that has mastered the TVC and movable fins. So now everyone is playing catch-up. It's interesting to see progress, everyone has stopped what they're doing to do what this guy is doing.
 

dhbarr

Amateur Professional
Joined
Jan 30, 2016
Messages
7,684
Reaction score
2,079
There is a guy in China that has mastered the TVC and movable fins. So now everyone is playing catch-up. It's interesting to see progress, everyone has stopped what they're doing to do what this guy is doing.
The latter doesn't necessarily follow the former, but a link would certainly be interesting.
 

sh4un

New Member
Joined
Dec 13, 2021
Messages
3
Reaction score
1
The latter doesn't necessarily follow the former, but a link would certainly be interesting.
This is what *everyone* is now trying to replicate. This guy is really brilliant and you can really see the change in how a lot of the 'youtube' rocket guys are are now inspired by a lot of his work. You can see

I am a telented guy, but wow, this guy makes me want to pack it up and go home, incredible attention to detail.
 

sh4un

New Member
Joined
Dec 13, 2021
Messages
3
Reaction score
1
Even the video itself looks extremely professional.
If you were doing anything before, watching this video will make you stop what you are doing and 'upgrade'. Most of the TVC and flight computers you see now are all derivative of just a few that were really just ignored till the youtubers came along to build rockets around it and made the every day man want to build something to reach out to space...

If I was young again, it'd be a crazy adventure.
 

DarthMuffin

Well-Known Member
Joined
Jun 30, 2021
Messages
78
Reaction score
61
This is what *everyone* is now trying to replicate. This guy is really brilliant and you can really see the change in how a lot of the 'youtube' rocket guys are are now inspired by a lot of his work. You can see

I am a telented guy, but wow, this guy makes me want to pack it up and go home, incredible attention to detail.
I feel so not worthy after watching that. Just giving up my geek card now.
 

Latest posts

Top