o1d_dude
'I battle gravity'
Excellent frame control.
The flutter went by so fast and the fins disappeared.
I remember thinking “plywood shouldn‘t ripple like that...” and then they were gone.
Excellent frame control.
Did you TAPs (plural) talk to you about flutter??? If not, why not?
"That sucks" is rather late and poor feedback....
Now the fins AND road are curved. Went so fast he fluttered the road? Not so sure the video is showing flutter or just poor video quality showing artifact.
I would be suspect of any bond on a L3 build that was made with wood glue. You say the whole thing except the fillets was done with wood glue, no mention of that was made when you explained your build to one of the taps, dont know if you mentioned it to the other?
I’d go full on epoxy on the rebuild.
My 7.5" has 3/8" plywood fins and I've never had problems except 1 flight where the fin was already cracked from landing on pavement. Flown on K through long burn N motors.
If video aberration can flutter the road it can give the same appearance to the fins, which was my point and why I stated i wasn't sure you were seeing flutter but possibly artifact/aberration, didn’t state it as fact, either way your fins separated for sure.
It’s not “just” the glue, looking at your external fillets they seemed way too small to me, and i run six giant fillets to every fin, premium epoxy with milled fiberglass. The weakest part of your build is what gets tested during a L3 flight, any structural part starts to fail and it will unravel the entire thing.
Understand you’re not happy, don’t blame you, kind of hard to put a post flight update on a fatal flight in front of a bunch of rocket nerds and not get opinions though.
Takes multiple attempts for some, part of the game i guess, if it was easy evrybody would be doing it right? Or is it if it was affordable, hell i dont know, lol.
Was a hell of a flight to watch though, think thats the first L3 failure ive witnessed in that manner.
Check this out...only one fin had extensive damage on it. Does that mean only one fin fluttered? The 2 white ones in the middle could easily be reused. The black one only has that small patch missing....hmmmmView attachment 418162
And right there is why I didn't even consider flutter as being an issue prior to this flight. The only difference in mine was that the leading and trailing edges were beveled but I have a really hard time believing that would cause flutter.
There’s a high probability that all of the fins suffered internal damage. That damage was bad enough in two of them that pieces shed. I wouldn’t use any of them again. In fact, I would use them as patterns and make the next set of fins out of at least one size thicker birch aircraft plywood.Check this out...only one fin had extensive damage on it. Does that mean only one fin fluttered? The 2 white ones in the middle could easily be reused. The black one only has that small patch missing....hmmmmView attachment 418162
Where Is an NY resident flying a 6XL L3 project...
There’s a high probability that all of the fins suffered internal damage. That damage was bad enough in two of them that pieces shed. I wouldn’t use any of them again. In fact, I would use them as patterns and make the next set of fins out of at least one size thicker birch aircraft plywood.
You flew on the M1297 right Dave? I think Loc has a video of this kit on that exact motor
With that fin span my technique would be to skeletonize, fill the holes with endgrain balsa or composite foam and two layers of glass or carbon, and make sure the fin tabs meet the motor tube as well as locked in with fin pockets. I hate seeing that much work put into a rocket for the type of failure that occured.There’s a high probability that all of the fins suffered internal damage. That damage was bad enough in two of them that pieces shed. I wouldn’t use any of them again. In fact, I would use them as patterns and make the next set of fins out of at least one size thicker birch aircraft plywood.
How much did the rocket weigh RTF?
31 pounds on the pad.
Here's another data point if anyone is interested...Finally got around to looking at the RRC3 data and according to that little gizmo the top speed was 542 mph - if those fins could have held on for juuuuuuust one more second and additional 40 mph. Oh well.
From these pics, it looks like the outer wood grain is parallel to the body axis of the rocket. Can you confirm that? You get quite a bit more flutter resistance when the outer plies are parallel to the leading edge. Seems like something LOC should change.Check this out...only one fin had extensive damage on it. Does that mean only one fin fluttered? The 2 white ones in the middle could easily be reused. The black one only has that small patch missing....hmmmmView attachment 418162
From these pics, it looks like the outer wood grain is parallel to the body axis of the rocket. Can you confirm that? You get quite a bit more flutter resistance when the outer plies are parallel to the leading edge. Seems like something LOC should change.
And my video for those who wish to examine it yourselves:
I am currently working on my LVL2 project and find people like you inspirational !!
The honest, heartfelt, constructive feedback and MOST of the members; is what makes this forum so cool !!!
I have so much to learn, and I appreciate all of this forum.
Best of luck on your rebuild and next attempt !!
Three of the fins...Can't tell without sanding off the paint. The messed up one - yes the outer grain is parallel to the body tube. But, does that really make a difference considering how plywood is made? All the layers have the grain placed perpendicular to each other.
It's kind of amazing how many public figures will respond to tweets by some random dude on the internet (no offense to DAllen here).So this happened on Twitter:
View attachment 418369View attachment 418370
Torrey Freaking Bruno everyone. The prez of ULA responded to my tweet. How cool is that????? (Please pardon my nerding out)
Enter your email address to join: